CN103046894A - Injection process of refracturing plugging agent - Google Patents
Injection process of refracturing plugging agent Download PDFInfo
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- CN103046894A CN103046894A CN 201110325839 CN201110325839A CN103046894A CN 103046894 A CN103046894 A CN 103046894A CN 201110325839 CN201110325839 CN 201110325839 CN 201110325839 A CN201110325839 A CN 201110325839A CN 103046894 A CN103046894 A CN 103046894A
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- refracturing
- blocking agent
- rock core
- plugging agent
- injection
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Abstract
The invention discloses an injection process of a refracturing plugging agent. The process includes (a) preparing the refracturing plugging agent for preparation; (b) respectively splitting the selected rock core to manufacture an artificial fracture; (c) injecting the refracturing plugging agent to the rock core to form glue; (d) injecting water solution containing refracturing plugging agent into the rock core after the plugging agent portion is subjected to glue breaking; (e) placing the rock core into a drying box in different times, finally measuring rock core permeability and considering permeability restoring condition. The injection process is capable of quickly injecting the refracturing plugging agent into a substance to be sealed, good in injection effect, simple in injection process and low in injection cost.
Description
Technical field
The present invention relates to a kind of injection technology of refracturing blocking agent.
Background technology
Low-permeability oil deposit is to refer generally to the oil reservoir that the oil reservoir of permeability between 10-50 * 10-3 μ m2 consists of in China.Along with the continuous intensification of exploration and development degree, China's low-permeability oil pool total proved reserves and in the mining-employed reserves shared ratio more and more higher, keep and the promotion development of oil industry in the effect brought into play increasing.As take China National Petroleum Corporation (CNPC) as example, at the bottom of calendar year 2001, verify petroleum-in-place 145 * 108t, wherein hyposmosis reserves 44 * 108t accounts for 30%; Employ petroleum-in-place 110 * 108t, wherein hyposmosis reserves 21 * 108t accounts for 19%; Residue is verified and is not employed petroleum-in-place 35 * 108t, and wherein hyposmosis reserves 22 * 108t accounts for 62%.In the reserves of verifying then in the recent period, the shared ratio of hyposmosis reserves is larger, up to 65%～70%.How to employ and developed the low permeability oil field reserves, to the sustainable and stable development of China Petroleum with guarantee that the safe tool of China's oil is of great significance.
Hydraulic fracturing technology has been widely used in the exploitation in low-permeability oil gas field as the major measure of well production increment, intensified injection of wells, for the stable yields of oil gas field has been made significant contribution.Improve near the seepage flow condition the shaft bottom by fracturing, linked up the oil gas gathering area and change the gas stream flowing mode, improved Oil ﹠ Gas Productivity.The output of domestic hypotonic oil gas field and the output that obtains by the fracturing transformation are all increasing sharply year by year.
Through oil, gas, the well after the fracturing, owing to be subjected to the at that time restriction of fracturing technology, material, equipment tool, the reason such as it is little that scale is owed, and material selection is improper, and plant capacity is limited can cause the hydraulic fracture flow conductivity significantly to reduce and ineffective gradually; Some then selects improper because of the well layer or the operation reasons also fails effectively to pass through simultaneously long period of development, and the major oil gas field has entered the development phase of middle and high Water-cut Period, and the difficulty of stable high yield is increasing; To this class Oil/gas Well, in order to obtain high yield and economic exploitation benefit, need to carry out refracturing.
