阅读说明：本技术 页岩钻井辅溶蚀剂及其制备和使用方法及混合溶蚀剂 (Shale drilling auxiliary corrosion inhibitor, preparation and use methods thereof and mixed corrosion inhibitor ) 是由 刘伟 陆灯云 韩烈祥 袁志平 吴正良 杨晓峰 谢意 戴昆 景岷嘉 王娟 朱思远 于 2020-04-03 设计创作，主要内容包括：本发明提供了一种页岩钻井辅溶蚀剂及其制备和使用方法和混合溶蚀剂,所述制备方法通过将第一粉末、第二粉末和第三粉末混合均匀制得页岩钻井辅溶蚀剂,按重量计,第一粉末通过将20～25份环氧琥珀酸胺、9～20份羟基亚丁基磷酸镁及12～15份乙二烯三胺五乙酸胺混合均匀,研磨破碎、过筛后,搅拌制得；第二粉末通过将8～12份活性凹凸棒土、8～12份过硫酸铵及12～17份磺化琥珀酸酯混合均匀,过筛后制得；第三粉末通过将7～13份丙酸丁酯、8～14份十二烷基苯磺酸钠及3～9份有机络合剂混合均匀,过筛后制得。本发明适用于石英含量为35％以上、层理发育且脆性系数为0.2以上的页岩地层(例如,龙马溪页岩地层)的解卡。(The invention provides a shale drilling auxiliary corrosion inhibitor, a preparation method and a use method thereof, and a mixed corrosion inhibitor, wherein the preparation method comprises the steps of uniformly mixing a first powder, a second powder and a third powder to obtain the shale drilling auxiliary corrosion inhibitor, wherein the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic amine, 9-20 parts by weight of hydroxy butylidene magnesium phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring; the second powder is prepared by uniformly mixing 8-12 parts of active attapulgite, 8-12 parts of ammonium persulfate and 12-17 parts of sulfonated succinate and sieving; the third powder is prepared by uniformly mixing 7-13 parts of butyl propionate, 8-14 parts of sodium dodecyl benzene sulfonate and 3-9 parts of organic complexing agent and sieving. The method is suitable for unfreezing the shale stratum (such as the Longmaxi shale stratum) with the quartz content of more than 35 percent, the bedding development and the brittleness coefficient of more than 0.2.)

1. The shale drilling mixed corrosion dissolving agent is characterized in that the shale drilling main corrosion dissolving agent and the shale drilling auxiliary corrosion dissolving agent are mixed according to the weight ratio of 1-3: 1, wherein the mixture ratio is mixed, wherein,

the shale drilling main corrosion inhibitor is obtained by uniformly mixing a corrosion inhibitor, a surfactant carrier material and a catalyst adsorption material, wherein the corrosion inhibitor is prepared by uniformly mixing 28-35 parts by weight of sodium polyepoxysuccinate, 15-25 parts by weight of sodium gluconate, 4-6 parts by weight of dimethylethanolamine and 8-10 parts by weight of ethyl polylactate, grinding, crushing, sieving and stirring; the surfactant carrier material is prepared by uniformly mixing 5-8 parts by weight of sodium fatty alcohol-polyoxypropylene ether sulfate, 6-9 parts by weight of magnesium amino acid and 3-4 parts by weight of a complexing agent, and sieving; the catalyst adsorption material is prepared by uniformly mixing 8-12 parts by weight of catalytic lipase, 12-17 parts by weight of sodium p-hydroxysulfonate and 2-6 parts by weight of hydroxybutylate amine and sieving;

the shale drilling auxiliary corrosion inhibitor is obtained by uniformly mixing a first powder, a second powder and a third powder, wherein the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic acid amine, 9-20 parts by weight of magnesium hydroxy butylene phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring; the second powder is prepared by uniformly mixing 8-12 parts by weight of active attapulgite, 8-12 parts by weight of ammonium persulfate and 12-17 parts by weight of sulfosuccinate and sieving; the third powder is prepared by uniformly mixing 7-13 parts by weight of butyl propionate, 8-14 parts by weight of sodium dodecyl benzene sulfonate and 3-9 parts by weight of an organic complexing agent and sieving the mixture.

2. The shale drilling compound eroding agent of claim 1, wherein the particle size of the second eroding material is capable of passing through a 20 mesh screen, the particle size of the second surfactant carrier material is capable of passing through a 20 mesh screen, and the second catalyst sorbent material is capable of passing through a 40 mesh screen.

