WO2021128745A1 - Oil-based drilling fluid and preparation method therefor, and preparation method for anti-settling stabilizer - Google Patents

Abstract

An oil-based drilling fluid and a preparation method therefor, and a method for preparing an anti-settling stabilizer. The method for preparing an anti-settling stabilizer comprises: using lithium bentonite and attapulgite as raw materials, and using an organic cationic surfactant and a non-ionic amine-terminated polyether compound as modifiers to modify the raw materials to obtain the anti-settling stabilizer. On the basis of the sum of the volumes of a base oil and a water phase being 100ml, the oil-based drilling fluid comprises: 80ml to 95ml of the base oil, 5ml to 20ml of the water phase, 3g to 6g of an emulsifier, 0.5g to 2g of a wetting agent, 0.25g to 2g of a viscosity regulator, 2g to 8g of a fluid loss agent, 2g to 4g of an alkalinity regulator, 0.2g to 1g of the anti-settling stabilizer and a weighting agent. The oil-based drilling fluid of the present application has better anti-settling stability and rheological properties under high temperature and high pressure conditions.

Description

Oil-based drilling fluid and preparation method thereof and preparation method of anti-settling stabilizer Technical field

This application relates to but not limited to the field of petroleum drilling technology, and in particular to but not limited to a high-temperature, high-pressure, anti-settling and stable oil-based drilling fluid, a preparation method thereof, and a preparation method of an anti-settling stabilizer.

Background technique

With the development of the petroleum exploration and development industry, high-temperature and high-pressure operation areas have gradually become key areas for petroleum operations. In particular, high-temperature and high-pressure horizontal well drilling operations have the characteristics of high bottom hole temperature, high formation pressure, and long horizontal well sections, which have brought great challenges to drilling technology. Drilling operations in high-temperature and high-pressure operating areas require oil-based drilling fluid systems with high temperature resistance stability, system rheological stability, sedimentation stability, and low filtration loss under conditions of high solids content.

Traditional oil-based drilling fluid system (density greater than or equal to 1.8g/cm ³ ) in the presence of 5% to 10% (mass volume fraction) of activated contaminated soil, the system rheology, high temperature and high pressure fluid loss are difficult to control; After 72 hours of static aging at 232°C, gelation and barite sedimentation occurred.

Moreover, the traditional oil-based drilling fluid system is prone to the settlement of the weighted material under the condition of high temperature and high density. Especially under long-term high-temperature standing conditions, the sedimentation of the aggravating material is serious. In order to solve the settlement problem of the weighted material, the settlement stability of the drilling fluid system is usually improved by increasing the dynamic shear force and gel strength of the drilling fluid system. However, the method of increasing the dynamic shear force and gel strength will inevitably make the system thicker and deteriorate the rheological properties, which is not conducive to the cyclic equivalent density control during the on-site operation of the system, and it is easy to cause downhole pressure excitement and induce lost circulation. , Wells and other complicated situations.

Summary of the invention

The following is an overview of the topics detailed in this article. This summary is not intended to limit the scope of protection of this application.

This application provides an oil-based drilling fluid and a preparation method thereof and a preparation method of an anti-settling stabilizer. The prepared anti-settling stabilizer can solve the suspension of solid particles in a high-temperature and high-pressure horizontal well under the premise of maintaining a relatively low viscosity. The problem of poor stability. The oil-based drilling fluid has good anti-settling stability and rheology under high temperature and high pressure conditions.

This application provides a method for preparing an anti-settling stabilizer, comprising: using lithium bentonite and attapulgite as raw materials, using organic cationic surfactants and non-ionic amine-terminated polyether compounds as modifiers The raw materials are modified to obtain the anti-settling stabilizer.