USDOE in 1987 change the pressure break experiment of stress in many wells experiments, first proved stress field be subject to the impact of offset well crack.Dowell company is thought according to experiment and simulated ground stress research, exist supporting crack will change near the stress distribution of well in the stratum, make the crack initiation orientation of refracturing perpendicular to first crack, leave to redirect to again after the well certain limit and be parallel to first fracture orientation and extend.Chen ﹠amp; The researchs such as Minner are thought that pore pressure changes and are caused new crack approximately perpendicular to crack last time or with last time the crack was in an acute angle.Chevron Oil Tech Inc shows in the test in U.S. Lost Hill oil field, refracturing fracture orientation and 30 ° of first fractuer direction skews; Unocal company has confirmed that in the test of the refracturing in Van oil field the refracturing crack may depart from 60 ° with fracture orientation last time.The development of multiple fracturing technique that these have tested the promotion strong with research has obtained extremely significant economic benefit.For example, Rangely oil field, one of oil field that the U.S. develops the earliest, many well refracturings reach 4 times, and success rate reaches 70-80%; Refracturing is 185 mouthfuls in 385 mouthfuls of producing wells in Kuparuk River oil field, U.S. Alaska, and productivity index has on average improved twice after pressing.
A large amount of refracturing operations has also been carried out in the oil fields such as recent year grand celebration, triumph, long celebrating, huge port, Jilin, and has done certain exploration from theory and practice, has obtained some experiences and understanding.Since nineteen ninety-five, Southwest Petrol University has successively carried out STUDY ON REPETITIVE FRACTURING TECHNOLOGY with Liaohe Oil Field, long celebrating oil field, Xinjiang Oilfield and Shengli Oil Field, and with the changed course refracturing test that has launched the new seam of the stifled old seam pressure of high water-cut stage in length celebrating oil field, the Xinjiang Oilfield cooperation, obtain good effect of increasing production, opened up the new direction of refracturing research.
The process of stifled pressure integrated technique is to use first the long-acting shutoff of blocking agent or the temporary transient old crack of shutoff, and then other orientation presses off new crack on the stratum with fracturing technique, again transforms reservoir to reach, and improves the purpose of reservoir recovery.Behind the blocking agent shutoff crack, follow-up fracturing fluid must have extruding and penetration to it, therefore requires the refracturing blocking agent to have the performance higher than conventional blocking agent.
After entering old crack, refracturing blocking agent working solution forms gel, under follow-up fracturing fluid effect, blocking agent will be subject to of the fracturing fluid extruding and penetration, therefore the performance of refracturing blocking agent will satisfy the requirement of two aspects: the one, and the strongly adherent between blocking agent-crack wall stops fracturing fluid to penetrate toward first man-made fracture; The 2nd, self has high strength blocking agent, can resist of the fracturing fluid extruding.Blocking agent not only has high intensity and adhesiveness in a word, and certain stress deformation ability will be arranged.This just requires the breakthrough pressure of blocking agent will be higher than the extruding force that is subject to.
The appearance of refracturing crack steering mechanism is the major progress of multiple pressure technology, has roughly passed through three phases:
Early stage (1) 20 nineties in century, at first be the understanding that the refracturing fracture orientation turns to, obtained at the scene checking: Chevron Oil Tech Inc is in U.S. LostHill oil field, utilize dipmeter survey refracturing fracture orientation, then with the first time fracturing fracture orientation compare, the inferior average fracture orientation of refracturing of 167 wells is N25 ° of E as a result, and the inferior first fracturing fracture orientation of well more than 100 is N55 ° of E, the two differs 30 °, illustrates that thus the fracture orientation that refracturing forms is different from first fracturing fracture orientation; And the mechanism that the refracturing crack turns to also obtained further developing, and people recognize that gradually manufacturing process reservoir pore space pressure changes the stress state that finally can change reservoir.
Because reservoir all directions decline of pressure is unbalanced, in containing vertically fractured reservoir, form oval decay area, its longitudinal crack axial ratio vertical fractures axle is much longer, the decline of horizontal total stress that is parallel to man-made fracture is just large than vertical (minimum) stress components, and this is the key of stress reorientation.If the STRESS VARIATION that produces is enough large, be enough to offset the impact of initial level deviator stress, the direction of minimum level stress will local half-twist so, in this case, the refracturing crack should be perpendicular to original crack growth, but refracturing is redirected and depends on many factors, comprises permeability and the production history of original deviator stress, pre-existing fracture length, reservoir, so be redirected also not necessarily perpendicular to former crack in actual crack.
