RU2547857C1 - Method of development of multireservoir oil deposits - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: method comprises run in the production well of the pipes string with filter below liquid level in well, product recovery from top deposit, oil and water separation in the wellbore, water injection to bottom deposit, oil lifting to surface. The filter is pipe in pipe, the internal pipe has hydrophilic surface with hydrophilic degree 99% min, capillary holes with diameter 2 mm min, and density 50 holes/m min. Outside pipe has hydrophobic surface with hydrophilic degree 99% min, capillary holes with diameter 2 mm max, and density 50 holes/m min. Pipes string diameter used for filter run is equal to diameter on internal filter pipe. Internal pipe has length exceeding length of outside pipe. Outside pipe is located not below the top deposit, and internal pipe - not below bottom deposit. Between the casing string and bottom of the outside pipe above the top deposit the parker is installed, ensuring fluid from top deposit ingress directly in space between the internal and outside pipes of the filter. Between the casing string and bottom of the internal pipe above the bottom deposit the parker is installed also, excluding fluid from bottom deposit ingress in space between the internal and outside pipes of the filter. Moving from top production deposit to the wellbore the fluid enters the space between the internal and outside pipes of the filter, where it is filtered via the capillary holes of the appropriate filter pipes with hydrophobic and hydrophilic coatings, separating to oil that entering in the outside pipe and then in annulus by the pump is lifted to surface, and to water that entering in the internal pipe by the pump is pumped in the bottom deposit.EFFECT: increased efficiency of oil and water separation in the wellbore, increased efficiency of waterflooding and increased oil recovery of the deposit.2 dwg

Description

The invention relates to the oil industry and may find application in the development of multilayer oil deposits, the layers of which coincide structurally, with the selection of products from the upper layer and pumping water into the lower layer.

There is a method of operating a high-water well oil well, which includes separate, thanks to a packer installed between the strata, pumping oil from the reservoir to the surface with preliminary gravitational separation of the products in the well into oil and water and pumping the separated water into the receiving reservoir. Above the packer installed above the reservoir, a pump is placed on the pipe string, communicated with an inlet with a sub-packer space, and with an outlet through a radial hole in a pipe string with an over-packer space, and pipes of a smaller diameter are placed under the radial holes from the conditions of gravitational separation of products into oil and water while the separated oil is lifted along the annulus and the pipe string with the possibility of regulating its flow rate at the mouth, and water, controlling its amount, is pumped along the annulus space to the receiving reservoir due to the pressure of the liquid column in the well and the excess pressure generated by the pump, the interval of the receiving formation being reported as a separate tube with wellhead measuring equipment, based on the readings of which control the quality of the water pumped into the receiving formation. In addition, the emulsion in the production of the formation before injection into the annulus is separated into oil and water by a separator (RF patent 2394153, class E21 B43 / 00, publ. 10.07.2010).

Closest to the technical essence of the proposed method is a method of operating a well, which consists in the fact that the well is supplied from bottom to top with a string of tubing with a packer at the end, a deep pump, a commutator, two concentrically arranged outer and inner tubing tubing columns, nozzles with holes on the outer tubing string, the well is separated by a packer above the reservoir, the reservoir products are fed by the downhole pump in a cyclic mode “p supply-stop ”from the reservoir through the tubing string, through the switch, the annulus between the inner and outer tubing strings, the nozzle and nozzle openings into the annulus between the production well and the outer tubing string, create and maintain in the upper part of the well a pressure of not less than the degassing pressure of oil and not more than the permissible pressure on the production casing; the formation of products for oil and water, regulate the completeness of the separation of the half-cycle operation of the deep-well pump “stop” and the distance between the switch and nozzles with holes, direct oil to the oil line, supply water through the switch to the inner column of the tubing and through the pipeline to the discharge borehole by pumping water and / or through the annulus between the production string and the outer tubing string and tubing string with a packer in the reservoir above the packer with downhole pumping of water (RF patent No. 2490436, cl. E21 B43 / 12, E21 B43 / 38, publ. 08/20/2013 - prototype).

