Self-repairing well cementation cement paste as well as preparation method and application thereof

Abstract

The invention discloses self-repairing well cementation cement paste as well as a preparation method and application thereof. The self-repairing material comprises an acyl sulfuric acid modified thermoplastic elastomer and an inorganic material, and the mass ratio of the acyl sulfuric acid modified thermoplastic elastomer to the inorganic material is 1: (0.5-2). According to the invention, the acyl sulfate modified thermoplastic elastomer and the inorganic material are matched for use, so that the self-repairing material has low elastic modulus and self-repairing capability at the same time, and can be used as a functional additive of a well cementation cement slurry system, so that the well cementation cement slurry system has low elastic modulus and self-repairing capability at the same time; and then micro cracks and micro gaps of the well cementation cement sheath can be repaired in time, long-acting sealing of the cement sheath is greatly guaranteed, and then the service life of an oil and gas well can be prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas well cementing technology, in particular to a self-repairing cementing slurry and a preparation method and application thereof. BACKGROUND

[0002] Most of the unconventional horizontal wells need to be fractured and completed in stages in the later stage, which requires not only good cementing quality but also good mechanical properties of the cement stone, such as low enough elastic modulus. The materials commonly used to improve the elastic properties of the cement stone mainly include: butadiene-styrene latex, styrene-acrylic latex, rubber particles and organic resin, etc. Among them, the latex and organic resin are limited in their wide use due to their high price, and the rubber particles and resin materials affect their application in oil and gas well cementing due to their poor temperature resistance and their own defects.

[0003] The rubber particles have become the first choice of many elastic cement slurry systems due to their wide sources and low price. Through surface modification treatment of the rubber material and matching with other cementing additives, an elastic cement slurry system is formed, which has an elastic modulus in the range of 7GPa-9GPa and a compressive strength >8MPa, basically meeting the needs of shale gas well cementing at present. However, various well testing, testing and production operations will inevitably affect the casing and cement sheath due to the large changes in temperature and pressure, which will inevitably cause micro gaps and micro cracks at the cementing interface, thereby forming a channel for the channeling of downhole formation fluid (especially natural gas), and further channeling to the wellhead, forming casing annulus pressure, and causing interlayer isolation failure. SUMMARY

[0004] The present application aims to overcome the problem of micro gaps and micro cracks at the cementing interface in the prior art, and provides a self-repairing cementing slurry and a preparation method and application thereof. The self-repairing cementing slurry has low elastic modulus and gas self-repairing ability, can repair the micro cracks and micro gaps of the cement sheath in time, achieves the purpose of "prevention first and treatment later" in unconventional shale oil and gas cementing, ensures the long-term sealing effectiveness of the annular cement, and further saves the workover cost.

[0005] In order to achieve the above-mentioned purpose, the present application provides a self-repairing material, which comprises an acyl sulfate modified thermoplastic elastomer and an inorganic material, wherein the mass ratio of the acyl sulfate modified thermoplastic elastomer to the inorganic material is 1:0.5-2.

[0006] The second aspect of the present application provides a preparation method of a self-repairing material, which comprises the following steps:

[0007] The thermoplastic elastomer is subjected to a sulfonation reaction with acyl sulfate in a solvent to obtain an acyl sulfate modified thermoplastic elastomer;

[0008] Mixing the acyl sulfate-modified thermoplastic elastomer with inorganic materials.

[0009] The third aspect of the present application provides an application of the self-repairing material of the first aspect or the self-repairing material prepared by the preparation method of the second aspect in well cementing cement.

[0010] The fourth aspect of the present application provides a self-repairing well cementing slurry, which comprises, in parts by weight, oil well cement 100, self-repairing material 5-15, fluid loss additive 4-8, high-temperature retarder 1-4, thermal stable material 30-60, auxiliary lightening material 0-100, auxiliary weighting material 0-100 and water 30-100; wherein the self-repairing material is the self-repairing material of the first aspect or the self-repairing material prepared by the preparation method of the second aspect.

[0011] Through the above technical solution, the present application has the following beneficial technical effects:

[0012] The present application uses acyl sulfate-modified thermoplastic elastomer and inorganic materials together, so that the self-repairing material has low elastic modulus and self-repairing ability, and can be used as a functional additive of well cementing slurry system, so that the well cementing slurry system has low elastic modulus and self-repairing ability, and can repair micro-cracks and micro-gaps of the well cementing ring in time, greatly ensuring long-term sealing of the cement ring.