(2) the 20 later stages nineties in century, recognize to turn to refracturing to be rich in residual oil area and greatly to improve output and recoverable reserves by the effective communication reservoir, stimulated Chinese scholars to turning to the research of refracturing.Because the refracturing fissure extension mode still depends on the reservoir stress state, not controlled by objective stress condition take people's subjective will as shifting.Proposed to simulate the variation model of in-situ stress field under many wells (comprising oil well and well) and the varying flow rate condition therebetween, abroad.Result of study shows, the variation of in-situ stress field depend primarily on time that the distance apart from oil-water well, whole oil gas field drop into exploitation, injection-production well not, the anisotropy of original level deviator stress, permeability and produce fluence etc.And further carry out refracturing well and story selecting technology, people expect the technology such as integrated application expertise, artificial neural network technology and fuzzy logic, develop the model of refracturing well and story selecting, implement refracturing to find out those oil reservoirs that might turn to.
(3) enter 21 century after, turn to multiple fracturing technique to further develop, some experts and scholars of Southwest Petrol University have proposed a kind of new technology of forcing the crack to turn to, namely new crack multiple fracturing technique is pressed in stifled old crack.Through exploitation after a while, the less permeable layer in oil field has been in high water-cut stage, and the crude oil of primary fracture control is near whole extraction, and the crack has become the central core of circulation of water, but the still control under existing extraction condition of some well has certain residual recoverable reserves.If at this moment take to extend the effect that the conventional refracturing of primary fracture does not have certainly, best bet is that primary fracture is blocked, pressure break again, with primary fracture at an angle direction make new seam, but so both water blockoffs can increase oil production again.Namely study a kind of high-intensity crack blocking agent shutoff primary fracture, enter selectively after in blocking agent pumps into well and the shutoff primary fracture, but can not infiltrate formation pore and stop up blowhole, simultaneously shutoff preforation tunnel effectively around pit shaft; Then adopt the oriented perforating technology again perforation to guarantee that (best orientation is perpendicular to the orientation of primary fracture) redirects perforation and impel the crack to turn in the orientation that is different from primary fracture, namely form new crack, thereby extraction minimum principal stress direction or near the oil gas of minimum principal stress direction drainage area realizes water-control oil-increasing.
Refracturing refers to the well layer of taking once or several times pressing crack construction measure is implemented fracturing reform again.As far back as the 1950's, just carried out refracturing abroad, development through more than 50 years, reservoir reevaluating, well and story selecting new technology, fracturing fluid, fractured well dynamic prediction, refracturing crack steering mechanism, refracturing optimal design and the aspects such as technology research, crack Diagnosis and effect assessment all are rapidly developed before refracturing, not only become the increasing yield and injection means of oil-gas reservoir, also become economical and effective and develop key technology hypotonic, ultra-low permeability reservoir.
The refracturing blocking agent is in the process of using, and in order to bring into play its maximum effect, it is particularly important that its injection technology seems.
Summary of the invention
The object of the invention is to overcome the shortcoming and defect of above-mentioned prior art, a kind of injection technology of refracturing blocking agent is provided, and this injection technology can be injected the material that needs sealing with the refracturing blocking agent by Quick Measuring, and injects effective, injection technology is simple, and it is low to inject cost.
Purpose of the present invention is achieved through the following technical solutions: a kind of injection technology of refracturing blocking agent may further comprise the steps:
(a) preparation refracturing blocking agent is for subsequent use;
(b) rock core of choosing is rived respectively, make a man-made fracture;
(c) the refracturing blocking agent being injected rock core allows it become glue;
(d) then until blocking agent partly behind the broken glue, the aqueous solution that will contain the refracturing blocking agent injects rock core;
(e) then in baking oven, place different time, measure at last core permeability, investigate the resume permeability situation.
In the described step (b), rock core is rived vertically.
In the described step (d), the content of refracturing blocking agent in the aqueous solution is 30%.
In the described step (e), the temperature of baking oven is 80 ℃.
In sum, the invention has the beneficial effects as follows: can Quick Measuring the refracturing blocking agent be injected the material that needs sealing, and inject effectively, injection technology is simple, and it is low to inject cost.