In the embodiment of the present application, the preparation method of the anti-settling stabilizer may include:

(a) adding lithium bentonite and attapulgite into water, stirring and dispersing to obtain a suspension, and heating the suspension to a first set temperature;

(b) Mixing the organic cationic surfactant and the non-ionic amine-terminated polyether compound to obtain a modifier. The modifier is heated to a second set temperature and then dissolved in an aqueous ethanol solution to obtain the modifier. Ethanol aqueous solution, slowly adding the ethanol aqueous solution of the modifier to the suspension obtained in step (a), and then keeping the reaction at a third set temperature;

(c) After the reaction is completed, the reaction solution obtained in step (b) is cooled to room temperature, the precipitate is separated into layers, filtered, and the filter cake is washed with water to neutrality;

(d) removing unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds in the solid obtained in step (c);

(e) Dry the solid obtained in step (d), grind it into a powder, and sieve to obtain the anti-settling stabilizer.

In the embodiment of the present application, in step (a), the weight ratio of the lithium-based bentonite to the attapulgite may be 1:1 to 5:1.

In the embodiment of the present application, in step (a), the first set temperature is 70°C to 85°C, the second set temperature is 70°C to 85°C, and the third set temperature is 70°C to 85°C, preferably, the first set temperature, the second set temperature, and the third set temperature are all the same.

In the embodiment of the present application, in step (a), the cation exchange capacity of the lithium bentonite may be 40 meq/100 g to 50 meq/100 g, and the cation exchange capacity of the attapulgite may be 25 meq/100g to 40 meq/100g.

In the embodiment of the present application, in step (a), the lithium-based bentonite and the attapulgite can be added to water under continuous stirring.

In the embodiment of the present application, in step (b), the reaction time of the reaction may be 2 hours to 6 hours.

In the embodiment of the present application, in step (b), the organic cationic surfactant can be selected from the group consisting of octadecyl trimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, dihydrogenated cattle Ester dimethyl ammonium chloride, dihydrogenated tallow methyl benzyl ammonium chloride, cetyl trimethyl ammonium bromide, didodecyl dimethyl ammonium chloride, ditetradecyl Any one or more of dimethyl ammonium bromide and ditetradecyl dimethyl ammonium chloride.

In the embodiment of the present application, in step (b), the non-ionic amine-terminated polyether compound may be selected from any one or more of amine-terminated polyether D230, D400, M600 and M1000.

In the embodiment of the present application, in step (b), the total amount of the cation in the organic cationic surfactant and the amine group in the nonionic amine-terminated polyether compound can be the amount of step (a) The mixed lithium bentonite and attapulgite have 80% to 120% of the total cation exchange capacity.

In the embodiment of the present application, in step (b), the weight ratio of the organic cationic surfactant and the nonionic amine-terminated polyether compound may be 2:1 to 5:1.

In the embodiment of the present application, in step (b), the ethanol aqueous solution may be prepared from anhydrous ethanol and water in a volume ratio of 1:1 to 1:2.

In the embodiment of the present application, in step (c), the neutral pH value may be 6-7.

In the embodiment of the present application, in step (d), the unreacted organic cationic surfactant and non-ionic amine-terminated polyether compound in the solid obtained in step (c) can be removed by centrifugal separation.

In the embodiment of the present application, in step (e), the sieving may be a sieve of 80 to 200 mesh, and optionally, a sieve of 100 mesh.

In the embodiment of the present application, the preparation method of the anti-settling stabilizer may include:

(a) Under continuous stirring, mix lithium bentonite and attapulgite according to a weight ratio of 1:1 to 5:1, then slowly add to water, stir to make the dispersion uniform to obtain a suspension, and then add the suspension Heat to 70°C to 85°C;

(b) After mixing the organic cationic surfactant and the nonionic amine-terminated polyether compound in a weight ratio of 2:1 to 5:1, heating to 70°C to 85°C, and then dissolving In an ethanol aqueous solution (prepared from anhydrous ethanol and water in a volume ratio of 1:1 to 1:2), an ethanol aqueous solution of the modifier is obtained, and the ethanol aqueous solution of the modifier is slowly added to step (a) to obtain In the suspension, the reaction is kept at 70°C to 85°C for 2 hours to 6 hours;

