A temperature and pressure response type lost circulation material evaluation device and evaluation method

Abstract

The present application belongs to the field of performance evaluation of plugging agents for oil drilling, and particularly relates to a temperature and pressure response type plugging agent evaluation device and method. The device comprises a hydraulic device; a heating box, wherein a plurality of temperature and pressure reaction kettles are arranged in the heating box, and each temperature and pressure reaction kettle is connected to the hydraulic device. The device can control the temperature and pressure of the plugging agent through hydraulic and heating methods, thereby providing conditions for further using a universal testing machine and a rheometer system to evaluate the tensile, compression and rheological strength of the sample under different temperatures and pressures, so as to determine the mechanical and rheological properties of the plugging agent under different temperature and pressure conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of performance evaluation of plugging agents for oil drilling, and particularly relates to a temperature and pressure response type plugging agent evaluation device and method. BACKGROUND

[0002] In the drilling process, problems such as well leakage, collapse, and damage to oil and gas layers often occur due to the lack of sealing performance of the wellbore, which is particularly serious in high temperature and high pressure wells. In recent years, in order to improve the energy security level of China and alleviate the pressure of China's energy dependence on foreign countries, oil and gas exploration in China has gradually moved to deep layers, and situations and problems such as high temperature and high salinity, stuck pipe, and wellbore instability often occur. The bottom hole temperature of ultra-deep wells is high, and the geological conditions are complex. The sealing performance of drilling fluid is greatly affected by the bottom hole environment, especially in harsh environments such as high temperature and high pressure. Therefore, it is particularly important to systematically evaluate the influence of temperature and pressure on plugging agents.

[0003] The temperature and pressure response type plugging agent mainly refers to a material that is excited at a certain temperature or pressure, and gradually changes in properties or performance. At present, the performance of plugging agents is mainly evaluated by assessing the pressure-bearing performance of plugging agents at a certain temperature to determine their stability, but this evaluation method cannot determine the differences and changes in the mechanical and rheological properties of plugging agents under corresponding temperature or pressure conditions. In particular, for temperature and pressure sensitive temperature and pressure response type plugging agents, systematic evaluation of their mechanical and rheological properties under different temperatures and pressures can determine the influence of temperature and pressure coupling on the performance of plugging agents, and optimize the best application conditions of plugging agents. According to the response performance under different temperatures and pressures, the response characteristics and mechanism of the plugging agent can be explored, which provides a complete and scientific laboratory evaluation basis for the research and development of high temperature and high pressure plugging agents and the plugging of fractures in ultra-deep wells. Therefore, it is necessary to invent a temperature and pressure response type plugging agent evaluation device and method to meet the current demand for evaluating the performance of temperature and pressure response type plugging agents. SUMMARY

[0004] To solve the problems of the prior art, the present application provides a temperature and pressure response type plugging agent evaluation device and method. By combining hydraulic pressure and air blowing heating, and combining the temperature and pressure response plugging agent evaluation device with a universal testing machine and a rheometer, the tensile, compressive and rheological strength of the plugging agent can be studied. Further, according to the response characteristics of the plugging agent under different temperatures and pressures, the influence of temperature and pressure coupling on the performance of the plugging agent can be determined, and the best application conditions of the plugging agent can be optimized. According to the performance changes under different temperatures and pressures, the response characteristics and mechanism of the plugging agent can be explored. This provides a basis for the research and development of high temperature and high pressure plugging agents and the plugging of fractures in ultra-deep wells.

[0005] The technical solutions provided by the present application are as follows:

[0006] A temperature and pressure response type plugging agent evaluation device comprises:

[0007] hydraulic device;

[0008] a heating box, a plurality of temperature and pressure reaction kettles are arranged in the heating box, and each temperature and pressure reaction kettle is communicated with the hydraulic device.

[0009] Based on the above technical scheme, the temperature and pressure of the plugging agent can be controlled through hydraulic and heating methods, so as to provide conditions for further using a universal testing machine and a rheometer system to evaluate the tensile, compression and rheological strength of the sample under different temperatures and pressures, so as to determine the mechanical properties and rheological properties of the plugging agent under different temperature and pressure conditions.

[0010] Specifically, the temperature and pressure reaction kettle comprises:

[0011] a plurality of vertically arranged barrel bodies;

[0012] a detachable upper plug head mounted at an upper opening of the barrel body, and the upper plug head is communicated with an exhaust valve;

[0013] a lower plug head fixedly mounted at a lower opening of the barrel body, and the lower plug head is provided with an oil inlet communicated with the hydraulic device;

[0014] and a piston slidingly fitted in the barrel body.