A common disadvantage of the known methods is the insufficiently effective separation of oil and water, the complexity of the design, excessive rise to the surface of the water. The methods also do not allow the efficient use of shared water in order to maintain reservoir pressure by flooding, which leads to low oil recovery in the development of deposits with two or more layers that are structurally identical.

The proposed invention solves the problem of increasing the efficiency of separation of oil and water in the wellbore, increasing the efficiency of water flooding and, as a result, increasing the oil recovery of the reservoir.

The problem is solved in that in the method of developing multilayer oil deposits, which includes lowering a pipe string with a filter below the liquid level in the well into the wellbore of the producing well, taking products from the upper formation, separating oil and water in the wellbore, injecting water into the lower formation, raising oil to the surface, according to the invention, the filter is a pipe in a pipe, the inner pipe has a hydrophilic surface with a degree of hydrophilicity of at least 99%, capillary holes with a diameter of not more than 2 mm and a density of at least 50 holes. / m, the outer pipe has a hydrophobic surface with a degree of hydrophobicity of not less than 99%, capillary holes with a diameter of not more than 2 mm and a density of not less than 50 holes / m, and the diameter of the pipe string on which the filter is lowered is equal to the diameter of the filter’s inner pipe, inner the pipe has a length greater than the outer one, the outer pipe is placed no lower than the upper layer, and the inner pipe is not lower than the lower layer, a packer is installed between the casing and the bottom of the outer pipe above the upper layer, which allows fluid from the upper layer to enter Directly into the space between the inner and outer pipes of the filter, and between the casing and the bottom of the inner pipe above the lower layer, a packer is also installed, which does not allow water from the lower layer to enter the space between the inner and outer pipes of the filter, moving from the upper productive layer into the barrel wells, the fluid enters the space between the inner and outer filter pipes, where it is filtered through the capillary holes of the corresponding filter pipes with a hydrophobic and hydrophilic coating s, separating into oil, which is entering the outer pipe and then into the annular space, the pump rises to the surface and water, which, falling into the inner tube, the pump is pumped into the lower reservoir.

SUMMARY OF THE INVENTION

The oil recovery of an oil deposit is significantly affected by the system of maintaining reservoir pressure by water flooding. One of the ways to increase it is to use production wells for simultaneous fluid production in one formation and water injection in another. At the same time, no water pipes are brought to the well, but separation in the well of the selected fluid from the upper reservoir into oil and water is used. Water is used for injection in the same well into the lower reservoir. Thus, they increase the efficiency of the waterflooding system of the reservoir, consisting of at least two reservoirs. In the absence of flooding in the deposits, this method is used to dispose of water in the lower layer. However, existing technical solutions do not fully allow these tasks to be completed.

The proposed invention solves the problem of increasing the efficiency of separation of oil and water in the wellbore, increasing the efficiency of water flooding and, as a result, increasing the oil recovery of the reservoir. The problem is solved as follows. In FIG. 1 is a schematic representation of a section of an oil reservoir with two formations uncovered by a well. In FIG. 2 is a schematic view of a section of a section of an oil deposit perpendicular to the wellbore. Designations: 1 - lower production formation, 2 - upper production formation, 3 - non-reservoir, 4 - production well, 5 - casing, 6 - cement ring, 7 - perforations, 8 - pipe string, 9 - filter, 10 - the inner pipe of the filter 9 with a hydrophilic coating, 11 - the outer pipe of the filter 9 with a hydrophobic coating, 12 - the packer for sealing the annular space 15, 13 - the space between the outer 11 and the inner 10 pipes of the filter 9, 14 - the packer for sealing the space 13, 15 - annulus (the space between the casing 5 and Olona pipe 8 as well as between the casing 5 and the outer tube 11 of the filter 9), 16 - pump for lifting wellbore production (oil) to the surface, 17 - pump for pumping water into the bottom layer 1.

The method is implemented as follows.

The oil reservoir area, represented by the lower 1 and upper 2 reservoirs (Fig. 1) with a terrigenous or carbonate type of reservoir and separated by a non-reservoir 3, is opened by a well 4. Well 4 is cased by a column 5, cemented by a cement ring 6 and re-opened by perforation 7 in the productive layers 1 and 2. Either the productive part of the layers 1 and / or 2 may have an open trunk.