(c) After the reaction is completed, cool the reaction solution obtained in step (b) to room temperature, precipitate until the layers are clear, filter and wash the filter cake with distilled water to a pH of 6 to 7;

(d) Use a high-speed centrifuge to perform centrifugal separation to maximize the removal of unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds in the solid obtained in step (c);

(e) Dry the solid obtained in step (d), grind it into a powder, and pass it through a sieve of 80 mesh to 200 mesh to obtain the anti-settling stabilizer;

Wherein, in step (a), the cation exchange capacity of the lithium bentonite is 40 meq/100 g to 50 meq/100 g, and the cation exchange capacity of the attapulgite is 25 meq/100 g to 40 Milligram equivalent/100g;

In step (b), the organic cationic surfactant is selected from octadecyl trimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, dihydrogenated tallow dimethyl ammonium chloride, Dihydrogenated tallow methyl benzyl ammonium chloride, cetyl trimethyl ammonium bromide, didodecyl dimethyl ammonium chloride, ditetradecyl dimethyl ammonium bromide and double ten Any one or more of tetraalkyl dimethyl ammonium chloride; the non-ionic amine-terminated polyether compound is selected from any one or more of amine-terminated polyether D230, D400, M600 and M1000 , D230 and D400 can be purchased from BASF and Huntsman, etc., M600 and M1000 can be purchased from Huntsman, etc.; the cation in the organic cationic surfactant and the amine in the non-ionic amine-terminated polyether compound The total amount of radicals is 80% to 120% of the total amount of the cation exchange capacity of the mixed lithium bentonite and attapulgite in step (a).

The application also provides an anti-settling stabilizer prepared by the method described above.

The application also provides an oil-based drilling fluid, which includes the anti-settling stabilizer as described above.

In the examples of the present application, based on the total volume of the base oil and the water phase being 100ml, the oil-based drilling fluid may include: base oil 80ml to 95ml, water phase 5ml to 20ml, emulsifier 3g to 6g, Wetting agent 0.5g to 2g, viscosity regulator 0.25g to 2g, fluid loss agent 2g to 8g, alkalinity regulator 2g to 4g, said anti-settling stabilizer 0.2g to 1g and weighting agent. The added amount of the weighting agent can be selected according to the desired density of the oil-based drilling fluid.

Optionally, based on the total volume of the base oil and the water phase being 100 ml, the added amount of the wetting agent is 1 g to 2 g.

In the embodiments of the present application, the base oil may be selected from any one or more of diesel, white oil, and gas-to-liquid.

In the embodiment of the present application, the aqueous phase may be an inorganic salt solution, and optionally, may be selected from any one or more of calcium chloride aqueous solution, sodium chloride aqueous solution, and potassium chloride aqueous solution; optionally Ground, the mass fraction of the solute in the inorganic salt solution may be 20 wt% to 30 wt%.

In the embodiments of the present application, the emulsifier can be selected from any one or more of nonionic surfactant emulsifiers, for example, can be selected from fatty acid polyamide emulsifiers, fatty acid polyoxyethylene esters Any one or more of emulsifiers and fatty acid polyoxyethylene ether emulsifiers.

Optionally, the emulsifier may be selected from any one or more of tall oil fatty acid polyamide, polyoxyethylene oleate and polyoxyethylene stearate.

In the embodiments of the present application, the wetting agent can be selected from alkylbenzene sulfonate wetting agents, polyoxyethylene (propylene) alkyl sulfate ester salts or sulfonate wetting agents (ie polyoxy Ethylene alkyl sulfate ester salt wetting agent, polyoxyethylene alkyl sulfonate wetting agent, polyoxypropylene alkyl sulfate ester salt wetting agent, polyoxypropylene alkyl sulfonate wetting agent) And any one or more of polyoxyethylene alkyl alcohol ether wetting agents.

Optionally, the alkylbenzene sulfonate wetting agent may include any one of calcium dodecylbenzenesulfonate, sodium cetylbenzenesulfonate and calcium stearylbenzenesulfonate or Many kinds.