[0015] Based on the above technical scheme:

[0016] the piston can give pressure to the sample upward under the pressure of the hydraulic device; the barrel body is made of a heat-conducting material, so that the temperature and pressure of the plugging agent can be controlled.

[0017] In addition, the sample can be conveniently added by detaching the upper plug head, or the sample can be taken out after the reaction is completed.

[0018] Further:

[0019] an upper pressing cap is detachably mounted at an upper end of the barrel body, and the upper pressing cap is detachably connected with the upper plug head;

[0020] a lower pressing cap is fixedly mounted at a lower end of the barrel body, and the lower pressing cap is fixedly connected with the lower plug head.

[0021] Based on the above technical scheme, the corresponding plug head can be limited or fixed by the pressing cap.

[0022] Further:

[0023] the upper plug head is provided with a sealing ring at a contact surface with the barrel body;

[0024] the lower plug head is provided with a sealing ring at a contact surface with the barrel body;

[0025] The upper plug passes through the upper pressure cap and is detachably connected to the upper pressure cap via a retaining spring;

[0026] The lower plug passes through the lower pressure cap and is detachably connected to the lower pressure cap via a retaining spring.

[0027] Specifically, the hydraulic device includes:

[0028] Hydraulic pump;

[0029] A pair of hydraulic master valves and a back pressure master valve;

[0030] Several sets of hydraulic valves and back pressure valves, each of which is connected to the corresponding lower plug via a pipeline.

[0031] The present invention also provides a method for evaluating temperature-pressure responsive sealant, which uses the temperature-pressure responsive sealant evaluation device provided by the present invention for evaluation.

[0032] Based on this technical solution, the temperature and pressure of the sealing agent can be controlled by hydraulic pressure and heating. Then, a universal testing machine and rheometer system can be used to evaluate the tensile, compressive and rheological strength of samples under different temperatures and pressures, thereby determining the mechanical and rheological properties of the sealing agent under different temperature and pressure conditions.

[0033] Specifically, the evaluation method for temperature and pressure responsive sealant includes the following steps:

[0034] Step S1: Mix the thermo-pressure responsive sealant and the working fluid, and stir until homogeneous at room temperature;

[0035] Step S2: Add the mixture obtained in step S1 to the pistons in each of the thermo-pressure reactors, and keep each exhaust valve open.

[0036] Step S3: Close the hydraulic main valve and open the back pressure main valve, and then inject back pressure into each of the thermo-pressure reactors in sequence;

[0037] Step S4: Close the back pressure main valve and open the hydraulic main valve, then inject pressure into each of the thermo-pressure reactors in sequence. After the pressure inside the reactor stabilizes, close each of the exhaust valves.

[0038] Step S5: Heating the reaction in a heating chamber;

[0039] Step S6: After the reaction is complete, turn off the heating button and open the main hydraulic valve, each of the hydraulic valves and each of the exhaust valves;

[0040] Step S7: After the heating device cools to room temperature, open the thermostatic reactor, remove the sealing agent, and conduct a test.

[0041] The above technical solution provides an operational method for evaluating temperature-pressure responsive plugging agents.

[0042] Specifically, the working fluid in step S1 is one of 5% bentonite slurry, water, 5% NaCl solution, 10% NaCl solution or polysulfonated drilling fluid;

[0043] Specifically, the mass ratio of the plugging agent to the working fluid in step S1 is (5-10):100, and the stirring time is 10-60 min;

[0044] Specifically, the mixed solution added in step S2 is 120-200 g;

[0045] Specifically, the back pressure injected into each of the warm pressure reaction kettles in step S3 is 0-20 MPa;

[0046] Specifically, the pressure injected into each of the warm pressure reaction kettles in step S4 is 0-20 MPa;

[0047] Specifically, the reaction temperature in step S5 is 25-250°C;

[0048] Specifically, the reaction time in step S6 is 6-24 h.

[0049] Further, the plugging agent obtained in step S7 is cut into a cuboid, and the tensile property thereof is tested by a universal testing machine at a certain tensile rate, wherein the breaking stress is taken as the tensile property index.

[0050] Further, the plugging agent obtained in step S7 is cut into a cylinder, and the compressive property thereof is tested by a universal testing machine at a certain compression rate, wherein the stress under a fixed strain is taken as the compressive property index.