Filter 9 is lowered into the borehole 4 on the pipe string 8. Filter 9 is a pipe in the pipe and has the following structure (Fig. 1, 2): the inner pipe 10 has a hydrophilic surface with a degree of hydrophilicity of at least 99%, capillary holes with a diameter of not more than 2 mm and a density of at least 50 holes / m, the outer pipe 11 has a hydrophobic surface with a degree of hydrophobicity of at least 99%, capillary holes with a diameter of not more than 2 mm and a density of at least 50 holes / m.

These extreme values were identified by studies that showed that in the vast majority of cases with these parameters, depression in the wellbore allows water to penetrate through the surface of the outer pipe 11 with holes with a hydrophilic coating, and oil through the surface of the inner pipe 10 with holes with a hydrophobic coating. In this case, oil does not penetrate through the surface with holes with a hydrophilic coating, and water does not penetrate through the surface with holes with a hydrophobic coating.

The diameter of the pipe string 8, on which the filter 9 descends, is equal to the diameter of the inner pipe 10 of the filter 9. The inner pipe 10 has a length greater than the outer 11. The outer pipe 11 is placed no lower than the upper layer 2, and the inner 10 is not lower than the lower layer 1. A packer 12 is installed between the casing 5 and the bottom of the outer pipe 11 above the upper formation 2, which allows liquid from the upper formation 2 to flow directly into the space 13 between the inner 10 and the outer 11 of the filter pipes 9. Also between the casing 5 and the bottom of the inner pipe 10 above lower its formation one set packer 14 that does not allow the water to fall from the lower reservoir 1 into the space 13 between the inner 10 and outer 11 filter tubes 9.

Moving from the upper reservoir 2 to the borehole 4, the fluid enters the space 13 between the inner 10 and outer 11 of the filter pipes 9, where it is filtered through the capillary holes of the corresponding filter pipes with a hydrophobic and hydrophilic coating. The liquid is separated into oil, which, falling into the outer pipe 11 and then into the annular space 15, rises to the surface with the pump 16, and water, which, falling into the inner pipe 10, is pumped into the lower layer 1 by the pump 17.

Injection of water from the upper layer 2 into the lower 1 must be carried out with the compatibility of their formation water, in order to avoid the loss of salts. Or add reagents against the precipitation of salts from the surface into the pipe string 8, which is connected to the inner pipe 10 of the filter 9.

Similar operations are carried out in other wells. Thus, a development system is created in which production wells of the upper formation 2 are simultaneously injection wells of the lower formation 1.

Development is carried out until the full economically viable development of deposits.

The result of the implementation of this method is to increase the efficiency of separation of oil and water in the wellbore, increase the efficiency of water flooding and, as a result, increase the oil recovery of the reservoir.

An example of a specific implementation of the method

The oil reservoir area, represented by the lower 1 and upper 2 productive formations (Fig. 1) with a terrigenous type of reservoir, and separated by a clay layer of non-reservoir 3, are opened by a vertical well 4. Formation 1 with an effective oil-saturated thickness of 7 m lies at a depth of 1690 m, reservoir 2 with an effective oil saturated thickness of 6 m lies at a depth of 1635 m.

Well 4 is cased with a column 5 with a diameter of 168 mm, cemented with a cement ring 6 and re-opened by perforation 7 in the productive formations 1 and 2.

Preliminary studies of the compatibility of formation waters of both layers showed the possibility of their mutual use for the purpose of maintaining reservoir pressure.

Filter 9 is lowered into the wellbore 4 between the upper 2 and lower 1 layers on a tubing string 8 with a diameter of 60 mm.

The filter 9 is a pipe in a pipe and has the following design (Fig. 1, 2): the inner pipe 10 with a diameter of 60 mm has a hydrophilic surface with a degree of hydrophilicity of 99% (product of the company "Quartz", brand K1-3FS; the surface is obtained by dilution of this product with water-based paint, applied to the surface and subsequent drying), capillary holes with a diameter of 2 mm and a density of 50 holes / m, the outer pipe 11 with a diameter of 102 mm has a hydrophobic surface with a degree of hydrophobicity of 99% (product of the company "Quartz", K1-3GF brand; surface be prepared by dilution of the product with a hydrocarbon-based paint, coating the surface and subsequent drying), capillary hole diameter of 2 mm and a density of 50 holes. / m.