3. The shale drilling hybrid etchant of claim 1, wherein the sodium polyepoxysuccinate is 30-32 parts and the sodium gluconate is 18-22 parts.

4. The shale drilling mixed eroding agent as claimed in claim 1, wherein the catalytic lipase is 9-10 parts and the sodium p-hydroxysulfonate is 14-16 parts.

5. A preparation method of shale drilling dissolution agent is characterized in that the preparation method is used for preparing the shale drilling dissolution agent by uniformly mixing first powder, second powder and third powder, wherein,

the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic acid amine, 9-20 parts by weight of magnesium hydroxy butylene phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring;

the second powder is prepared by uniformly mixing 8-12 parts by weight of active attapulgite, 8-12 parts by weight of ammonium persulfate and 12-17 parts by weight of sulfosuccinate and sieving;

the third powder is prepared by uniformly mixing 7-13 parts by weight of butyl propionate, 8-14 parts by weight of sodium dodecyl benzene sulfonate and 3-9 parts by weight of an organic complexing agent and sieving the mixture.

6. The method of claim 5, wherein the first powder has a particle size that passes through a 20 mesh sieve, the second powder has a particle size that passes through a 20 mesh sieve, and the third powder has a particle size that passes through a 40 mesh sieve.

7. The method for preparing shale drilling dissolution aid according to claim 5, wherein the epoxy succinate amine is 22-24 parts, and the hydroxyl butylidene magnesium phosphate is 14-18 parts.

8. The shale drilling auxiliary corrosion inhibitor is obtained by the preparation method of any one of claims 5 to 7.

9. The use method of the shale drilling auxiliary eroding agent is characterized by comprising the steps of mixing the shale drilling auxiliary eroding agent according to claim 8 with water according to a ratio of 5-10: 100 and the unit of kg/L to form an auxiliary eroding liquid, and pumping the auxiliary eroding liquid into a shale formation stuck drilling section to erode shale chippings or rock fragments in shale formation drilling.

Technical Field

The invention relates to the technical field of corrosion agents for shale gas drilling in oil field development, in particular to an auxiliary corrosion agent for shale gas drilling, a preparation method and a use method thereof, and a mixed corrosion agent containing the auxiliary corrosion agent.

Background

At present, in the drilling process of the shale gas horizontal well in China (for example, the drilling process of the shale gas horizontal well in Longmaxi), multiple accidents such as instability of the well wall, block falling, blockage, drill sticking and the like exist. Generally, the shale chipping and sand setting stuck drilling accidents have large treatment difficulty and few treatment means.

At present, mechanical unfreezing is adopted in the process of unfreezing the stuck drill in the horizontal section of the Longmaxi shale, and the mechanical unfreezing of multiple wells is ineffective, so that tools are buried in wells, particularly shale gas horizontal wells with the well depth of more than 5000m, and the difficulty of mechanical unfreezing is higher. Some stuck drilling wells adopt acid soaking stuck release, although obvious advantages are provided in the aspects of stuck release speed and degree, the method is basically limited to be used in carbonate strata, and the used acid liquor has a plurality of limiting conditions in storage, transportation and construction, so that the method cannot be widely applied.

In the development process of Sichuan shale gas, wells 202H10-6, 204H6-4, YS117H1-4, YS108H9-2, YS108H7-3, 202 and 204H33-1, which have stuck drilling accidents at the horizontal section of shale gas, adopt acid soaking for unfreezing, wherein the YS117H1-4 also tries to adopt earth acid for unfreezing, but no well can be unfreezed successfully finally, and acid liquor has a corrosion effect on a drilling tool.

Therefore, a novel corrosion inhibitor of the shale stuck-releasing agent is needed.

Disclosure of Invention

The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, an object of the present invention is to provide an etchant that can be applied to shale chipping and stuck freeing or stuck sand freeing of a drilled shale in a shale formation having a quartz content of 35% or more, a bedding development, and a brittleness coefficient of 0.2 or more.