[0013] The well cementing slurry system based on the self-repairing material of the present application is especially suitable for unconventional shale oil and gas well cementing, and can achieve the purpose of "prevention first and treatment later", greatly ensuring long-term sealing of the cement ring, and prolonging the service life of the oil and gas well. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the thickening curve of the self-repairing well cementing slurry S1 obtained in application example 1 of the present application;

[0015] Figure 2 is the thickening curve of the self-repairing well cementing slurry S2 obtained in application example 2 of the present application;

[0016] Figure 3 is the thickening curve of the self-repairing well cementing slurry S3 obtained in application example 3 of the present application;

[0017] Figure 4 is the flow change curve of the self-repairing well cementing slurry S2 obtained in application example 2 of the present application curing into cement stone;

[0018] Figure 5 is the flow change curve of the self-repairing well cementing slurry D1 obtained in comparative application example 1 curing into cement stone. DETAILED DESCRIPTION

[0019] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not critical to the invention. Any numerical range recited herein is intended to include all sub-ranges of the same numbers (i.e., every subset of numbers within the indicated range). For ranges containing one or more endpoints, the endpoints are included in the range. For ranges excluding any endpoints, the range is intended to exclude the excluded endpoint(s). The endpoints of the ranges and any values are provided as a separate matter from the items being described, and are not intended to limit the items being described.

[0020] The first aspect of the present application provides a self-repairing material, the self-repairing material comprising an acyl sulfate modified thermoplastic elastomer and an inorganic material, wherein the mass ratio of the acyl sulfate modified thermoplastic elastomer to the inorganic material is 1:0.5-2, for example, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, and any value in the range composed of any two numerical values, preferably 1:0.6-1:1.6.

[0021] In the present application, since the thermoplastic elastomer is an oleophilic material with low density, it will float, agglomerate and other phenomena when directly added into the cement slurry, and cannot be uniformly dispersed. The thermoplastic elastomer is modified by acyl sulfate to be hydrophilic on the surface, and is densified by being combined with the inorganic material, so that it will not float in the cement slurry.

[0022] The self-repairing material of the present application has low elastic modulus and self-repairing ability at the same time by using the acyl sulfate modified thermoplastic elastomer and the inorganic material, and can be used as a functional additive of the cement slurry system for well cementing. The cement slurry system for well cementing based on the self-repairing material of the present application is especially suitable for unconventional shale oil and gas well cementing, and can achieve the purpose of "prevention first and treatment later" in unconventional shale oil and gas well cementing, greatly guaranteeing long-term sealing of the cement sheath, and further prolonging the service life of the oil and gas well.

[0023] According to some embodiments of the present application, the preparation method of the acyl sulfate modified thermoplastic elastomer comprises the following steps:

[0024] The thermoplastic elastomer is subjected to a sulfonation reaction with acyl sulfate in a solvent to obtain the acyl sulfate modified thermoplastic elastomer.

[0025] According to some embodiments of the present application, the mass ratio of the thermoplastic elastomer to acyl sulfate is 1:0.05-0.2, for example, 1:0.05, 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.18, 1:0.2, and any value in the range composed of any two numerical values, preferably 1:0.05-0.1.

[0026] According to the present application, the mass of the thermoplastic elastomer changes very little after sulfonation, and the influence of sulfonation on the mass of the thermoplastic elastomer can be ignored when calculating the mass ratio of the acyl sulfate-modified thermoplastic elastomer to the inorganic material. Therefore, the mass ratio of the thermoplastic elastomer to the inorganic material is directly used as the mass ratio of the acyl sulfate-modified thermoplastic elastomer to the inorganic material.

[0027] According to some embodiments of the present application, the acyl sulfate is selected from acetyl sulfate and / or formyl sulfate.

[0028] According to some embodiments of the present application, the solvent is selected from one or more of chloroform, 1,2-dichloroethane, n-hexane and methanol.

[0029] According to some embodiments of the present application, the inorganic material is selected from one or more of barium sulfate, calcium carbonate, iron ore powder and silicon powder.

[0030] According to some embodiments of the present application, the thermoplastic elastomer is selected from hydrogenated styrene-based thermoplastic elastomers.

[0031] According to some embodiments of the present application, the number average molecular weight of the thermoplastic elastomer is 10,000-100,000.

[0032] According to some embodiments of the present application, the real density of the self-repairing material is 1.2-1.8 g / cm 3 , the water contact angle is 70-80°, the gas swelling rate is 66-68%, and the oil swelling rate is 700-1400%.

[0033] The present application provides a preparation method of a self-repairing material, which comprises the following steps:

[0034] sulfonating the thermoplastic elastomer with acyl sulfate in a solvent to obtain an acyl sulfate-modified thermoplastic elastomer;

[0035] mixing the acyl sulfate-modified thermoplastic elastomer with an inorganic material.

[0036] According to the present application, the inorganic material can be added when the acyl sulfate-modified thermoplastic elastomer is prepared, or the inorganic material can be added after the preparation of the acyl sulfate-modified thermoplastic elastomer is completed, and the present application does not make specific limitations.

