METHOD FOR INTERVAL ACTION ON HORIZONTAL WELLS

Abstract

The present invention relates to the oil-and-gas industry, specifically, to the development and exploitation of oil reservoirs with various permeability zones, including by means of lateral horizontal bore segments. The method of interval action on horizontal wells includes the steps at which a horizontal segment of the wet is bored preliminarily, the same segment being constructed through the formation with various permeability zones. Geophysical survey is conducted and the number of the oil recovery intervals of various categories and their lengths are determined. A tail pipe (or tail filter) of the casing string with packers and drive shoe is lowered down and installed in the horizontal segment of the well. A pump and an assembly on the pipe string is lowered down into the well, the same assembly consisting of the electric valves with the pressure and temperature sensing devices, the cable and the packers separating the annular space of the well. The assembly packers are arranged opposite to the casing string packers. While lowering down the assembly, some electric valves are opened, and another electric valve (intended for circulation) is closed. The data obtained from the sensing devices are monitored. The formation segments are periodically treated by injecting a chemical composition into the corresponding interval of the well horizontal segment.

Claims

1. Method of interval action on horizontal wells that includes the following steps: a horizontal segment (8) of the well (9) is bored preliminarily, the same segment being constructed through the formation (12) with various permeability zones; geophysical survey is conducted and the number of the oil recovery intervals of various categories and their lengths are determined; a tail pipe or a tail filter (13) of the casing string (14) with the packers (15), (7) and the drive shoe (39) arranged on the string in accordance with the sizes of the said oil recovery intervals is lowered down into the horizontal segment (8) and installed there; an assembly on the pipe string (1) is lowered down into the horizontal segment (8) and installed inside the tail pipe (13), the same assembly consisting of the electric valves (3), (4), (18) with the pressure and temperature sensing devices (5), (6), (41), cable (2) and packers (16), while arranging packers (16) so that they would be located opposite to the corresponding packers (7) and (15) hermetically separating the annular space (17); a centrifugal pump (10) in the casing (19) rigidly connected with the pipe string (1) is arranged inside the production string (14); while lowering the assembly down into the well (9), the electric valves (3), (4) are opened for better filling of the tube side (11) of the pipe string (1) with the product of the well (9), and the circulation electric valve (18) is closed; the data obtained from the sensing devices are monitored; the formation (12) segments are periodically treated by injecting a chemical composition into the corresponding interval of the well (9) horizontal segment (8).

2. Method according to claim 1, characterized in that during the equipment lowering the tube side (11) of the pipe string (1) is filled with the production fluid of the well (9), and the electric valves (3), (4), (18) and (38) are opened when the well (9) is operated with the sucker-rod pump (32)

3. Method according to claim 1, characterized in that the electric valve (38) is closed before the production fluid of the well (9) is extracted with the help of the sucker-rod pump (32).

4. Method according to claim 1, characterized in that to monitor the data obtained from the sensing devices, the electric valves (3) and (4) are closed or opened.

5. Method according to claim 1, characterized in that to inject the chemical composition for the formation (12) treatment into the corresponding interval of the well (9) horizontal segment (8), the following steps are performed: the electric valves (3) and (4) are closed and the circulation electric valve (18) is opened; then the production fluid is pushed out from the tube side (11) to the surface through the annular space (43) of the casing string (14) by injecting the calculated volume of the chemical composition into the tube side (11) of the string (1) up to the circulation valve (18); the communication with the annular space (43) is shut off by the circulation valve (18), and the corresponding electric valve (3) or (4) is opened for performing the treatment of the necessary formation (12) interval; the necessary volume of the chemical composition is forced into the formation (12), and the electric valve (3) or (4) is closed for the technological exposure period; after the technological exposure, the corresponding electric valve (3) or (4) is opened, the pump is started, and the production fluid located in the tube side (11) is pumped out from the electric valve to the casing (19); the corresponding electric valve (3) or (4) is closed, the valve (18) is opened, and the reaction products are washed out from the tube side (11) to the surface; this operation is repeated until the formation (12) production fluid appears at the surface, then the extraction of the well 9 production fluid is continued in normal mode.

6. Method according to claim 1, characterized in that to provide for the interval treatment of the formation (12), for the wells operated with the help of the sucker-rod pump (32), the production fluid is pushed out to the surface through the annular space (43) by injecting the calculated volume of the chemical composition into the tube side (11) of the pipe string (1) through the lateral channels (37) of the adapter (33) and the opened electric valve (38), wherein the circulation electric valve (18) is opened beforehand, and the electric valves (3) and (4) are closed.