The inner pipe 10 of the filter 9 is 90 m long and the outer 11 is 41 m long. The outer pipe 11 is placed not lower than the upper layer 2, and the inner 10 is not lower than the lower layer 1. Between the casing 5 and the bottom of the outer pipe 11 above the upper layer 2 a packer 12 is installed, which allows liquid from the upper layer 2 to enter directly into the space 13 between the inner 10 and the outer 11 pipes of the filter 9. Also, between the casing 5 and the bottom of the inner pipe 10, a packer 14 is installed above the lower layer 1, which prevents water from entering lower pl one hundred into the space 13 between the inner 10 and outer 11 filter tubes 9.

The well is put into operation. Moving from the upper reservoir 2 to the borehole 4, the fluid enters the space 13 between the inner 10 and outer 11 of the filter pipes 9, where it is filtered through the capillary holes of the corresponding filter pipes with a hydrophobic and hydrophilic coating. The liquid is separated into oil, which, falling into the outer pipe 11 and then into the annular space 15, rises to the surface with the pump 16, and water, which, falling into the inner pipe 10, is pumped into the lower layer 1 by the pump 17.

Similar operations are carried out in other wells. Thus, a development system is created in which production wells of the upper formation 2 are simultaneously injection wells of the lower formation 1.

Development is carried out until the full economically viable development of deposits.

As a result, during the development of the reservoir, which was limited by the watering of production wells to 98%, a total of 167.3 thousand tons of oil were produced from one element, including one production well and, correspondingly, the same injection well in each formation (including 103 , 6 thousand tons - from the upper layer 2 and 63.7 thousand tons - from the lower layer 1 due to water injection) over 34 years of development, the oil recovery ratio (CIN) was 0.313. According to the prototype, ceteris paribus, 147.0 thousand tons of oil was produced (including 95.7 thousand tons - from the upper layer 2 and 51.3 thousand tons - from the lower layer 1 due to water injection) for 30 years of development, CIN amounted to 0.275. According to the prototype, the well was flooded to 98% 6 years earlier than by the proposed method. The increase in recovery factor by the proposed method is 0.038.

The proposed method allows to increase the CIN.

The application of the proposed method will solve the problem of increasing the efficiency of oil and water separation in the wellbore, increasing the efficiency of water flooding and, as a result, increasing the oil recovery of the reservoir.

Claims (1)

A method for developing multilayer oil deposits, including lowering a pipe string with a filter below the liquid level in a well into a well of a producing well, selecting products from the upper formation, separating oil and water in the well, pumping water into the lower formation, raising oil to a surface, characterized in that the filter is a pipe in a pipe, the inner pipe has a hydrophilic surface with a degree of hydrophilicity of at least 99%, capillary holes with a diameter of not more than 2 mm and a density of at least 50 holes / m, the outer pipe has a hyd a phobic surface with a degree of hydrophobicity of at least 99%, capillary holes with a diameter of not more than 2 mm and a density of at least 50 holes / m, the diameter of the pipe string on which the filter is lowered is equal to the diameter of the filter’s inner pipe, the inner pipe has a length greater than the outer , the outer pipe is placed no lower than the upper layer, and the inner pipe is not lower than the lower layer, a packer is installed between the casing and the bottom of the outer pipe above the upper layer, which allows liquid from the upper layer to flow directly into the space a packer is installed between the inner and outer pipes of the filter, and between the casing and the bottom of the inner pipe above the lower layer, which does not allow water from the lower layer to enter the space between the inner and outer pipes of the filter, moving from the upper productive layer to the wellbore, liquid enters the space between the inner and outer filter pipes, where it is filtered through the capillary holes of the corresponding filter pipes with hydrophobic and hydrophilic coatings, being separated into oil, which Paradise, falling into the outer pipe and then into the annular space, the pump rises to the surface and water, which, falling into the inner tube, the pump is pumped into the lower reservoir.

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