RU2540131C2 - Method for removal of sand and mechanical impurities in flow of oil, water and gas - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is referred to the sphere of operation of multipurpose wells, mainly to sandy oil wells, and is intended for treatment of the formation fluid from sand and mechanical impurities. The method for removal of sand and mechanical impurities in a flow of oil, water and gas includes catchment of sand from a flow of oil, water and gas, accumulation of sand and mechanical impurities in receiving hoppers. Catchment of sand and mechanical impurities from a flow of oil, water and gas is implemented mechanically due to reduced pressure and shock losses based on Bord effect intensified by Coanda effect and assumes installation in a flow of oil, water and gas the device design consisting of sand and mechanical impurities receiving hopper and pressure differentiator, which mechanical specifications allow maximum development of the above effects. The device may be installed in a pumped flow or a flow moved by own pressure both upwards and downwards any pumping mechanisms, at that it is envisaged to install one or several in series devices for complete treatment of a flow of oil, water and gas from sand and mechanical impurities.

EFFECT: reliable catchment of sand and mechanical impurities in a flow of oil, water and gas.

1 dwg

Description

The invention relates to the extraction and pumping of useful liquid and gaseous natural resources, in particular water, oil, water-oil mixtures, oil products and gases. It is known that extraction, pumping and processing in order to bring these natural resources to marketable condition is associated with great technical problems, and one of the main problems is the struggle with sand and mechanical impurities. Sand carried along with the extracted useful resources and mechanical impurities are one of the main causes of equipment failure and failure, premature wear of equipment components and parts, and accelerated corrosion of the entire pipeline system. To prevent and reduce the harmful effects of sand and solids on equipment and pipelines, many methods and methods have been applied. The first of them is the limitation of sand from the reservoir rock in which the extracted resources are located, the second is the maximum possible reduction of the harmful effects of the sands received from the producing reservoirs on the equipment and pipelines used. To solve the second problem, technological, chemical and mechanical methods and methods are used. Of these, the most widely used mechanical. But practice shows the low efficiency of the currently used mechanical methods of protection against sand. The operation of the mechanical type equipment used is based on the principle of sand cut-off from the main equipment for extraction and pumping using various types of filters, as well as the principle of sand deposition in various types of storage devices by changing the flow velocity vectors or decreasing the pressure along the flow path. A similar method of trapping sand is used in many inventions, for example, in patent No. 2004574, “Device for separating sand and gas from oil in a well”, in which the oil flow through radial holes enters the pipe under the pump, while the pressure of the stream decreases, then the change occurs flow velocity vectors and oil arrives at the pump intake. The applied method allows only to improve the separation of sand from oil, and, as practice shows, while not more than 40 percent of the sand is captured. Closest to the technical nature of the claimed "Method for trapping sand and solids in the flow of oil, liquid and gas" is the method described in patent No. 2232881 "Device for separating sand from reservoir fluid in the well during its operation", in which sand is collected in receiving column located under the intake of the downhole pump or lift column. Inside the intake column, a series of sand pockets are successively installed along the length into which sand accumulates under the influence of gravity and centrifugal forces from swirling the flow. The disadvantages of this device are the design complexity and low efficiency.

The aim of the invention is to more fully capture sand and solids to minimize the harmful effects of sand and solids on equipment and pipelines, increase their life and reduce material costs when using the proposed method of trapping sand.

The essence of the proposed method for trapping sand and solids in the flow of oil, water and gas is the integrated use of two effects of hydroaerodynamics - this is a sudden expansion of the flow (loss on impact). Based on the momentum theorem, the Bord formula was derived:

$$h_M=\frac{{({\vartheta }_{\mathrm{one}}-{\vartheta }_2)}^2}{2g}$$

(V.I. Kalitsun and others. "Hydraulics, water supply and sewerage". M: 1980, pp. 45-46).

And the Coanda effect, which consists in the fact that at the end of the flow of liquid or gas in the pipe, the reduced pressure in the inner wall of the pipe prevents the free flow of the stream, causing a decrease in pressure in the expiration zone and causing the flow to deviate (T.E. Faber, Hydroaerodynamics. in "Postmarket", 2001, 105-109, 543 pages).