[0051] Further, the plugging agent obtained in step S7 is cut into a circular sheet, and the rheological strength thereof is tested by a rheometer, wherein the average storage modulus in the viscoelastic interval is taken as the rheological property index.

[0052] Specifically, the plugging agent is cut into a cuboid with a length of 30-40 mm, a width of 10-15 mm and a height of 3-10 mm, and the tensile rate is 50-100 mm / min.

[0053] Specifically, the plugging agent is cut into a cylinder with a diameter of 8-10 mm and a height of 12-20 mm, the compression rate is 2-10 mm / min, and the compression strain is 50-95%.

[0054] Specifically, the lost circulation material is tailored into a round piece with a diameter of 8-15 mm and a height of 2-4 mm, the interval of rheological test is set to 1 mm, then the gel is placed on the lower plate of the test, the fixed oscillation scanning frequency is set to 1 Hz, the strain amplitude scanning range is set to 0.1%-1000%, the viscoelastic interval of the gel is determined through strain scanning, and the strain of the fixed oscillation scanning is fixed, and the frequency scanning is performed in the frequency range of 0.1-100 Hz.

[0055] More specifically, the warm pressure response type lost circulation material evaluation method comprises the following steps:

[0056] Step S1, mix the warm pressure response type lost circulation material and the working fluid, and stir them uniformly at room temperature;

[0057] Step S2, pour the mixed liquid obtained in step S1 into the warm pressure reaction kettles 1-3 respectively, close the kettle body, and keep the exhaust valve open;

[0058] Step S3, close the hydraulic total valve and open the back pressure total valve, then open the back pressure valve 1, close the back pressure valve 2 and the back pressure valve 3, and inject back pressure into the No. 1 warm pressure reaction kettle through the hydraulic hand pump;

[0059] Step S4, open the back pressure valve 2, close the back pressure valve 1 and the back pressure valve 3, and inject back pressure into the No. 2 warm pressure reaction kettle through the hydraulic hand pump;

[0060] Step S5, open the back pressure valve 3, close the back pressure valve 1 and the back pressure valve 2, and inject back pressure into the No. 3 warm pressure reaction kettle through the hydraulic hand pump;

[0061] Step S6, close the back pressure total valve and open the hydraulic total valve, then open the hydraulic valve 1, close the hydraulic valve 2 and the hydraulic valve 3, and inject pressure into the No. 1 warm pressure reaction kettle through the hydraulic hand pump, and close the exhaust valve after the kettle pressure stabilizes;

[0062] Step S7, open the hydraulic valve 2, close the hydraulic valve 1 and the hydraulic valve 3, and inject pressure into the No. 2 warm pressure reaction kettle through the hydraulic hand pump, and close the exhaust valve after the kettle pressure stabilizes;

[0063] Step S8, open the hydraulic valve 3, close the hydraulic valve 1 and the hydraulic valve 2, and inject pressure into the No. 3 warm pressure reaction kettle through the hydraulic hand pump, and close the exhaust valve after the kettle pressure stabilizes;

[0064] Step S9, turn on the air blowing heating power supply, set the reaction temperature and open the rapid heating and air blowing buttons, and start timing after the air blowing heating temperature stabilizes;

[0065] Step S10, after the reaction is completed, turn off the heating button, open the hydraulic total valve, the hydraulic valves 1-3 and the exhaust valve;

[0066] Step S11, after the heating device is cooled to room temperature, open the warm pressure reaction kettle, and take out the plugging agent;

[0067] Step S12, the plugging agent obtained in step S12 is cut into a cuboid, and the tensile property is tested by a universal testing machine at a certain tensile rate, wherein the breaking stress is taken as the tensile property index;

[0068] Step S13, the plugging agent obtained in step S12 is cut into a cylinder, and the compression property is tested by a universal testing machine at a certain compression rate, wherein the stress under fixed strain is taken as the compression property index;

[0069] Step S14, the plugging agent obtained in step S12 is cut into a circular sheet, and the rheological strength is tested by a rheometer, wherein the average storage modulus in the viscoelastic interval is taken as the rheological property index.

[0070] Advantages of the present application:

[0071] 1) The warm pressure response type plugging agent evaluation device and evaluation method provided by the present application can systematically test the warm pressure response characteristics of the plugging agent under 25 ~ 250℃, 0 ~ 20 MPa, and determine the tensile, compression and rheological properties of the plugging material under different warm pressures.