7. Method according to claim 1, characterized in that after the pushing out of the production fluid from the tube side (11), the communication with the annular space (43) is shut off by the circulation electric valve (18), and the corresponding electric valve (3) or (4) is opened for performing the treatment of the corresponding formation (12) interval: the necessary volume of the chemical composition is forced into the formation (12), and the electric valve (3) and (4) is closed for the technological exposure period; after the technological exposure, the electric valve (38) is closed, the electric valve (3) or (4) and the circulation valve (18) are opened, the sucker-rod pump (32) is started, and the production fluid located in the annular space (43) is pumped out up to the casing (19) of the pump (32); then the pump is stopped, the electric valve (3) or (4) is closed and the electric valve (38) is opened; the reaction products are evacuated to the surface by injecting the production fluid into the tube side (11) of the pipe string (1) through the circulation valve (18) and through the annular space (43); the operation is repeated until the formation (12) production fluid appears at the surface; then the extraction of the formation (12) production fluid is continued through the well (9) in normal mode.

8. Device for the interval action on horizontal wells operated by the downhole pumping equipment, comprising: a pipe string (1) with a cable (2), two or more electric valves (3) and (4) equipped with sensing devices, at least one packer separating the inner space of the horizontal segment (8) of the well (9) into two or more intervals, a centrifugal pump (10) arranged at a calculated distance from the well mouth; wherein the said electric valves (3), (4) and the sensing devices (5), (6) are connected through the cable (2) with the interface unit at the well mouth characterized in that the pipe string (1) above the electric valves (3) and (4) is equipped with the circulation electric valve (18) intended for connecting the tube side (11) of the pipe string (1) with the annular space (43) of the well (9) during the pipe string (1) flushing.

9. Device according to claim 8, characterized in that one or more of the said sensing devices is a pressure sensor.

10. Device according to claim 8, characterized in that one or more of the said sensing devices is a temperature sensor.

11. Device according to claim 8, characterized in that it additionally comprises a tail pipe or a tail filter (13) hermetically connected with the casing string (14), and the device is additionally equipped with packers (16) separating the annular space (17) into the corresponding permeable sections.

12. Device according to claim 8, characterized in that the pump is additionally enclosed in a protective casing (19).

13. Device according to claim 8, characterized in that each electric valve (3), (4) and (18) is made in the form of an electric motor (21) with a gear box (22) arranged in a case (20), wherein the electric motor rotates the shaft (23) connected through the spindle (24) with the valve (25) configured to tightly interact with the seats (27), wherein the inlet (28) and outlet (29) openings are arranged above the seats (27).

14. Device according to claim 13, characterized in that the valve (25) is made in the form of a ball (30) with a cylindrical through-hole (31) made across the case (20), wherein in the «open» position the opening (31) of the ball (30) connects the inlet opening (28) with the outlet opening (29) allowing the production fluid to get into the tube side (11) of the pipe string (1), and in the «closed» position it shuts off its entry into the tube side (11) of the pipe string (1).

15. Device according to claim 12, characterized in that the external casing (19) comprises the adapter (33) having radial channels (34) connecting the well (9) annulus with the central axial channel (35) and the sucker-rod pump (32), wherein the central channel (35) is closed with the blank plug (36) from below.

16. Device according to claim 15, characterized in that lateral channels (37) are made in the adapter (33) coaxially with the central channel (35).

17. Device according to claim 8, characterized in that the pipe string (1) is additionally equipped with the electric valve (38) for closing the tube side (11) of the pipe string (1) below the casing (19) when extracting the production fluid, and for its opening when injecting the active agent into the well (9) horizontal segment (8) during the bottomhole formation zone treatment.

18. Device according to claim 8, characterized in that the pump, the electric cables, the valves and the packers are made corrosion resistant.

19. Device according to claim 8, characterized in that the packers (15) and (7) are arranged so that they would isolate the recovery intervals with various permeability between themselves along the length of the horizontal segment (8), and the tail pipe (13) has perforation openings (40) or is equipped with a well strainer in each of the intervals.

20. Device according to claim 8, characterized in that the cable (2) in the horizontal well bore is arranged inside the tubing joint.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0030] FIG. 1 shows the device with centrifugal pump—general view;

[0031] FIG. 2 shows the device with centrifugal pump with the sucker-rod pump;

[0032] FIG. 3 shows cross-section A-A of FIG. 2;

[0033] FIG. 4 shows an electric valve—general view;

[0034] FIG. 5 shows cross-section A-A of FIG. 4 (magnified);

[0035] FIG. 6 shows cross-section 6-6 of FIG. 4 (magnified);

[0036] FIG. 7 shows cross-section B-B of FIG. 4 (magnified).