In order to achieve the purpose, the shale drilling mixed corrosion dissolving agent is prepared by mixing a shale drilling main corrosion dissolving agent and a shale drilling auxiliary corrosion dissolving agent according to the weight ratio of 1-3: 1, wherein the shale drilling main corrosion inhibitor is obtained by uniformly mixing a corrosion material, a surfactant carrier material and a catalyst adsorption material, wherein the corrosion material is prepared by uniformly mixing 28-35 parts by weight of sodium polyepoxysuccinate, 15-25 parts by weight of sodium gluconate, 4-6 parts by weight of dimethylethanolamine and 8-10 parts by weight of ethyl polylactate, grinding, crushing, sieving and stirring; the surfactant carrier material is prepared by uniformly mixing 5-8 parts by weight of sodium fatty alcohol-polyoxypropylene ether sulfate, 6-9 parts by weight of magnesium amino acid and 3-4 parts by weight of a complexing agent, and sieving; the catalyst adsorption material is prepared by uniformly mixing 8-12 parts by weight of catalytic lipase, 12-17 parts by weight of sodium p-hydroxysulfonate and 2-6 parts by weight of hydroxybutylate amine and sieving; the shale drilling auxiliary corrosion inhibitor is obtained by uniformly mixing a first powder, a second powder and a third powder, wherein the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic acid amine, 9-20 parts by weight of magnesium hydroxy butylene phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring; the second powder is prepared by uniformly mixing 8-12 parts by weight of active attapulgite, 8-12 parts by weight of ammonium persulfate and 12-17 parts by weight of sulfosuccinate and sieving; the third powder is prepared by uniformly mixing 7-13 parts by weight of butyl propionate, 8-14 parts by weight of sodium dodecyl benzene sulfonate and 3-9 parts by weight of an organic complexing agent and sieving the mixture.

The shale drilling auxiliary corrosion inhibitor is prepared by uniformly mixing a first powder, a second powder and a third powder, wherein the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic acid amine, 9-20 parts by weight of hydroxyl butylidene magnesium phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring; the second powder is prepared by uniformly mixing 8-12 parts by weight of active attapulgite, 8-12 parts by weight of ammonium persulfate and 12-17 parts by weight of sulfosuccinate and sieving; the third powder is prepared by uniformly mixing 7-13 parts by weight of butyl propionate, 8-14 parts by weight of sodium dodecyl benzene sulfonate and 3-9 parts by weight of an organic complexing agent and sieving the mixture.

The invention further provides a use method of the shale drilling auxiliary eroding agent, which comprises the steps of mixing the shale drilling auxiliary eroding agent with water according to the proportion of 5-10: 100 and the unit of kg/L to form an auxiliary eroding liquid, and pumping the auxiliary eroding liquid into a shale formation stuck drilling section to erode shale chippings or rock debris in shale formation drilling.

Drawings

The above and other objects and features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 shows an electron micrograph of Longmaxi shale;

fig. 2 shows an electron micrograph of the corresponding agalmaxi shale of fig. 1 after dissolution by the auxiliary corrosion inhibitor.

Detailed Description

Hereinafter, the shale drilling auxiliary corrosion inhibitor, the preparation and use method thereof and the mixed corrosion inhibitor of the invention will be described in detail with reference to the exemplary embodiments.

Through research, the inventor proposes an auxiliary corrosion inhibitor suitable for shale drilling, a preparation method and a use method thereof, and a mixed corrosion inhibitor containing the auxiliary corrosion inhibitor. The mixed corrosion dissolving agent and the auxiliary corrosion dissolving agent are particularly suitable for shale formations (such as the rock formation of Longmaxi) with the quartz content of more than 35 percent, the bedding development and the brittleness coefficient of more than 0.2, and the aim of removing the shale chipping and stuck drill is fulfilled by enabling the shale to be chipped or rock debris to be converted into water-soluble salt through chemical permeation, solubilization, oxidation, chain scission and conversion. Here, the term "bedding development" means that the natural bedding surface of the shale is flat or substantially flat, exfoliation along the bedding surface is significant, and a small amount of microporosities develop. For example, the opening of the micro-cracks in a natural state is 5 to 10 μm.

In an exemplary embodiment of the invention, the shale drilling dissolution agent can be prepared by uniformly mixing the first powder, the second powder and the third powder according to the weight ratio of 1:1:1, so as to prepare the desired shale drilling dissolution agent.

Specifically, the first powder is prepared by uniformly mixing 20-25 parts by weight of epoxy succinic acid amine, 9-20 parts by weight of magnesium hydroxy butylene phosphate and 12-15 parts by weight of ethylene triamine pentaacetic acid amine, grinding, crushing, sieving and stirring. Preferably, the epoxy succinic acid amine may be 22 to 24 parts, and the magnesium hydroxy butylene phosphate may be 14 to 18 parts.