[0072] 2) The warm pressure response type plugging agent evaluation device and evaluation method provided by the present application combines hydraulic pressure and blast heating, and uses the warm pressure response plugging agent evaluation device in combination with a universal testing machine and a rheometer to systematically explore the tensile, compression and rheological properties of the plugging agent. According to the response characteristics of the plugging agent under different warm pressures, the influence of temperature and pressure coupling on the performance of the plugging agent can be explored, and the best applicable conditions of the plugging agent can be optimized, and the response characteristics and mechanism of the plugging agent under different warm pressures can be explored. BRIEF DESCRIPTION OF DRAWINGS

[0073] Figure 1 is the overall structure schematic diagram of the warm pressure response type plugging agent evaluation device provided by the present application.

[0074] Figure 2 is the structure schematic diagram of the warm pressure reaction kettle of the warm pressure response type plugging agent evaluation device provided by the present application.

[0075] Figure 3 is the hydraulic principle diagram of the warm pressure response type plugging agent evaluation device provided by the present application.

[0076] ATTACHMENT Figure 1 , 2 , 3, the structure represented by each reference numeral is listed as follows:

[0077] 1. Hydraulic device; 2. Heating box; 3. Temperature and pressure reactor; 301. Shell; 302. Upper plug; 303. Lower plug; 304. Upper pressure cap; 305. Lower pressure cap; 306. Piston; 4. Hydraulic pump; 5. Hydraulic main valve; 6. Back pressure main valve; 7. Hydraulic valve; 8. Back pressure valve; 9. Exhaust valve; 10. Sealing ring; 11. Snap ring. Detailed Implementation

[0078] The principles and features of the present invention are described below. The embodiments given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0079] In one specific implementation, such as Figure 1 As shown, the thermo-pressure responsive sealant evaluation device includes: a hydraulic device 1; a heating chamber 2, in which several thermo-pressure reaction vessels 3 are installed, and each thermo-pressure reaction vessel 3 is connected to the hydraulic device 1.

[0080] like Figure 2 As shown, the thermostatic reactor 3 includes: several vertically arranged cylindrical bodies 301; a detachable upper plug 302 installed at the upper opening of the cylindrical bodies 301, the upper plug 302 being connected to an exhaust valve 9; a lower plug 303 fixedly installed at the lower opening of the cylindrical bodies 301, the lower plug 303 being provided with an oil inlet, the oil inlet being connected to a hydraulic device 1; and a piston 306 slidingly fitted inside the cylindrical bodies 301. An upper pressure cap 304 is detachably installed at the upper end of the cylindrical bodies 301, and the upper pressure cap 304 is detachably connected to the upper plug 302. A lower pressure cap 305 is fixedly installed at the lower end of the cylindrical bodies 301, and the lower pressure cap 305 is fixedly connected to the lower plug 303. Specifically, the number of thermostatic reactors 3 can be three. The upper pressure cap 304 and the cylindrical bodies 301 can be threadedly connected, and the lower pressure cap 305 and the cylindrical bodies 301 can be threadedly connected, allowing for the detachment and fixing of the upper pressure cap.

[0081] like Figure 3 As shown, the hydraulic device 1 includes: a hydraulic pump 4; a pair of hydraulic master valves 5 and a back pressure master valve 6; and several sets of hydraulic valves 7 and back pressure valves 8. Specifically, the hydraulic pump 4 can be a hydraulic hand-cranked pump. The hydraulic device 1 includes three sets, corresponding to the number of thermostatic reaction vessels 3. The hydraulic pump 4 is connected to a buffer tank, and then to the hydraulic master valves 5 and 6 respectively. The hydraulic master valves 5 are connected to each hydraulic valve 7, and the back pressure master valves 6 are connected to each back pressure valve 8. Each hydraulic valve 7 is connected to a corresponding lower plug 303 through a pipeline. Each back pressure valve 8 is connected to a piston container that balances the pressure through a buffer container, and each hydraulic valve 7 is also connected to a piston container that balances the pressure.

[0082] Based on the above specific implementation methods, such as Figure 2As shown, the upper plug 302 penetrates the upper pressure cap 304 and is detachably connected with the upper pressure cap 304 through the snap spring 11. The lower plug 303 penetrates the lower pressure cap 305 and is detachably connected with the lower pressure cap 305 through the snap spring 11, facilitating the disassembly and fixed installation of the upper pressure cap.

