Device and method for verifying connectivity between injection and production sections of horizontal well in low-permeability reservoir

Abstract

The invention relates to the technical field of separated layer water injection development of oil fields, and discloses a low-permeability reservoir horizontal well injection-production section connectivity verification device and method.The device comprises a first pressure measuring cylinder, a first packer, a second pressure measuring cylinder, an oil sleeve communicating vessel and a second packer which are sequentially connected in series through an oil pipe; the head end of the first pressure measuring cylinder and the tail end of the second packer are respectively connected with an oil pipe, and the tail end of the oil pipe connected with the tail end of the second packer is plugged by a plug. The invention aims to solve the problems that whether fluid channeling exists outside a pipe or not cannot be accurately judged, the test period is long, and the safety and environmental protection risk is higher.

Description

Technical Field

[0001] The invention relates to the technical field of oil field stratified water injection development, and in particular to a device and method for verifying connectivity between injection and production sections of a horizontal well in a low-permeability oil reservoir. Background Art

[0002] Horizontal wells have large contact areas with the formation and long penetration of the reservoir. They have the advantages of large single-well controlled reserves and high oil production rate. In recent years, horizontal well oil production and development technology has become one of the main technologies for the development of low-permeability reservoirs. Quasi-natural energy and directional well water injection well network production are mainly used. However, quasi-natural energy development has reservoir energy attenuation and rapid production decline; directional water injection well network production is shielded by fractures, and the middle water drive is ineffective or flooded, which seriously affects the production and final recovery rate. In order to effectively supplement the formation energy and improve the development effect of horizontal wells, lateral displacement between fractures in the same horizontal well is established. Since 2017, horizontal well formation energy supplement technology tests have been carried out. Taking synchronous well injection and production as an example: water injection at the root and oil production at the toe, the packer is gradually moved from the root to the toe according to the production situation in the later stage to achieve full well section displacement. A total of 9 wells have been tested, and 2,000 tons of oil have been increased. Through tracking, the failure of the test wells was due to pipe channeling, and the flooding period was 7-25 days, which was manifested as inter-section connectivity, accounting for 56% of the number of test wells. Therefore, pipe leakage is a key factor affecting the energy replenishment of horizontal well segmented injection and production, and determines the success or failure of the process.

[0003] Chinese patent CN105134184A discloses a horizontal well continuous channeling inspection process string and method. The patent injects water into the oil pipe and determines whether there is channeling outside the pipe according to the change of wellhead pressure and the return water situation at the wellhead; if water returns to the ground from the inner and outer annuli, it means that there is channeling outside the pipe. However, for horizontal wells with severe formation energy loss, the injected water will not return to the ground in a short period of time due to insufficient formation energy replenishment. Therefore, this patent cannot accurately determine whether there is channeling outside the pipe. Chinese patents CN109577959B and CN108729909A respectively disclose a method for determining the connectivity of fractures in adjacent fracturing sections using tracers and a method for monitoring the effect of staged fracturing of horizontal wells using trace element tracers. Both schemes judge the relationship between the layers by injecting tracers into different layers of the formation and the amount of adsorption. The test cycle is long and the safety and environmental protection risks are greater. Summary of the invention

[0004] In view of the problems existing in the prior art, the present invention provides a device and method for verifying the connectivity between injection and production sections of horizontal wells in low permeability oil reservoirs, which aims to solve the problems of being unable to accurately judge whether there is crossflow outside the pipe, long testing cycle and greater safety and environmental risks.

[0005] In order to solve the above technical problems, the present invention is implemented by the following technical solutions:

[0006] According to a first aspect of the present invention, there is provided a device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir, comprising: a first pressure measuring cylinder, a first packer, a second pressure measuring cylinder, an oil-casing connecting vessel and a second packer which are sequentially connected in series via an oil pipe, the head end of the first pressure measuring cylinder and the end of the second packer being connected to oil pipes respectively, and the end of the oil pipe to which the end of the second packer is connected is sealed with a plug.

