Plugging agent plugging process simulation device and plugging effect evaluation method

Abstract

The invention belongs to the technical field of petroleum and natural gas drilling, and particularly relates to a plugging agent plugging process simulation device and a plugging effect evaluation method. The device comprises a crack simulation part and a rock core clamping part. The crack simulation part comprises a first rock core and a second rock core, and a longitudinally arranged simulation crack is formed between the first rock core and the second rock core. The rock core clamping part comprises a first clamping plate, a second clamping plate, a third clamping plate and a fourth clamping plate which are located on the outer side of the crack simulation part, and a liquid inlet and a liquid outlet are formed in the third clamping plate and the fourth clamping plate respectively. The simulated crack in the device has an uneven inner surface and is closer to the shape of a real crack, so that the plugging agent plugging simulation process performed by using the device is closer to the actual plugging working condition, and a reliable structural foundation is provided for subsequent plugging effect evaluation of different plugging particle proportions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of oil and gas drilling, and particularly relates to a lost circulation material lost circulation process simulation device and a lost circulation effect evaluation method. BACKGROUND

[0002] Lost circulation is a common complex situation in the well in drilling engineering, and most drilling processes have different degrees of loss. Severe lost circulation can cause the wellbore pressure to drop, thereby affecting normal drilling, and can also cause wellbore instability, which can induce formation fluid to flow into the wellbore and cause blowout.

[0003] Therefore, effective lost circulation operation in the well has important significance for reducing the harm of lost circulation. A large number of practices have confirmed that, before the field lost circulation operation, through indoor experiments, the formation loss layer is effectively simulated by the lost circulation simulation device, and the optimal lost circulation particle ratio is selected, which is an effective method to improve the success rate of lost circulation. However, the existing lost circulation simulation device has the following problems. First, the existing simulation device does not consider the real formation fracture stress sensitivity and the uneven surface morphology of the fracture. Second, the existing simulation device does not consider the high temperature and high pressure environment of the real formation fracture. These defects in the prior art make the simulation results differ greatly from the real working conditions, thereby affecting the optimization results of the lost circulation particle ratio and further affecting the effectiveness of the field lost circulation operation.

[0004] How to overcome the defects in the prior art and develop a lost circulation simulation device with high simulation degree and related lost circulation effect evaluation method has become a technical problem to be solved. SUMMARY

[0005] In view of part or all of the problems in the prior art, the present application provides a lost circulation material lost circulation process simulation device and a lost circulation effect evaluation method.

[0006] According to a first aspect of the present application, a lost circulation material lost circulation process simulation device is provided.

[0007] The lost circulation material lost circulation process simulation device comprises:

[0008] a fracture simulation part comprising a first core and a second core, and a simulation fracture is longitudinally arranged between the first core and the second core; and

[0009] a core clamping part comprising a first clamping plate and a second clamping plate respectively located on the upper side and the lower side of the fracture simulation part, and a third clamping plate and a fourth clamping plate respectively located on the left side and the right side of the fracture simulation part, and a liquid inlet and a liquid outlet are respectively arranged on the third clamping plate and the fourth clamping plate,

[0010] The crack simulation part and the core clamping part are configured to enable the plugging agent to flow from the liquid inlet into the simulated crack to simulate a downhole plugging process.

[0011] As an extension of the above technical solution, the application further provides the following embodiments.

[0012] The core clamping part comprises a first movable plate and a second movable plate arranged respectively on the front and back sides of the crack simulation part.

[0013] The crack simulation part comprises an inner wall and an outer wall.

[0014] The crack simulation part comprises a heating part.

[0015] The crack simulation part comprises a confining pressure part.

[0016] The crack simulation part comprises a plugging agent collecting part.

[0017] The crack simulation part comprises a confining pressure sensor and a temperature sensor.

[0018] The crack simulation part comprises a plugging agent preparation part.

[0019] The plugging agent preparation part comprises a liquid storage pool.

[0020] According to a second aspect of the application, a plugging effect evaluation method is provided.