The second powder is prepared by uniformly mixing 8-12 parts by weight of active attapulgite, 8-12 parts by weight of ammonium persulfate and 12-17 parts by weight of sulfosuccinate and sieving.

The third powder is prepared by uniformly mixing 7-13 parts by weight of butyl propionate, 8-14 parts by weight of sodium dodecyl benzene sulfonate and 3-9 parts by weight of an organic complexing agent and sieving the mixture. Here, the organic complexing agent may be diethylenetriaminepentaacetic acid, nitrilotriacetic acid and carboxylic acids.

Further, the particle size of the first powder is controlled to pass a 20 mesh sieve, the particle size of the second powder is controlled to pass a 20 mesh sieve, and the third powder is controlled to pass a 40 mesh sieve. The first powder and the second powder have certain viscosity after being mixed and reacted, the particle size is larger, the product can be effectively screened out after passing through a 20-mesh sieve, and if the product passes through a sieve with smaller size, part of the product with larger particle size can be screened out, so that waste is caused. The resultant third powder was collected well by passing through a 40 mesh screen.

In another exemplary embodiment of the present invention, the preparation method of the shale drilling co-etchant can be realized by the following steps:

(1) 20-25 parts of epoxy succinic acid amine, 9-20 parts of hydroxyl butylidene magnesium phosphate and 12-15 parts of ethylene triamine pentaacetic acid amine are weighed and uniformly mixed according to parts by weight, a grinding machine is used for crushing, the crushed mixture is sieved by a 20-mesh sieve, the granularity of the sieved mixture is smaller than 20 meshes, and the sieved mixture is stirred for more than 30 minutes to obtain first powder with the functions of unblocking and the like.

(2) Weighing 8-12 parts of active attapulgite, 8-12 parts of ammonium persulfate and 12-17 parts of sulfonated succinate according to parts by weight, mixing by using a conical mixing stirrer, and stirring uniformly for more than 1 hour; sieving with 20 mesh sieve to obtain second powder with surface activity.

(3) Weighing 7-13 parts of butyl propionate, 8-14 parts of sodium dodecyl benzene sulfonate and 3-9 parts of organic complexing agent according to parts by weight, stirring for more than 40 minutes by using a conical mixer, and sieving by using a 40-mesh sieve to obtain third powder with the functions of adsorption and the like.

(4) And uniformly mixing and stirring the prepared first powder, second powder and third powder according to the weight ratio of 1:1:1 to obtain the shale drilling auxiliary solvent.

It should be noted that items (1), (2) and (3) in the above exemplary embodiments do not have a strict sequence, and may be performed sequentially or simultaneously.

In an exemplary embodiment of the invention, the mixed dissolution agent is prepared by mixing a shale drilling main dissolution agent and a shale drilling auxiliary dissolution agent as described above according to the weight ratio of 1-3: 1 by weight ratio.

The preparation method of the shale drilling main corrosion remover comprises the steps of uniformly mixing the corrosion material, the surfactant carrier material and the catalyst adsorbent material according to the weight ratio of 1:1:1, so as to prepare the expected shale drilling main corrosion remover.

Specifically, the corrosion inhibitor is prepared by uniformly mixing 28-35 parts by weight of sodium polyepoxysuccinate, 15-25 parts by weight of sodium gluconate, 4-6 parts by weight of dimethylethanolamine and 8-10 parts by weight of ethyl polylactic acid, grinding, crushing, sieving and stirring. Preferably, the sodium polyepoxysuccinate may be 30 to 32 parts, and the sodium gluconate may be 18 to 22 parts.

The surfactant carrier material is prepared by uniformly mixing 5-8 parts by weight of fatty alcohol-polyoxypropylene ether sodium sulfate, 6-9 parts by weight of magnesium amino acid and 3-4 parts by weight of a complexing agent, and sieving. Here, the complexing agent may be a carboxylic acid.

The catalyst adsorption material is prepared by uniformly mixing 8-12 parts by weight of catalytic lipase, 12-17 parts by weight of sodium p-hydroxysulfonate and 2-6 parts by weight of hydroxybutylate amine and sieving. Preferably, the catalytic lipase is 9-10 parts, and the p-hydroxysulfonic acid sodium salt is 14-16 parts.