[0083] Based on the above specific embodiments, as Figure 2 As shown, the upper plug 302 is provided with a sealing ring 10 at the contact surface with the cylinder 301. The lower plug 303 is provided with a sealing ring 10 at the contact surface with the cylinder 301 to avoid oil leakage.

[0084] Based on the above specific embodiments, a piston 306 tool push rod can be provided, the end of which is provided with external threads, and the corresponding internal threads are provided on the upper end surface of the piston 306. After disassembling the upper pressure cap 304 and the upper plug 302, the tool push rod is threadedly connected with the piston 306, that is, the piston 306 can be pushed downward or pulled upward.

[0085] Embodiment 1

[0086] Step S1, 5 parts by weight of the warm pressure response type plugging agent and 100 parts by weight of clean water are mixed, and continuously stirred at room temperature for 30 min.

[0087] Step S2, 150 parts by weight of the mixed solution obtained in step S1 is poured into each of the three warm pressure reactors 3, the reactor body is closed, and the exhaust valve 9 is kept open.

[0088] Step S3, the hydraulic main valve 5 is closed and the back pressure main valve 6 is opened, then the back pressure valve No. 1 is opened, the back pressure valve No. 2 and the back pressure valve No. 3 are closed, and the warm pressure reactor No. 1 3 is injected with back pressure 2 MPa through the hydraulic hand pump.

[0089] Step S4, the back pressure valve No. 2 is opened, the back pressure valve No. 1 and the back pressure valve No. 3 are closed, and the warm pressure reactor No. 2 3 is injected with back pressure 5 MPa through the hydraulic hand pump.

[0090] Step S5, the back pressure valve No. 3 is opened, the back pressure valve No. 1 and the back pressure valve No. 2 are closed, and the warm pressure reactor No. 3 3 is injected with back pressure 8 MPa through the hydraulic hand pump.

[0091] Step S6, the back pressure main valve 6 is closed and the hydraulic main valve 5 is opened, then the hydraulic valve No. 1 is opened, the hydraulic valve No. 2 and the hydraulic valve No. 3 are closed, and the warm pressure reactor No. 1 3 is injected with pressure 2 MPa through the hydraulic hand pump. After the pressure in the reactor is stable, the exhaust valve 9 is closed.

[0092] Step S7, the hydraulic valve No. 2 is opened, the hydraulic valve No. 1 and the hydraulic valve No. 3 are closed, and the warm pressure reactor No. 2 3 is injected with pressure 5 MPa through the hydraulic hand pump. After the pressure in the reactor is stable, the exhaust valve 9 is closed.

[0093] Step S8, open hydraulic valve No. 3, close hydraulic valve No. 1 and hydraulic valve No. 2, inject pressure 8 MPa into No. 3 warm pressure reactor 3 through hydraulic hand pump, and close exhaust valve 9 after the reactor pressure is stable.

[0094] Step S9, open the air blast heating power supply, set the reaction temperature to 150℃ and open the rapid heating and air blast buttons, and start timing after the air blast heating temperature is stable.

[0095] Step S10, after 6 h of reaction, close the heating button, open hydraulic main valve 5, hydraulic valves No. 1-3 and exhaust valve 9.

[0096] Step S11, after the heating device cools to room temperature, open the warm pressure reactor 3, and take out the plugging agent.

[0097] Step S12, cut the plugging agent obtained in step S11 into a cuboid with a length of 30 mm, a width of 12 mm and a height of 3 mm, and test the tensile properties by a universal testing machine at a tensile rate of 100 mm / min, and take the breaking stress as the tensile property index.

[0098] Step S13, cut the plugging agent obtained in step S11 into a cylinder with a diameter of 8 mm and a height of 20 mm, and test the compression properties at a compression strain of 90% by a universal testing machine at a compression rate of 5 mm / min, and take the stress at 90% strain as the compression property index.

[0099] Step S14, cut the plugging agent obtained in step S11 into a circular disc with a diameter of 8 mm and a height of 4 mm, test the rheological strength by a rheometer, and set the interval to 1 mm for the rheological test. Then place the gel on the lower test plate, fix the oscillation scanning frequency to 1 Hz, and scan the strain amplitude range to 0.1% ~ 1000%, determine the viscoelastic interval of the gel by strain scanning. Within the viscoelastic interval of the gel, fix the strain of oscillation scanning, and conduct frequency scanning within the frequency range of 0.1 ~ 100 Hz, and take the average storage modulus within the viscoelastic interval as the rheological property index.

