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EP0183482B1 - Werkzeug im Bohrloch - Google Patents

Werkzeug im Bohrloch Download PDF

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Publication number
EP0183482B1
EP0183482B1 EP85308446A EP85308446A EP0183482B1 EP 0183482 B1 EP0183482 B1 EP 0183482B1 EP 85308446 A EP85308446 A EP 85308446A EP 85308446 A EP85308446 A EP 85308446A EP 0183482 B1 EP0183482 B1 EP 0183482B1
Authority
EP
European Patent Office
Prior art keywords
compression chamber
housing
well
fluid
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP85308446A
Other languages
English (en)
French (fr)
Other versions
EP0183482A2 (de
EP0183482A3 (en
Inventor
Harold Kent Beck
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Halliburton Co
Original Assignee
Halliburton Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US06/676,022 external-priority patent/US4595060A/en
Priority claimed from US06/676,138 external-priority patent/US4617999A/en
Application filed by Halliburton Co filed Critical Halliburton Co
Publication of EP0183482A2 publication Critical patent/EP0183482A2/de
Publication of EP0183482A3 publication Critical patent/EP0183482A3/en
Application granted granted Critical
Publication of EP0183482B1 publication Critical patent/EP0183482B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B49/00—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells
    • E21B49/001—Testing the nature of borehole walls; Formation testing; Methods or apparatus for obtaining samples of soil or well fluids, specially adapted to earth drilling or wells specially adapted for underwater installations
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B34/00—Valve arrangements for boreholes or wells
    • E21B34/06—Valve arrangements for boreholes or wells in wells
    • E21B34/10—Valve arrangements for boreholes or wells in wells operated by control fluid supplied from outside the borehole
    • E21B34/108—Valve arrangements for boreholes or wells in wells operated by control fluid supplied from outside the borehole with time delay systems, e.g. hydraulic impedance mechanisms
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B2200/00—Special features related to earth drilling for obtaining oil, gas or water
    • E21B2200/04—Ball valves

Definitions

  • the present invention relates to a downhole tool, more particularly to a downhole tool utilizing a compression chamber within which is trapped a compressible fluid to provide a compressible fluid spring action to restore an actuating piston to an original position thereof.
  • downhole tools such as testing valves, circulating valves and samplers, can be operated by varying the pressure of fluid in a well annulus and applying that pressure to a differential pressure piston within the tool.
  • the predominant method of creating the differential pressure across the differential pressure piston has been to isolate a volume of fluid within the tool at a fixed reference pressure.
  • a fixed reference pressure has been provided in a number of different ways.
  • these prior art tools have often provided a volume offluid, either liquid or gas, through which this reference pressure is transmitted.
  • this volume of fluid provides a compressible fluid spring which initially stores energy when the differential area piston compresses that fluid, and which then aids in returning the differential area piston to its initial position.
  • One manner of providing a fixed reference pressure is by providing an essentially empty sealed chamber on the low pressure side of the power piston, which chamber is merely filled with air at the ambient pressure at which the tool was assembled.
  • Such a device is shown, for example, in U.S. Patent No. 4,076,077.
  • this type of device does not balance hydrostatic annulus pressure across the power piston as the tool is run into the well, and nor does it provide a fluid spring to aid in return of the power piston.
  • the U.S. 3,856,085 device utilizes the energy stored in compression of the nitrogen gas within a chamber to assist in returning the power piston to its upper position.
  • U.S. Patent No. 4,341,266 is shown in U.S. Patent No. 4,341,266.
  • This is a trapped reference pressure device which uses a system of floating pistons and a differential pressure valve to accomplish actuation of the tool.
  • the reference pressure is trapped by a valve which shuts upon the initial pressurizing up of the well annulus after the packer is set.
  • This tool does balance hydrostatic pressure across its various differential pressure components as it is run into the well.
  • the power piston of this device is returned to its original position by a mechanical coil compression spring without the aid of any compressed volume of fluid.
  • U.S. Patent No. 4,113, 012 utilizes fluid flow restrictors to create a time delay in any communication of changes in well annulus pressure to the lower side of its power piston. During this time delay, the power piston moves from a first position to a second position.
  • the particular tool disclosed utilizes a compressed nitrogen gas chamber in combination with a floating shoe which transmits the pressure from the compressed nitrogen gas to a relatively non- compressible liquid filled chamber.
  • This liquid- filled chamber is communicated with the well annulus through pressurizing and depressurizing passages, each of which includes one of the fluid flow restrictors plus a back pressure check valve. Hydrostatic pressure is balanced across the power piston as the tool is run into the well, except for the relatively small differential created by the back pressure check valve in the pressurizing passage.
  • the present invention provides a tool which does not use silicone oil and which provides both a trapped reference pressure and a trapped fluid spring without the use of an initially highly pressurized inert gas such as, for example, in US-A-3,856,085.
  • a downhole tool apparatus comprising: a housing having a compression chamber defined therein which chamber contains gas; fill passage means disposed through said housing to communicate with a well annulus exterior of the housing; isolation valve means for selectively closing said fill passage means to trap well fluid; an operating element disposed in said housing; an actuating piston means slidably disposed in said housing, said actuating piston means being operably associated with said operating element; wherein movement of said actuating piston means between first and second positions thereof decreases the volume of said compression chamber; characterised in that said fill passage means serves to place said compression chamber in open flow fluid communication with the well annulus exterior of said housing so that well fluid may flow into said compression chamber as said apparatus is lowered into a well, whereby the gas in the compression chamber contacts directly the well fluid at a gas/well fluid interface within the chamber, and said isolation valve means traps said gas and well fluid in said compression chamber.
  • the apparatus also preferably comprises means for injecting a gas (such as air for example) into the compression
  • a method of operating a downhole tool having a housing having a compression chamber defined therein which chamber contains gas; fill passage means disposed through said housing to communicate with a well annulus exterior of the housing; isolation valve means for selectively closing said fill passage means to trap well fluid; an operating element disposed in said housing; and actuating piston means slidably disposed in said housing, said actuating piston means being operably associated with said operating element; wherein movement of said actuating piston means between first and second positions thereof decreases the volume of said compression chamber, the method comprising the steps of: injecting pressurized gas into said compression chamber; lowering said tool connected to a tubing string, to a desired location in a well while providing open flow fluid communication through said fill passage means; trapping said well fluid in said tool; moving said actuating piston between first and second positions to operate said operating element and to decrease the volume of the compression chamber; characterised in that the apparatus is in accordance with the present invention and said pressurized gas is injected into said compression
  • the downhole tool of the present invention has a compression chamber which in use contains both gas and well fluid which directly contact each other at a gas-well fluid interface within the chamber.
  • the gas need not initially be highly pressurized. Instead, only a relatively low pressure need initially be applied to the gas, and this relatively low pressure pressurized gas can be provided from a typical rig air system of a drilling rig which provides compressed air at a pressure in the range of 100 to 140 psi (690 to 965 kPa).
  • an injection means is provided for admitting pressurized gas into the compression chamber at a location within the compression chamber such that the injected gas will directly contact at a gas-well fluid interface an upper surface of any well fluid which flows into the compression chamber.
  • a majority of the total volume of the compression chamber is preferably contained in a diametrically irregular elongate annular space defined between a plurality of interconnected tubular outer housing sections and a plurality of interconnected tubular inner housing sections.
  • the downlole tool apparatus of the invention has a trapped reference pressure and a compressible fluid spring for aiding in the return of the actuating piston to its original position, yet does not require the use of an initially highly pressurized volume of inert gas or of silicone oil. Instead, the apparatus relies on the compressibility of a relatively large volume of initially relatively low pressurized and/or a relatively large volume of well fluid obtained from the well annulus.
  • the compression chamber contains a volume of well fluid sufficient that, when the actuating piston means moves between first and second positions to operate the operating element, the volume of well fluid in the compression chamber changes by a first amount greater than one-half of the amount by which the volume of said compression chamber decreases.
  • the compression chamber contains a mass of air substantially equal to the mass of air required to fill it at atmospheric pressure and ambient temperature at a surface of said well, and the pressure of the mass of air is at least as great as the hydrostatic pressure of well fluid inthewell at a depth at which the apparatus is located within the well.
  • the downhole tool apparatus 10 may also be referred to as a well tester valve apparatus 10.