The specific embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but embodiments of the present invention are not limited only to this.
Embodiment:
The injection technology of a kind of refracturing blocking agent that the present invention relates to, its concrete steps are as follows:
(a) preparation refracturing blocking agent is for subsequent use;
(b) rock core of choosing is rived respectively, make a man-made fracture;
(c) the refracturing blocking agent being injected rock core allows it become glue;
(d) then until blocking agent partly behind the broken glue, the aqueous solution that will contain the refracturing blocking agent injects rock core;
(e) then in baking oven, place different time, measure at last core permeability, investigate the resume permeability situation.
In the described step (b), rock core is rived vertically.
In the described step (d), the content of refracturing blocking agent in the aqueous solution is 30%.
In the described step (e), the temperature of baking oven is 80 ℃.
As shown in the table by the result that said method records:
As seen from the above table: in the situation of the broken glue of part, the injection pressure during follow-up injection gel breaker is not high, illustrates that the gel breaker injection is good; Along with the prolongation of broken glue time, the recovery rate of fracture permeabgility is also more and more higher, and at broken glue after 3 hours, it is initial 96.7% that fracture permeabgility reverts to, and illustrates that follow-up injection method can recover the production capacity in crack effectively, realizes the purpose of blocking up temporarily.When suggestion is constructed at the scene, cooperate follow-up injection method.
The above only is preferred embodiment of the present invention, is not the present invention is done any pro forma restriction, and every foundation technical spirit of the present invention, any simple modification, equivalent variations to above embodiment does all fall within protection scope of the present invention.
Claims (4)
1. the injection technology of a refracturing blocking agent is characterized in that, may further comprise the steps:
(a) preparation refracturing blocking agent is for subsequent use;
(b) rock core of choosing is rived respectively, make a man-made fracture;
(c) the refracturing blocking agent being injected rock core allows it become glue;
(d) then until blocking agent partly behind the broken glue, the aqueous solution that will contain the refracturing blocking agent injects rock core;
(e) then in baking oven, place different time, measure at last core permeability, investigate the resume permeability situation.
2. the injection technology of a kind of refracturing blocking agent according to claim 1 is characterized in that, in the described step (b), rock core is rived vertically.
3. the injection technology of a kind of refracturing blocking agent according to claim 1 is characterized in that, in the described step (d), the content of refracturing blocking agent in the aqueous solution is 30%.
4. the injection technology of a kind of refracturing blocking agent according to claim 1 is characterized in that, in the described step (e), the temperature of baking oven is 80 ℃.
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| CN 201110325839 CN103046894A (en) | 2011-10-13 | 2011-10-13 | Injection process of refracturing plugging agent |
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| CN 201110325839 CN103046894A (en) | 2011-10-13 | 2011-10-13 | Injection process of refracturing plugging agent |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104727798A (en) * | 2015-03-30 | 2015-06-24 | 中国石油集团川庆钻探工程有限公司长庆井下技术作业公司 | Low permeability gas reservoir turning repeated fracturing technological method |
| CN106351634A (en) * | 2015-07-16 | 2017-01-25 | 中国石油化工股份有限公司 | Casing horizontal well multi-segment refracturing method |
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2011
- 2011-10-13 CN CN 201110325839 patent/CN103046894A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104727798A (en) * | 2015-03-30 | 2015-06-24 | 中国石油集团川庆钻探工程有限公司长庆井下技术作业公司 | Low permeability gas reservoir turning repeated fracturing technological method |
| CN104727798B (en) * | 2015-03-30 | 2017-03-08 | 中国石油集团川庆钻探工程有限公司长庆井下技术作业公司 | A kind of low permeability gas reservoir turns to refracturing process |
| CN106351634A (en) * | 2015-07-16 | 2017-01-25 | 中国石油化工股份有限公司 | Casing horizontal well multi-segment refracturing method |
| CN106351634B (en) * | 2015-07-16 | 2019-03-05 | 中国石油化工股份有限公司 | Casing horizontal well multistage refracturing method |
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Application publication date: 20130417 |