Further, the particle size of the erosion material is controlled to pass through a 20 mesh sieve, the particle size of the surfactant carrier material is controlled to pass through a 20 mesh sieve, and the catalyst adsorption material is controlled to pass through a 40 mesh sieve. The corrosion material and the surfactant carrier material are mixed and react to form a product with certain viscosity and larger particle size, the product can be effectively screened out by sieving with a 20-mesh sieve, and if the product is sieved with a sieve with smaller size, part of the product with larger particle size can be screened out, so that waste is caused. The resultant third powder was collected well by passing through a 40 mesh screen.

The preparation method of the shale drilling main corrosive agent can be realized by the following steps:

A. 28-35 parts of polyepoxy succinic acid, 15-25 parts of sodium gluconate, 4-6 parts of dimethylethanolamine and 8-10 parts of poly ethyl lactate are weighed and uniformly mixed according to parts by weight, crushed by a grinding machine, sieved by a 20-mesh sieve to enable the particle size of the mixture to be smaller than 20 meshes, and stirred for more than 30 minutes to obtain the corrosion-resistant material.

B. 5-8 parts of sodium fatty alcohol-polyoxypropylene ether sulfate, 6-9 parts of magnesium amino acid and 3-4 parts of a complexing agent are weighed according to parts by weight, mixed by a conical mixing stirrer and stirred uniformly, and the stirring time can be more than 1 hour; then sieving the mixture by a 20-mesh sieve to obtain the uniform complex surfactant carrier material.

C. Weighing 8-12 parts of catalytic lipase, 12-17 parts of sodium p-hydroxysulfonate and 2-6 parts of hydroxybutyl diamine according to parts by weight, stirring for more than 40 minutes by using a conical mixer-stirrer, and sieving by using a 40-mesh sieve to obtain the catalyst adsorbent.

D. And uniformly stirring the prepared erosion material, the surfactant carrier material and the catalyst adsorbent material to prepare the shale drilling well main erosion agent.

It should be noted that item A, B, C in the above exemplary embodiment does not have a strict sequence, and may be performed sequentially or simultaneously.

In order that the above-described exemplary embodiments of the invention may be better understood, further description thereof with reference to specific examples is provided below.

Example 1

In this example, the mixed erodible agent for shale drilling is prepared by mixing shale drilling primary erodible agent with shale drilling secondary erodible agent according to the ratio of 2: 1 by mixing.

The main corrosion inhibitor is prepared from the following raw materials in parts by weight:

the preparation process of the main corrosion inhibitor comprises the following steps:

a. forming an erosion material: 30Kg of polyepoxy succinic acid, 18Kg of sodium gluconate, 5Kg of dimethylethanolamine and 8Kg of poly ethyl lactate are weighed and mixed evenly according to the parts by weight, crushed by a grinder, sieved by a 20-mesh sieve to ensure that the granularity is smaller than 20 meshes, and stirred for 30 minutes to obtain the polyepoxy succinic acid-sodium salt-water-soluble polymer.

b. Forming a surfactant carrier material: weighing 6Kg of fatty alcohol-polyoxypropylene ether sodium sulfate, 7Kg of magnesium amino acid and 3Kg of nitrilotriacetic acid according to parts by weight, mixing by using a conical mixer, and stirring uniformly for 1 hour; and then the mixture is sieved by a 20-mesh sieve to obtain the product.

c. Forming a catalyst adsorbent: 10Kg of catalytic lipase, 14Kg of sodium p-hydroxysulfonate and 4Kg of hydroxybutyl diamine are weighed according to parts by weight, stirred for 40 minutes by a conical mixer-blender and sieved by a 40-mesh sieve to obtain the finished product.

And then, mixing the erosion material prepared in the items a, b and c, a surfactant carrier material and a catalyst adsorbent material according to the proportion of 1:1:1, and uniformly stirring to prepare the shale drilling well main erosion agent.

The auxiliary corrosion inhibitor is prepared from the following raw materials in parts by weight:

the preparation process of the dissolution assisting agent is as follows:

(i) 22Kg of epoxy succinic acid amine, 18Kg of hydroxyl butylidene magnesium phosphate and 15Kg of ethylene triamine pentaacetic acid amine are weighed and uniformly mixed according to the parts by weight, crushed by a grinder, sieved by a 20-mesh sieve to ensure that the granularity is smaller than 20 meshes, and stirred for 25 minutes to obtain first uniform powder.

