A device and method for interference testing simulation of thick fault-controlled karst connected fracture-cave reservoirs

Abstract

The present invention discloses a device and method for simulating interference testing of a huge thick fault-controlled karst connected fracture-cave oil reservoir. The device comprises a simulated huge thick connected fracture-cave reservoir manufactured by 3D printing, wherein the simulated huge thick connected fracture-cave reservoir manufactured by 3D printing is provided with a fracture-cave space, a first slit interface connected to one side of the fracture-cave space, and a second slit interface connected to the other side of the fracture-cave space; a box body, inside of which is provided a cavity for placing the simulated huge thick connected fracture-cave reservoir manufactured by 3D printing; two wellbores are respectively arranged in the box body and located on both sides of the simulated huge thick connected fracture-cave reservoir manufactured by 3D printing; the present invention performs an inter-well interference test on the simulated fracture-cave reservoir manufactured by 3D printing through the above device, thereby obtaining reservoir physical property parameters and fracture-cave space structure of the fault-controlled karst connected fracture-cave oil reservoir.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field development experiments, and in particular to an interference test simulation device and method for a huge and thick fault-controlled karst connected fracture-cave reservoir. Background Art

[0002] Fault-controlled karst interconnected fractures and caves are a type of reservoir landform with complex spatial structure and strong heterogeneity. After carbonate rocks are subjected to multiple stages of tectonic compression, brittle limestone fracture zones are formed along deep fault zones. When karst fluids infiltrate along the fault zones or local hydrothermal fluids upwell, dissolution occurs in the fracture zones to form interconnected fracture-cavern systems, which are then formed under the sealing of overlying caprocks such as marl and mudstone and the shielding of lateral dense limestone. The oil reservoirs in the Tarim Basin in northwest my country are typical fault-controlled karst interconnected carbonate reservoirs, with large strike-slip faults as the core. The overall vertical depth is much greater than the reservoir plane width, and they have obvious ultra-deep, extremely thick, and plate-like morphological characteristics.

[0003] In order to obtain the reservoir physical parameters and fracture-cavity spatial structure of fault-controlled karst connected reservoirs, well testing methods are often used on site. However, since the bottom of the test well is directly connected to the reservoir fractures and caves, the single well test data often show large disturbances, poor quality, and data distortion. As an improved well testing method, the interference well testing method has gradually played an irreplaceable advantage in the testing of fault-controlled karst connected reservoirs. Interference well testing refers to the production / pressure interference between two or more wells, which causes the reservoir pressure to be excited through the working system of the exciting well, and a high-precision pressure gauge is placed in one or several observation wells to observe the excitement signal of the bottom hole pressure. Whether the observation well can observe the pressure change can be used to judge whether they are connected to each other, and further analyze the quality of the reservoir connectivity between wells and the differences in reservoir physical properties between wells. However, the on-site interference well testing not only takes a long time to test, but also can only perform interference tests on the specific type of reservoir in the mine, which cannot meet the efficient production needs of the mine.

[0004] At present, the experimental equipment and interference test method technology of laboratory physical simulation of complex reservoir interference test are becoming more and more mature. However, in recent years, the new special carbonate oil and gas reservoirs newly discovered in exploration - the thick fault-controlled karst oil and gas connected reservoirs, have not yet developed interference well test simulation experimental equipment and methods for them. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to propose a simulation device and method for interference testing of a thick, fault-controlled, karst, connected fracture-cavern oil reservoir. The simulated thick, connected fracture-cavern reservoir is manufactured by 3D printing. According to the system method provided by the present invention, the inter-well interference test is performed on the simulated fracture-cavern reservoir manufactured by 3D printing, so as to obtain the reservoir physical property parameters and fracture-cavern spatial structure of the fault-controlled, karst, connected fracture-cavern oil reservoir. The present invention can meet the efficient production needs of the mine, can cope with complex fault-controlled, karst, connected reservoirs, and is simple, convenient, efficient, and highly repeatable.

