Self-consolidating plugging agent and application thereof

Abstract

The application provides a self-consolidating plugging agent and application thereof. The self-consolidating plugging agent comprises a thermosetting resin, an inorganic composite material, a silane coupling agent, dicyandiamide, dimethyl imidazole and an amide compound.

Description

Technical Field

[0001] This invention relates to the field of well cementing and plugging, and particularly to a self-consolidating plugging agent. Background Technology

[0002] Well leakage is a global technical challenge in oil and gas well exploration and development, accounting for 20% to 25% of all well leakage cases worldwide. Losses due to well leakage reach hundreds of millions of US dollars annually, causing incalculable damage to oil and gas well development. Severe leakage, such as cavernous leakage and large fracture leakage, severely restricts the progress of oil and gas well exploration and development. Currently, there are no effective sealing technologies for severe leakage, both domestically and internationally, which can ultimately lead to drill bit burial, well collapse, and even the abandonment of the well. Summary of the Invention

[0003] One aspect of the present invention provides a self-curing sealant comprising a thermosetting resin, an inorganic composite material, a silane coupling agent, dicyandiamine, dimethylimidazole, and an amide compound.

[0004] In one specific embodiment, the epoxy value of the thermosetting resin is above 0.44.

[0005] In one specific embodiment, the thermosetting resin is thermosetting resin E44.

[0006] In one specific embodiment, the inorganic composite material is calcium carbonate and glass fiber.

[0007] In one specific embodiment, the mass ratio of the calcium carbonate to the glass fiber is (5 to 8):3.

[0008] In one specific embodiment, the calcium carbonate has a particle size of 800 to 1200 mesh; the glass fiber has a length of 0.2 to 0.6 mm.

[0009] In one specific embodiment, the silane coupling agent is silane coupling agent KH550.

[0010] In one specific embodiment, the amide compound is dimethylacetamide (DMA) and / or dimethylformamide (DMF).

[0011] In one specific embodiment, the mass ratio of the thermosetting resin to the inorganic composite material is (8.1 to 19):1.

[0012] In one specific embodiment, the mass ratio of the thermosetting resin to the amide compound is (4 to 5):1.

[0013] In one specific embodiment, the mass ratio of the thermosetting resin, the dicyandiamine, and the dimethylimidazole is 100:(6 to 10):(0.2 to 0.6).

[0014] In one specific embodiment, the silane coupling agent accounts for 2% to 4% of the total mass of the inorganic composite material, which is 100% of the total mass of the inorganic composite material.

[0015] The second aspect of the present invention provides a method for preparing a self-consolidating sealant as described in any one of the first aspects of the present invention, comprising the following steps:

[0016] 1) Dicyandiamine and dimethylimidazole are dissolved in an amide compound to obtain a first mixture;

[0017] 2) Add the thermosetting resin to the first mixture and mix thoroughly to obtain the second mixture;

[0018] 3) Add the silane coupling agent to the second mixture and mix thoroughly to obtain the third mixture;

[0019] 4) Add the inorganic composite material to the third mixture and mix evenly to obtain the self-consolidating sealant.

[0020] The third invention provides the application of the self-consolidating plugging agent according to any one of the inventions in oil and gas drilling plugging.

[0021] The beneficial effects of this invention are:

[0022] The purpose of this invention is to overcome the shortcomings of the prior art and provide a controllable self-consolidating plugging agent for sealing malignant leakage formations and its preparation method.

[0023] This invention solves the problem of high viscosity and pumping difficulty of thermosetting resins at room temperature, resulting in a controllable self-curing sealant with good flowability and pumpability at room temperature, thus exhibiting room-temperature pumpability. Its temperature resistance can reach 150℃, and the curing time is controllable from 0.5h to 4.5h, particularly from 1.2h to 2.5h, thus exhibiting temperature-controlled curing time. Furthermore, the self-curing sealant of this invention has high curing compressive strength, greater than 40MPa, and good pressure-bearing sealing performance for 1cm cracks, with a pressure gradient exceeding 85MPa / m. Therefore, it can effectively seal large cracks, such as 1cm, demonstrating significant advantages in the treatment of severe leakage.

[0024] Furthermore, the self-consolidating plugging agent of this invention has a drillability of level 5 to 6 after solidification, indicating good drillability. When placed in water-based drilling fluid and simulated formation water, it does not dissolve or deform at 150°C, maintains a complete structure, and has good anti-pollution properties. Moreover, it can be effectively dissolved by environmentally friendly solvents to achieve the purpose of unblocking, avoiding wellbore blockage and safety accidents. This represents a significant new breakthrough in conventional malignant leakage control technology. Attached Figure Description

[0025] Figure 1 The image shows product 6# after the solidification of the sealant prepared in Example 6.