  • the apparatus 10 includes a housing generally designated by the numeral 12.
  • the housing 12 includes a plurality of threadedly connected tubular members, the uppermost one of which is an upper adapter 14.
  • upper seat housing 18 of housing 12 Threadedly connected at 16 to upper adapter 14 is an upper seat housing 18 of housing 12, with a seal being provided therebetween by resilient O-ring seal means 20.
  • Housing 12 includes a ball valve housing 22 which has a plurality of radially inward directed splines 24 which mesh with a plurality of radially outward directed splines 26 of upper seat housing 18.
  • An upper inner cylindrical surface 32 of ball valve housing 22 is closely received about a cylindrical outer lower surface 34 of upper adapter 14 with a seal being provided therebetween by resilient 0-ring seal means 36.
  • a first housing adapter 38 of housing 12 has its upper end threadedly connected at 40 to ball valve housing 22, with a seal being provided therebetween by resilient 0-ring seal means 42.
  • a lower end of first housing adapter 38 is threadedly connected at 44 to a spring chamber housing 46 of housing 12, with a seal being provided therebetween by resilient O-ring seal means 48.
  • a lower end of spring chamber housing 46 is threadedly connected at 48 to an air injection adapter 50 of housing 12 with a seal being provided therebetween by resilient 0-ring seal means 52.
  • a lower end of air injection adapter 50 is threadedly connected at 54 to an outer lubricant chamber housing 56 of housing 12 with a seal being provided therebetween by resilient 0-ring seal means 58.
  • air injection adapter 50 has an upper inner lubricant chamber housing 60 of housing 12 threadedly connected to an internal thread 62 thereof with a seal being provided therebetween by resilient O-ring seal means 64.
  • Outer lubricant chamber housing 56 has a lubricant chamber adapter 66 of housing 12 threadedly connected thereto at 68 with a seal being provided therebetween by resilient O-ring seal means 70.
  • Upper inner lubricant chamber housing 60 has a lower inner lubricant chamber housing 72 threadedly connected thereto at 74 with a seal provided therebetween by resilient O-ring seal means 76.
  • Lubricant chamber adapter 66 has a first outer compression housing section 78 threadedly connected thereto at 80 with a seal being provided therebetween by resilient O-ring seal means 82.
  • the first outer compression housing section 78 includes an upper outer compression housing adapter 84 threadedly connected at 86 to an outer compression housing 88 which has its lower end threadedly connected at 90 to a lower outer compression housing adapter 92 of housing means 12.
  • the upper outer compression housing adapter 84 and the outer compression housing 88 of first outer compression housing section 78 are further connected by a circumferential weld 94. Also, outer compression housing 88 and lower outer compression housing adapter 92 of first outer compression housing section 78 are further connected by a circumferential weld 96 therebetween.
  • the upper outer compression housing adapter 84, the outer compression housing 88, and the lower outer compression housing adapter 92 are all permanently connected together by welds 94 and 96 to form the first outer compression housing section 78.
  • first inner compression housing section 98 of housing 12 Concentrically received within the first outer compression housing section 78 of housing 12 is a first inner compression housing section 98 of housing 12.
  • the first inner compression housing section 98 includes an upper inner compression housing adapter 100 and an inner compression housing 102 threadedly connected together at 104 and further connected by a circumferential weld 106 therebetween.
  • a plurality of notches 105 are disposed in a lower outer edge of upper inner compression housing adapter 100 to allow fluid flow, through notches 105, between upper inner compression housing adapter 100 and an upward facing shoulder 107 of upper outer compression housing adapter 84.
  • Upper inner compression housing adapter 100 has an upper inner bore 108 within which is closely received an external cylindrical surface 110 of lower inner lubricant chamber housing 72 with a seal being provided therebetween by resilient O-ring seal means 12.
  • Housing 12 further includes a tube receiving adapter 114 threadedly connected to a lower end of lower outer compression housing adapter 92 at 116 with a seal being provided therebetween by resilient O-ring seal means 118.
  • Tube receiving adapter 114 has an upper inner cylindrical bore 120 within which is closely received a cylindrical outer surface 122 of a lower end of inner compression housing 102 with a seal being provided therebetween by resilient 0-ring seal means 124.
  • the apparatus 10 includes a plurality of interconnected outer compression housing sections such as 78, and a complimentary plurality of interconnected inner compression housing sections 98, as is schematically illustrated in Fig. 3.
  • outside diameter of outer surface 122 of the inner compression housing 102 is the same as the outside diameter of outer surface 110 of lower inner lubricant chamber housing 72.
  • a plurality of inner compression housing sections 98 may be interconnected merely by sliding the lower end of each of the inner compression housings such as 102 into the bore such as 108 of each of the upper inner compression housing adapters such as 100.
  • additional outer compression housing sections 78 may be threadedly connected together since the internal threads at threaded connection 80 of upper outer compression housing adapter 84 are complimentary with the external threads at threaded connection 116 of the lower outer compression housing adapter 92.
  • the housing 12 also includes a valve adapter 126 connected to the lower end of tube receiving adapter 114 at threaded connection 128 with a seal being provided therebetween by resilient O-ring seal means 130.
  • a bypass housing 132 of housing 12 is connected to the lower end of valve adapter 126 at threaded connection 134.
  • a lower housing shoe 136 of housing 12 is connected to a lower end of bypass housing 132 at threaded connection 138.
  • An actuating piston means 140 which may also be referred to as a power piston means 140, is slidably disposed within a bore 142 of spring chamber housing 46 of housing 12 with a seal being provided therebetween by resilient O-ring piston seal 144.
  • the actuating piston 140 is integrally formed on the upper end of a lower actuating mandrel 146.
  • the lower actuating mandrel 146 has a cylindrical outer surface 148 of a lower end thereof closely and slidably received within a bore 150 of air injection adapter 50 of housing 12, with a pair of seals being provided therebetween by resilient 0-ring seal means 152 and 154.
  • An inner annular groove 156 is disposed in bore 150 of air injection adapter 50 and is communicated with an exterior surface 158 of air injection adapter 50 by an oblique port shown in dashed lines and designated by the numeral 160.
  • the port 160 and annular groove 156 prevent any hydraulic blockage of movement of lower actuating mandrel 146 within the bore 150.
  • An operating element 162 which may also be described as a spherical full opening ball valve 162, is disposed within the housing 12 between upper and lower annular seats 164 and 166, respectively.
  • Upper seat 164 is received within a lower inner bore 168 of upper seat housing 18 with a seal being provided therebetween by resilient 0-ring seal means 170.
  • Lower seat 166 is received within an upper inner bore 172 of a lower seat holder 174 with a seal being provided therebetween by resilient 0- ring seal means 176.
  • a single Belleville spring 178 biases lower seat 166 upward relative to lower seat holder 174.
  • Lower seat holder 174 is held in place relative to upper seat holder 118 by a plurality of C-clamps (not shown) which span grooves 180 and 182 in upper seat holder 18 and lower seat holder 174, respectively.
  • the actuating piston means 140 and the ball valve 162 are operably related so that the ball valve 162 is moved from its first closed position illustrated in Fig. 1A, corresponding to the first uppermost position of actuating piston 140 relative to housing 12 seen in Fig. 1C, by movement of actuating piston 140 downward to a second lower position corresponding to a second open position of ball valve 162. This is accomplished as follows:
  • the actuating piston means 140 is connected to an upper actuating mandrel 184 at threaded connection 186. A seal is provided therebetween by O-ring 187.
  • Upper actuating mandrel 184 includes a plurality of radially outward directed splines 183 which are interlocked with a plurality of radially inward directed splines 185 of first housing adapter 38 so as to permit relative longitudinal motion therebetween while preventing relative rotational motion therebetween.
  • Upper actuating mandrel 184 has a retaining collar 188 threadedly connected to the upper end thereof at threaded connection 190.
  • Retaining collar 188 is longitudinally located between a downward facing shoulder 200 of an actuating sleeve 202 and an upper end 204 of an actuating coller 206.
  • the actuating collar 206 and actuating sleeve 202 are connected together at threaded connection 208.
  • An upper external cylindrical surface 210 of upper actuating mandrel 184 is closely received within an inner bore 212 of actuating collar 206 with a seal being provided therebetween by resilient 0-ring seal means 214.