The main condition for the successful implementation of the task, that is, the maximum manifestation of these effects of hydroaerodynamics, is the selection of the optimal type and design of the device and its structural parameters. At the same time, sand and solids are trapped in a simple mechanical way due to a sharp decrease in pressure in the trapping zone — impact loss, based on the Bord effect, enhanced by the use of the Coanda effect. To do this, a sand accumulator is installed inside the fluid or gas flow in its direction, which is a pipe with a plugged end, a pressure differentiator, which is a metal cylinder, is installed coaxially with a non-plugged pipe end at a distance from the pipe end along the fluid or gas flow smaller than the diameter of the sand storage pipe. The entire design of the device is rigidly fixed in the pipeline through which the flow of liquid or gas flows.

The proposed method for trapping sand is illustrated by a device diagram, where 1 is a pipeline, 2 is a pressure differentiator, 3 is a sand accumulator, 4 is a device mounting system in a pipeline. Here is the hydraulic calculation of the proposed method for trapping sand, implemented by such a device, when installed in a tubing string above a deep plunger pump, with the device mounted in a rod suspension. With this embodiment, the fastening system in the pipeline, that is, in the tubing string, is not required and the device consists only of a sand accumulator and a pressure differentiator. When pumping oil, the device together with the rod string in accordance with the set number of swings will move up and down. We choose the option of the rocking machine, in which the movement of the suspension rods will be up as the most difficult. The calculation is based on the fact that at the beginning of the movement of the pump plunger upward in the area above the pump, liquid compression occurs due to the presence of the gas factor and liquid leakage between the plunger and the pump cylinder. Therefore, the liquid first moves relative to the device for trapping sand down. This explains the difference between the real supply of SHGN and ideal.

The rate of fluid movement down is mainly determined by the magnitude of the gas factor and the depth of the pump. When a certain critical point is reached, at which the gas no longer contracts, the liquid begins to move mainly upward and oil is pumped out.

For calculation, we take the pump descent depth equal to 1000 m, tubing inner diameter = 60 mm, pressure differentiator diameter = 40 mm.

We calculate the pressure loss after the pressure differentiator using the laws of hydraulics.

и $$\overline{II}-\overline{II}$$

.To do this, we determine the coefficients of local hydraulic resistance in sections $$\overline{I}-\overline{I}$$

and $$\overline{II}-\overline{II}$$

.

When the pump plunger moves upward, the fluid flow first rushes down, therefore, under the pressure differentiator 2, a sudden expansion of the flow occurs (shock loss). According to Bord's theorem:

, где ϑ₁ и ϑ₂ - скорости потока в сечениях $$\overline{I}-\overline{I}$$

и $$\overline{II}-\overline{II}$$

, $$h_M=\frac{{({\vartheta }_{\mathrm{one}}-{\vartheta }_2)}^2}{2g}$$

, where ϑ ₁ and ϑ ₂ are the flow velocities in sections $$\overline{I}-\overline{I}$$

and $$\overline{II}-\overline{II}$$

,

g is the acceleration of gravity.

Given that ϑ ₁ × F ₁ = ϑ ₂ × F ₂ , where F ₁ and F ₂ are the corresponding cross-sectional areas:

$$h_M={\left(\frac{F_2}{F_{\mathrm{one}}}-\mathrm{one}\right)}^2\times \frac{{\vartheta }_2^2}{2g}$$

or

$$h_M={\left(\mathrm{one}-\frac{F_{\mathrm{one}}}{F_2}\right)}^2\times \frac{{\vartheta }_{\mathrm{one}}^2}{2g}$$

, где ∂ - коэффициент местного сопротивления.Comparing these formulas with the Weisbach formula $$h_M=\partial \frac{{\vartheta }^2}{2g}$$

where ∂ is the local resistance coefficient.

We get:

и $${\partial }_2={\left(\frac{F_2}{F_1}-1\right)}^2$$

; $${\partial }_{\mathrm{one}}={\left(\mathrm{one}-\frac{F_{\mathrm{one}}}{F_2}\right)}^2$$

and $${\partial }_2={\left(\frac{F_2}{F_{\mathrm{one}}}-\mathrm{one}\right)}^2$$

;

Since we have F ₁ = 15.7 mm ² and F ₂ = 25.12 mm ² ,

we get:

$${\partial }_{\mathrm{one}}={\left(\mathrm{one}-\frac{\mathrm{fifteen},7}{25,12}\right)}^2=0,140$$

$${\partial }_2={\left(\frac{25,12}{\mathrm{fifteen},7}-\mathrm{one}\right)}^2=0,360$$