[0006] Technical solution: To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A simulation device for interference testing of extremely thick fault-controlled karst connected fracture-cave reservoirs, comprising:

[0008] A simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing, wherein the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing is provided with a fracture-cave space, a first slit interface connected to one side of the fracture-cave space, and a second slit interface connected to the other side of the fracture-cave space;

[0009] A box body, inside of which is provided a cavity for placing the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing;

[0010] A first wellbore is arranged in the box body and adjacent to the first slit interface, an end of the first wellbore is provided with an inlet connected to a fluid supply device, and a first valve is provided on the wall of the first wellbore at a position corresponding to the first slit interface;

[0011] A second wellbore is arranged in the box body and adjacent to the second slit interface. The end of the second wellbore is provided with a discharge port for discharging fluid. A second valve is provided on the wall of the second wellbore at a position corresponding to the second slit interface.

[0012] The external fluid enters the first wellbore through the first inlet on the first wellbore, the first valve at the first slit interface on the first wellbore and the second valve at the second slit interface on the second wellbore corresponding to the first slit interface are opened, and the fluid enters the first wellbore and is discharged in sequence through the first valve, the first slit interface, the slit hole space, the second slit interface, the second valve and the discharge port of the second wellbore;

[0013] A first flow meter, a first flow control valve and a first pressure gauge are provided at the entrance of the upper end of the first wellbore;

[0014] A second flow meter, a second flow control valve and a second pressure gauge are provided at the upper discharge port of the second wellbore;

[0015] A first bottom hole temperature and pressure storage device is provided at the bottom end of the first wellbore;

[0016] A second bottom hole temperature and pressure storage device is provided at the bottom end of the second wellbore.

[0017] After the first wellbore is inserted into the box, a contact seal is formed between the inner wall of the box, the first wellbore and the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing;

[0018] After the second wellbore is inserted into the box, a contact seal is formed between the inner wall of the box, the second wellbore and the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing.

[0019] A first arc-shaped groove is provided on the side of the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing where the first slot interface is opened, and the curvature of the first arc-shaped groove is adapted to the curvature of the wall of the first wellbore;

[0020] A second arc-shaped groove is provided on the side of the simulated huge-thick interconnected fracture-cavity reservoir manufactured by 3D printing where the second slit interface is opened, and the curvature of the second arc-shaped groove is matched with the curvature of the wall of the second wellbore.

[0021] The first slit interfaces on the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing include multiple ones, and a first valve is provided on the first wellbore corresponding to each of the first slit interfaces; the second slit interfaces on the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing include multiple ones, and a second valve is provided on the second wellbore corresponding to each of the second slit interfaces.

[0022] The first wellbore comprises a wellbore body made of non-conductive material, a wall of one side of the wellbore body is provided with a plurality of openings along the wellbore height direction, each opening is provided with a corresponding first valve, and each first valve has the same structure and comprises:

[0023] A tile-shaped iron core is attached to the outer wall of the shaft; an energized coil is wound around the tile-shaped iron core;

[0024] A spring, made of a non-conductive material, is disposed in the shaft body, the axis of the spring is perpendicular to the shaft axis of the shaft, one end of the spring is fixedly connected to the inner wall of the shaft adjacent to the tile-shaped iron core, and the other end of the spring is connected to an inner sealing ring capable of opening or closing the opening, the inner sealing ring being made of a material that can be attracted by a magnet;

[0025] The second wellbore has the same structure as the first wellbore.

[0026] The box body includes a box body with an upper opening and a sealing cover capable of sealing the upper opening of the box body. The simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing is placed into the cavity inside the box body through the upper opening. The upper end of the wellbore is provided with an external thread section, and the upper end of the sealing cover is provided with an internal thread section that threadably cooperates with the external thread section at the upper end of the wellbore.

[0027] The wellbore material is any one of copper, aluminum and tin; the spring material is consistent with the wellbore material.

[0028] The inner sealing ring is made of any one of iron, cobalt and nickel.

[0029] The present invention further discloses a testing method based on the interference testing simulation device for the huge-thick fault-controlled karst connected fracture-cave reservoir.