  • An external cylindrical surface 216 of actuating collar 206 is closely and slidably received within a cylindrical inner surface 218 of ball valve housing 22 with a seal being provided therebetween by resilient O-ring sliding seal means 220.
  • the actuating sleeve 202 has a radially outer annular groove 222 disposed therein within which is received a radially inward directed flange 224 of a first actuating arm 226.
  • Actuating arm 226 has a lug 228 which is received within an eccentric radial bore 230 of spherical ball valve 162.
  • a second actuating arm (not shown) is similarly constructed and is peripherally spaced from the first actuating arm 226, so that longitudinal movement of actuating piston means 140 within the housing 12 is transmitted through the lugs such as 228 to the spherical ball valve member 162 to rotate the spherical ball valve member 162 from its closed first position to an open second position as the actuating piston 140 moves downward within the housing 12 from its initial position shown in Fig. 1C.
  • the housing 12 has an elongated compression chamber 232 defined therein. Housing 12 also has a fill passage means 234 disposed therethrough for placing the compression chamber 232 in open flow fluid communication with a well annulus 236 (see Fig. 3) exterior of the housing 12 so that well fluid may flow into the compression chamber 232 as the apparatus 10 is lowered into a well such as the one defined by casing 238 in Fig. 3.
  • a well annulus 236 see Fig. 3
  • open flow fluid communication means that fluid can actually flow from one of the two designated points to the other. This is to be distinguished from the broader, more general terms such as “fluid communication” or “fluid pressure communication” used elsewhere herein which only require that fluid pressure can be transmitted between the two designated points, but do not require that it be possible for fluid to actually flow between the two designated points.
  • An isolation valve means 240 is defined on a valve sleeve 242 and provides a means for selectively closing the fill passage means 234 and for thereby trapping well fluid within the compression chamber 232.
  • the compression chamber 232 includes a main compression chamber portion 244 defined between the outer compression housing sections 78 and the inner compression housing sections 98.
  • the main compression chamber portion 244 includes the annular space defined between all of the outer compression housing sections 78 and all of the inner compression housing sections 98. It will be appreciated in viewing Figs. 1E-1G that the main compression chamber portion 244 can be described as a diametrically irregular annular space 244 located between the plurality of interconnected tubular outer housing sections 78 and the plurality of interconnected tubular inner housing sections 98.
  • Compression chamber 232 extends from the main compression chamber portion 244 upward through annular spaces 246, 248, and 250 to a lubricant chamber 252.
  • Lubricant chamber 252 is communicated through a plurality of longitudinal passageways such as 254 disposed longitudinally through air injection adapter 50 with an annular spring chamber 256.
  • a coil compression spring 258 is disposed in spring chamber 256.
  • An annular floating piston 260 is disposed in lubricant chamber 252 and has a plurality of radially inner seals 262 and 264 which seal against upper inner lubricant chamber housing 60, and a plurality of outer seals 266 and 268 which seal against outer lubricant chamber housing 56.
  • annular floating piston 260 The purpose of annular floating piston 260 is to permit spring chamber 256 to be filled with a non-corrosive fluid such as lubricating oil to protect the coil springs 258.
  • the lubricating member 252 is filled with lubricating oil above annular piston 260, and will be filled with well fluid and/or possibly some entrapped air below the annular piston 260.
  • the annular floating piston 260 may be eliminated.
  • the compression chamber 232 also extends downward from main compression chamber 244 through a plurality of longitudinal passageways 270 disposed through tube receiving adapter 114 to an annular cavity 272 defined between valve sleeve 242 and valve adapter 126.
  • the actuating piston means 140 is a differential area piston means 140 having its lower side 274 communicated with compression chamber 232.
  • Lower side 274 may also be referred to as a first side or as a low pressure side of actuating piston means 140.
  • Housing 12 has a power passage means 276 disposed therethrough for communicating the well annulus 236 exterior of the housing 12 with an upper side 278 of actuating piston means 140.
  • the upper side 278 of actuating piston means 140 may also be referred to as a second side or a high pressure side of actuating piston means 140.
  • the power passage means 278 includes a power port 280 and an annular cavity 282 defined between upper actuating mandrel 184 and spring chamber housing 46.
  • the actuating piston means 140 will move downward relative to housing 12 from its first position shown in Fig. 1C in response to increases in pressure in well annulus 236 relative to pressure within compression chamber 232 as is further described below.
  • the coil spring 258 previously mentioned can generally be described as a resilient mechanical spring biasing means 258 for biasing the actuating piston means 140 from its lower second position back toward its upper first position shown in Fig. 1C.
  • the coil compression spring 258 is disposed within spring chamber portion 256 of compression chamber 232 between the lower side 274 of actuating piston means 140 and an upper end 284 of air injection adapter 50.
  • Fig. 2 is a section view taken along line 2-2 of Fig. 1D and it illustrates the manner in which the air injection passage means 286 is communicated with longitudinal passageway 254 of compression chamber 232.
  • Fig. 2 has been rotated 90° clockwise from the manner in which it would normally be shown in a section of Fig. 1D, in order to more easily fit the same on the sheet of drawings.
  • Air injection passage means 286 includes a threaded inlet 288, which is shown in Fig. 2 as being temporarily closed by a threaded plug 290.
  • an air line 292 from a source of rig air 294 is connected to threaded inlet 288 so as to communicate the source of rig air 294 with the air injection passage means 286.
  • a needle valve 296 is disposed in a valve carrier body 298 which itself is threadedly engaged at 300 with a threaded bore 302 of air injection adapter 50.
  • Fig. 2 the needle valve 296 is shown in a closed position where it sealingly engages a short portion 304 of air injection passage means 286.
  • valve carrier body 298 is rotated through use of a wrench inserted in socket 306 thereof so as to back off the threaded connection 300 and move the needle valve 296 out of engagement with the short portion 304 of air injection passage means 286.
  • the manner of use of air injection passage means 286 is further described below in the section headed "Second Mode of Operation of the Embodimennt of Figs. 1A-1H".
  • the housing 12 has a central flow passage 308 disposed therethrough.
  • the ball valve member 162 is disposed within the flow passage 308 and, when in its closed position as illustrated in Fig. 1A, closes flow passage 308 to prevent fluid flow therethrough, and when in its second open position, has its ball valve bore 310 aligned with flow passage 308 to allow fluid flow through the flow passage 308.
  • the housing 12 has a bypass passage means 312 (see Fig. 1G) disposed therethrough for communicating the flow passage 308 of housing 12 with the well annulus 236 exterior of the housing 12.
  • the valve sleeve 242 includes a bypass valve portion 314 for selectively closing the bypass passage means 312.
  • the bypass passage means 312 includes a bypass port 316 disposed radially through bypass housing 132, an annular cavity 318 defined between valve sleeve 242 and bypass housing 132, and a bypass valve port 320 disposed through valve sleeve 242.
  • the valve sleeve 242 has an upper cylindrical outer surface 322 which is closely and slidingly received within a lower inner bore 324 of tube receiving adapter 114 and a bore 326 of valve adapter 126.
  • An 0-ring seal 328 is disposed in a complementary groove of bore 324 and provides a sliding seal between valve mandrel 242 and bore 324 above the annular cavity 272.
  • An 0-ring seal 310 is disposed within a complimentary groove in bore 326 of valve adapter 126 and provides a sliding seal between valve mandrel 242 and bore 326 below annular cavity 272.
  • a pair of 0-ring seals 332 and 334 are disposed in complimentary grooves in a lower portion of bore 326 of valve adapter 126 just above a lower end thereof.
  • the valve mandrel 242 further includes a lower enlarged outer diameter cylindrical surface 336 which is closely slidably received within a reduced inner diameter bore 338 of bypass housing 132 with a sliding seal being provided therebetween by resilient O-ring seal means 340. Cylindrical outer surface 336 is also closely slidingly received within a bore 342 of lower housing shoe 136 with a sliding seal being provided therebetween by resilient O-ring seal means 344.
  • a metering chamber 346 is defined between cylindrical outer surface 336 on the inside and bypass housing 132 and lower housing shoe 136 on the outside, with its upper and lower extremities being defined by seals 340 and 344, respectively.