[0037] Numbers in the drawings indicate the following items:

[0038] 1—pipe string; 2—cable; 3—electric valve; 4—electric valve; 5—sensing device; 6—sensing device; 7—packer; 8—inner space of the horizontal segment of the well; 9—well; 10—electric submersible pump; 11—tube side; 12—formation; 13—tail pipe or tail filter; 14—casing string; 15—packer; 16—additional packer; 17—annular space; 18—circulation electric valve; 19—external casing; 20—case; 21—electric motor; 22—gear box; 23—rotation shaft; 24—spindle; 25—valve; 26—sealing ring; 27—seat; 28—inlet opening; 29—output opening; 30—ball; 31—cylindrical through-hole; 32—sucker-rod pump; 33—adapter; 34—radial channels; 35—central axial channel; 36—blank plug; 37—lateral channels; 38—electric valve; 39—drive shoe; 40—perforation openings; 41—sensing device; 42—longitudinal channel; 43—annular space.

DISCLOSURE OF THE INVENTION

[0039] Device for the interval action on horizontal wells operated by the downhole pumping equipment (FIG. 1); comprises a pipe string (1) with a cable (2), two or more electric valves (3 and 4) with the pressure (and temperature) sensing devices (5, 6), a packer (or packers) (7) separating the inner space of the horizontal segment (8) of the well (9) into two or more intervals.

[0040] The electric valves (3, 4) and sensing devices (5, 6) are connected through the cable (2) with the interface unit at the well mouth. An electric submersible pump (10) is arranged at a calculated distance from the well mouth, for the production fluid recovery through the tube side (11).

[0041] The horizontal segment (8) of the well (9) is constructed through the formation (12) with various impermeability zones, separating the formation (12) with the help of packers (7) into the intervals (low permeability and medium- or high permeability) based on the geophysical survey results.

[0042] If a tail pipe or a tail filter (13) of the casing string (14) is used, that is lowered down to the measured depth and is hermetically (e.g., with the help of the packer (15)) connected with the casing string (14), packers (16) are additionally installed that separate the annular space (17) into the corresponding permeable sections.

[0043] The novelty consists in the fact that the pipe string (1) is equipped with the circulation electric valve (18) located above the electric valves (3) and (4), which is intended for connecting the tube side (11) of the pipe string (1) with the space of the well (9) during the pipe string (1) flushing, e.g., of the remnants of the chemical composition that has been injected into the horizontal segment (8) during the bottomhole formation zone treatment.

[0044] The centrifugal pump (10) is enclosed in the casing (19) to exclude the action of the chemicals and of the high pressure on the production string walls (14) during the chemical composition injection into the horizontal segment (8) of the well (9).

[0045] That said, each electric valve (3), (4) and (18) is made in the form of an electric motor (21) with a gear box (22) arranged in the case (20) (FIG. 4), the rotatory shaft (23) of the said electric motor and gear box being connected through the spindle (24) with the valve (25) configured to tightly interact (e.g., thanks to the sealing rings (26) (FIG. 6)) with the seats (27). The inlet (28) (FIG. 4) and outlet (29) openings are arranged above the seats (27).

[0046] The novelty consists in the fact that the valve (25) is made in the form of a ball (30) with a cylindrical through-hole (31) made across the case (20). Wherein in the «open» position the opening (31) of the ball (30) connects the inlet opening (28) with the outlet opening (29) allowing the production fluid to get into the tube side (11) (FIG. 1) of the pipe string (1), and in the «closed» position (when the ball (30) (FIG. 4) is turned 90 degrees) it shuts off its entry into the tube side (11) (FIG. 1) of the pipe string (1).

[0047] If the sucker-rod pump is used (FIG. 2), the production fluid is extracted from the horizontal segment (8) of the well (9) through the opened electric valves (3), (4) and the opened circulation electric valve (18) from whence it comes into the well bore of the well (9) and to the sucker-rod pump (32).

[0048] The novelty consists in the fact that the external casing (19) comprises the adapter (33) having radial channels (34) (FIG. 2, 3) connecting the space of the well (9) (FIG. 2) with the central axial channel (35) and the sucker-rod pump (32), wherein the central channel (35) is closed with the blank plug (36) from below. To inject the chemical composition into the horizontal segment (8) of the well (9), the adapter (33) features lateral channels (37) (FIG. 2, 3) that are coaxial with the central channel (35).