[0030] S1, first open the first flow control valve, so that the fluid is injected from the first flow control valve;

[0031] S2. Secondly, according to the simulation scheme, the first valve at the first slotted interface on the first wellbore and the second valve at the corresponding second slotted interface on the second wellbore are opened, so that the injected fluid enters the fracture-cavity space of the reservoir from the first slotted interface on the first wellbore and the first slotted interface on the 3D-printed reservoir, and finally flows out from the second wellbore to form an injection-production channel;

[0032] S3, in the process of simulating stable production, by adjusting the first flow control valve on the first wellbore and the second flow control valve on the second wellbore to simulate the interference process caused by the opening and closing of adjacent wellbores; by changing the opening and blocking state of the first valve on the first wellbore and the opening and blocking state of the second valve on the second wellbore during the production process, to simulate the interference production process under different connectivity degrees;

[0033] S4. When the second pressure gauge reading and the second flow meter reading on the second wellbore are stable, the bottom hole temperature and pressure storage data of the second wellbore are output for analyzing the bottom hole temperature and pressure change characteristics under the well opening, well closing and well inter-well connectivity test.

[0034] In step S4, in the first case, when both wells are to be shut in, the pressure and temperature values ​​of the two well bottoms are read respectively through the first well bottom temperature and pressure storage device and the second well bottom temperature and pressure storage device;

[0035] In the second case, when the two wells are injection wells and test wells, that is, the first well is an injection well and the second well is a test well, the bottom hole pressure and temperature values ​​fed back by the second bottom hole temperature and pressure storage are read;

[0036] When the first well is a test well and the second well is an injection well, the bottom hole pressure and temperature values ​​fed back by the first bottom hole temperature and pressure storage are read.

[0037] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0038] (1) The present invention can manufacture complex interconnected fracture-cave reservoirs through 3D printing technology, without the need for real rock samples of fault-controlled karst fracture-cave reservoirs, thus solving the problem that it is impossible to completely core the fault-controlled karst interconnected fracture-cave reservoirs.

[0039] (2) The present invention is provided with a sealing top cover, a wellbore slit and a switch for controlling the wellbore slit. By covering the sealing top cover, the entire device is in a closed state, the injection and production system is connected, and the switch for controlling the wellbore slit is turned on, the interference test process under the connection of different layers can be simulated, and the operation is simple, safe and convenient.

[0040] (3) The present invention is provided with a wellhead pressure gauge, a flow meter and a temperature and pressure storage device, and records the unstable interference pressure and temperature data through the bottom hole temperature and pressure storage device. By directly reading the wellhead pressure gauge and the flow meter to detect whether the interference is stable, the result is intuitive and reliable, and the data can be monitored in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a schematic diagram of the appearance of the testing device of the present invention;

[0042] Figure 2 It is a longitudinal cross-sectional view of the testing device of the present invention;

[0043] Figure 3 It is a transverse cross-sectional view of the testing device of the present invention;

[0044] Figure 4 A wellbore structure of the testing device of the present invention;

[0045] Figure 5 This is a structural diagram of the first valve of the present invention;

[0046] Figure 6 This is a schematic diagram of the 3D printed thick interconnected fracture-cavern reservoir in the present invention.

[0047] Among them, A1 is a box body, A2 is a valve control switch, A3 is a sealing cover, A4 is an internal thread section, A5 is a first flow control valve, A6 is a second pressure gauge, and A7 is a second flow meter;

[0048] B1 is the cavity, B2 is the first shaft, B3 is the opening, B4 is the inner sealing ring, B5 is the spring, B6 is the energized coil, B7 is the tile-shaped iron core, B8 is the temperature and pressure storage, and B9 is the shaft external thread;

[0049] C1 is the first arc-shaped groove, C2 is the first slit interface, C3 is the slit hole space, and C4 is the non-porous space. DETAILED DESCRIPTION

[0050] The present invention is further described below in conjunction with the accompanying drawings:

[0051] The invention discloses an interference test simulation device and method for a huge thick fault-controlled karst connected fracture-cave oil reservoir.

[0052] like Figure 1 , Figure 2 and Figure 6 , use a 3D printer to print a thick fault-controlled karst connected fracture-cave reservoir, and then put the fracture-cave reservoir vertically into the test device. The fracture-cave space C3 is connected to the first slot interface C2; ​​then the thick fault-controlled karst connected fracture-cave reservoir is placed in the cavity B1 of the box A1, so that the first wellbore B2 passes through the first arc-shaped groove C1, wherein the fracture-cave space C3 is a fluid flow channel, and the non-porous space C4 has no connectivity, which has the effect of closing the fluid.