[0100] According to the above steps, the properties of the samples in the three warm pressure reactors (3) are shown in the following table:

[0101]

[0102] Example 2

[0103] Step S1, mix 10 parts by weight of the warm pressure responsive plugging agent and 100 parts by weight of 5% bentonite slurry, and continuously stir at room temperature for 30 min.

[0104] Step S2, 150 parts by weight of the mixed solution obtained in step S1 were poured into three warm pressure reaction kettles 3 respectively, the kettle body was closed and the exhaust valve 9 was kept open.

[0105] Step S3, the hydraulic total valve 5 was closed and the back pressure total valve 6 was opened, then the back pressure valve No. 1 was opened, the back pressure valve No. 2 and the back pressure valve No. 3 were closed, and the warm pressure reaction kettle No. 1 was injected with back pressure 5 MPa through the hydraulic hand pump.

[0106] Step S4, the back pressure valve No. 2 was opened, the back pressure valve No. 1 and the back pressure valve No. 3 were closed, and the warm pressure reaction kettle No. 2 was injected with back pressure 10 MPa through the hydraulic hand pump.

[0107] Step S5, the back pressure valve No. 3 was opened, the back pressure valve No. 1 and the back pressure valve No. 2 were closed, and the warm pressure reaction kettle No. 3 was injected with back pressure 15 MPa through the hydraulic hand pump.

[0108] Step S6, the back pressure total valve 6 was closed and the hydraulic total valve 5 was opened, then the hydraulic valve No. 1 was opened, the hydraulic valve No. 2 and the hydraulic valve No. 3 were closed, and the warm pressure reaction kettle No. 1 was injected with pressure 5 MPa through the hydraulic hand pump, and after the kettle pressure was stable, the exhaust valve 9 was closed.

[0109] Step S7, the hydraulic valve No. 2 was opened, the hydraulic valve No. 1 and the hydraulic valve No. 3 were closed, and the warm pressure reaction kettle No. 2 was injected with pressure 10 MPa through the hydraulic hand pump, and after the kettle pressure was stable, the exhaust valve 9 was closed.

[0110] Step S8, the hydraulic valve No. 3 was opened, the hydraulic valve No. 1 and the hydraulic valve No. 2 were closed, and the warm pressure reaction kettle No. 3 was injected with pressure 15 MPa through the hydraulic hand pump, and after the kettle pressure was stable, the exhaust valve 9 was closed.

[0111] Step S9, the air blowing heating power was turned on, the reaction temperature was set to 220℃, and the fast heating and air blowing buttons were opened, and after the air blowing heating temperature was stable, the timing was started.

[0112] Step S10, after the reaction was carried out for 24 h, the heating button was closed, the hydraulic total valve 5, the hydraulic valve No. 1-3 and the exhaust valve 9 were opened.

[0113] Step S11, after the heating device was cooled to room temperature, the warm pressure reaction kettle 3 was opened, and the plugging agent was taken out.

[0114] Step S12, the plugging agent obtained in step S11 was cut into a cuboid with a length of 30 mm, a width of 12 mm and a height of 3 mm, and the tensile properties were tested by a universal testing machine at a tensile rate of 100 mm / min, and the breaking stress was taken as the tensile property index.

[0115] Step S13, the lost circulation material obtained in step S11 is cut into a cylinder with a diameter of 8 mm and a height of 20 mm, and the compression performance at a compression strain of 90% is tested by a universal testing machine at a compression rate of 5 mm / min, and the stress at a strain of 90% is taken as the compression performance index.

[0116] Step S14, the lost circulation material obtained in step S11 is cut into a disc with a diameter of 8 mm and a height of 4 mm, and the rheological strength is tested by a rheometer, and the interval is set to 1 mm. Then the gel is placed on the lower test plate, the fixed oscillation scanning frequency is 1 Hz, and the strain amplitude scanning range is 0.1% ~ 1000%, and the viscoelastic interval of the gel is determined by strain scanning. Within the viscoelastic interval of the gel, the strain of the fixed oscillation scanning is fixed, and the frequency scanning is carried out in the frequency range of 0.1 ~ 100 Hz, and the average storage modulus in the viscoelastic interval is taken as the rheological performance index.

[0117] According to the above steps, the performance of the samples in the three warm pressure reaction kettles (3) is shown in the following table:

[0118]

[0119] Example 3

[0120] Step S1, 20 parts by weight of the warm pressure responsive lost circulation material and 100 parts by weight of 5% bentonite slurry are mixed, and stirring is continued at room temperature for 30 min.