  • a metering piston 348 is disposed on valve mandrel 242 and is closely slidingly received within an inner bore 350 of bypass housing 132 with a seal being provided therebetween by resilient 0-ring piston seal 352.
  • the metering piston 348 divides metering chamber 346 into an upper portion 354 and a lower portion 356.
  • Metering chamber 346 is filled with a suitable fluid such as oil.
  • Metering piston 348 has a fluid flow restricting orifice 358 disposed therethrough communicating upper and lower portions 354 and 356 of metering chamber 346.
  • the metering piston 348 with its orifice 358 therethrough impedes movement of valve mandrel 242 relative to housing 12.
  • the metering fluid contained in metering chamber 346 must flow through orifice 358 between upper and lower metering chamber portions 354 and 356.
  • the metering piston 348 and associated structure are shown only in a schematic fashion in Figs. 1 G and 1H.
  • valve mandrel 242 has a lower adapter 360 connected thereto at threaded connection 362 with a seal being provided therebetween resilient O-ring seal means 364.
  • valve mandrel 242 has the bypass valve port 320 disposed therethrough.
  • Valve mandrel 242 also has an isolation port 366 disposed therethrough communicating the flow passage 308 with annular cavity 272 of compression chamber 232.
  • the isolation port 232 may also be considered to be a portion of the fill passage means 234.
  • the valve mandrel 242 is shown in Figs. 1 G-1 H in the position which it is in when apparatus 10 is run into a well.
  • the isolation port 366 is located below seal 328 and provides open communication between the flow passage 308 and the compression chamber 232.
  • bypass valve port 320 is located below seal 334 and provides open communication between flow passage 308 and annular cavity 318 and bypass port 316.
  • weight is set down on the apparatus 10 to set a packer means 368 (see Fig. 3) located therebelow, and to close the isolation valve means 240 and the bypass valve means 314.
  • valve mandrel 242 When weight is set down on the apparatus 10 for a sufficient period of time determined by the construction of the metering piston 348 and its orifice 358, the housing 12 moves longitudinally downward relative to valve mandrel 242 until an upper end 370 of lower adapter 360 abuts a lower end 372 of lower housing shoe 136. When the ends 370 and 372 abut, the valve mandrel 242 is in a position relative to housing 12 such that isolation port 366 is located above seat 328 and bypass valve port 320 is located above seal 334.
  • isolation valve means 240 and the bypass valve means 314 are operatively associated so that they are both open at the same time and are both closed at the same time.
  • the fill passage means 234 can be further described as including a first portion 376 which is coincident with a portion of flow passage 308.
  • Fill passage means 234 further includes a second portion 378 which is coincident with bypass passage means 312 and thus communicates flow passage 308 with the well annulus 236.
  • the isolation valve means 240 can be described as being located between the compression chamber 232 and the first portion 376 of fill passage means 234, and the bypass valve means 314 may be described as being located between the first and second portions 376 and 378 of fill passage means 234.
  • the apparatus 10 is constructed so that the compression chamber 232 has a total volume sufficiently large that an equal volume of water containing no absorbed gases would have a volume decrease when subjected to a pressure increase equivalent to a predetermined operating pressure of the actuating piston means 140, at least as great as the decrease in volume of the compression chamber 232 when the actuating piston means 140 is moved between its first and second positions relative to the housing 12.
  • the majority of this volume of the compression chamber 232 is defined within the main compression chamber portion 244 located between the outer compression housing section 78 and the inner compression housing sections 98.
  • the actual total volume required for the compression chamber 230 will depend upon a number of parameters.
  • the volume change which the compression chamber 232 must undergo when it is compressed is equal to the displacement of actuating piston means 140 as it moves from its first upper position illustrated in Fig. 1C to a lower second position corresponding to an open position of ball valve member 162.
  • This displacement is equal to the annular area of actuating piston 140 defined between seals 144 and 152, multiplied by the longitudinal displacement of actuating piston means 140 as it moves downward between its first and second positions.
  • the required total volume for compression chamber 232 to accommodate that displacement of actuating piston means 140 depends upon a number of parameters.
  • the well fluid involved will be drilling mud, which normally has a compressibility factor at least as great as that of water which has no absorbed gases contained therein.
  • the compression chamber 232 of the apparatus 10 of the present invention is designed based on the assumption that the well fluid will have a compressibility factor equal to that of water with no absorbed gases under the appropriate conditions.
  • Those appropriate conditions which also must be taken into consideration include the operating temperature of the well at the particular depth involved, the hydrostatic pressure within the well annulus 236 at the depth at which it is desired to operate the apparatus 10, and the operating pressure which permissibly can be applied across the actuating piston means 140.
  • the operating temperature and the hydrostatic pressure are of course determined by the particular location in the well where it is necessary to utilize the apparatus 10, and thus they are fixed parameters in a given well situation.
  • the operating pressure which can permissibly be applied across actuation piston means 140 depends upon the maximum pressure increase which permissibly can be applied to the well annulus 236.
  • the apparatus 10 of the present invention will normally be designed for an operating pressure in the range of about 1500 to 2000 psi (10.3 to 13.8 MPa). That is, the well annulus 236 will be pressurized to a pressure 1500 to 2000 psi (10.3 to 13.8 MPa) greater than the hydrostatic pressure normally present within the annulus.
  • This permissible operating pressure is based upon the strength of the well casing and the tubular members connected to the tubing string lowered into the well casing. It must be sufficiently low that it does not rupture the well casing or collapse the tubular members immersed within the well.
  • the required volume of compression chamber 232 can be calculated.
  • the appropriate volume of compression chamber 232 for a given displacement of actuating piston means 140 one particular design for the apparatus 10 involves an actuating piston displacement of 14.68 cubic inches (0.23 dm 3 ) when the actuating piston moves between its first and second positions. For that displacement, the compression chamber 232 must have a volume of at least approximately 8,500 cubic inches (136 dm 3 ).
  • the apparatus 10 can operate in most commonly encountered well environments.
  • FIG. 1A-1H A first mode of operation of the embodiment of apparatus 10 shown in Figs. 1A-1H will now be described.
  • this first mode of operation no pressurized gas is provided in the compression chamber 232, and during the operation of the apparatus 10, the apparatus 10 relies upon the compressibility of trapped well fluid within the compression chamber 232 as the primary source of fluid compressibility to provide a compressible fluid spring.
  • the appartaus 10 is assembled and initially oriented in the manner shown in Figs. 1A-1H.
  • the compression chamber 232 is communicated with the surrounding ambient air at the surface 388 of the well through the fill passage means 234, and thus the compression chamber 232 will initially be filled with air at the atmospheric pressure and ambient temperature prevailing at the surface location 388 of the well.
  • the upper adapter 14 of housing 12 is threadedly connected to a tubing string 380 as shown in Fig. 3.
  • the lower adapter 360 is threadedly connected to a packer housing 382 of the packer means 368.
  • a perforated tail pipe 384 is connected to the lower end of the packer housing 382.
  • tubing string 380 with the apparatus 10 and other apparatus just described attached as shown in Fig. 3 is lowered into the well defined by well casing 238.
  • FIG. 3 illustrates the apparatus 10 connected to the tubing string 380, after the apparatus 10 has been partially lowered into the well defined by well casing 238. Those portions of Fig. 3 near the upper end thereof relating to the rig air source 294 and rig air supply line 292 are not utilized in this first mode of operation of the apparatus 10, and thus they may be ignored for the purpose of the present description of this first mode of operation.
  • the apparatus 10 is lowered on the tubing string 380 into the well 238 to a desired location. Normally this location will be such that the packer means 368 is located immediately above a subsurface formation (not shown) intersecting the well 238, so that the packer 368 may be set to allow the subsurface formation to be tested through the tubing string 380 or to allow treatment fluids to be pumped down the tubing string 380 into the subsurface formation located immediately below the packer means 368.
  • the pressure of the well fluid at a given elevation within the compression chamber 232 will be substantially equal to the hydrostatic pressure of well fluid in well annulus 236 at that same elevation.
  • the well fluid entering compression chamber 232 will contact the air already present in compression chamber 232 at an air-well fluid interface 386.
  • well-air fluid interface 386 moves upward through the compression chamber 232 as the apparatus 10 is lowered deeper into the well 238, the air initially present within the compression chamber 232 will be compressed into a relatively small volume located above air-well fluid interface 386.