[0007] In a possible implementation of the first aspect, the first pressure measuring cylinder and the second pressure measuring cylinder have the same structure and both include a pressure measuring cylinder body, a side wall of the pressure measuring cylinder body is provided with a pressure measuring component accommodating groove, a pressure measuring element is arranged in the pressure measuring component accommodating groove, a groove cover plate is matched with the groove opening of the pressure measuring component accommodating groove, and a through hole connected to the pressure measuring component accommodating groove is provided on the groove cover plate.

[0008] In a possible implementation manner of the first aspect, a power supply element is further disposed in the pressure measuring component accommodating groove, and the power supply element is electrically connected to the pressure measuring element.

[0009] In a possible implementation manner of the first aspect, a plurality of limiting and fixing components are arranged in the pressure measuring component accommodating groove, and the pressure measuring element and the power supply element are limited and fixed by the limiting and fixing components.

[0010] In a possible implementation manner of the first aspect, pressure measuring assembly protection pieces are provided at both ends of the pressure measuring assembly accommodating groove.

[0011] In a possible implementation manner of the first aspect, an external threaded joint is provided at one end of the pressure measuring cylinder body, and an internal threaded joint is provided at the other end.

[0012] In a possible implementation manner of the first aspect, the slot cover plate is detachably connected to the pressure measuring cylinder body.

[0013] In a possible implementation manner of the first aspect, the first packer is a compression cup packer.

[0014] In a possible implementation manner of the first aspect, the second packer is a TDY packer.

[0015] According to a second aspect of the present invention, a method for verifying connectivity between injection and production sections of a horizontal well in a low permeability reservoir is provided, comprising:

[0016] The device for verifying connectivity between injection and production sections of a low permeability oil reservoir horizontal well according to any one of claims 1 to 9 is lowered into a horizontal well of a low permeability oil reservoir to be verified, so that the first packer is located between the first injection and production section and the second injection and production section of which connectivity is to be verified, and the second packer is located between the second injection and production section and the third injection and production section;

[0017] Controlling the first packer and the second packer to be in sealing contact with the well wall at corresponding positions respectively;

[0018] A large-volume water injection is performed from the oil pipe connected to the head end of the first pressure measuring cylinder, and the injected water is discharged from the oil-casing communicating vessel and enters between the first packer and the second packer;

[0019] Using the first pressure measuring tube to monitor the pressure in the well in front of the first packer, and using the second pressure measuring tube to monitor the pressure in the well between the first packer and the second packer;

[0020] When the pressure monitored by the first pressure measuring cylinder is the same as the pressure monitored by the second pressure measuring cylinder within a set error range, there is connectivity between the first injection and production section and the second injection and production section;

[0021] When the pressure monitored by the first pressure measuring cylinder is different from the pressure monitored by the second pressure measuring cylinder within a set error range, there is no connectivity between the first injection and production section and the second injection and production section.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] The present invention provides a device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir. The device adopts a double-seal single card + a pressure measuring cylinder, senses changes in the pressure field inside and outside the oil pipe by pressure excitation on the ground, monitors the pressure values ​​between different sections, and quantitatively determines the connectivity between sections of the horizontal well, thereby realizing efficient, accurate and quantitative verification of horizontal well channeling, ensuring effective isolation of segmented injection and production, and effective injection and production between sections, and completing the verification and production of the horizontal well with one trip of the tubing string, ensuring the normal progress of segmented injection and production development construction in the same well, saving construction costs, and having a simple design, strong process reliability, simple operation and high construction efficiency.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the specific implementation modes of the present invention, the drawings required for use in the description of the specific implementation modes will be briefly introduced below. Obviously, the drawings described below are some implementation modes of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of a device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir according to an embodiment of the present invention is shown in FIG.

[0027] Figure 2 The present invention is a schematic diagram of a pressure measuring cylinder in a device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir according to an embodiment of the present invention.