[0121] Step S2, 150 parts by weight of the mixed solution obtained in step S1 is poured into each of the three warm pressure reaction kettles 3, the kettle body is closed and the exhaust valve 9 is kept open.

[0122] Step S3, close the hydraulic main valve 5 and open the back pressure main valve 6, then open the back pressure valve 2, close the back pressure valve 1 and the back pressure valve 3, and inject back pressure 6 MPa into the No. 2 warm pressure reaction kettle 3 through the hydraulic hand pump.

[0123] Step S4, open the back pressure valve 3, close the back pressure valve 1 and the back pressure valve 2, and inject back pressure 12 MPa into the No. 3 warm pressure reaction kettle 3 through the hydraulic hand pump.

[0124] Step S5, close the back pressure main valve 6 and open the hydraulic main valve 5, then open the hydraulic valve 2, close the hydraulic valve 1 and the hydraulic valve 3, and inject pressure 6 MPa into the No. 2 warm pressure reaction kettle 3 through the hydraulic hand pump, and close the exhaust valve 9 after the kettle pressure stabilizes.

[0125] Step S6, open the hydraulic valve 3, close the hydraulic valve 1 and the hydraulic valve 2, and inject pressure 12 MPa into the No. 3 warm pressure reaction kettle 3 through the hydraulic hand pump, and close the exhaust valve 9 after the kettle pressure stabilizes.

[0126] Step S7, open the blast heating power supply, set the reaction temperature to 250℃ and open the rapid heating and blast buttons, and start timing after the blast heating temperature is stable.

[0127] Step S8, after 14 hours of reaction, close the heating button, open the hydraulic main valve 5, hydraulic valves 1-3 and exhaust valve 9.

[0128] Step S9, after the heating device cools to room temperature, open the autoclave 3 and take out the plugging agent.

[0129] Step S10, cut the plugging agent obtained in step S9 into a cuboid with a length of 30 mm, a width of 12 mm and a height of 3 mm, and test the tensile properties by a universal testing machine at a tensile rate of 100 mm / min, and take the breaking stress as the tensile property index.

[0130] Step S11, cut the plugging agent obtained in step S9 into a cylinder with a diameter of 8 mm and a height of 20 mm, and test the compression properties at a compression rate of 5 mm / min by a universal testing machine, and take the stress at 90% strain as the compression property index.

[0131] Step S12, cut the plugging agent obtained in step S9 into a circular disc with a diameter of 8 mm and a height of 4 mm, test the rheological strength by a rheometer, and set the interval to 1 mm. Then place the gel on the lower test plate, fix the oscillation scan frequency to 1 Hz, and the strain amplitude scan range to 0.1%-1000%, determine the viscoelastic interval of the gel by strain scanning. Within the viscoelastic interval of the gel, fix the oscillation scan strain, and perform frequency scanning within the frequency range of 0.1-100 Hz, and take the average storage modulus within the viscoelastic interval as the rheological property index.

[0132] According to the above steps, the properties of the samples in the three autoclaves (3) are shown in the following table:

[0133]