  • the air-well fluid interface 386 moves upward through the main compression chamber portion 244, which may also be referred to as a diametrically irregular annular space 244, the air-well fluid interface 386 moves past a number of upset diameters on both the inner surfaces of the outer compression housing sections 78 and the outer surfaces of the inner compression housing sections 98.
  • the pressure of the air trapped within compression chamber 232 above the air-well fluid interface 386 will be equal to the hydrostatic pressure of the well fluid within well annulus 236 at the elevation of the air-well fluid interface 386.
  • the tubing string 380 is manipulated to set the packer means 368 so that it seals against the casing 238 thus anchoring the tubing string 380 and the apparatus 10 relative to the casing 238.
  • a preferred tool for use as the packer means 368 is a packer made by Halliburton Services Division of Halliburton Company, the assignee of the present invention, and referred to as a "Retrievable Test-Treat-Squeeze Packer" as shown at pages 4014-4015 of Halliburton Services Sales and Service Catalog, No. 41. This particular packer is set by setting down weight on the packer and applying righthand torque to the tool string 380.
  • weight is slacked off on tubing string 380 for a sufficient period of time to allow the housing 12 to move downward relative to valve mandrel 242 thus closing the bypass passage means 312 and also closing the fill passage means 234 thus trapping well fluid within the compression chamber 232.
  • This trapped well fluid will initiallly be at a pressure equal to the hydrostatic pressure within the well annulus 236 at the same elevation at the time the fluid was trapped.
  • fluid pressure is increased within the well annulus 232 by a pump (not shown) located at the surface and communicated with the annulus 236 in a manner well known to those skilled in the art.
  • This increased well annulus pressure is communicated through the power port 280 of power passage means 276 to the upper side 278 of actuating piston means 140, thus creating a downward pressure differential across actuating piston means 140.
  • the apparatus 10 will typically be designed for an apparatus pressure in the range of approximately 1500 to 2000 psi (10.3 to 13.8 MPa).
  • This downward pressure differential of approximately 1500 to 2000 psi causes the actuating piston means 140 to move downward relative to housing 12, thus moving the ball valve member 162 to its open position and allowing fluid to flow from the subsurface formation upward through the perforated tail pipe 384, the central bore (not shown) of packer housing 382, the flow passage 308 of apparatus 10, and the tubing bore (not shown) of tubing string 380.
  • a first amount by which the volume of the trapped well fluid is decreased is approximately equal to a second amount by which the entire volume of the compression chamber 232 is decreased. This second amount is of couse equal to the displacement of the actuating piston means 140.
  • the mass of air present within the compression chamber 232 is so small that it contributes very little to the volume compression required to accommodate the displacement of actuating piston 140. That is, the volume change which occurs within the compression chamber 232 must primarily be accounted for by a decrease in volume in the well fluid contained within compression chamber 232, and only a relatively small amount of that volume decrease is accommodated by compression of the air which might be trapped in the compression chamber 232. This is because the amount of air is so small that it has already been compressed to a very small volume as the apparatus 10 is lowered into the well.
  • the apparatus 10 when the apparatus 10 is operated in its normal manner just described above, and when the actuating piston means 140 moves between its first and second positions, the volume of the well fluid trapped within the compression chamber 232 changes by an amount greater than one-half of the amount by which the total volume of the compression chamber changes.
  • the apparatus 10 when used in the manner just described, relies primarily upon the compressibility of the well fluid to accommodate the displacement of the actuating piston 140. A majority of the total amount of fluid pressure energy which is stored within the various fluids trapped in the compression chamber is thus stored by compression of the trapped well fluid.
  • actuating piston means 140 This upward movement of actuating piston means 140 is aided by the coil compression spring 258.
  • the coil compression spring 258 is sufficiently sized so that in most situations it could return the actuating piston means 140 to its first position thus closing the ball valve 162 even in the absence of the upward force from the compressed fluid within compression chamber 233.
  • the packer means 368 is released from its engagement with the well casing 238 and the apparatus 10 may be removed from the well or moved to another location within the well.
  • the housing 12 of apparatus 10 is returned to its upward position relative to valve mandrel 242 so that the fill passage means 234 and bypass passage means 312 are both again opened.
  • the apparatus 10 of Figs. A-1 H may be utilized when it is desired to lower the operating pressure which must be applied to the well annulus 236 to operate the apparatus 10.
  • the compression chamber 10 is initially injected with relatively low pressure pressurized air.
  • the mass of injected air is sufficient that when operated in this second mode, the apparatus 10 generally relies primarily on compression of the air rather than compression of the trapped well fluid to accommodate the displacement of actuating piston 140.
  • the rig air system 294 which is a source of compressed air normally at a pressure in the range of 100 to 140 psi, is connected through the rig air line 292 to the inlet 288 of air injection passage means 286.
  • the needle valve 296 is opened and a valve 390 in the rig air line 292 is opened so that the compressed air from the rig air source 294 is communicated with the longitudinal passageway 254 of compression chamber 232.
  • fill passage means 234 is open, it will be understood that priorto connection of the rig air source 294 to the compression chamber 232, well fluid will have risen into the compression chamber 232 so that the air-well fluid interface 386 is at some intermediate location as shown in Fig. 3.
  • the compressed air which remains within the compression passage 232 when the apparatus 10 is located as shown in Fig. 3 and the rig air source 294 has been communicated with the compression passage 232 will be at an initial pressure substantially equal to a hydrostatic pressure of well fluid within the well annulus 236 at the elevation of a lower end of the compression chamber 232, which in the embodiment illustrated in Figs. 1A-1H is the elevation of isolation port 366.
  • the initial air pressure in chamber 232 will be approximately 50 psi (345 kPa).
  • the needle valve 296 is closed and the rig air line 292 is removed.
  • the apparatus 10 may be further lowered into the well to its final desired location.
  • the gas-well fluid interface 386 will again move upward through the diametrically irreguler elongated space defined by main com- presion chamber portion 244 past a number of irregular upset diameters defined by the various portions of the inner and outer tubular housing sections 98 and 78.
  • Figs. 4F-41 The lower portion of an alternative embodiment of the downhole tool apparatus of the present invention is illustrated in Figs. 4F-41, and is generally designated by the numeral 400.
  • the upper portion of the downhole tool apparatus 400 is identical to the structure shown in Figs. 1A-1E, except that the annular floating piston 260 shown in Fig. 1D is eliminated in order that the air injection passage means 286 may be utilized to provide a charge of compressed air to the compression chamber 232 from the rig air system 294 in a manner similar to that previously described with regard to Fig. 3.
  • the downhole tool apparatus 400 preferably has four outer tubular compression housing sections 78 and four inner tubular compression housing sections 98, each approximately ten feet (3 m) long, so that the main compression chamber portion 244 of apparatus 400 will have a length of approximately forty feet (12 m).
  • the housing of the apparatus 400 As seen near the bottom of Fig. 4F, the housing of the apparatus 400 as compared to that of the apparatus 10, is modified below the lowermost outer compression housing section 78.
  • An upper outer check valve housing adapter 402 is threadedly connected at 404 to the lowermost outer tubular compression housing section 78 with a seal being provided therebetween by resilient O-ring seal means 406.
  • An outer check valve housing 408 has its upper end threadedly connected to the lower end of upper outer check valve housing adapter 402 at threaded connection 410 with a seal being provided therebetween by resilient 0-ring seal means 412.
  • outer check valve housing 408 is connected at threaded connection 414 to a modified tube receiving adapter 416 with a seal being provided therebetween by resilient O-ring seal means 418.
  • modified tube receiving adapter 416 is connected at threaded connection 420 to the valve adapter 126 previously described with regard to the apparatus 10, with a seal being provided therebetween by resilient O-ring seal means 422.
  • Modified tube receiving adapter 416 of the apparatus 400 is similar in function to the tube receiving adapter 114 previously described with regard to Fig. 1G, and has the longitudinal passageways 270 of compression chamber 232 disposed therethrough.
  • valve adapter 126 and other associated structure shown in Figs. 4H-41 is identical to the similar structure shown in Figs. 1G-1H, and is designated by the same numerals previously used in Figs. 1G and 1H.