[0049] Besides, the pipe string (1) is additionally provided with an electric valve (38) for closing the tube side (11) of the pipe string (1) below the casing (19) when extracting the production fluid, and for its opening when injecting the chemical composition into the horizontal segment (8) of the well (9) during the bottomhole formation zone treatment.

[0050] The method is effected as follows.

[0051] In the formation (12) (FIG. 1), a horizontal segment (8) of the well (9) is bored preliminarily. After conducting the geophysical survey and determining the number and lengths of the oil recovery intervals (low permeability, medium- or high permeability), a tail pipe (or tail filter) (13) of the casing string (14) with packers (15), (7) and drive shoe (39) is lowered down into the horizontal segment (8) and installed there (FIG. 1).

[0052] In the process, the packers (15) and (7) are arranged so that they would isolate the recovery intervals with various permeability along the length of the horizontal segment (8) (FIG. 1 shows two intervals), and the tail pipe (13) is perforated with openings (40) (or provided with well strainers) located opposite each of the intervals.

[0053] Then an assembly on the pipe string (1) is lowered down into the horizontal segment (8) and installed inside the tail pipe (13), the same assembly consisting of the electric valves (3), (4) with the pressure and temperature sensing devices (5), (6) (FIG. 1), cables (2) and packers (16) (FIG. 1), while arranging the packers (16) so that they would be located opposite to the corresponding packers (7) and (15) hermetically separating the annular space (17). A circulation electric valve (18) is installed into the pipe string (1) above the tail pipe (13) packer (15), and a centrifugal pump (10) in the casing (19) rigidly connected with the pipe string (1) is arranged inside the vertical well bore of the well (9).

[0054] In so doing, the electric valves (3), (4) are opened for better filling of the tube side (11) of the pipe string (1) with the well (9) production fluid, and the circulation electric valve (18) is closed.

[0055] The production fluid is recovered from the horizontal segment (8) using the centrifugal pump (10) through the tube side (11) of the pipe string (1).

[0056] Based on the information transferred from the sensing devices (5), (6) through the cable (2) to the well (9) mouth, the pressure and corresponding temperature values are determined in each of the segments.

[0057] When the well (9) is operated with the sucker-rod pump (32) (FIG. 2), the filling of the tube side (11) of the pipe string (1) with the production fluid of the well (9) while lowering down the equipment is performed with the electric valves (3), (4), (18) and (38) opened. Before extracting the production fluid of the well (9) with the help of the sucker-rod pump (32), the electric valve (38) is closed.

[0058] The data obtained from the sensing devices (5), (6), (41) are monitored continuously. When necessary, the electric valves (3) and (4) are closed (or opened). For this end, a signal is sent through the cable (2) from the well (9) mouth to the corresponding electric valve (3) or (4). In doing so, the electric motor (21) (FIG. 4) located in the case (20) of the electric valve (3) or (4) starts rotating the shaft (23) with the spindle (24) through the gear box (22), turning the ball (30) with the cylindrical through-hole (31) so as to connect (disconnect) the inlet opening (28) with the outlet opening (29), i.e., to «open» (or «close») the electric valve (3) or (4). The design of the circulation electric valve (18) is similar to the design of the electric valves (3) or (4).

[0059] In the process, the production fluid from the corresponding interval of the horizontal segment (8) (FIG. 1) comes through the longitudinal channel (42) (FIG. 4) made in the case (20) of the electric valve (3) or (4) and is drawn up through the tube side (11) (FIG. 1) into the casing (19) and to the inlet of the centrifugal pump (10) with the circulation electric valve (18) closed.

[0060] When it is necessary to inject the chemical composition for the formation (12) treatment into the corresponding horizontal segment (8) interval of the well (9), the electric valves (3) and (4) are closed and the circulation electric valve (18) is opened, after which the production fluid is pushed out from the tube side (11) to the surface through the annular space (43) of the casing string (14) by injecting the calculated volume of the chemical composition into the tube side (11) of the string (1) up to the circulation valve (18).

[0061] That said, the centrifugal pump, the electric cables, the electric valves and the packers should be made corrosion resistant.

[0062] Then the communication with the annular space (43) is shut off in the circulation valve (18), and the corresponding electric valve (3) or (4) is opened for performing the treatment of the necessary formation (12) interval. For this end, the necessary volume of the chemical composition is forced into the formation (12), and the electric valve (3) or (4) is closed for the technological exposure period.