Optionally, the polyoxyethylene (propylene) alkyl sulfate or sulfonate wetting agent may include a polyoxypropylene alkyl sulfate containing 14 carbons and 8 propoxy groups, containing 12 to Any one or more of 13 carbons and 8 propoxy groups of polyoxypropylene alkyl sulfate, alkyl aryl polyoxyethylene sulfonate (the substituent aryl group may be a phenyl group).

Optionally, the polyoxyethylene alkyl alcohol ether type wetting agent may include fatty alcohol polyoxyethylene ethers (for example, MOA-3, MOA-4 or MOA-5) and isomeric deca alcohol polyoxyethylene ethers. Any one or more of.

In the embodiment of the present application, the viscosity modifier may be organic clay.

Optionally, the organic clay can be selected from any one or more of long-chain quaternary ammonium salt-modified sodium bentonite, wherein the number of carbon atoms in the long-chain can be twelve, fourteen, sixteen and Eighteen, the number of long chains can be one or two.

In the embodiments of the present application, the fluid loss control agent may be selected from long-chain organic amine-modified humic acids (for example, organic amine-modified humic acids with twelve to eighteen carbon atoms), Any one or more of oxidized pitch and sulfonated pitch.

Optionally, the number of carbon atoms of the organic amine in the organic amine-modified humic acid may be fourteen, sixteen or eighteen.

In the embodiment of the present application, the alkalinity regulator can be selected from any one or two of calcium oxide and calcium hydroxide.

In the embodiment of the present application, the weighting agent may be selected from any one or more of barite, limestone powder and galena powder.

In the embodiment of the present application, the density of the oil-based drilling fluid may be 1.8 g/cm ³ to 2.5 g/cm ³ .

The application also provides a preparation method of the oil-based drilling fluid as described above, including:

(1) Add the emulsifier and the wetting agent to the base oil, stir and mix;

(2) Add the viscosity modifier and the alkalinity modifier to the mixture obtained in step (1), and stir and mix;

(3) Adding the aqueous phase to the mixture obtained in step (2), stirring and mixing;

(4) Add the fluid loss control agent and the anti-settling stabilizer to the mixture obtained in step (3), and stir and mix;

(5) Add the weighting agent to the mixture obtained in step (4) and stir to adjust the density of the drilling fluid to a desired value to obtain the oil-based drilling fluid.

In the embodiment of the present application, the stirring and mixing time in step (1) to step (4) may be 5 min to 30 min, and the rotation speed of the stirring and mixing may be 8000 rpm to 12000 rpm.

The beneficial effects obtained by this application are:

The oil-based drilling fluid provided in this application is an oil-based drilling fluid that has good rheology, sedimentation stability, and anti-pollution ability under high temperature and high pressure conditions, and has low fluid loss.

Oil-based drilling fluids are water-in-oil emulsified drilling fluids. The water droplets are stably dispersed in the oil phase by adding surfactants such as emulsifiers and wetting agents, but under high temperature conditions, water droplets are easily desorbed from the oil-water interface , It is not easy to stably disperse in the oil phase, but the oil-based drilling fluid of the present application has excellent high temperature stability; meanwhile, the oil-based drilling fluid system of the present application has good rheological properties, anti-pollution properties, and both It has the effect of reducing fluid loss.

In addition, because the anti-settling stabilizer prepared by the specific method of the present application can form a stable three-dimensional space grid structure based on hydrophobically modified flake-shaped lithium bentonite and rod-shaped attapulgite, so that the oil-based drilling fluid of the present application The problem of poor suspension stability of solid particles in high-temperature and high-pressure horizontal wells can be solved under the premise of maintaining a low viscosity.

Other features and advantages of the present application will be described in the following description, and partly become clearer from the description, or understood by implementing the present application. Other advantages of the present application can be realized and obtained through the solutions described in the specification.

Detail

In order to make the objectives, technical solutions, and advantages of the present application clearer, the embodiments of the present application will be described in detail below. It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other arbitrarily if there is no conflict.