(ii) Weighing 10Kg of active attapulgite, 9Kg of ammonium persulfate and 16Kg of sulfonated succinate according to parts by weight, mixing by using a conical mixer, and uniformly stirring for 50 minutes. And sieved again through a 20 mesh sieve to obtain a second uniform powder.

(iii) Weighing 12Kg of butyl propionate, 13Kg of sodium dodecyl benzene sulfonate and 8Kg of organic complexing agent according to parts by weight, stirring for 30 minutes by a conical mixer, and sieving by a 40-mesh sieve to obtain third powder.

And (3) mixing the first powder, the second powder and the third powder prepared in the (i), (ii) and (iii) according to the proportion of 1:1:1, and uniformly stirring to prepare the shale drilling corrosion inhibitor.

Example 2

In this example, the mixed erodible agent for shale drilling is prepared by mixing shale drilling primary erodible agent with shale drilling secondary erodible agent in a ratio of 1.5: 1 by mixing.

The main corrosion inhibitor is prepared from the following raw materials in parts by weight:

the preparation process of the main corrosion inhibitor comprises the following steps:

a. forming an erosion material: 32Kg of polyepoxy succinic acid, 16Kg of sodium gluconate, 6Kg of dimethylethanolamine and 9Kg of poly ethyl lactate are weighed and mixed evenly according to the parts by weight, crushed by a grinder, sieved by a 20-mesh sieve to ensure that the granularity is smaller than 20 meshes, and stirred for 35 minutes to prepare the polyepoxy succinic acid.

b. Forming a surfactant carrier material: weighing 7Kg of fatty alcohol-polyoxypropylene ether sodium sulfate, 6Kg of magnesium amino acid and 3Kg of nitrilotriacetic acid according to parts by weight, mixing by using a conical mixer, and uniformly stirring; and then the mixture is sieved by a 20-mesh sieve to obtain the product.

c. Forming a catalyst adsorbent: weighing 8Kg of catalytic lipase, 15Kg of sodium p-hydroxysulfonate and 3Kg of hydroxybutyl diamine according to parts by weight, stirring for 35 minutes by using a conical mixer-blender, and sieving by using a 40-mesh sieve to obtain the finished product.

And then, mixing the erosion material prepared in the items a, b and c, a surfactant carrier material and a catalyst adsorbent material according to the proportion of 1:1:1, and uniformly stirring to prepare the shale drilling well main erosion agent.

The auxiliary corrosion inhibitor is prepared from the following raw materials in parts by weight:

the preparation process of the dissolution assisting agent is as follows:

(i) uniformly mixing the epoxy succinic acid amine, the hydroxyl butylene magnesium phosphate and the ethylene triamine pentaacetic acid amine according to the parts by weight, crushing by using a grinding machine, sieving by using a 20-mesh sieve to ensure that the granularity is smaller than 20 meshes, and stirring for 30 minutes to obtain first uniform powder.

(ii) Mixing the active attapulgite, the ammonium persulfate and the sulfosuccinate according to the parts by weight by using a conical mixing stirrer, and uniformly stirring for 1 hour. And sieved again through a 20 mesh sieve to obtain a second uniform powder.

(iii) And (3) stirring the butyl propionate, the sodium dodecyl benzene sulfonate and the diethylenetriamine pentaacetic acid in the parts by weight for 40 minutes by using a conical mixing stirrer, and sieving by using a 40-mesh sieve to obtain third powder.

And (3) mixing the first powder, the second powder and the third powder prepared in the (i), (ii) and (iii) according to the proportion of 1:1:1, and uniformly stirring to prepare the shale drilling corrosion inhibitor.

The shale drilling mixed solution and shale drilling assistant solution in the example 1 and the example 2 are compared and evaluated for the shale agglomerated core corrosion rate performance through different tests, the corrosion condition is analyzed and evaluated, and the compatibility of the shale drilling mixed solution and the drilling fluid is also analyzed and evaluated.

Test one: and (4) carrying out comparative evaluation on the corrosion rate of the rock core of the Longmaxi shale blocks.

The rock core of the rock shale block (the mass of a single rock is about 60 g) is respectively soaked in clean water, earth acid and the mixed corrosion dissolving agent of the example 1 and the example 2, the rock core and the mixed corrosion dissolving agent are respectively put into an aging tank, the aging tank is kept at a constant temperature of 100 ℃ for 48 hours, then the rock core is taken out and opened, and the rock core and the mixed corrosion dissolving agent are screened by 6-mesh sieve cloth with clean water, dried at 80 ℃, weighed and the dissolution rate of the shale is calculated, and the result is shown in the table 1.