  • a lower end of a lowermost inner tubular compression housing section 98 has its external cylindrical surface 110, as seen in Figs. 4F and 4G, closely received within a cylindrical internal surface 424 of an upper inner check valve housing adapter 426 with a seal being provided therebetween by resilient 0-ring seal means 428.
  • An inner check valve housing 430 has its upper end threadedly connected to upper inner check valve housing adapter 426 at threaded connection 432.
  • a lower portion of an external cylindrical surface 434 of inner check valve housing 430 is closely and slidably received within an upper inner bore 436 of modified tube receiving adapter 416 with a seal being provided therebetween by resilient 0-ring seal means 438.
  • annular check valve chamber portion 440 of compression chamber 232 Between the outer check valve housing 408 and the inner check valve housing 430, there is defined an annular check valve chamber portion 440 of compression chamber 232.
  • the annular check valve chamber portion 440 is communicated at its lower end with the longitudinal passageways 270 disposed through modified tube receiving adapter 416, and is communicated at its upper end with annular spaces 442 and 444 of compression chamber 232.
  • the upper inner check valve housing adapter 426 is constructed in a fashion similar to that for the upper inner compression housing adapter 100 previously described, and includes a notch 446 in its lower end which engages an upward facing shoulder 448 of upper outer check valve housing adapter 402.
  • the notches 446 allow fluid to flow between the upper inner check valve housing adapter 446 and the upper outer check valve housing adapter 402.
  • a check valve means 450 Disposed in the annular check valve chamber portion 440 is a check valve means 450 for initially sealing pressurized gas within the compression chamber 232 at an initial pressure greater than a pressure in fill passage means 234, and for subsequently permitting well fluid to flow through the fill passage means 234 into the compression chamber 232 to directly contact the pressurized gas within compression chamber 232 when the pressure in the fill passage means 234 exceeds an initial pressure of the pressurized gas within the compression chamber 232.
  • the check valve means 450 is an annular valve ring, or may also be referred to as an annular valve piston, slidably disposed in the annular check valve chamber portion 440 of compression chamber 232.
  • the check valve ring 450 includes a pair of annular inner O-ring seals 452 which provide a sliding seal between check valve ring 450 and inner check valve housing 430.
  • Check valve ring 450 also includes a pair of outer O-rings 454 which provide a sliding seal between check valve ring 450 and outer check valve housing 408.
  • Check valve ring 450 is shown in Fig. 4G in its initial position in which it is located when the compression chamber 232 has been filled with an initial charge of pressurized air, before any well fluid has entered the compression chamber 232 to directly contact that pressurized air. In this initial position, the check valve ring 450 abuts an upper end 456 of modified tube receiving adapter 16.
  • the upper end 456 may be referred to as a stop means 456, engaging the annular check valve ring 450, for preventing movement of the annular check valve ring 450 toward the fill passage means 234.
  • Check valve ring 450 includes a plurality of longitudinally extending radially outer grooves 458 in its exterior surface below outer O-rings 454, which grooves 458 may be referred to as fluid fill bypass grooves 458.
  • a latch means 464 is provided for latching annular check valve ring 450 in a final position wherein the fluid fill bypass grooves 458 are communicated with enlarged internal diameter 462 of outer check valve housing 408, which may be defined as an open position of the fill fluid bypass grooves 458.
  • the latch means 464 includes a plurality of upward extending spring collet fingers 466 attached to annular check valve ring 450, and includes an annular latching collar 468 which is threadedly connected at 470 to the lower end of upper outer check valve housing adapter 402.
  • annular check valve ring 450 moves upward a distance sufficient that the fill fluid bypass groove 458 thereof are communicated with the enlarged internal diameter 462 of outer check valve housing 408, a plurality of radially outward extending lugs 472, one of which is located on each of the spring collet fingers 466, snap over a radially inwardly extending annular latching lug 474 of latch collar 468, to latch the check valve ring 450 in its open position.
  • the downhole tool apparatus 10 previously described with regard to Figs. 1A-1H, as previously mentioned preferably has eight interconnected tubular outer compression housing sections 78, each having a length of approximately ten feet (3.0 m), so that the total length of the apparatus 10 is on the order of ninety feet (27 m) or more.
  • the apparatus 400 of Figs. 4F-41 preferably has only four of the interconnected tubular outer housing sections 78, each having a length of approximately ten feet (3.0 m), so that the overall length of the apparatus 400 is more on the order of approximately fifty feet (15 m). This shorter apparatus can be handled by many smaller drilling rigs which could not handle a ninety-foot (27 m) tool.
  • the volume of the compression chamber 232 is so reduced that this volume is generally not large enough that the tool can be operated based upon compressibility of well fluid trapped in the compression chamber 232.
  • the check valve means 340 allows the compression chamber 232 to be initially pressurized to a pressure in excess of the pressure within fill passage 234. Subsequently, as the tool is further lowered into a well, the check valve means 250 will allow well fluid to move upward into the compression chamber 234 to directly contact this mass of initially pressurized air, when the pressure within fill passage 234 exceeds the initial pressure of the pressurized air within compression chamber 232.
  • the apparatus 400 is first partially lowered into the well 238 to an intermediate position wherein a lower portion of the apparatus 400 is within the well 238 and is immersed in well fluid in a manner like that illustrated in Fig. 3 for the apparatus 10.
  • An upper portion of the apparatus 400 will extend above the ground surface 388, again in a manner similar to that shown in Fig. 3 for the apparatus 10.
  • the apparatus 400 will have its annular check valve ring 450 initially positioned as shown in Fig. 4G.
  • the check valve ring 450 has sufficient frictional engagement with the inner and outer check valve housings 430 and 408 that the upward pressure differential caused by the initial lowering of the apparatus 400 within the well 238 will not move the check valve ring 450 up to a latched position.
  • the rig air system 294 is connected through the rig air line 292 to the inlet 288 of air injection passage means 286.
  • compression chamber 232 that portion of the compression chamber 232 above check valve ring 450, which of course is the vast majority volume-wise of the compression chamber 232, will be filled with pressurized air from the rig air source 294.
  • the initial pressure applied to compression chamber 232 will preferably be in the range of approximately 100 to 140 psi.
  • the rig air source 284 is disconnected from compression chamber 232, and the apparatus 400 may be further lowered into the well to its final desired location.
  • the initial charge of pressurized air injected into compression chamber 232 above annular check valve ring 450 has a mass sufficient that when the fill passage means 234 is closed by isolation valve means 240, and the actuating piston means 140 moves between first and second positions thereof relative to the housing 12 in order to operate the ball valve 162, a volume of said initial mass of compressed air changes by a first amount greater than one-half of a second amount by which a total volume of the compression chamber 232 changes.
  • the first mode of operation is provided by the use of the apparatus 10 of Figs. 1A ⁇ 1H, without the injection of any pressurized air into the compression chamber 232 thereof.
  • the second mode is provided by utilizing the apparatus 10 of Figs. 1A-1H, in combination with the procedure of injecting pressurized air into the compression chamber 232 after the apparatus has been partially lowered into a well, so that the initial pressure of the pressurized air within compression chamber 232 is equal to the hydrostatic pressure of a column of well fluid having a height substantially equal to a length of the compression chamber.
  • the third mode is provided by the modified shortenend apparatus shown in Figs. 4F-41 which utilizes the check valve ring 450 to initially hold a mass of pressurized air within the tool.
  • a compression chamber provides a trapped reference pressure for the actuating piston 140, and also provides a compressible fluid spring for aid in returning the actuating piston 140 to its initial position.
  • this compression chamber is a relatively large compression chamber which is to some extent filled with well fluid as the apparatus is lowered into the well, with that well fluid directly contacting any gas present within the chamber at a gas-well fluid interface.
  • This gas- well fluid interface moves upwardly through the elongated compression chamber past a number of irregular diameters thereof as the tool is lowered into the well.
  • the apparatus of the present invention in its various embodiments, provides a downhole tool having a trapped reference pressure and providing a compressible fluid spring, without the use of either an initial highly pressurized volume of gas such as that currently used in the prior art in pressurized nitrogen tools, and without the use of a large volume of silicone oil.