[0021] The plugging effect evaluation method utilizes the plugging process simulation device as described above and comprises the following steps:

[0022] 1) Plugging agent is introduced into the crack simulation part, and when the plugging agent starts to flow out of the liquid outlet, the initial time T0 is recorded, and the liquid flow out of the liquid outlet is continuously observed;

[0023] 2) When the liquid outlet has no leak-stopper flowing out, record the time as T1, define the difference between T1 and T0 as the plugging effect time, and restore the fracture simulation part to the original state;

[0024] 3) Repeat the operation of the step 1) and the step 2) by using different proportions of the leak-stopper, obtain the plugging effect time of each different proportion of the leak-stopper and compare.

[0025] The present application has the following advantages compared with the prior art:

[0026] 1. The fracture is simulated by the first core and the second core, and the inner side has a rough surface morphology, which is closer to the real fracture, thereby improving the similarity between the leak-stopper plugging simulation process and the actual working condition, and providing an equipment basis for obtaining reliable leak-stopper particle proportion in the subsequent process;

[0027] 2. The heating part and the confining pressure part are arranged, which provides a high temperature and high pressure environment similar to the real formation environment for the fracture simulation part, thereby further improving the similarity between the leak-stopper plugging simulation process and the actual working condition, and also providing an equipment basis for obtaining reliable leak-stopper particle proportion in the subsequent process;

[0028] 3. The leak-stopper plugging effect evaluation method provided by the present application uses the leak-stopper plugging process simulation device provided by the present application, which can conveniently, quickly and effectively evaluate the plugging effect of the leak-stopper particle proportion, thereby providing reliable technical support for the actual plugging operation. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural schematic view of the leak-stopper plugging process simulation device according to the present application;

[0030] Figure 2 It is a structural schematic view of the leak-stopper plugging process simulation device according to the present application; Figure 1 It is a lateral cross-sectional view of the fracture simulation part and the core clamping part;

[0031] Figure 3 It is a left view of the core clamping part;

[0032] Figure 4 It is a right view of the core clamping part.

[0033] All the drawings in the present application are schematic views for illustrating the structure and principle, and are not necessarily drawn according to the actual size and proportion.

[0034] The specific meanings of the various reference signs in the drawings are as follows:

[0035] 1, fracture simulation part; 11, first core; 12, second core; 13, simulated fracture; 14, support tube; 2, core clamping part; 21, first clamping plate; 22, second clamping plate; 23, third clamping plate; 231, liquid inlet; 24, fourth clamping plate; 241, liquid outlet; 25, first movable plate; 26, second movable plate; 3, in-fracture pressure sensor; 4, heating part; 41, heating plate; 42, power supply; 5, confining pressure part; 51, confining pressure pump; 52, confining pressure pipeline; 6, plugging agent collection part; 61, collection tank; 62, liquid outlet pipeline; 621, liquid outlet pipeline valve; 7, confining pressure sensor; 8, temperature sensor; 9, plugging agent preparation part; 91, preparation tank; 911, tank body; 912, liquid inlet pipeline; 9121, liquid pumping pump; 9122, displacement pump; 913, feeding port; 914, first isolation plate; 915, connecting channel; 916, second isolation plate; 92, stirring assembly; 921, rotary motor; 922, stirring shaft; 923, stirring paddle; 93, liquid storage tank; 94, liquid injection port; 941, liquid injection port valve; 95, wall; 100, plugging agent plugging process simulation device. DETAILED DESCRIPTION

[0036] The embodiments of the present application will be described in more detail below with reference to the accompanying drawings.

[0037] According to a first aspect of the present application, a plugging agent plugging process simulation device 100 is provided.