[0028] In the figure: 1-first pressure measuring cylinder; 10-pressure measuring cylinder body; 100-pressure measuring assembly receiving groove; 101-pressure measuring element; 102-groove cover; 103-through hole; 104-power supply element; 105-limiting fixing component; 106-pressure measuring assembly protection member;

[0029] 2-first packer; 3-second pressure measuring tube; 4-oil casing connecting vessel; 5-second packer; 6-plug. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figure 1 As shown, an embodiment of the present invention is a device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir, comprising a first pressure measuring cylinder 1, a first packer 2, a second pressure measuring cylinder 3, an oil-casing communicating vessel 4 and a second packer 5. The first pressure measuring cylinder 1, the first packer 2, the second pressure measuring cylinder 3, the oil-casing communicating vessel 4 and the second packer 5 are connected in series in sequence through an oil pipe, and oil pipes are respectively connected to the head end of the first pressure measuring cylinder 1 and the end of the second packer 5, and the end of the oil pipe connected to the end of the second packer 5 is blocked by a plug 6.

[0032] When the connectivity verification device for injection and production sections of a low permeability oil reservoir horizontal well of this embodiment is used to verify the connectivity between injection and production sections, the details are as follows:

[0033] a. The connectivity verification device between injection and production sections of a low permeability reservoir horizontal well is lowered into the horizontal well of the low permeability reservoir to be verified, so that the first packer 2 is located between the first injection and production section and the second injection and production section of the connectivity to be verified, and the second packer 5 is located between the second injection and production section and the third injection and production section;

[0034] b. Control the first packer 2 and the second packer 5 to be in sealing contact with the wellbore wall at corresponding positions respectively;

[0035] c. A large amount of water is injected from the oil pipe connected to the head end of the first pressure measuring cylinder 1, and the injected water is discharged from the oil casing communicating vessel 4 and enters between the first packer 2 and the second packer 5;

[0036] d. Using the first pressure measuring tube 1 to monitor the pressure in the well in front of the first packer 2, and using the second pressure measuring tube 3 to monitor the pressure in the well between the first packer 2 and the second packer 5;

[0037] e. When the pressure monitored by the first pressure measuring cylinder 1 and the pressure monitored by the second pressure measuring cylinder 3 are the same within the set error range, there is connectivity between the first injection and production section and the second injection and production section, indicating that leakage will occur between the first injection and production section and the second injection and production section; when the pressure monitored by the first pressure measuring cylinder 1 and the pressure monitored by the second pressure measuring cylinder 3 are different within the set error range, there is no connectivity between the first injection and production section and the second injection and production section, that is, there will be no leakage between the first injection and production section and the second injection and production section. This embodiment can test more than 6 sections in one drilling trip.

[0038] Preferably, since there are many horizontal well sections, multiple connectivity verifications are required. To ensure multiple effective sealing and unsealing effects in the later stage, the first packer 2 uses a compression cup packer and the second packer 5 uses a TDY packer.

[0039] In one embodiment, in combination Figure 2 As shown, the first pressure measuring cylinder 1 and the second pressure measuring cylinder 3 have the same structure, and their specific structures both include a pressure measuring cylinder body 10, a pressure measuring component accommodating groove 100 is opened on the side wall of the pressure measuring cylinder body 10, a pressure measuring element 101 is arranged in the pressure measuring component accommodating groove 100, and a groove cover plate 102 is matched with the groove opening of the pressure measuring component accommodating groove 100, and a through hole 103 connected to the pressure measuring component accommodating groove 100 is opened on the groove cover plate 102.

[0040] Specifically, the working fluid in the well enters the pressure measuring component receiving groove 100 through the through hole 103 opened on the groove cover plate 102, and then the pressure test is performed using the pressure measuring element 101 in the pressure measuring component receiving groove 100.

[0041] Preferably, a plurality of pressure measuring component accommodating grooves 100 are evenly distributed along the circumferential direction on the pressure measuring cylinder body 10, and a pressure measuring element 101 is arranged in each pressure measuring component accommodating groove 100. The groove opening of the pressure measuring component accommodating groove 100 is matched with a groove cover plate 102, and the groove cover plate 102 is provided with a through hole 103 connected to the pressure measuring component accommodating groove 100, so that the pressure in the well can be taken more accurately from the side.