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Claims (22)

1. Bohrlochwerkzeug enthaltend ein Gehäuse (12) mit einer darin bestimmten, Gas enthaltenden Druckkammer (232); Füllkanalmittel (234), die sich zur Verbindung mit einem Bohrlochringraum (236) außerhalb des Gehäuses durch das Gehäuse erstrecken; Isolierventilmittel (240) zum wahlweisen Schließen der Füllkanalmittel (234) zum Einschließen von Bohrlochfluid; ein in dem Gehäuse angeordnetes Bedienungselement (162); innerhalb des Gehäuses gleitfähig angeordnete Betätigungskolbenmittel (140), die dem Bedienungselement zu dessen Bedienung zugeordnet sind, wobei eine Verstellung der Betätigungskolbenmittel zwischen deren erster und zweiter Stellung das Volumen der Druckkammer verringert,
dadurch gekennzeichnet, daß die Füllkanalmittel (234) dazu dienen, die Druckkammer in eine offene Fluid-Durchflußverbindung mit dem Bohrlochringraum (236) außerhalb des Gehäuses zu bringen, so daß Bohrlochfluid in dem Maße in die Druckkammer fließt, in dem das Bohrlockwerkzeug in das Bohrloch abgesenkt wird, wobei das Gas in der Druckkammer mit dem Bohrlochfluid an einer Gas-Bohrlochfluidgrenzfläche innerhalb der Druckkammer direkt in Berührung steht, und daß die Isolierventilmittel (240) das Gas und das Bohrlochfluid in der Druckkammer (232) einschließen.
2. Bohlochwerkzeug nach Anspruch 1, dadurch gekennzeichnet, daß das Volumen der Druckkammer (232) ausreichend groß ist, so daß ein gleiches Volumen Wasser, das keine absorbierten Gase enthält, unter einer Druckzunahme, die einem vorgegebenen Betriebsdruck der Betätigungskolbenmittel (140) gleichwertig ist, eine Volumabnahme erfahren würde, die wenigstens so groß ist wie die Volumverringerung der Druckkammer bei der Verstellung der Betätigungskolbenmittel zwischen deren erster und zweiter Stellung.
3. Bohrlochwerkzeug nach Anspruch 1 oder 2, gekennzeichnet, durch federnde mechanische Federvorspannmittel (258) vorzugsweise in der Druckkammer zum Vorspannen der Betätigungskolbenmittel von deren zweiter in ihre erste Stellung.
4. Bohrlochwerkzeug nach Anspruch 3, gekennzeichnet durch einen ringförmigen Schwimmkolben (260), der in der Druckkammer angeordnet ist und diese Druckkammer in einen ersten und einen zweiten Druckkammerteil unterteilt, und dadurch, daß die federnden mechanischen Federvorspannmittel (258) in dem ersten Druckkammerteil (256) angeordnet sind, daß der erste Druckkammerteil (256) mit einem relativ nichtkorrodierenden Fluid gefüllt und durch den Schwimmkolben (260) gegen eine offene Fluid-Durchflußverbindung mit dem zweiten Druckkammerteil isoliert ist, und daß die Füllkanalmittel (234) den zweiten Druckkammerteil mit dem Bohrlochringraum außerhalb des Gehäuses verbinden.
5. Bohrlochwerkzeug nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß ein Großteil des Volumens der Druckkammer einen im Durchmesser unregelmäßigen Ringraum bildet, der durch eine Mehrzahl miteinander verbundener, rohrförmiger äußerer Gehäuseabschnitte (46, 50, 56, 66, 78, 92, 114) und eine Mehrzahl miteinander verbundener, rohrförmiger innerer Gehäuseabschnitte (60, 72, 98, 102) bestimmt ist.
6. Bohrlochwerkzeug nach einem der vorstehenden Ansprüche, gekennzeichnet durch Bypasskanalmittel (312), die sich durch das Gehäuse erstrecken und einen Durchflußkanal (308) des Gehäuses mit dem Bohrlochringraum außerhalb des Gehäuses verbinden, und Bypassventilmittel (314) zum wahlweisen Schließen der Bypasskanalmittel, welche Bypassventilmittel vorzugsweise im Betrieb den Isolierventilmitteln (240) zugeordnet sind, so daß beide jeweils zur selben Zeit geöffnet bzw. geschlossen sind.
7. Bohrlochwerkzeug nach Anspruch 6, dadurch gekennzeichnet, daß ein erster Teil der Füllkanalmittel (234) mit einem Teil des Durchflußkanals (308) und ein zweiter Teil der Füllkanalmittel mit den Bypasskanalmitteln (312) zusammenfällt und daß sich die Isolierventilmittel (240) zwischen der Druckkammer (232) und dem ersten Teil der Füllkanalmittel und die Bypassventilmittel (314) zwischen dem ersten und zweiten Teil der Füllkanalmittel befinden.
8. Bohrlochwerkzeug nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß die Isolierventilmittel (240) und die Bypassventilmittel (314) jeweils Ringschieberventile sind, die durch einen einzigen, gemeinsamen, hülsenförmigen Stößel (242) betätigbar sind, der gleitfähig im Gehäuse angeordnet ist, und daß die Isolierventilmittel und die Bypassventilmittel so eingerichtet sind, daß sie durch vertikale Hin- und Herbewegung eines an das Bohrlochwerkzeug angeschlossenen Rohrstranges betätigbar sind.
9. Bohrlochwerkzeug nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß das Bohrlochwerkzeug ein Testventil und das Bedienungselement ein Durchflußventil (162) in dem Durchflußkanal (308) des Gehäuses zum wahlweisen Öffnen und Schließen des Durchflußkanals ist.
10. Bohrlochwerkzeug nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die Betätigungskolbenmittel (140) ein Differentialdruckflächenkolben ist, dessen eine Seite mit der Druckkammer in Verbindung steht, und daß das Gehäuse durchgehende Arbeitskanalmittel (276) enthält, die eine Verbindung des Bohrlochringraumes außerhalb des Gehäuses mit einer zweiten Seite der Betätigungskolbenmittel herstellen, so daß sich die Betätigungskolbenmittel beim Ansprechen auf Änderungen des Bohrlochringraumdruckes außerhalb des Gehäuses zwischen ihrer ersten und zweiten Stellung verstellen.
11. Bohrlochwerkzeug nach einem der Ansprüche 1 bis 10, gekennzeichnet durch Mittel (286) zur Einführung eines Gases in die Druckkammer bei oder vor dem Absenken des Bohrlochwerkzeuges in das Bohrloch.
12. Bohrlochwerkzeug nach Anspruch 11, gekennzeichnet durch Rückschlagventilmittel (450) zur anfänglichen Einschließung der eingegebenen Luft oder des eingegebenen Gases in die Druckkammer (232) unter einen Anfangsdruck, der größer ist als ein an den Füllkanalmitteln (234) anstehender Druck, und zum nachfolgenden Durchfluß von Bohrlochfluid durch die Füllkanalmittel in die Druckkammer in direkten Kontakt mit der komprimierten Luft bzw. dem komprimierten Gas, wenn der an den Füllkanalmitteln anstehende Druck den Anfangsdruck der eingegebenen Luft bzw. des eingegebenen Gases übersteigt.
13. Bohrlochwerkzeug nach Anspruch 12, dadurch gekennzeichnet, daß die Druckkammer zwischen einem aüßeren Zylinderteil und einem inneren Zylinderteil des Gehäuses einen Ringkammerteil (440) enthält, daß die Rückschlagventilmittel (450) einen gleitbeweglich in dem Ringkammerteil angeordneten Ventrilring aufweisen, der den äußeren und inneren Zylinderteilen des Gehäuses abdichtend anliegt, daß das Gehäuse Anschlagmittel (456) aufweist, die an dem Ventilring angreifen und eine Verstellung des Ventilringes in Richtung auf die Füllkanalmittel (234) verhindern, und daß die Rückschlagventilmittel (450) weiterhin Bypassmittel (458, 460) für das Füllfluid enthalten, die im Betrieb dem Ventilring zugeordnet sind und Durchfluß von Bohrlochfluid von den füllkanal,itteln am Ventilring vorbei in die Druckkammer gestatten, nachdem der Ventilring um eine vorgegebene Strecke von den Anschlagmitteln (456) wegbewegt worden ist.
14. Bohrlochwerkzeug nach Anspruch 13, dadurch gekennzeichnet, daß die Bypassmittel für das Füllfluid von einem aufgestauchten Durchmesser (460) an einem von den äußeren und inneren Zylinderteilen des Gehäuses gebildet sind.