[0063] After the technological exposure, the corresponding electric valve (3) or (4) is opened, the centrifugal pump (10) is started, and the production fluid located in the tube side (11) is pumped out. During the pumping out of the production fluid, the reaction products fill the tube side (11) up to the casing (19). The pump is stopped, the electric valve (3) or (4) is closed, the electric valve (18) is opened, and the reaction products are evacuated to the surface through the annular space (43). This operation is repeated until the production fluid appears at the surface.

[0064] Then the extraction of the production fluid is continued in normal mode.

[0065] The formation (12) interval treatment technology for the wells operated with the help of the sucker-rod pump (32) (FIG. 2) provides for the pushing out of the production fluid from the annular space (43) by injecting the calculated volume of the chemical composition into the tube side (11) of the pipe string (1) through the lateral channels (37) of the adapter (33) and opened electric valve (38). In the process, the circulation electric valve (18) is opened and the electric valves (3) and (4) are closed beforehand.

[0066] Then, after the pushing out of the production fluid from the tube side (11), the communication with the annular space (43) in the circulation electric valve (18) is shut off and the corresponding electric valve (3) or (4) is opened for performing the treatment of the corresponding formation (12) interval. For this end, the necessary volume of the chemical composition is forced into the formation (12), and the electric valve (3) or (4) is closed for the technological exposure period.

[0067] After the technological exposure, the electric valve (38) is closed, the electric valve (3) or (4) and the circulation valve (18) are opened, the sucker-rod pump (32) is started, and the production fluid located in the annular space (43) is pumped out. During the pumping out of the production fluid, the reaction products fill the annular space (43) up to the lower part of the sucker-rod pump (32). The pump is stopped, the electric valve (3) or (4) is closed and the electric valve (38) is opened. By injecting the production fluid into the tube side of the pipe string (1) (e.g., using the TsA-320 unit) through the circulation valve (18) and the annular space (43), the reaction products are evacuated to the surface. This operation is repeated until the production fluid appears at the surface.

[0068] Then the extraction of the production fluid is continued in normal mode.

[0069] Thus, the use of the invention allows expanding technological capabilities when extracting products from the wells with horizontal segments cased with the tail pipes through placing the pipe string with the electric valves in the tail pipe, wherein the electric valves, thanks to the packers, are hermetically arranged opposite to the various permeability intervals, with the possibility of shutting off the watered out intervals without stopping the oil extraction; wherein additional independent channels are used for the interval treatment of the formations with the chemical composition (without raising the downhole pumping equipment or the involvement of the well production maintenance' and well workover crews), the same channels excluding the action of the chemical reagents and of the high pressure on the production string walls and allowing changing the downhole pumping equipment without withdrawing the device to the surface; and, additionally, thanks to using the electric valves with the swinging type shutting-off device, their reliability is improved.

EXAMPLE

[0070] The formation (12) interval treatment technology for the wells operated with the help of the sucker-rod pump mode (32) (FIG. 2) provides for the pushing out of the production fluid from the annular space (43) by injecting a chemical composition, e.g., 10-16% hydrochloric acid water solution in the amount of 0.6-1 m3 per 1 m of the exposed formation thickness into the tube side (11) of the pipe string (1) through the lateral channels (37) of the adapter (33) and the opened electric valve (38). In the process, the circulation electric valve (18) is opened and the electric valves (3) and (4) are closed beforehand.

[0071] Then, after the pushing out of the production fluid from the tube side (11), the communication with the annular space (43) in the circulation electric valve (18) is shut off and the corresponding electric valve (3) or (4) is opened for performing the treatment of the corresponding formation (12) interval. For this end, the necessary volume of the chemical composition is forced into the formation (12), and the electric valve (3) or (4) is closed. The chemical composition exposure time is 2 h. After the technological exposure, the electric valve (38) is closed, the electric valve (3) or (4) and the circulation valve (18) are opened, the sucker-rod pump (32) is started and the production fluid located in the annular space (43) is pumped out. During the pumping out of the production fluid, the reaction products fill the annular space (43) up to the lower part of the sucker-rod pump (32). The pump is stopped, the electric valve (3) or (4) is closed and the electric valve (38) is opened. By injecting the production fluid into the tube side of the pipe string (1) (e.g., using the TsA-320 unit) through the circulation valve (18) and the annular space (43), the reaction products are evacuated to the surface. This operation is repeated until the production fluid appears at the surface.