[0026] Figure 2 The image shows the solidified state of product 6# of the sealing agent prepared in Example 6 after being dissolved in solvent GY-1 for 2 hours.

[0027] Figure 3 The solidified product 6# of the sealing agent prepared in Example 6 is shown in its solidified state after being dissolved in solvent GY-1 for 8 hours.

[0028] Figure 4 The image shows the solidified state of product 6# of the sealing agent prepared in Example 6 after being dissolved in solvent GY-1 for 24 hours. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0030] Dicyandiamine (DCD), dimethylimidazole (GC), dimethylacetamide (DMA), and dimethylformamide (DMF) were all purchased from Chengdu Kelong Chemical Co., Ltd., and were of analytical grade.

[0031] Thermosetting resin E44 with an epoxy value of 0.44 and thermosetting resin E12 with an epoxy value of 0.12 were purchased from Nantong Xingchen Synthetic Materials Co., Ltd.

[0032] KH550 was purchased from Dongguan Shanyi Plastics Co., Ltd.

[0033] Both calcium carbonate and glass fiber were purchased from Guangdong Bohao Composite Materials Co., Ltd.

[0034] Sodium chloride, calcium chloride, and magnesium chloride hexahydrate were all analytical grade and purchased from Chengdu Kelong Chemical Co., Ltd.

[0035] Example 1

[0036] The calcium carbonate used in this embodiment is 800 mesh; the glass fiber has an average length of 0.2 mm and an average diameter of 0.4 mm.

[0037] The preparation method of the controllable self-consolidating sealant is as follows:

[0038] Step 1: Weigh 2.136g of DCD and 0.0712g of GC into graduated glass test tubes with stoppers, respectively;

[0039] Step 2: Weigh 7.12g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0040] Step 3: Weigh 35.6g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0041] Step 4: Weigh 0.088g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0042] Step 5: Weigh 3.2g of calcium carbonate and 1.2g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0043] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 2 MPa. It was then placed in an oven and heated at 150°C for 2.5 hours to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product 1#.

[0044] Example 2

[0045] In this embodiment, the calcium carbonate used is 1000 mesh, and the glass fiber has an average length of 0.6 mm and an average diameter of 0.35 mm.

[0046] The preparation method of the controllable self-consolidating sealant is as follows:

[0047] Step 1: Weigh 2.880g of DCD and 0.144g of GC into graduated glass test tubes with stoppers, respectively;

[0048] Step 2: Weigh 7.20g of DMF and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC, and obtain the first mixture.

[0049] Step 3: Weigh 36g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0050] Step 4: Weigh 0.12g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0051] Step 5: Weigh 2.8g of calcium carbonate and 1.2g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0052] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 2.2 hours to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product #2.

[0053] Example 3

[0054] In this embodiment, the calcium carbonate used is 1200 mesh, and the glass fiber has an average length of 0.4 mm and an average diameter of 0.5 mm.

[0055] The preparation method of the controllable self-consolidating sealant is as follows:

[0056] Step 1: Weigh 3.640g of DCD and 0.218g of GC into graduated glass test tubes with stoppers, respectively;

[0057] Step 2: Weigh 8.008g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0058] Step 3: Weigh 36.4g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0059] Step 4: Weigh 0.144g of KH550 and add it to the second mixture. Stir thoroughly to obtain the third mixture.

[0060] Step 5: Weigh 2.4g of calcium carbonate and 1.2g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0061] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 2 hours to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product #3.

[0062] Example 4

[0063] In this embodiment, the calcium carbonate used is 1000 mesh, and the glass fiber has an average length of 0.3 mm and an average diameter of 0.45 mm.

[0064] The preparation method of the controllable self-consolidating sealant is as follows:

[0065] Step 1: Weigh 2.208g of DCD and 0.074g of GC into graduated glass test tubes with stoppers, respectively;

[0066] Step 2: Weigh 8.096g of DMF and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0067] Step 3: Weigh 36.8g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0068] Step 4: Weigh 0.064g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0069] Step 5: Weigh 2.0g of calcium carbonate and 1.2g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0070] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 2 MPa. It was then placed in an oven and heated at 150°C for 1.9 h to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product #4.

[0071] Example 5

[0072] In this embodiment, the calcium carbonate used is 1200 mesh, and the glass fiber has an average length of 0.5 mm and an average diameter of 0.6 mm.