[0038] Figures 1 to 4 A structural schematic diagram and related views of the plugging agent plugging process simulation device 100 according to the present application (hereinafter referred to as "device 100") are shown in the figure. As shown in the figure, the device 100 includes a fracture simulation part 1 and a core clamping part 2. The fracture simulation part 1 includes a first core 11 and a second core 12 formed by splitting a core, the first core 11 and the second core 12 having uneven fracture surfaces, and the first core 11 and the second core 12 being arranged longitudinally with the fracture surfaces facing each other, and a simulated fracture 13 being formed longitudinally between the first core 11 and the second core 12. The core clamping part 2 includes a first clamping plate 21 and a second clamping plate 22 located on the upper side and the lower side of the fracture simulation part 1 respectively, and a third clamping plate 23 and a fourth clamping plate 24 located on the left side and the right side of the fracture simulation part 1 respectively, and a liquid inlet 231 and a liquid outlet 241 are respectively provided on the third clamping plate 23 and the fourth clamping plate 24 for facilitating the flow of plugging agent. In addition, the fracture simulation part 1 and the core clamping part 2 are further configured to allow the plugging agent to flow from the liquid inlet 231 into the simulated fracture 13 to simulate the plugging process in the well.

[0039] In the specific operation, the staff member delivers the prepared plugging agent into the simulated fracture 13 through the liquid inlet 231 to simulate the plugging operation process of the plugging agent under real well conditions, thereby realizing the simulation plugging function of the device 100.

[0040] This design enables the simulated crack 13 provided by the device 100 to have an uneven internal surface morphology that is highly similar to that of a real crack, thereby greatly improving the similarity between the simulated plugging process of the device 100 and the real plugging conditions, and providing reliable equipment support for subsequent activities such as evaluating the plugging particle ratio using the device 100.

[0041] In one embodiment of the present invention, in order to ensure that the sealing agent can flow smoothly into the core clamping part 2 and the fracture simulation part 1 through the inlet 231, the shape of the inlet 231 is the same as the cross-sectional shape of the leftmost side of the simulated fracture 13.

[0042] like Figure 1 and Figure 2 As shown, in one embodiment of the present invention, the core clamping part 2 includes a first movable plate 25 and a second movable plate 26, and the first movable plate 25 and the second movable plate 26 are respectively disposed on the front and rear sides of the crack simulation part 1. This design allows the operator to adjust the distance between the first core 11 and the second core 12 by laterally adjusting the distance between the first movable plate 25 and the second movable plate 26, thereby adjusting the width of the simulated crack 13. This enables the device 100 to effectively simulate real cracks of various widths, expanding the applicability of the device 100.

[0043] like Figure 2 As shown, in one embodiment of the present invention, a fracture pressure sensor 3 is provided on the core clamping part 2. The pressure probe of the fracture pressure sensor 3 is inserted into the interior of the simulated fracture 13, thereby enabling the fracture pressure sensor 3 to measure the pressure in the simulated fracture 13. This design allows operators to measure the magnitude and changes in pressure within the simulated fracture 13 in real time during the simulation process, providing richer data support for evaluating the plugging performance of the plugging particles and helping to improve the accuracy of the plugging performance evaluation of the plugging agent.

[0044] like Figure 1 As shown, in one embodiment of the present invention, the device 100 includes a heating unit 4, which includes a heating plate 41 disposed inside the core clamping unit 2. Specifically, the heating plate 41 is embedded inside the first clamping plate 21, the second clamping plate 22, the third clamping plate 23, the fourth clamping plate 24, the first movable plate 25, and the second movable plate 26. This design allows workers to heat the fracture simulation unit 1 by activating the heating unit 4, thereby providing a high-temperature simulated working environment for the simulated fracture 13. This makes the simulation process of the device 100 more similar to the high-temperature environment in real formations, providing reliable equipment support for subsequent activities such as evaluating the proportion of plugging particles using the device 100.

[0045] Furthermore, in one embodiment of the present invention, the heating part 4 includes a power supply 42 connected to the heating plate 41.

[0046] In one embodiment of the invention, the heating plate 41 is made of a metal material that is easy to conduct heat.

[0047] like Figure 1 As shown, in one embodiment of the present invention, the device 100 includes a confining pressure section 5, which includes a confining pressure pump 51 and a confining pressure pipe 52 connecting the confining pressure pump 51 to the core clamping section 2. The confining pressure pipe 52 is also configured to be located outside the core clamping section 2 and to apply confining pressure to the core clamping section 2 under the action of the high-pressure fluid pumped by the confining pressure pump 51. With this design, the operator can control the movement and deformation of the core clamping section 2 by operating the confining pressure section 5, thereby achieving the purpose of applying pressure to the first core 11 and the second core 12, and thus providing a high-pressure simulated working environment for simulating the fracture 13. This makes the simulation process of the device 100 more similar to the high-pressure environment in the real formation, providing reliable equipment support for subsequent activities such as evaluating the plugging particle ratio using the device 100.