TABLE 1 comparison of dissolution rate results for shale cores

Item	Corrosion rate of × 48h at 100 ℃%
		Clean water	0.56
Earth acid	4.79
		Example 1 Mixed etchant	56.20
Example 2 Mixed etchant	55.60

By analyzing the comparison results of table 1, it can be seen that: the mixed corrosion inhibitors of examples 1 and 2 have high corrosion rates and have good corrosion effects on shale chipping.

And (2) test II: evaluation of corrosion of the main corrosion inhibitor of examples 1 and 2 on N80 standard steel sheets.

The main corrosion inhibitor and the auxiliary corrosion inhibitor in example 1 were dissolved in 400ml of clear water, stirred at a low speed to be uniform, prepared into a solution with a mass concentration of 3%, loaded into an aging tank, subjected to hanging of a standard N80 steel sheet (the number is shown in Table 2), and placed in a 100 ℃ oven to be kept static for 8 hours for corrosion experiments.

TABLE 2 Corrosion of standard N80 steel sheet in the main etchant of EXAMPLE 1

As can be seen from Table 2, the main etchant of example 1 has a corrosion rate of 0.4211 g/(m) at most after soaking for 6 hours²H) the corrosion rate after soaking in the cosolvent for 6h is 0.6798 g/(m) at most²H) are all less than 6 g/(m) specified by the national standard²H) indicating that the corrosion rate of the main corrosion dissolving agent, the auxiliary corrosion dissolving agent and the mixed corrosion dissolving agent on the N80 standard steel sheet meets the requirements specified by the national standard. Similarly, the corrosion rates of the auxiliary soluble corrosion agent and the mixed soluble corrosion agent of the example 2 to the N80 standard steel sheet at different times are less than 6 g/(m) specified by the national standard after similar tests²H) meets the requirements specified by the national standard.

And (3) test III: the compatibility of the primary and secondary dissolution agents of example 1 with water-based drilling fluids was evaluated.

10g of the main corrosion inhibitor of example 1 and 10g of the auxiliary corrosion inhibitor of example 1 were dissolved in 100ml of water, respectively, to prepare a main corrosion solution and an auxiliary corrosion solution each having a mass percentage of 10% by volume, and the main corrosion solution and the auxiliary corrosion solution were mixed with a drilling fluid (base slurry), respectively, and the compatibility was evaluated, and the results are shown in Table 3.

TABLE 3 compatibility test of primary/secondary corrosion inhibitor solutions with water-based drilling fluids (sulfonated systems)

The preparation method comprises the steps of ① experiment conditions, rolling temperature of 100 ℃ of × 16h, rheological property measurement temperature of 55 ℃, ② high-temperature high-pressure filtration measurement temperature of 100 ℃, ③ 'base slurry + 5% of main/auxiliary corrosion solution and' base slurry + 10% of main/auxiliary corrosion solution ', wherein the main/auxiliary corrosion solution with 5 and 10 formulas is added into 100 formulas of drilling fluid respectively, the volume ratio can be called as follows, ④ AV is apparent viscosity, PV is plastic viscosity, YP is dynamic shear force, G10'/G10 is static shear force, F L is medium-pressure water loss, and HTHP is high-temperature high-pressure water loss.

As can be seen from Table 3, after the drilling fluid is respectively polluted by adding the main corrosion inhibitor solution or the auxiliary corrosion inhibitor solution with the volume ratio of 5-10%, the drilling fluid still has excellent rheological property and better filtration wall-building property, and the mixed corrosion inhibitor and the auxiliary corrosion inhibitor have good compatibility with the water-based drilling fluid system. In addition, similar tests prove that the main corrosion solution with the mass volume percentage of 10-15% has good compatibility with a water-based drilling fluid system under the condition that the volume ratio is 5-10%; the auxiliary corrosion solution with the mass volume percentage of 5-10% has good compatibility with a water-based drilling fluid system under the condition that the volume ratio is 5-10%.

And (4) testing: the compatibility of the primary and secondary corrosion inhibitors of example 1 with oil-based drilling fluids was evaluated.