[0037] According to some embodiments of the present application, the preparation method specifically comprises the following steps: 50 g of thermoplastic elastomer is added into a three-necked flask containing 500 mL of CHCl3, and is stirred by an electric motor until dissolved, then an appropriate amount of freshly prepared acetyl sulfate is added as a sulfonating agent for sulfonation reaction, after a period of reaction, 50 g of inorganic material is added, stirred quickly and uniformly, then 2000 mL of methanol is added to form granular thermoplastic elastomer / inorganic material, which is filtered, then the thermoplastic elastomer / barium sulfate is washed to neutral with methanol, dried in a vacuum drying oven at 40°C, crushed, and sieved to obtain the low-elastic modulus self-repairing material for well cementing.

[0038] According to some embodiments of the present application, the mass ratio of the thermoplastic elastomer to acyl sulfate is 1:0.05-0.2, for example, 1:0.05, 1:0.08, 1:0.1, 1:0.12, 1:0.15, 1:0.18, 1:0.2, and any value in the range consisting of any two numerical values, and preferably 1:0.05-0.1.

[0039] According to some embodiments of the present application, the mass ratio of the acyl sulfate modified thermoplastic elastomer to barium sulfate is 1:0.5-2, for example, 1:0.5, 1:0.6, 1:0.8, 1:1, 1:1.2, 1:1.5, 1:1.8, 1:2, and any value in the range consisting of any two numerical values, and preferably 1:0.6-1:1.6.

[0040] According to some embodiments of the present application, the acyl sulfate is selected from acetyl sulfate and / or formyl sulfate.

[0041] According to some embodiments of the present application, the solvent is selected from one or more of trichloromethane, 1,2-dichloroethane, n-hexane and methanol.

[0042] According to some embodiments of the present application, a cosolvent is added during the mixing of the acyl sulfate modified thermoplastic elastomer and inorganic material;

[0043] According to the present application, the cosolvent functions to promote the mixing of the acyl sulfate modified thermoplastic elastomer and barium sulfate, so that they are mixed more uniformly, and after the two are mixed uniformly, the cosolvent is removed by filtration and drying.

[0044] According to some embodiments of the present application, the cosolvent is selected from one or more of methanol, acetone and ethanol.

[0045] According to some embodiments of the present application, the preparation method of the acyl sulfate comprises the following steps:

[0046] The preparation method of the acyl sulfate comprises the following steps:

[0047] The acetyl sulfate is obtained by reacting acetic anhydride with concentrated sulfuric acid in an organic solvent under ice bath, and then reacting at room temperature.

[0048] Preferably, the organic solvent is selected from one or more of chloroform, 1,2-dichloroethane, n-hexane and methanol.

[0049] According to the present application, the preparation method of the acyl sulfate specifically comprises the following steps: under ice bath, a certain amount of acetic anhydride is added in an organic solvent (such as chloroform) as a solvent, and stirred uniformly, when the temperature is below 5℃, a certain amount of concentrated sulfuric acid is added dropwise, after 30 minutes of reaction, the ice bath is removed, and the mixture is stirred rapidly at room temperature for 10 minutes, to obtain fresh acetyl sulfate.

[0050] The third aspect of the present application provides an application of the self-repairing material of the first aspect or the self-repairing material prepared by the preparation method of the second aspect in well cementing cement.

[0051] The fourth aspect of the present application provides a self-repairing well cementing slurry, which comprises, by weight parts, 100 parts of oil well cement, 5-15 parts of self-repairing material, 4-8 parts of fluid loss additive, 1-4 parts of high-temperature retarder, 30-60 parts of thermal stabilizing material, 0-100 parts of auxiliary lightening material, 0-100 parts of auxiliary weighting material and 30-100 parts of water; wherein the self-repairing material is the self-repairing material of the first aspect or the self-repairing material prepared by the preparation method of the second aspect.

[0052] The acyl sulfate ester modified thermoplastic elastomer and barium sulfate are used as the self-repairing material, which can be used for preparing the self-repairing well cementing slurry, so that the self-repairing well cementing slurry has low elastic modulus and self-repairing capacity, and can repair the micro-cracks and micro-gaps of the well cementing cement ring in time, thereby greatly ensuring the long-term sealing of the cement ring.

[0053] The self-repairing well cementing slurry can repair the micro-cracks and micro-gaps of the well cementing cement ring in time, and when the integrity of the annular cement ring is damaged at any time, the annular cement can be automatically repaired to prevent the formation fluid from flowing along the micro-gap through the potential leakage channel. The self-repairing cement slurry (SHC, self-healing cement) contains a self-repairing material in the cement slurry, which is activated when the hydrocarbon compound fluid from the formation contacts the exposed surface, so as to expand the cement ring to seal the leakage channel. The production of the oil and gas well does not need to be interrupted during the repair process. This is of great significance to ensure the long-term sealing effectiveness of the annular cement and save the workover cost, and achieves the purpose of “prevention first and treatment later” in the well cementing of unconventional shale oil and gas.