[0073] The preparation method of the controllable self-consolidating sealant is as follows:

[0074] Step 1: Weigh 3.008g of DCD and 0.150g of GC into graduated glass test tubes with stoppers, respectively;

[0075] Step 2: Weigh 9.024g of DMF and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0076] Step 3: Weigh 37.6g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0077] Step 4: Weigh 0.072g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0078] Step 5: Weigh 1.6g of calcium carbonate and 0.8g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0079] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.7 h to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product #5.

[0080] Example 6

[0081] The calcium carbonate used in this embodiment is 800 mesh, and the glass fiber has an average length of 0.2 mm and an average diameter of 0.45 mm.

[0082] The preparation method of the controllable self-consolidating sealant is as follows:

[0083] Step 1: Weigh 3.8g of DCD and 0.228g of GC into graduated glass test tubes with stoppers, respectively;

[0084] Step 2: Weigh 9.5g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0085] Step 3: Weigh 38.0g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0086] Step 4: Weigh 0.08g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0087] Step 5: Weigh 1.6g of calcium carbonate and 0.4g of glass fiber into the third mixture, stir thoroughly to obtain a self-consolidating sealant.

[0088] The graduated glass test tube containing the self-consolidating sealant was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.2 h to solidify. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product 6#.

[0089] Comparative Example 1

[0090] The glass fibers used in this embodiment have an average length of 0.2 mm and an average diameter of 0.45 mm.

[0091] The preparation method of the sealing agent is as follows:

[0092] Step 1: Weigh 3.8g of DCD and 0.228g of GC into graduated glass test tubes with stoppers, respectively;

[0093] Step 2: Weigh 9.5g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0094] Step 3: Weigh 38.0g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0095] Step 4: Weigh 0.08g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0096] Step 5: Weigh 2.0g of glass fiber and add it to the third mixture, stir thoroughly to obtain the sealant.

[0097] The graduated glass test tube containing the sealing agent was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.2 h to solidify the reaction. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product D1#.

[0098] Comparative Example 2

[0099] The calcium carbonate used in this embodiment is 800 mesh.

[0100] The preparation method of the sealing agent is as follows:

[0101] Step 1: Weigh 3.8g of DCD and 0.228g of GC into graduated glass test tubes with stoppers, respectively;

[0102] Step 2: Weigh 9.5g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0103] Step 3: Weigh 38.0g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0104] Step 4: Weigh 0.08g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0105] Step 5: Weigh 2.0g of calcium carbonate and add it to the third mixture, stir thoroughly to obtain the sealing agent;

[0106] The graduated glass test tube containing the sealing agent was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.2 h to solidify the reaction. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product D2#.

[0107] Comparative Example 3

[0108] The calcium carbonate used in this embodiment is 800 mesh, and the glass fiber has an average length of 0.2 mm and an average diameter of 0.45 mm.

[0109] The preparation method of the sealing agent is as follows:

[0110] Step 1: Weigh 3.8g of DCD and 0.228g of GC into graduated glass test tubes with stoppers, respectively;

[0111] Step 2: Weigh 9.5g of DMA and pour it into a graduated glass test tube containing DCD and GC. Stir thoroughly at room temperature to completely dissolve DCD and GC to obtain the first mixture.

[0112] Step 3: Weigh 38.0g of heated thermosetting resin E44 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0113] Step 4: Weigh 1.6g of calcium carbonate and 0.4g of glass fiber into the second mixture, stir thoroughly to obtain the sealant.

[0114] The graduated glass test tube containing the sealing agent was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.2 h to solidify the reaction. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product D3#.

[0115] Comparative Example 4

[0116] The calcium carbonate used in this embodiment is 800 mesh, and the glass fiber has an average length of 0.2 mm and an average diameter of 0.45 mm.

[0117] The preparation method of the sealing agent is as follows:

[0118] Step 1: Weigh 3.8g of curing agent 593 and 0.228g of triethanolamine into graduated glass test tubes with stoppers, respectively;

[0119] Step 2: Weigh 9.5g of DMA and pour it into a graduated glass test tube containing curing agent 593 and triethanolamine. Stir thoroughly to dissolve curing agent 593 and triethanolamine completely to obtain the first mixture.

[0120] Step 3: Weigh 38.0g of heated thermosetting resin E12 (poor flowability at room temperature), add it to the first mixture, and stir thoroughly to obtain the second mixture;

[0121] Step 4: Weigh 0.08g of KH550 and add it to the second mixture, stir thoroughly to obtain the third mixture;

[0122] Step 5: Weigh 1.6g of calcium carbonate and 0.4g of glass fiber into the third mixture, stir thoroughly to obtain the sealing agent.