[0048] like Figure 1 As shown, in one embodiment of the present invention, support tubes 26 with high hardness and a certain degree of deformation capability are provided on both the left and right sides of the simulated crack 13. This design ensures that a high-pressure environment can be generated inside the simulated crack 13 while preventing the simulated crack 13 from closing during the simulation process and after being subjected to confining pressure, thus ensuring the smooth operation of the device 100.

[0049] Preferably, in order to enable the device 100 to adapt to various confining pressure conditions, the length of the support tube is appropriately extended as the confining pressure applied by the confining pressure section 5 increases.

[0050] like Figure 1 As shown, in one embodiment of the present invention, the device 100 includes a sealant collection section 6. The sealant collection section 6 includes a collection tank 61 and an outlet pipe 62, and the outlet pipe 62 is configured to connect to the outlet 241 and extend into the interior of the collection tank 61. This design allows the sealant flowing out of the crack simulation section 1 to be effectively collected, which facilitates the reuse of the sealant and maintains a good working environment.

[0051] like Figure 1As shown, in one embodiment of the present invention, the device 100 includes a confining pressure sensor 7 and a temperature sensor 8 disposed on the core clamping part 2, and the confining pressure sensor 7 and the temperature sensor 8 are respectively configured to measure the pressure and temperature inside the fracture simulation part 1. This design allows operators to monitor the pressure and temperature inside the fracture simulation part 1 in real time, thereby facilitating the control of the confining pressure part 5 and the heating part 4, so that the fracture simulation part 1 can reach the set pressure and temperature for better simulation operations.

[0052] like Figure 1 As shown, in one embodiment of the present invention, the device 100 includes a plugging agent mixing unit 9. The plugging agent mixing unit 9 is configured to communicate with the core clamping unit 2 via an inlet 231 located on the third clamping plate 23. The plugging agent mixing unit 9 includes a mixing tank 91 and a stirring assembly 92. The mixing tank 91 includes a tank body 911 and an inlet pipe 912 and a feeding port 913 disposed on the tank body 911. The inlet pipe 912 is used to pass plugging liquid into the mixing tank 91, and the feeding port 913 is used to add plugging particles into the mixing tank 91. The stirring assembly 92 includes a rotary motor 921, a stirring shaft 922 connected to the rotary motor 921 and extending into the tank body 911, and a stirring paddle 923 disposed on the stirring shaft 922. This design allows staff to easily prepare various types of plugging agents using the plugging agent mixing unit 9. The prepared plugging agent, kept uniformly mixed by the stirring component 92, can be directly delivered to the core clamping unit 2 and then flow into the fracture simulation unit 1 for simulated plugging operations. This avoids the need for off-site transportation of the plugging agent, improving overall work efficiency. Furthermore, it significantly reduces the occurrence of uneven mixing, such as sedimentation, and minimizes the adverse effects of the plugging agent's mixing state on the simulation results.

[0053] Preferably, in order to facilitate observation of the liquid level, the mixing tank 91 is made of a transparent material, such as glass.

[0054] like Figure 1 As shown, in one embodiment of the present invention, the mixing tank 91 includes a first baffle 914 disposed between the feeding port 913 and the tank body 911. This design facilitates the control of the dispensing of the plugging particles by the operator, ensuring the smooth operation of the device 100.

[0055] like Figure 1As shown, in one embodiment of the present invention, the mixing tank 91 includes a connecting channel 915 with openings at both ends, disposed between the mixing tank 91 and the third clamping plate 23. This design allows the mixing tank 91 to maintain a certain distance from the third clamping plate 23 while simultaneously delivering sealing agent to the interior of the core clamping part 2 via the connecting channel 915. This avoids mutual interference between the mixing tank 91 and the core clamping part 2, enabling the device 100 to perform simulation operations smoothly and stably.