[0054] According to some embodiments of the present application, the fluid loss additive is a mixture of three or four of 2-acrylamido-2-methyl-propanesulfonic acid sodium (AMPS), acrylamide (AM) and N-vinylpyrrolidone acrylic acid (NVP), acrylic acid (AC) polymerization type fluid loss additive;

[0055] According to some preferred embodiments of the present application, the fluid loss additive is a mixture of three or four of 2-acrylamido-2-methyl-propanesulfonic acid sodium (AMPS), acrylamide (AM) and N-vinylpyrrolidone acrylic acid (NVP), acrylic acid (AC) polymerization type fluid loss additive.

[0056] Preferably, the fluid loss additive is a mixture of 2-acrylamido-2-methyl-propanesulfonic acid sodium, acrylamide and N-vinylpyrrolidone acrylic acid, with a weight ratio of 30-50:10-50:20-40, preferably 30-40:40-50:20-30.

[0057] According to some embodiments of the present application, the oil well cement is selected from the group consisting of Jiahua G-grade oil well cement.

[0058] According to some embodiments of the present application, the retarder is selected from one or more of lignin sulfonate, organic acid and polysaccharide derivative.

[0059] According to some embodiments of the present application, the heat-stable material is selected from one or more of ultra-fine silicon powder, quartz sand and metakaolin.

[0060] According to some embodiments of the present application, the auxiliary weighting agent is selected from one or more of microsilica, floating beads and hollow glass beads.

[0061] According to some embodiments of the present application, the heavy agent is selected from one or more of barite, hematite powder and ilmenite powder.

[0062] According to some embodiments of the present application, the cement formed after curing of the self-repairing cementing slurry has an elastic modulus of 6-7 GPa.

[0063] The self-repairing cementing slurry of the present application has an applicable density of 1.45-2.2 g / cm 3 , a wide applicable density range, good rheological properties, good slurry stability, a cement elastic modulus as low as 4.8 GPa, preferably 6-7 GPa, a compressive strength > 18 MPa, a self-repairing rate of 100% when encountering natural gas, an applicable temperature of 50-180℃, a maximum temperature of 180℃, good stability, adjustable thickening time, and good comprehensive performance, which can meet the requirements of 180℃ cementing engineering.

[0064] The following preparation examples, examples and comparative examples are not specified in the specific conditions, according to the conventional conditions or manufacturer's recommended conditions. The reagents or instruments used are not specified by the manufacturer, which are conventional products that can be obtained by commercial means.

[0065] The test method of the real density is carried out according to the general method for determining the tap density of powder products specified in GB / T 21354-2008.

[0066] The test method of the gas and oil swelling rate is that the low-elasticity self-repairing material is wrapped with paper into a cylinder with a diameter of 25 mm, placed in a self-developed natural gas or diesel seepage system device, and static for 24 h, and the volume change of the low-elasticity self-repairing material absorbing gas and oil is tested.

[0067] The test method of the cement slurry density, rheological property, settlement stability and cement stone compressive strength is carried out according to the test method for oil well cement specified in GB / T 19139.

[0068] The test method of the elastic modulus is carried out according to the performance test method for oil well cement stone specified in SY / T 6466.

[0069] The test method of the water contact angle is carried out according to the method for measuring the contact angle of nanometer powder by Washburn dynamic pressure method specified in GB / T 36086 nanometer technology.

[0070] Thermoplastic elastomer: hydrogenated styrene-based thermoplastic elastomer produced by Sinopec Baling Petrochemical Branch; wherein, the linear structure thermoplastic elastomer with an alkyl / polystyrene content of 70 / 30; the polystyrene block (PS block) content is about 30wt%, and the polyethylene / butadiene block (EB block) saturation is 98%.

[0071] Oil well cement: G-grade high-sulfur-resistant oil well cement produced by Jiuhua Cement Plant.

[0072] Fluid loss reducer: oil well cement fluid loss reducer SCFL-80J developed by Sinopec Petroleum Engineering Technology Research Institute Co., Ltd.

[0073] Thermal stabilizing material: oil well cement thermal stabilizer SCLK developed by Sinopec Petroleum Engineering Technology Research Institute Co., Ltd.

[0074] Auxiliary lightening material: glass microbeads Y12000 developed by Maanshan Mining Research General Institute Co., Ltd.

[0075] Auxiliary weighting material: magnetite powder type I of Emeishan Toyang Oilfield Engineering Technology Co., Ltd.

[0076] Preparation Example 1

[0077] In the condition of ice bath, 400 mL of chloroform was used as solvent, 80 mL of formic anhydride was added, and stirred at a constant speed. When the temperature was below 5℃, 30 mL of concentrated sulfuric acid with a concentration of 98% was added dropwise. After 40 min of reaction, the ice bath was removed, and then stirred rapidly at room temperature for 20 min to obtain formic sulfuric acid.

[0078] Preparation Example 2

[0079] In the condition of ice bath, 400 mL of chloroform was used as solvent, 80 mL of formic anhydride was added, and stirred at a constant speed. When the temperature was below 5℃, 30 mL of concentrated sulfuric acid with a concentration of 98% was added dropwise. After 40 min of reaction, the ice bath was removed, and then stirred rapidly at room temperature for 20 min to obtain formic sulfuric acid.