[0123] The graduated glass test tube containing the sealing agent was placed in an aging tank and pressurized to 3 MPa. It was then placed in an oven and heated at 150°C for 1.2 h to solidify the reaction. The oven was then closed, and the graduated glass test tube was left to cool slowly and naturally to room temperature in the oven before being removed, yielding the solidified product D4#.

[0124] Performance testing

[0125] Water-based drilling fluid formulation: 300mL tap water, 10.5g bentonite N V -1 (purchased from Bohai Drilling Engineering Co., Ltd.), 12g sodium carbonate (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 1.8g coating agent KPAM (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 3g filtration loss reducer PAC-LV (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 12g filtration loss reducer SMP-2 (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 12g filtration loss reducer SMC (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 9g anti-collapse agent FT-1 (purchased from Chengdu Chuanfeng Chemical Co., Ltd.), 12g lubricant RH220 (purchased from Chengdu Chuanfeng Chemical Co., Ltd.).

[0126] 1. Determination of the rheological properties, temperature resistance, and stain resistance of the sealing agent.

[0127] Simulated formation water formulation: Add 262.5g sodium chloride, 22.5g calcium chloride and 15g magnesium chloride hexahydrate to 300mL of tap water, so that the mass ratio of sodium chloride:calcium chloride:magnesium chloride hexahydrate is 7:0.6:0.4.

[0128] (1) The sealing agents of each embodiment and comparative example were prepared and placed at room temperature for different times to investigate the flow of the sealing agent at room temperature before curing. The results are shown in Table 1.

[0129] (2) The sealant prepared in each example and comparative example was placed in an oven at 150°C for different times to examine the high temperature resistance of the sealant after curing. The results are shown in Table 1.

[0130] (3) 100g of the cured plugging agent prepared in each example and comparative example was placed in 350mL of water-based drilling fluid or simulated formation water and placed in an oven at 150℃ for 24h to test the anti-pollution performance of the plugging agent. The results are shown in Table 1.

[0131] The results are shown in Table 1.

[0132] Table 1 Evaluation of the rheological properties, temperature resistance, and stain resistance of the sealing agent.

[0133]

[0134] As shown in Table 1, the plugging agent before curing does not gel at room temperature for a long time and has good fluidity, ensuring good pumpability before well entry. The plugging agent does not melt after 72 hours at 150℃, and its structure remains intact, demonstrating good temperature resistance. Furthermore, when the plugging agent is placed in water-based drilling fluid and simulated formation water and reacted in a 150℃ oven for 24 hours, it does not dissolve, does not deform, maintains its intact structure, and exhibits good anti-fouling properties.

[0135] 2. Determination of compressive strength, pressure-bearing sealing performance, and drillability of the sealing agent.

[0136] (1) The plugging agents prepared in the various embodiments and comparative examples of the present invention were cut into cylindrical samples with a diameter of 23 mm and a height of 50 mm in accordance with the requirements of GB / T 2567-2008 "Performance Testing of Resin Castings". The compressive strength mechanical properties of the product after the plugging agent was solidified were tested using the American MTS rock stress testing device.

[0137] (2) Artificial drilling was performed on the natural rock core to create cracks with a width of about 1 cm. Then, the rock core with a 1 cm crack was placed in a beaker with vacuum silicone grease applied to the bottom. The sealing agents prepared in each example and comparative example were dripped into the round holes of the rock core until they were filled. Then, the beaker was placed in an oven and heated to 130°C for 1.5 h. Then, the temperature was raised to 150°C and heated to solidify for 2 h. After solidification, the temperature was lowered to room temperature to obtain the pressure-bearing sealing test rock core.

[0138] After placing the test core sample into the fracture plugging device, water-based drilling fluid filtrate that has been filtered by a flow meter is injected until fluid flows out of the core sample outlet or the injection pressure begins to decrease. This injection pressure is the breakthrough pressure (plugging pressure).

[0139] (3) The drillability of the plugging agent was tested using a micro-drilling test method. During the test, the solidified plugging agents obtained in each example and comparative example were cut into pieces with a diameter of 3.8 cm and a length of 2 cm. Two PDC drill bits were then used to simulate drilling parameters such as drilling pressure, torque, and drill bit speed during formation drilling (blade backslope angle 20°, side rotation angle 15°, blade thickness 4.5 mm, drill bit outer diameter 32 mm). During the test, a 1 mm pre-drill was first performed, and then the time taken to drill 3 mm was recorded (this time can be converted to footage, such as m / d or m / h, but no conversion was performed here).

[0140] The drillability rating of the plugging agent is determined based on the drilling speed of the micro-drill. Grades one to four are called "soft rock"; grades five to seven are called "medium-hard rock"; and grades eight to ten are called "hard rock", as shown in Table 2.