[0056] Preferably, a second sealing plate 916 is provided on the connecting channel 915, configured to control the opening and closing state of the connecting channel 915 through its own movement. This design allows the operator to control the supply of sealing agent in the core clamping part 2 and the fracture simulation part 1 according to the needs of the operation, thereby ensuring the smooth operation of the device 100 simulation operation.

[0057] like Figure 1 As shown, in one embodiment of the present invention, the sealant mixing unit 9 includes a storage tank 93. The storage tank 93 serves to store the sealant, and the inlet pipe 912 provided on the mixing tank 91 is configured to extend into the interior of the storage tank 93. This design provides a dedicated storage container for the sealant, and the sealant stored inside the storage tank 95 can enter the mixing tank 91 through the inlet pipe 912 for sealant mixing.

[0058] Preferably, a pumping pump 9121 and a displacement pump 9122 are sequentially installed on the inlet pipe 912 along the flow direction of the plugging liquid, so that when needed, the workers can inject the plugging liquid inside the storage tank 93 into the mixing tank 91.

[0059] In one embodiment of the present invention, the sealant preparation unit 9 includes an injection port 94 disposed on the wall 95 for injecting sealant into the storage tank 93, and an injection port valve 941 is provided on the injection port 94. This design facilitates the injection of sealant into the storage tank 93 by personnel, and also allows personnel to control the injection status and injection speed of the sealant by controlling the injection port valve 941, thus ensuring the smooth operation of the device 100.

[0060] According to the device 100 of the present invention, a simulated crack 13 with an uneven inner surface and similar height to a real crack is generated by the crack simulation unit 1. The heating unit 4 and the confining pressure unit 5 provide the crack simulation unit 1 with a high temperature and high pressure working environment similar to a real stratum, so that the leakage simulation process of the plugging agent performed by the device 100 is closer to the real leakage process, thereby providing reliable equipment support for subsequent activities such as evaluating the proportion of plugging particles using the device 100.

[0061] According to a second aspect of the present invention, a method for evaluating the sealing effect of a sealing agent is provided.

[0062] The method for evaluating the sealing effect of the sealant is performed using the device 100 described above, and includes the following steps:

[0063] 1) Pour sealing agent into the crack simulation section 1. When the sealing agent starts to flow out from the outlet 241, record this time as the initial time T0, and continue to observe the liquid flow at the outlet 241.

[0064] 2) When no sealant flows out of outlet 241, record the time as T1. Define the difference between T1 and T0 as the sealing effectiveness time, and restore the crack simulation part 1 to its original state.

[0065] 3) Repeat steps 1) and 2) using different ratios of sealant to obtain and compare the sealing time of sealant with different ratios.

[0066] The shorter the sealing onset time, the better the sealing effect of the corresponding sealant. The design of the above steps allows workers to easily measure the sealing onset time and effectively evaluate the sealing performance of the sealant, providing crucial data support for subsequent actual sealing operations.

[0067] In one embodiment of the present invention, step 2) after no more plugging agent flows out of the outlet 241 further includes the following: closing the outlet pipe valve 621, and simultaneously starting to record the rise time and rise amplitude of the pressure sensor 3 inside the gap until the value of the pressure sensor 3 inside the gap no longer changes, which is recorded as the sealing pressure rise time T2 and the sealing pressure rise peak P1. For various plugging agents with different plugging particle ratios, the shorter the sealing pressure rise time and the larger the sealing pressure rise peak, the better the plugging effect of the plugging agent. Through the design of this step, the staff can obtain the sealing pressure rise time T2 and sealing pressure rise peak P1 of different plugging agents, thereby enabling a more comprehensive and accurate evaluation of the performance of the plugging agent, and thus enabling the evaluation results to effectively guide the actual production process.

[0068] In one embodiment of the present invention, in step 1), the plugging agent is introduced into the core clamping part 2 and the fracture simulation part 1 through the plugging agent mixing part 9.

[0069] The method for evaluating the sealing effect of the sealing agent according to the present invention can also achieve other technical effects that the device 100 described above can achieve, which will not be elaborated here.