[0080] Example 1

[0081] 50 g of thermoplastic elastomer was added to a three-necked flask containing 500 mL of chloroform, and stirred by electricity until dissolved. Then, fresh acetyl sulfuric acid prepared in Preparation Example 1 was added as a sulfonating agent, and the mass ratio of thermoplastic elastomer to acetyl sulfuric acid was controlled to be 1:0.05. After sulfonation at 50℃ for 100 min, 30 g of barium sulfate was added and stirred rapidly and uniformly. Then, 2000 mL of methanol was added to form granular modified thermoplastic elastomer / barium sulfate. The mixture was filtered, and the modified thermoplastic elastomer / barium sulfate was washed to neutral with methanol. The mixture was dried in a vacuum drying oven at 40℃, crushed, sieved, and then a self-repairing material M1 was obtained. The mass ratio of modified thermoplastic elastomer to barium sulfate was 1:0.6.

[0082] It was detected that the real density of the self-repairing material M1 was 1.30 g / cm 3 , the water contact angle was 76.12°, the air swelling rate was 67.8%, and the oil swelling rate was 1300%.

[0083] Example 2

[0084] 50 g of thermoplastic elastomer was added to a three-necked flask containing 500 mL of chloroform, and stirred by electricity until dissolved. Then, fresh acetyl sulfuric acid prepared in Preparation Example 1 was added as a sulfonating agent, and the mass ratio of thermoplastic elastomer to acetyl sulfuric acid was controlled to be 1:0.05. After sulfonation at 50℃ for 100 min, 30 g of barium sulfate was added and stirred rapidly and uniformly. Then, 2000 mL of methanol was added to form granular modified thermoplastic elastomer / barium sulfate. The mixture was filtered, and the modified thermoplastic elastomer / barium sulfate was washed to neutral with methanol. The mixture was dried in a vacuum drying oven at 40℃, crushed, sieved, and then a self-repairing material M1 was obtained. The mass ratio of modified thermoplastic elastomer to barium sulfate was 1:0.6.

[0085] It was detected that the real density of the self-repairing material M2 was 1.50 g / cm 3It has a water contact angle of 75.20°, a swelling rate of 67.2% when exposed to air, and a swelling rate of 1000% when exposed to oil.

[0086] Example 3

[0087] 50g of thermoplastic elastomer was added to a three-necked flask containing 500mL of chloroform and stirred electrically until dissolved. Then, fresh acetylsulphuric acid prepared in Preparation Example 1 was added as a sulfonating agent, and the mass ratio of thermoplastic elastomer to acetylsulphuric acid was controlled at 1:0.1. After sulfonation at 60℃ for 110min, 80g of barium sulfate was added and stirred rapidly until homogeneous. Then, 2000mL of ethanol was added to generate granular modified thermoplastic elastomer / barium sulfate. The mixture was filtered, and then washed with methanol until neutral. It was dried in a vacuum drying oven at 40℃, pulverized, and sieved to obtain self-healing material M3. The mass ratio of modified thermoplastic elastomer to barium sulfate was 1:1.6, the swelling rate upon exposure to air was 66.1%, and the swelling rate upon exposure to oil was 700%.

[0088] The actual density of self-healing material M3 was tested to be 1.77 g / cm³. 3 The water contact angle is 72.18°.

[0089] Example 4

[0090] 50g of thermoplastic elastomer was added to a three-necked flask containing 500mL of chloroform and stirred electrically until dissolved. Then, fresh formyl sulfuric acid prepared in Preparation Example 2 was added dropwise as a sulfonation reagent, and the mass ratio of thermoplastic elastomer to acetylsulphic acid was controlled at 1:0.2. After sulfonation at 60℃ for 120min, 30g of calcium carbonate was added and stirred rapidly until homogeneous. Then, 2000mL of acetone was added to generate granular modified thermoplastic elastomer / calcium carbonate. The mixture was filtered, and the modified thermoplastic elastomer / calcium carbonate was washed with methanol until neutral. It was then dried in a vacuum drying oven at 40℃, pulverized, and sieved to obtain self-healing material M1. The mass ratio of modified thermoplastic elastomer to calcium carbonate was 1:0.5.

[0091] The actual density of self-healing material M1 was tested to be 1.13 g / cm³. 3 It has a water contact angle of 78.6°, a swelling rate of 67.2% when exposed to air, and a swelling rate of 1000% when exposed to oil.

[0092] Comparative Example 1

[0093] The self-repairing material is prepared according to the method of Example 1, except that the thermoplastic elastomer is not modified, but 50 g of the thermoplastic elastomer is quickly stirred with 30 g of barium sulfate to be uniform, 2000 mL of methanol is then added to form granular thermoplastic elastomer / barium sulfate, the thermoplastic elastomer / barium sulfate is filtered, the thermoplastic elastomer / barium sulfate is washed to be neutral with methanol, and the thermoplastic elastomer / barium sulfate is dried in a vacuum drying oven at 40 DEG C, is crushed, is sieved, and the self-repairing material DM1 is obtained.