[0141] The test results are shown in Table 3.

[0142] According to the results in Table 3, the plugging agents prepared in each embodiment have high compressive strength, all greater than 40 MPa; good pressure-bearing sealing performance, with breakthrough pressure gradients all greater than 85 MPa / m; and good drillability, ranging from level 5 to level 6. However, the plugging agents prepared in Comparative Examples 1 to 3 have relatively low strength due to their uneven structure, resulting in unsatisfactory sealing effects; the plugging agent prepared in Comparative Example 4 has poor strength and cannot meet the requirements for treating severe leakage.

[0143] Table 2 Classification Standards for Rock Drillability

[0144]

[0145] Table 3. Determination of compressive strength, pressure-bearing sealing performance, and drillability of the sealing agent.

[0146]

[0147] 3. Determination of the solubility of the sealant

[0148] (1) Take 10g of the solidified product obtained from each example and comparative example and put it into an aging tank, and add 100mL of environmentally friendly solvent GY-1 (purchased from Dongguan Jiequan Technology Co., Ltd.);

[0149] (2) The aging tank was pressurized to 1MPa and placed in an oven at 150℃ for dissolution reactions for 2h, 4h, 8h, 18h and 24h.

[0150] (3) After the reaction, take out the undissolved plugging agent, place it in a 105℃ oven to constant weight, weigh it, and record the mass of the undissolved plugging agent at different times;

[0151] (4) Calculate the dissolution rate of the plugging agent: Dissolution rate = (initial plugging agent mass - remaining undissolved plugging agent mass) / initial plugging agent mass × 100. The results are shown in Table 4.

[0152] in, Figure 1 Product 6# of the sealant prepared in Example 6 after solidification is shown; Figure 2 The solidified product 6# of the plugging agent prepared in Example 6 is shown in the state of the solidified product after being dissolved in solvent GY-1 for 2 hours; Figure 3 The solidified product 6# of the plugging agent prepared in Example 6 is shown in the state of the solidified product after being dissolved in solvent GY-1 for 8 hours; Figure 4 The image shows the solidified state of product 6# of the sealing agent prepared in Example 6 after being dissolved in solvent GY-1 for 24 hours.

[0153] Table 4. Determination of Solubility of Leak-Sealing Agent

[0154]

[0155] According to the results in Table 4, the sealing agents prepared in each embodiment of the present invention have a fast dissolution rate. After 2 hours of dissolution, the structure is obviously destroyed and peeled into blocks. After 8 hours of dissolution, the blocks further dissolve and gradually become smaller, forming extremely small particles. After 24 hours, the dissolution rate is greater than 90%, which meets the technical requirements of being soluble and easy to unblock after subsequent sealing construction.

[0156] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. A self-curing sealant, comprising a thermosetting resin, an inorganic composite material, a silane coupling agent, dicyandiamine, dimethylimidazole, and an amide compound; The thermosetting resin is thermosetting resin E44; The inorganic composite material is calcium carbonate and glass fiber; The calcium carbonate has a particle size of 800 to 1200 mesh; the glass fiber has a length of 0.2 to 0.6 mm; The epoxy value of the thermosetting resin is above 0.44; The mass ratio of the calcium carbonate to the glass fiber is (5 to 8):3; The mass ratio of the thermosetting resin to the inorganic composite material is (8.1 to 19):1; The mass ratio of the thermosetting resin to the amide compound is (4 to 5):1; The mass ratio of the thermosetting resin, the dicyandiamine, and the dimethylimidazole is 100:(6 to 10):(0.2 to 0.6); The total mass of the inorganic composite material is taken as 100%, and the mass of the silane coupling agent is 2% to 4% of the inorganic composite material.

2. The self-consolidating sealant according to claim 1, characterized in that, The silane coupling agent is silane coupling agent KH550.

3. The self-consolidating sealant according to claim 1, characterized in that, The amide compound is dimethylacetamide and / or dimethylformamide.

4. A method for preparing a self-consolidating sealant as described in any one of claims 1 to 3, comprising the following steps: 1) Dicyandiamine and dimethylimidazole are dissolved in an amide compound to obtain a first mixture; 2) Add the thermosetting resin to the first mixture and mix thoroughly to obtain the second mixture; 3) Add the silane coupling agent to the second mixture and mix thoroughly to obtain the third mixture; 4) Add the inorganic composite material to the third mixture and mix evenly to obtain the self-consolidating sealant.

5. The application of the self-consolidating plugging agent according to any one of claims 1 to 3 in oil and gas drilling plugging.

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