15. Bohrlochwerkzeug nach Anspruch 13 oder 14, gekennzeichnet durch Rastmittel (464) zum Einrasten des Ventrilringes in einer Endstellung, in der die Bypassmittel (458, 460) für das Füllfluid geöffnet sind.
16. Bohrlochwerkzeug nach einem der Ansprüche 11 bis 15, dadurch gekennzeichnet, daß die Druckkammer (232) während des Gebrauchs eine ausreichende Masse von eingegebener Luft oder eingegebenem Gas enthält, um bei Schließen der Füllkanalmittel durch die Isolierventilmittel (240) und bei der Verstellung der Betätigungskolbenmittel (140) zwischen der ersten und zweiten Stellung das Volum der Luft- oder Gemasse um einen ersten Betrag zu ändern, der größer ist als der halbe Betrag der Volumänderung der Druckkammer.
17. Verfahren zum Betrieb eines Bohrlochwerkzeug, das ein Gehäuse (12) mit einer darin bestimmten, Gas enthaltenden Druckkammer (232) enthält, sowie Füllkanalmittel (234), die sich zur Verbindung mit einem Bohrlockringraum (236) außerhalb des Gehäuses durch das Gehäuse erstrecken; Isolierventilmittel (240) zum wahlweisen Schließen der Füllkanalmittel (234) zum Einschließen von Bohrlochfluid; ein in dem Gehäuse angeordnetes Bedienungselement (162); innerhalb des Gehäuses gleitfähig angeordnete Betätigungskolbenmittel (140), die dem Bedienungselement zu dessen Bedienung zugeordnet sind, wobei eine Verstellung der Betätigungskolbenmittel zwischen derer erster und zweiter Stellung das Volumen der Druckkammer verringert, enthaltend die folgenden Schritte: Eingeben von komprimiertem Gas in die Druckkammer; Absenken des mit einem Rohrstrang verbundenen Bohrlochwerkzeuges bis zu einer gewünschten Stelle in einem Bohrloch bei geöffneter Fluid-Durchflußverbindung durch die Füllkanalmittel (234); Einschließen des Bohrlochfluids in das Bohrlockwerkzeug; Verstellen der Betätigungskolbenmittel zwischen der ersten und zweiten Stellung zur Betätigung des Bedienungselementes und Verringerung des Volumens der Druckkammer,
dadurch gekennzeichnet, daß das Bohrlockwerkzeug gemäß Anspruch 1 ausgebildet und das komprimierte Gas an einer solchen Stelle in die Druckkammer eingegeben wird, daß das eingegebene Gas an einer Gas-Bohrlochfluidgrenzfläche mit dem in die Druckkammer einfließenden Bohrlochfluid in direktem Kontakt steht, daß das Bohrlochfluid aus dem Bohrlochringraum in dem Maße in die Druckkammer einfließt, in dem das Bohrlockwerkzeug in das Bohrloch zu der gewünschten Stelle abgesenkt wird, so daß das Bohrlochfluid bei einer gegebenen Teufe in der Druckkammer unter einem Druck steht, der dem hydrostatischen Druck der Bohrlochfluids im Bohrlochringraum bei dieser Teufe im wesentlichen gleich ist, daß das Bohrlochfluid in die Druckkammer des Bohrlochwerkzeuges eingeschlossen wird, und daß die Volumverringerung der Druckkammer das komprimierte Gas un das darin eingeschlossene Bohrlockfluid komprimiert, wobei das Vulumen des komprimierten Gases um einen ersten Betrag verringert wird, der größer ist als die Hälfte der Volumverringerung der Druckkammer, so daß die gesamte in der Druckkammer gespeicherte Fluiddruckenergie mehrheitlich als Kompression des komprimierten Gases gespeichert wird.
18. Verfahren nach Anspruch 17, dadurch gekennzeichnet, daß das komprimierte Gas Druckluft ist, die vom Luftsystem eines Bohrturmes zur Verfügung gestellt werden kann.
19. Verfahren nach Anspruch 17 oder 18, dadurch gekennzeichnet, daß die Druckkammer langgestreckt und mit einem Füllkanal zur Verbindung ihres unteren Endes mit dem Bohrlochringraum und zur Verbindung der Betätigungskolbenmittel mit ihrem oberen Ende ausgebildet wird, daß das Bohrlockwerkzeug zunächst teilweise bis zu einer Zwischenstellung in das Bohrloch abgesenkt wird, in der ein unterer Teil des Bohrlochwerkzeuges innerhalb des Bohrloches in das Bohrlochfluid eingetaucht ist und sich ein oberer Teil des Bohrlochwerkzeuges noch oberhalb der Erdoberfläche erstreckt, und daß das komprimierte Gas in die Druckkammer eingegeben wird bis im wesentlichen das ganze Bohrlochfluid aus der Druckkammer hinausgedrückt ist, so daß das komprimierte Gas in der Druckkammer dann unter einem Druck steht, der dem hydrostatischen Druck des Bohrlochfluids in dem Bohrloch bei einer Teufe, die dieselbe ist wie die Teufe des unteren Endes der Druckkammer, im wesentlichen gleich ist.
20. Verfahren nach Anspruch 17 oder 18, gekennzeichnet durch die weiteren Schritte, daß das komprimierte Gas vor Absenken des Bohrlochwerkzeuges in die Druckkammer eingeschlossen wird, und daß aber anschließend Bohrlochfluid in die Druckkammer eingelassen wird, um mit dem komprimierten Gas direkt in Kontakt zu treten und die Gas-Bohrlochfluidgrenzfläche zu bilden, wenn der Bohrlochringraumdruck den Anfangsdruck des komprimierten Gases übersteigt.
21. Verfahren nach Anspruch 20, dadurch gekennzeichnet, daß die Druckkammer langgestreckt ausgebildet ist und daß beim Einschließen der Druck anfänglich größer ist als der Druck einer Bohrlochfluidsäule, deren Höhe gleich der Länge der langgestrecken Druckkammer ist.
22. Verfahren nach einem der Ansprüche 17 bis 21, dadurch gekennzeichnet, daß die Betätigungskolbenmittel verstellt werden, indem deren von der Druckkammer abgewandte Seite mit dem Bohrlochringraum in Verbindung gebracht wird, und daß der Druck im Bohrlochringraum geändert wird, so daß die Betätigungskolbenmittel unter Ansprechen auf die Druckdifferenz zwischen dem Bohrlochringraum und der Druckkammer verstellt werden.
EP85308446A 1984-11-28 1985-11-20 Werkzeug im Bohrloch Expired - Lifetime EP0183482B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US06/676,022 US4595060A (en) 1984-11-28 1984-11-28 Downhole tool with compressible well fluid chamber
US06/676,138 US4617999A (en) 1984-11-28 1984-11-28 Downhole tool with compression chamber
US676138 1984-11-28
US676022 1984-11-28

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EP0183482A2 EP0183482A2 (de) 1986-06-04
EP0183482A3 EP0183482A3 (en) 1988-07-20
EP0183482B1 true EP0183482B1 (de) 1991-01-30

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GB8909892D0 (en) * 1989-04-28 1989-06-14 Exploration & Prod Serv Well control apparatus
DK179662B1 (en) 2015-02-26 2019-03-13 Smartcoil Solution As SYSTEM AND METHOD FOR CONTROLLING PLACEMENT OF A FLOWABLE MATERIAL IN A WELL WITH A LOW FORMATION PRESSURE

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Publication number Priority date Publication date Assignee Title
US3664415A (en) * 1970-09-14 1972-05-23 Halliburton Co Method and apparatus for testing wells
US3856085A (en) * 1973-11-15 1974-12-24 Halliburton Co Improved annulus pressure operated well testing apparatus and its method of operation
US4083409A (en) * 1977-05-02 1978-04-11 Halliburton Company Full flow bypass valve
US4341266A (en) * 1980-09-15 1982-07-27 Lynes, Inc. Pressure operated test tool
US4444268A (en) * 1982-03-04 1984-04-24 Halliburton Company Tester valve with silicone liquid spring

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DE3581602D1 (de) 1991-03-07
EP0183482A3 (en) 1988-07-20

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