[0094] The self-repairing material DM1 has a real density of 1.30 g / cm 3 , a water contact angle of 134.72 DEG, a gas swelling rate of 68%, and an oil swelling rate of 1400%.

[0095] Comparative Example 2

[0096] 50 g of the thermoplastic elastomer is added to a three-necked flask containing 500 mL of chloroform, and is stirred by electricity until dissolved, and then fresh acetyl sulfate prepared in Preparation Example 1 is added dropwise as a sulfonating agent, wherein the mass ratio of the thermoplastic elastomer to the acetyl sulfate is 1:0.04, after sulfonation at 50 DEG C for 120 min, 125 g of barium sulfate is added, and is quickly stirred to be uniform, 2000 mL of methanol is then added to form granular modified thermoplastic elastomer / barium sulfate, the modified thermoplastic elastomer / barium sulfate is filtered, the modified thermoplastic elastomer / barium sulfate is washed to be neutral with methanol, and the modified thermoplastic elastomer / barium sulfate is dried in a vacuum drying oven at 40 DEG C, is crushed, is sieved, and the self-repairing material DM2 is obtained; wherein the mass ratio of the modified thermoplastic elastomer to the barium sulfate is 1:2.5.

[0097] The self-repairing material DM2 has a real density of 2.10 g / cm 3 , a water contact angle of 81.4 DEG, a gas swelling rate of 67.2%, and an oil swelling rate of 1000%.

[0098] Application Example 1

[0099] 370 g of tap water, 30 g of a fluid loss additive, and 10 g of a high-temperature retarder are weighed with a cement slurry cup, and are stirred into mixed water on a stirrer; 500 g of G-grade oil well cement, 50 g of the self-repairing material M1 prepared in Example 1, and 400 g of an auxiliary lightening material are then weighed, are mixed, and are added to the mixed water while stirring to obtain self-repairing cementing slurry S1.

[0100] The performance test results of the self-repairing cementing slurry S1 are shown in Table 1.

[0101] The thickening curve of the self-repairing cementing slurry S1 obtained in Application Example 1 of the present application is shown in FIG. 1. Figure 1 Figure 1 ​It can be seen that the self-repairing material has good fluidity in the low-density cement slurry system, the cement stone has a compressive strength greater than 14 MPa, and an elastic modulus less than 6.0 GPa, and each performance meets the requirements for entering a well.

[0102] Application Example 2

[0103] The self-repairing cementing slurry S2 is obtained by weighing tap water 190 g, a fluid loss additive 20 g, and a high-temperature retarder 10 g in a cement slurry cup, stirring to form mixed water, then weighing G-grade oil well cement 500 g, heat-stable material 300 g, and the self-repairing material M2 prepared in Example 2 240 g, uniformly mixing, and then adding to the mixed water while stirring.

[0104] It is detected that the performance detection results of the self-repairing cementing slurry S2 are shown in Table 1.

[0105] The thickening curve of the self-repairing cementing slurry S2 obtained in the application example 2 of the present application is shown in FIG. 1, and it can be seen from Table 1 and FIG. 1 that the self-repairing material has good rheological properties (fluidity > 20) in the high-temperature resistant conventional density cement slurry system, the maximum applicable temperature is 180℃, the cement stone has high compressive strength (> 24 MPa / 48h) and low elastic modulus (< 7 GPa), which helps to improve the long-term sealing ability of the cement sheath and meets the requirements for cementing construction in ultra-deep wells. Figure 2 Figure 2 It can be seen that the self-repairing material has good rheological properties (fluidity > 20) in the high-temperature resistant conventional density cement slurry system, the maximum applicable temperature is 180℃, the cement stone has high compressive strength (> 24 MPa / 48h) and low elastic modulus (< 7 GPa), which helps to improve the long-term sealing ability of the cement sheath and meets the requirements for cementing construction in ultra-deep wells.

[0106] Application Example 3

[0107] The self-repairing cementing slurry S3 is obtained by weighing tap water 230 g, a fluid loss additive 40 g, and a high-temperature retarder 30 g in a cement slurry cup, stirring to form mixed water, then weighing G-grade oil well cement 500 g, heat-stable material 300 g, weighting material 450 g, and the self-repairing material M3 prepared in Example 3 40 g, uniformly mixing, and then adding to the mixed water while stirring.

[0108] It is detected that the performance detection results of the self-repairing cementing slurry S3 are shown in Table 1.