[0042] Preferably, the slot cover 102 is detachably connected to the pressure measuring cylinder body 10, so as to facilitate replacement and inspection of components disposed in the pressure measuring assembly receiving slot 100. In a specific example, the slot cover 102 is connected to the pressure measuring cylinder body 10 by bolts.

[0043] In one embodiment, if Figure 2 As shown, a power supply element 104 is also arranged in the pressure measuring component receiving groove 100, and the power supply element 104 is electrically connected to the pressure measuring element 101, and the power supply element 104 is used to power the pressure measuring element 101 to ensure the sustainability and reliability of the pressure measuring cylinder. For example, the power supply element 104 is a battery.

[0044] Preferably, Figure 2 As shown, a plurality of position-limiting fixing components 105 are arranged in the pressure measuring component receiving groove 100, and the pressure measuring element 101 and the power supply element 104 are position-limited and fixed by the position-limiting fixing components 105. Specifically, the position-limiting fixing components 105 are used to realize the position-limiting fixing of the pressure measuring element 101 and the power supply element 104, thereby ensuring the reliability of the pressure measuring cylinder during the underground working process.

[0045] More preferably, Figure 2 As shown, pressure measuring component protection members 106 are provided at both ends of the pressure measuring component receiving groove 100, and the pressure measuring component protection members 106 are used to protect the components installed in the pressure measuring component receiving groove 100. Specifically, the pressure measuring component protection member 106 is a conical protective cap for shock absorption, which alleviates the pressure fluctuation caused by different pressures entering the pressure measuring component receiving groove 100, resulting in a decrease in the accuracy of monitoring pressure.

[0046] In one embodiment, in combination Figure 1 and Figure 2 As shown, an external thread joint is provided at one end of the pressure measuring cylinder body 10, and an internal thread joint is provided at the other end, that is, the pressure measuring cylinder is connected to the oil pipe by threaded connection. Similarly, the packer and the oil casing connecting vessel are also connected to the oil pipe by threaded connection.

[0047] In one embodiment, the specific working process of the device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir may be:

[0048] On the horizontal well segmented injection and production process oil pipe, the horizontal well injection and production inter-segment connectivity verification device is threadedly connected, and the first pressure measuring tube 1, the first packer 2, the second pressure measuring tube 3, the oil casing connecting tube 4 and the second packer 5 are threadedly connected from top to bottom. After the oil pipe is connected, the pressure is pressed through the wellhead. After a period of stabilization, the pressure values ​​P1 and P2 of the first pressure measuring tube 1 and the second pressure measuring tube 3 are observed. At this time, since the wellbore and the reservoir are connected, the pressure values ​​monitored by the first pressure measuring tube 1 and the second pressure measuring tube 3 are almost equal, that is, P1≈P2. Continue to increase the pressure, pressurize the first packer 2 (seat compression cup packer) and the second packer 5 (TDY packer), and start large-volume water injection. The packer is used to divide the oil layer into two upper and lower layers. At this time, the pressure enters the pressure measuring component receiving groove 100 through the through hole 103, and the pressure measuring element 101 senses the different pressures of the wellbore and the formation to monitor and store the pressure value. Due to the action of the oil-casing connecting tube 4, the lower section of the oil pipe and the reservoir section are in the same pressure field. At this time, the second pressure measuring tube 3 monitors the lower section formation pressure P3. The first pressure measuring tube 1 monitors the pressure value P4 of the oil-casing annulus and the upper section of the oil layer; the connectivity between sections is judged by observing the pressure values ​​of the first pressure measuring tube 1 and the second pressure measuring tube 3. If P3≈P4, it means that there is connectivity between sections, and there is leakage between sections in the staged injection, which affects the process effect; if P3≠P4, it means that there is a pressure difference between the upper and lower oil layers, the packer is well sealed, the sections are not connected, and there is no leakage.