TABLE 4 compatibility experiment of Primary/Secondary Corrosion Agents with oil-based drilling fluids

Note that the rolling temperature under ① experimental conditions is 100 ℃ and × 16h, the rheological property measuring temperature is 55 ℃, the high-temperature high-pressure fluid loss measuring temperature under ② is 100 ℃, and other conditions which are not indicated are the same as those of the third experiment ③.

As can be seen from Table 4, after the drilling fluid is respectively polluted by adding the main corrosion inhibitor solution or the auxiliary corrosion inhibitor solution with the volume ratio of 5-10%, the drilling fluid still has excellent rheological property and better filtration wall-building property, and after the drilling fluid is added with 10% dissolved pollution, the apparent viscosity of the drilling fluid is increased, but the shear force and other properties are similar to the properties of the drilling fluid, which indicates that the mixed corrosion inhibitor or the auxiliary corrosion inhibitor and the oil-based drilling fluid system have good compatibility. In addition, similar tests prove that the main corrosion solution with the mass volume percentage of 10-15% has good compatibility with an oil-based drilling fluid system under the condition that the volume ratio is 5-10%; the auxiliary corrosion solution with the mass volume percentage of 5-10% has good compatibility with an oil-based drilling fluid system under the condition that the volume ratio is 5-10%.

FIG. 1 shows the results of electron microscopy scanning analysis of Longmaxi shale (well: Wei 202H); fig. 2 shows the results of the sem analysis of the corresponding agalmaxi shale of fig. 1 after dissolution by the auxiliary corrosion inhibitor of example 1. Table 5 shows a comparison of the elemental content of the ramajxi shale before and after soaking in the auxiliary eroding agent of example 1.

TABLE 5 comparison of contents (%) of various elements before and after dissolution of the shale lumps

Condition	C	O	Na	Mg	Al	Si	K	Ti	Fe	Ca	Total up to
												Before soaking	5.03	51.33	0.57	1.53	9.63	24.19	3.31	0.26	4.15	0	100
After soaking	0	49.25	0	1.66	9.92	27.21	4.21	0.48	6.90	0.38	100

As shown in fig. 1 to 2 and table 5, the corrosion effect of the auxiliary corrosion inhibitor on the agalmaxi shale can be clearly seen. Moreover, after the shale falling blocks are soaked by the auxiliary corrosion agent, the content of the carbon element is reduced to zero, which shows that the auxiliary corrosion agent can dissolve organic matter components in the shale, and other corresponding elements are changed to a certain extent.

Generally, the shale drilling auxiliary solvent and the mixed solvent can be used for shale formations with quartz content of more than 35%, bedding development and brittleness coefficient of more than 0.2, and have the following excellent technical effects:

1. the corrosion inhibitor consists of a plurality of surfactants, has pH of 6-7, does not contain inorganic acid, organic acid, harmful ions such as hydrogen ions, chloride ions, sulfate radicals and the like, and has corrosion rate of less than 0.7 g/(m)²H) is far less than 6 g/(m) specified by the national standard²H), achieving corrosion-free safe corrosion and corrosion-free action on the downhole drilling tool;

2. the complex mechanism is used, the complex mechanism and the main corrosion dispersing agent act together to supplement each other, and the complex reaction is carried out on the complex mechanism and organic matters in the falling shale blocks or rock debris to break organic matter chains, so that the integral frame structure of the falling shale blocks is damaged, the subsequent full reaction of the shale is facilitated, and the aims of cracking the falling shale blocks or cracking the settled sand stuck in the drill are favorably fulfilled; the auxiliary corrosion inhibitor can react with organic matters in the shale chipping or rock debris to a certain degree, and is beneficial to breaking carbon chains in the organic matters, so that a grid structure formed by the carbon chains is broken up, and the shale is corroded;

3. the temperature resistance is more than or equal to 140 ℃, the shale gas heat exchanger can be used under the conditions of deep burial, long horizontal section of shale gas and high bottom temperature, and is in the form of solid powder, so that the shale gas heat exchanger is convenient to transport;

4. the oil-water separation device is easy to degrade, can generate degradable small-molecular salts by reacting with shale chipping or rock debris, and can meet the requirements of an underground oil layer on the quality of water quality and environmental protection, for example, after the Longmaxi stratum is stuck and stuck, waste liquid discharged circularly does not need to be specially recovered and treated, the treatment process and cost of the waste liquid are reduced, and the pollution to the environment is reduced.

While the present invention has been described above in connection with exemplary embodiments, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.