[0109] The thickening curve of the self-repairing cementing slurry S3 obtained in the application example 3 of the present application is shown in FIG. 2, and it can be seen from Table 1 and FIG. 2 that the self-repairing material has good rheological properties (fluidity > 20) in the high-temperature resistant conventional density cement slurry system, the maximum applicable temperature is 180℃, the cement stone has high compressive strength (> 24 MPa / 48h) and low elastic modulus (< 7 GPa), which helps to improve the long-term sealing ability of the cement sheath and meets the requirements for cementing construction in ultra-deep wells. Figure 3 Figure 3 It can be seen that the self-repairing material has good rheological properties (fluidity > 20) in the high-temperature resistant conventional density cement slurry system, the maximum applicable temperature is 180℃, the cement stone has high compressive strength (> 24 MPa / 48h) and low elastic modulus (< 7 GPa), which helps to improve the long-term sealing ability of the cement sheath and meets the requirements for cementing construction in ultra-deep wells. 3 . The maximum applicable temperature is 160℃, the cement stone has a compressive strength of 19.2 MPa, and an elastic modulus between 6.0-7.0 GPa, indicating excellent impact and fatigue resistance, which meets the requirements for long-term sealing of a wellbore.

[0110] Application Example 4

[0111] ​​A cement slurry cup is used to take tap water 370g, a fluid loss additive 30g, and a high-temperature retarder 10g, which are stirred into mixed water on a stirrer; then G-grade oil well cement 500g, auxiliary lightening material 400g, and the self-repairing material M4 prepared in Example 4 440g are weighed, mixed, and then added to the mixed water while stirring to obtain a low-density self-repairing cement slurry S4 for well cementation.

[0112] It is detected that the performance test results of the self-repairing cement slurry S4 for well cementation are shown in Table 1.

[0113] The self-repairing cement slurry for well cementation obtained in the application example 4 has good rheological properties (a flowability > 20) in a low-density cement slurry system, the cement stone has a compressive strength greater than 14 MPa, and an elastic modulus less than 6.0 GPa, and each performance meets the requirements for well cementation.

[0114] Comparative application example 1

[0115] A cement slurry cup is used to take tap water 190g, a fluid loss additive 20g, and a high-temperature retarder 10g, which are stirred into mixed water on a stirrer; then G-grade oil well cement 500g, heat-stable material 300g, and the self-repairing material DM1 prepared in Comparative Example 1 140g are weighed, mixed, and then added to the mixed water while stirring to obtain a self-repairing cement slurry D1 for well cementation.

[0116] It is detected that the performance test results of the self-repairing cement slurry D1 for well cementation are shown in Table 1.

[0117] The self-repairing cement slurry for well cementation obtained in the application example 1 has good rheological properties (a flowability > 20) in a low-density cement slurry system, the cement stone has a compressive strength greater than 14 MPa, and an elastic modulus less than 6.0 GPa, and each performance meets the requirements for well cementation.

[0118] Comparative application example 2

[0119] A cement slurry cup is used to take tap water 190g, a fluid loss additive 20g, and a high-temperature retarder 10g, which are stirred into mixed water on a stirrer; then G-grade oil well cement 500g, heat-stable material 300g, and the self-repairing material DM2 prepared in Comparative Example 2 240g are weighed, mixed, and then added to the mixed water while stirring to obtain a self-repairing cement slurry D2 for well cementation.

[0120] The self-repairing cement slurry for well cementation obtained in the application example 2 has good rheological properties (a flowability > 20) in a low-density cement slurry system, the cement stone has a compressive strength greater than 14 MPa, and an elastic modulus less than 6.0 GPa, and each performance meets the requirements for well cementation.

[0121] Table 1 Performance test results of the self-repairing cement slurry for well cementation

[0122]

[0123] From the data of Table 1, it can be seen that the materials of Examples 1-4 have an applicable density of 1.45-2.2 g / cm 3 , a wide applicable density range, good rheological properties, good slurry stability, a minimum cement stone elastic modulus of 4.8 GPa, a maximum applicable temperature of 180℃, good stability, adjustable thickening time, and good comprehensive performance.

[0124] Test Example

[0125] The self-repairing cementing cement slurries obtained in Application Examples 1-4 were cured into cement stones, simulated fracture formation, and formed natural gas channeling flow channels in a gas-repair evaluation instrument, and the outlet natural gas flow rate was measured using natural gas to characterize the self-repairing performance of the cement stones in the presence of natural gas. Under a natural gas pressure of 5 MPa at 80℃, the natural gas flow rate in the open gas channeling flow channel decreased from 870 mL / min to 0 within 17 h, which was detected using an outlet flow monitoring instrument. It was found through the detection that the cement stones cured from the self-repairing cementing cement slurries S1-S4 obtained in Application Examples 1-4 were completely repaired. However, the cement stones cured from the self-repairing cementing cement slurries D1-D2 obtained in Comparative Application Examples 1-2 still had a flow rate after being re-aerated for a period of time, indicating that they were not completely repaired.

[0126] The flow rate change curve of the cement stone cured from the self-repairing cementing cement slurry S2 obtained in Application Example 2 is shown in Figure 4 , indicating that the gas channeling flow channel was closed and the cement stone was completely repaired.