[0070] In this invention, the sealing agent is a mixture of sealing liquid and sealing particles.

[0071] In this invention, the specific meanings of terms such as "upper," "lower," "left," "right," "inner," "outer," "middle," and "side" when indicating location are as follows: Figure 1 Figure 1 The drawing state of the middle device 100 is for reference.

[0072] Finally, it should be noted that although the present invention has been described in detail with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A device for simulating the process of plugging with a sealing agent, comprising: The fracture simulation unit (1) includes a first core (11) and a second core (12), with a longitudinally arranged simulated fracture (13) formed between the first core (11) and the second core (12); and The core clamping part (2) includes a first clamping plate (21) and a second clamping plate (22) located on the upper and lower sides of the fracture simulation part (1), respectively, and a third clamping plate (23) and a fourth clamping plate (24) located on the left and right sides of the fracture simulation part (1), respectively. An inlet (231) and an outlet (241) are respectively provided on the third clamping plate (23) and the fourth clamping plate (24). The fracture simulation section (1) and the core clamping section (2) are configured to allow the plugging agent to flow from the inlet (231) into the simulated fracture (13) to simulate the downhole plugging process.

2. The device for simulating the plugging process of a plugging agent according to claim 1, characterized in that: The core clamping part (2) includes a first movable plate (25) and a second movable plate (26) respectively disposed on the front and rear sides of the fracture simulation part (1).

3. The device for simulating the plugging process of a plugging agent according to claim 2, characterized in that: This includes an intracranial pressure sensor (3) disposed on the core clamping part (2) and configured to measure the pressure in the simulated fracture (13).

4. The device for simulating the plugging process of a plugging agent according to claim 3, characterized in that: It includes a heating part (4), which includes a heating plate (41) disposed inside the core clamping part (2).

5. The device for simulating the plugging process of a plugging agent according to claim 4, characterized in that: It includes a confining pressure section (5), which includes a confining pressure pump (51) and a confining pressure pipe (52) connecting the confining pressure pump (51) to the core clamping section (2).

6. The device for simulating the plugging process of a plugging agent according to claim 5, characterized in that: It includes a sealant collection section (6), which includes a collection tank (61) and an outlet pipe (62) connected to the outlet (241) and extending into the collection tank (61).

7. The device for simulating the plugging process of a plugging agent according to claim 6, characterized in that: This includes a confining pressure sensor (7) and a temperature sensor (8), both of which are disposed on the core clamping part (2) and are respectively configured to measure the pressure and temperature in the crack simulation part (1).

8. The device for simulating the plugging process of a plugging agent according to any one of claims 1 to 7, characterized in that: The system includes a plugging agent preparation unit (9) connected to the core clamping part (2) via the liquid inlet (231). The plugging agent preparation unit (9) includes a preparation tank (91) and a stirring assembly (92). The preparation tank (91) includes a tank body (911) and a liquid inlet pipe (912) and a feed port (913) provided on the tank body (911). The stirring assembly (92) includes a rotary motor (921), a stirring shaft (922) connected to the rotary motor (921) and extending into the tank body (911), and a stirring paddle (923) provided on the stirring shaft (922).

9. The device for simulating the plugging process of a plugging agent according to claim 8, characterized in that: The plugging agent preparation unit (9) includes a storage tank (93) for storing the plugging liquid, and the inlet pipe (912) extends into the interior of the storage tank (93).

10. A method for evaluating the sealing effect of a sealing agent, using a sealing agent sealing process simulation device as described in any one of claims 1 to 9, comprising the following steps: 1) Pour a sealing agent into the crack simulation section (1). When the sealing agent starts to flow out from the outlet (241), record this time as the initial time T0, and continue to observe the liquid flow at the outlet (241). 2) When no sealant flows out of the outlet (241), record the time as T1, define the difference between T1 and T0 as the sealing effect time, and restore the crack simulation part (1) to its original state; 3) Repeat steps 1) and 2) using different ratios of sealant to obtain and compare the sealing effectiveness time of each sealant with different ratios.

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