и $$\overline{II}-\overline{II}$$

, то естьOn this basis, the pressure drop after the pressure differentiator is determined by the difference in local hydraulic resistances over the sections $$\overline{I}-\overline{I}$$

and $$\overline{II}-\overline{II}$$

, i.e

∂ = ∂ ₂ -∂ ₁ = 0.220

и выше, то падение давления после дифференциатора давления будет довольно существенным и будет определяться разницей местных гидравлических сопротивлений по сечениям $$\overline{I}-\overline{I}$$

и $$\overline{II}-\overline{II}$$

и оно будет тем больше, чем больше разница площадей потока и его расширившейся части. Дополнительное снижение давления обеспечивается эффектом Коанды. Именно это возникновение понижения давления у приема накопителя обеспечивает поступление песка в накопитель и предохраняет песок от вымывания. При движении плунжера насоса вниз поток нефти относительно устройства движется вверх и понижение давления у приема накопителя песка будет еще больше.Since when the plunger rises, the pressure reaches $$\mathrm{one\; hundred}\text{kg}\times \raisebox{1ex}{$\text{from}$}\!\left/ \!\raisebox{-1ex}{${\text{<figure-callout id="2" label="cm" filenames="00000019.png" state="{{state}}">cm</figure-callout>}}^{\text{2}}$}\right.$$

and higher, then the pressure drop after the pressure differentiator will be quite significant and will be determined by the difference in local hydraulic resistances over the sections $$\overline{I}-\overline{I}$$

and $$\overline{II}-\overline{II}$$

and it will be the greater, the greater the difference in the area of the flow and its expanding part. An additional reduction in pressure is provided by the Coanda effect. It is this occurrence of a decrease in pressure at the intake of the drive that ensures the entry of sand into the drive and protects the sand from leaching. When the pump plunger moves down, the oil flow relative to the device moves up and the pressure decrease at the reception of the sand accumulator will be even greater.

The decrease in pressure in the sand accumulator created by the proposed method for trapping sand and mechanical impurities in the flow of oil, water and gas has a complex dependence and is determined by the general design of the system, its structural parameters, and its value is determined by many factors (oil viscosity, distance from the pressure differentiator to the sand accumulator and others), and the nature of the pressure distribution depends on the point in time. When the device is operating in the steady state flow of liquid or gas, the reduced pressure in the sand accumulator remains unchanged. This is typical when installing devices for trapping sand before and after pumps and compressors of a centrifugal type. The application of the proposed method for trapping sand with the installation of such devices in wells has its own characteristics, in particular, to ensure the reliable operation of deep-well pumps of the ESP type, it is necessary to use mechanical packers installed independently before the pump, onto which the device is mounted by the proposed method.

To completely clean the flow of liquid, oil and gas, several devices are installed in series. The proposed method for trapping sand and solids in a stream of oil, water and gas, including trapping from a stream of oil, water and gas and the accumulation of sand and solids in reservoirs, differs from those used and proposed by the operating principle underlying the operation of devices created by the principle by which the capture of sand and solids from the flow of oil, water and gas is carried out mechanically by lowering the pressure in the local area - loss on impact, based on the Bord effect, caused by the use of the Coanda effect and involving the installation of a stream of oil, water and gas, such a device design consisting of a sand accumulator and mechanical impurities and a pressure differentiator, the structural parameters of which allow for the maximum manifestation of these effects. The effectiveness of the proposed method and the simplicity of the devices created by this method allows them to be placed in the flow of a pumped or moving stream of liquid with gas or gas that already has its own pressure, both before and after any pumping mechanisms.

Claims (1)

The method of trapping sand and solids in a stream of oil, water and gas, including trapping from a stream of oil, water and gas, and the accumulation of sand and solids in storage, characterized in that the trapping of sand and solids from a stream of oil, water and gas the method of reducing pressure — loss on impact, based on the Bord effect, enhanced by the use of the Coanda effect and involving the installation of such a device structure consisting of accumulate in a stream of oil, water and gas For sand and mechanical impurities and a pressure differentiator, the design parameters of which allow for the maximum manifestation of these effects, the device can be placed in the stream being pumped or moving under its own pressure both before and after any pumping mechanisms, and it is possible to install one or several series-installed devices for the complete cleaning of the flow of oil, water and gas from sand and solids.

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