[0127] The flow rate change curve of the cement stone cured from the self-repairing cementing cement slurry D1 obtained in Comparative Application Example 1 is shown in Figure 5 , indicating that the cement stone was not completely repaired.

[0128] As can be seen from the above, the self-repairing material of the present application has the effect of repairing cracks in the cement stone in the presence of gas.

[0129] The above describes preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A self-healing material, characterized in that, The self-repairing material comprises an acyl sulfate modified thermoplastic elastomer and an inorganic material, wherein the mass ratio of the acyl sulfate modified thermoplastic elastomer to the inorganic material is 1:0.5-2.

2. The self-repairing material of claim 1, wherein, The preparation method of the acyl sulfate modified thermoplastic elastomer comprises the following steps: sulfonating the thermoplastic elastomer with acyl sulfate in a solvent to obtain the acyl sulfate modified thermoplastic elastomer; Preferably, the mass ratio of the thermoplastic elastomer to acyl sulfate is 1:0.05-0.2, preferably 1:0.05-0.1; Preferably, the acyl sulfate is selected from acetyl sulfate and / or formyl sulfate; Preferably, the solvent is selected from one or more of chloroform, 1,2-dichloroethane, n-hexane and methanol.

3. The self-repairing material according to claim 1 or 2, wherein, The inorganic material is selected from one or more of barium sulfate, calcium carbonate, iron ore powder and silicon powder; And / or, the thermoplastic elastomer is selected from a hydrogenated styrene-based thermoplastic elastomer; Preferably, the number average molecular weight of the thermoplastic elastomer is 10,000-100,000.

4. The self-repairing material according to any one of claims 1-3, wherein, The self-repairing material has a real density of 1.2-1.8 g / cm 3 , a water contact angle of 70-80°, an air-induced swelling rate of 66-68%, and an oil-induced swelling rate of 700-1400%.

5. A method for preparing a self-healing material, characterized in that, The preparation method comprises the following steps: sulfonating the thermoplastic elastomer with acyl sulfate in a solvent to obtain the acyl sulfate modified thermoplastic elastomer; Mixing the acyl sulfate modified thermoplastic elastomer with an inorganic material.

6. The production method according to claim 5, wherein The mass ratio of the thermoplastic elastomer to acyl sulfate is 1:0.05-0.2, preferably 1:0.05-0.1; And / or, the mass ratio of the acyl sulfate modified thermoplastic elastomer to the inorganic material is 1:0.5-2; And / or, the acyl sulfate is selected from acetyl sulfate and / or formyl sulfate; And / or, the solvent is selected from one or more of chloroform, 1,2-dichloroethane, n-hexane and methanol.

7. The production method according to claim 5 or 6, wherein An auxiliary solvent is added during the mixing of the acyl sulfate modified thermoplastic elastomer with the inorganic material; Preferably, the auxiliary solvent is selected from one or more of methanol, acetone and ethanol.

8. The method of making according to any one of claims 5-7, wherein, The preparation method of the acyl sulfate comprises the following steps: First, acetic anhydride and concentrated sulfuric acid are reacted in an organic solvent under ice bath conditions; then, the reaction is carried out at room temperature to obtain acetyl sulfate; Preferably, the organic solvent is selected from one or more of chloroform, 1,2-dichloroethane, n-hexane and methanol.

9. The self-repairing material of any one of claims 1-4 or the self-repairing material prepared by the preparation method of any one of claims 5-8 is applied in well cementing cement.

10. A self-healing cementing slurry, characterized in that, The self-repairing well cementing slurry comprises, in parts by weight, oil well cement 100 parts, self-repairing material 5-15 parts, fluid loss additive 4-8 parts, high-temperature retarder 1-4 parts, thermal stabilizing material 30-60 parts, auxiliary lightening material 0-100 parts, auxiliary weighting material 0-100 parts and water 30-100 parts; The self-repairing material is the self-repairing material of any one of claims 1-4 or the self-repairing material prepared by the preparation method of any one of claims 5-8.

11. The self-healing cementing slurry of claim 10, wherein, The fluid loss additive is a mixture of three or four of sodium 2-acrylamido-2-methyl-propanesulfonate, acrylamide, N-vinylpyrrolidone and acrylic acid polymerized fluid loss additive; Preferably, the fluid loss additive is a mixture of 2-acrylamido-2-methyl-propane sulfonic acid sodium, acrylamide and N-vinyl pyrrolidone, with a weight ratio of 30-50:10-50:20-40.

12. The self-healing cementing slurry of claims 10 or 11, wherein, The oil well cement is selected from the group consisting of G-class high-sulfur-resistant oil well cement of Jiahua; And / or, the retarder is selected from one or more of lignin sulfonate, organic acid and polysaccharide derivative; And / or, the heat-stable material is selected from one or more of ultra-fine silicon powder, quartz sand and metakaolin; And / or, the auxiliary lightening agent is selected from one or more of microsilica, floating beads and hollow glass beads; And / or, the weighting agent is selected from one or more of barite, hematite powder and ilmenite powder.

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