[0049] In the description of the present invention, it is necessary to understand that the terms "upper", "lower", "bottom", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In the present invention, unless otherwise clearly specified and limited, the terms "connected", "connection" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0054] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A device for verifying connectivity between injection and production sections of horizontal wells in low permeability oil reservoirs, characterized in that: include: A first pressure measuring cylinder (1), a first packer (2), a second pressure measuring cylinder (3), an oil-casing connecting vessel (4) and a second packer (5) are connected in series in sequence through an oil pipe, the head end of the first pressure measuring cylinder (1) and the tail end of the second packer (5) are respectively connected to oil pipes, and the tail end of the oil pipe connected to the tail end of the second packer (5) is blocked by a plug (6).

2. A low permeability reservoir horizontal well inter-stage connectivity verification device according to claim 1, characterized in that: The first pressure measuring cylinder (1) and the second pressure measuring cylinder (3) have the same structure, and both comprise a pressure measuring cylinder body (10), a pressure measuring assembly accommodating groove (100) is provided on the side wall of the pressure measuring cylinder body (10), a pressure measuring element (101) is arranged in the pressure measuring assembly accommodating groove (100), a groove cover plate (102) is matched with the groove opening of the pressure measuring assembly accommodating groove (100), and a through hole (103) communicating with the pressure measuring assembly accommodating groove (100) is provided on the groove cover plate (102).

3. A low permeability reservoir horizontal well inter-stage connectivity verification device according to claim 2, characterized in that: A power supply element (104) is also arranged in the pressure measuring component accommodating groove (100), and the power supply element (104) is electrically connected to the pressure measuring element (101).

4. A low permeability reservoir horizontal well inter-stage connectivity verification device according to claim 3, characterized in that: A plurality of position-limiting and fixing components (105) are arranged in the pressure measuring component accommodating groove (100), and the pressure measuring element (101) and the power supply element (104) are position-limited and fixed by the position-limiting and fixing components (105).

5. A low permeability reservoir horizontal well inter-stage connectivity verification device according to claim 4, characterized in that: Pressure measuring component protection pieces (106) are provided at both ends of the pressure measuring component accommodating groove (100).

6. A low permeability reservoir horizontal well inter-stage connectivity verification device according to claim 2, characterized in that: One end of the pressure measuring cylinder body (10) is provided with an external thread joint, and the other end is provided with an internal thread joint.

7. The device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir according to claim 2, characterized in that: The groove cover plate (102) is detachably connected to the pressure measuring cylinder body (10).

8. The device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir according to claim 1, characterized in that: The first packer (2) is a compression type leather cup packer.

9. The device for verifying connectivity between injection and production sections of a horizontal well in a low permeability oil reservoir according to claim 1, characterized in that: The second packer (5) is a TDY packer.

10. A method for verifying connectivity between injection and production sections of horizontal wells in low permeability oil reservoirs, characterized in that: include: The device for verifying connectivity between injection and production sections of a low permeability oil reservoir horizontal well according to any one of claims 1 to 9 is lowered into a horizontal well of a low permeability oil reservoir to be verified, so that the first packer (2) is located between the first injection and production section and the second injection and production section of which connectivity is to be verified, and the second packer (5) is located between the second injection and production section and the third injection and production section; Controlling the first packer (2) and the second packer (5) to be in sealing contact with the well wall at corresponding positions respectively; A large amount of water is injected from the oil pipe connected to the head end of the first pressure measuring cylinder (1), and the injected water is discharged from the oil casing communicating vessel (4) and enters between the first packer (2) and the second packer (5); The first pressure measuring tube (1) is used to monitor the pressure in the well in front of the first packer (2), and the second pressure measuring tube (3) is used to monitor the pressure in the well between the first packer (2) and the second packer (5); When the pressure monitored by the first pressure measuring cylinder (1) and the pressure monitored by the second pressure measuring cylinder (3) are the same within a set error range, there is connectivity between the first injection and production section and the second injection and production section; When the pressure monitored by the first pressure measuring cylinder (1) and the pressure monitored by the second pressure measuring cylinder (3) are different within a set error range, there is no connectivity between the first injection and production section and the second injection and production section.

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