[0134] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for evaluating a temperature and pressure responsive lost circulation material, characterized in that, The temperature and pressure response type plugging agent evaluation device comprises a hydraulic device (1), a heating box (2) provided with a plurality of temperature and pressure reaction kettles (3), and each temperature and pressure reaction kettle (3) is communicated with the hydraulic device (1). The temperature and pressure response type plugging agent evaluation device comprises a hydraulic device (1), a heating box (2) provided with a plurality of temperature and pressure reaction kettles (3), and each temperature and pressure reaction kettle (3) is communicated with the hydraulic device (1). The temperature and pressure reaction kettle (3) comprises a plurality of vertically arranged cylinder bodies (301), a detachable upper plug (302) mounted on the upper end opening of the cylinder body (301), and the upper plug (302) is communicated with an exhaust valve (9), a lower plug (303) fixedly installed at the lower end opening of the cylinder body (301), and the lower plug (303) is provided with an oil inlet communicated with the hydraulic device (1), and a piston (306) slidingly fitted in the cylinder body (301). The hydraulic device (1) comprises a hydraulic pump (4), a pair of hydraulic total valve (5) and back pressure total valve (6), a plurality of groups of hydraulic valve (7) and back pressure valve (8), each hydraulic valve (7) is communicated with the corresponding lower plug (303) through a pipeline, the hydraulic pump (4) is communicated with a buffer tank, and then is respectively communicated with the hydraulic total valve (5) and the back pressure total valve (6), the hydraulic total valve (5) is connected with each hydraulic valve (7), and the back pressure total valve (6) is connected with each back pressure valve (8). The temperature and pressure response type plugging agent evaluation method comprises the following steps: Step S1, mix the temperature and pressure response type plugging agent and the working liquid, and stir uniformly at room temperature; Step S2, the mixed liquid obtained in step S1 is added above the piston (306) in each temperature and pressure reaction kettle (3), and each exhaust valve (9) is kept in an open state; Step S3, close the hydraulic total valve (5) and open the back pressure total valve (6), then inject back pressure into each temperature and pressure reaction kettle (3) in turn; Step S4, close the back pressure total valve (6) and open the hydraulic total valve (5), then inject pressure into each temperature and pressure reaction kettle (3) in turn, and after the pressure in the kettle is stable, close each exhaust valve (9); Step S5, heat the heating box (2); Step S6, after the reaction is completed, close the heating button, open the hydraulic total valve (5), each hydraulic valve (7) and each exhaust valve (9); Step S7, after the heating device is cooled to room temperature, open the temperature and pressure reaction kettle (3), take out the plugging agent, and test the mechanical properties or rheological properties. At least one of the following conditions is met: The working liquid in step S1 is one of 5% bentonite slurry, water, 5% NaCl solution, 10% NaCl solution or polysulfonate drilling fluid; The mass ratio of the plugging agent to the working liquid in step S1 is (5-10):100, and the stirring time is 10-60 min; The mixed liquid added in step S2 is 120-200 g; The back pressure injected into each temperature and pressure reaction kettle (3) in step S3 is 0-20 MPa; ​ ​ ​ ​ ​ 2. The method according to claim 1, wherein ​ ​ ​ ​ ​ The pressure injected in each of the warm pressure reaction kettles (3) in step S4 is 0-20 MPa; The reaction temperature in step S5 is 25-250°C; The reaction time in step S6 is 6-24 h.

3. The method according to claim 1, wherein Further comprising at least one of the following steps: The plugging agent obtained in step S7 is cut into a cuboid, and its tensile property is tested by a universal testing machine at a certain tensile rate, wherein the breaking stress is taken as the tensile property index; The plugging agent obtained in step S7 is cut into a cylinder, and its compression property is tested by a universal testing machine at a certain compression rate, wherein the stress under a fixed strain is taken as the compression property index; The plugging agent obtained in step S7 is cut into a round sheet, and its rheological strength is tested by a rheometer, wherein the average storage modulus in the viscoelastic interval is taken as the rheological property index.

4. The warm pressure response type plugging agent evaluation method according to claim 3, wherein The plugging agent is cut into a cuboid with a length of 30-40 mm, a width of 10-15 mm, and a height of 3-10 mm, and the tensile rate is 50-100 mm / min; The plugging agent is cut into a cylinder with a diameter of 8-10 mm and a height of 12-20 mm, the compression rate is 2-10 mm / min, and the compression strain is 50-95%; The plugging agent is cut into a round sheet with a diameter of 8-15 mm and a height of 2-4 mm, the interval for rheological testing is set to 1 mm, then the gel is placed on the lower testing plate, the fixed oscillation scanning frequency is set to 1 Hz, the strain amplitude scanning range is set to 0.1%-1000%, the viscoelastic interval of the gel is determined by strain scanning, the strain of the fixed oscillation scanning is fixed, and the frequency scanning is performed in the frequency range of 0.1-100 Hz.

5. The warm pressure response type plugging agent evaluation method according to claim 1, wherein: An upper pressure cap (304) is detachably mounted at the upper end of the barrel (301), and the upper pressure cap (304) is detachably connected with the upper plug (302); A lower pressure cap (305) is fixedly mounted at the lower end of the barrel (301), and the lower pressure cap (305) is fixedly connected with the lower plug (303).

6. The warm pressure response type plugging agent evaluation method according to claim 5, wherein: The upper plug (302) is provided with a sealing ring (10) at the contact surface with the barrel (301); The lower plug (303) is provided with a sealing ring (10) at the contact surface with the barrel (301); The upper plug (302) penetrates through the upper pressure cap (304) and is detachably connected with the upper pressure cap (304) through a clasp spring (11); The lower plug (303) penetrates through the lower pressure cap (305) and is detachably connected with the lower pressure cap (305) through a clasp spring (11).

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