[0053] Put on the sealing cover A3, and seal the wellbore external thread B9 at the upper end of the first wellbore B2 with the internal thread section at the upper end of the sealing cover A3, so that the entire simulation device is in a sealed state, and the injection and production system is connected. According to the production and interference test simulation plan, connect the external fluid equipment, among which the first flow control valve A5 is used as a component for fluid injection and can simulate well opening / closing. The second pressure gauge A6 is used to display the change of wellhead pressure, and the second flow meter A7 is used to display the change of wellhead flow after stabilization.

[0054] like Figure 2 , Figure 4 and Figure 5 , the opening and closing of the opening B3 is controlled by the valve control switch A2 on the box A1, simulating the interference test process under the connection of different layers. In the initial state, the spring B5 presses the inner sealing ring B4 against the inner side of the opening B3, so that the wellbore slit is in a blocked state. The opening state of the slit is controlled by the valve control switch A2 on the side of the box A1: when the valve control switch A2 is turned on, the energized coil B6 is energized, and the tile-shaped iron core B7 is magnetized. Under the electromagnetic attraction, the inner sealing ring B4 is attracted, and then the spring B5 is compressed, so that the opening B3 is in an open state.

[0055] Taking the injection of the left well and the production of the right well as an example, the production process is simulated. First, the first flow control valve A5 is opened to allow the fluid to be injected from the first flow control valve A5. Then, according to the simulation scheme, the valve control switch A2 corresponding to the left and right wellbores is opened to allow the injected fluid to enter the cavity B1 from the first wellbores B2, and enter the fracture space C3 of the reservoir through the opening B3 and the first slit interface C2 of the 3D-printed reservoir, and finally flow out from the second wellbores to form an injection and production channel.

[0056] Take the injection of the left well and the production of the right well as an example to simulate the interference test process. In the simulated stable production process, the interference process caused by the opening and closing of the adjacent wells is simulated by adjusting the flow control valve A5 of the first wellbore and the second wellbore. By changing the opening and blocking state of the openings B3 of the first wellbore and the second wellbore during the production process, the interference production process under different connectivity levels is simulated.

[0057] When the second pressure gauge A6 and the second flow meter A7 are stable, the data of the bottom hole temperature and pressure storage B8 are output for analyzing the variation characteristics of bottom hole temperature and pressure under the test of opening and closing the well and changing the inter-well connectivity.

Claims

1. A simulation device for interference testing of thick fault-controlled karst connected fracture-cave reservoirs, characterized in that: include: A simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing, wherein the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing is provided with a fracture-cave space, a first slit interface connected to one side of the fracture-cave space, and a second slit interface connected to the other side of the fracture-cave space; A box body, inside of which is provided a cavity for placing the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing; A first wellbore is arranged in the box body and adjacent to the first slit interface, an end of the first wellbore is provided with an inlet connected to a fluid supply device, and a first valve is provided on the wall of the first wellbore at a position corresponding to the first slit interface; A second wellbore is arranged in the box body and adjacent to the second slit interface. The end of the second wellbore is provided with a discharge port for discharging fluid. A second valve is provided on the wall of the second wellbore at a position corresponding to the second slit interface. The external fluid enters the first wellbore through the inlet on the first wellbore, and the first valve on the first wellbore corresponding to the first slit interface and the second valve on the second wellbore corresponding to the second slit interface are opened, and the fluid enters the first wellbore and is discharged in sequence through the first valve, the first slit interface, the slit hole space, the second slit interface, the second valve, and the discharge port of the second wellbore; A first flow meter, a first flow control valve and a first pressure gauge are provided at the entrance of the upper end of the first wellbore; A second flow meter, a second flow control valve and a second pressure gauge are provided at the upper discharge port of the second wellbore; A first bottom hole temperature and pressure storage device is provided at the bottom end of the first wellbore; A second bottom hole temperature and pressure storage device is provided at the bottom end of the second wellbore.

2. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 1 is characterized in that: After the first wellbore is inserted into the box, a contact seal is formed between the inner wall of the box, the first wellbore and the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing; After the second wellbore is inserted into the box, a contact seal is formed between the inner wall of the box, the second wellbore and the simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing.

3. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 2 is characterized in that: A first arc-shaped groove is provided on the side of the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing where the first slot interface is opened, and the curvature of the first arc-shaped groove is adapted to the curvature of the wall of the first wellbore; A second arc-shaped groove is provided on the side of the simulated huge-thick interconnected fracture-cavity reservoir manufactured by 3D printing where the second slit interface is opened, and the curvature of the second arc-shaped groove is matched with the curvature of the wall of the second wellbore.

4. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 1 is characterized in that: The first slit interfaces on the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing include multiple ones, and a first valve is provided on the first wellbore corresponding to each of the first slit interfaces; the second slit interfaces on the simulated huge thick interconnected fracture-cavity reservoir manufactured by 3D printing include multiple ones, and a second valve is provided on the second wellbore corresponding to each of the second slit interfaces.

5. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 1 is characterized in that: The first wellbore comprises a wellbore body made of non-conductive material, a plurality of openings are opened on a wall of one side of the wellbore body along the wellbore height direction, each opening is correspondingly provided with a first valve, and each first valve has the same structure, and comprises: a tile-shaped iron core attached to the outer wall of the wellbore; an energized coil is wound around the tile-shaped iron core; A spring, made of a non-conductive material, is disposed in the shaft body, the axis of the spring is perpendicular to the shaft axis of the shaft, one end of the spring is fixedly connected to the inner wall of the shaft adjacent to the tile-shaped iron core, and the other end of the spring is connected to an inner sealing ring capable of opening or closing the opening, the inner sealing ring being made of a material that can be attracted by a magnet; The second wellbore has the same structure as the first wellbore.

6. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 1 is characterized in that: The box body includes a box body with an upper opening and a sealing cover capable of sealing the upper opening of the box body. The simulated huge thick interconnected fracture-cave reservoir manufactured by 3D printing is placed into the cavity inside the box body through the upper opening. The upper end of the wellbore is provided with an external thread section, and the upper end of the sealing cover is provided with an internal thread section that threadably cooperates with the external thread section at the upper end of the wellbore.

7. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 5 is characterized in that: The wellbore material is any one of copper, aluminum and tin; the spring material is consistent with the wellbore material.

8. The interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 5 is characterized in that: The inner sealing ring is made of any one of iron, cobalt and nickel.

9. A test method based on the interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir as claimed in any one of claims 1 to 8, characterized in that: S1, first open the first flow control valve, so that the fluid is injected from the first flow control valve; S2. Secondly, according to the simulation scheme, the first valve at the first slotted interface on the first wellbore and the second valve at the corresponding second slotted interface on the second wellbore are opened, so that the injected fluid enters the fracture-cavity space of the reservoir from the first slotted interface on the first wellbore and the first slotted interface on the 3D-printed reservoir, and finally flows out from the second wellbore to form an injection-production channel; S3, in the process of simulating stable production, by adjusting the first flow control valve on the first wellbore and the second flow control valve on the second wellbore to simulate the interference process caused by the opening and closing of adjacent wellbores; by changing the opening and blocking state of the first valve on the first wellbore and the opening and blocking state of the second valve on the second wellbore during the production process, to simulate the interference production process under different connectivity degrees; S4. When the second pressure gauge reading and the second flow meter reading on the second wellbore are stable, the bottom hole temperature and pressure storage data of the second wellbore are output for analyzing the bottom hole temperature and pressure change characteristics under the well opening, well closing and well inter-well connectivity test.

10. The test method of the interference test simulation device for the huge thick fault-controlled karst connected fracture-cave reservoir according to claim 9 is characterized in that: In step S4, in the first case, when both wells are shut in, the pressure and temperature values ​​of the two well bottoms are read respectively through the first well bottom temperature and pressure storage device and the second well bottom temperature and pressure storage device; In the second case, when the two wells are injection wells and test wells, that is, the first well is an injection well and the second well is a test well, the bottom hole pressure and temperature values ​​fed back by the second bottom hole temperature and pressure storage are read; When the first well is a test well and the second well is an injection well, the bottom hole pressure and temperature values ​​fed back by the first bottom hole temperature and pressure storage are read.

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