The raw materials and reagents used in the following cases, unless otherwise specified, are common commercial products.

The basis for performance testing includes:

(1) Measure the density of the drilling fluid using the methods and instruments specified in the Chinese national standard "GB/T 16783.2-2012 Oil and Gas Industry Drilling Fluid Field Test Part 2 Oil-based Drilling Fluid";

(2) Measure the plastic viscosity of the drilling fluid using the methods and instruments specified in the Chinese national standard "GB/T 16783.2-2012 Oil and Gas Industry Drilling Fluid Field Test Part 2 Oil-based Drilling Fluid";

(3) Use the methods and instruments specified in the Chinese national standard "GB/T 16783.2-2012 Oil and Gas Industry Drilling Fluid Field Test Part 2 Oil-based Drilling Fluid" to determine the dynamic shear force of the drilling fluid;

(4) Determine the demulsification voltage of the drilling fluid using the methods and instruments specified in the Chinese national standard "GB/T 16783.2-2012 Oil and Gas Industry Drilling Fluid Field Test Part 2 Oil-based Drilling Fluid";

(5) Use the methods and instruments specified in the Chinese national standard "GB/T 16783.2-2012 Oil and Gas Industry Drilling Fluid Field Test Part 2 Oil-based Drilling Fluid" to determine the high temperature and high pressure (HTHP) filter loss of the drilling fluid; The loss measurement temperature is 176°C and the pressure is 3.5MPa.

Example 1

Prepare anti-settling stabilizer according to the composition of Table 1, including the following steps:

(a) Under continuous stirring, mix the lithium bentonite and attapulgite according to a certain ratio and slowly add them to water, stir to make the dispersion uniform to obtain a suspension, and then heat the suspension to 70°C;

(b) The organic cationic surfactant and the non-ionic amine-terminated polyether compound are mixed in a ratio of 4:1 and then heated to 70°C, and the heated modifier mixture is dissolved in the ethanol aqueous solution ( It is prepared from anhydrous ethanol and water with a volume ratio of 1:1), is formulated into an ethanol aqueous solution of the modifier with a mass fraction of the modifier of 15 wt%, and then is slowly added to the suspension obtained in step (a) In the turbid liquid, the reaction was kept at 70°C for 2 hours;

(c) After the reaction is completed, cool the reaction solution obtained in step (b) to room temperature, precipitate until the layers are clear, filter and wash the filter cake with distilled water to a neutral pH of 6;

(d) Add the washed filter cake obtained in step (c) to a high-speed centrifuge, set the speed of the high-speed centrifuge to 13000r/min, and centrifuge for 20 minutes to maximize the amount of solids in the solid obtained in step (c) Removal of unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds;

(e) Place the solid obtained in step (d) in an electric heated blast dryer at 105° C. to dry for 2 hours, grind into a powder, and pass through a 100-mesh sieve to obtain an anti-settling stabilizer.

Example 2

Prepare anti-settling stabilizer according to the composition of Table 1, including the following steps:

(a) Under continuous stirring, mix the lithium bentonite and attapulgite according to a certain ratio and slowly add them to water, stir to make the dispersion uniform to obtain a suspension, and then heat the suspension to 85°C;

(b) The organic cationic surfactant and the non-ionic amine-terminated polyether compound are mixed in a ratio of 5:1 and then heated to 85°C, and the heated modifier mixture is dissolved in the ethanol aqueous solution ( It is prepared from anhydrous ethanol and water with a volume ratio of 1:1), is formulated into an ethanol aqueous solution of the modifier with a mass fraction of the modifier of 18% by weight, and then is slowly added to the suspension obtained in step (a) In the turbid liquid, the reaction was kept at 85°C for 6 hours;

(c) After the reaction is completed, cool the reaction solution obtained in step (b) to room temperature, precipitate until the layers are clear, filter and wash the filter cake with distilled water to a neutral pH of 7;

(d) Add the washed filter cake obtained in step (c) to a high-speed centrifuge, set the speed of the high-speed centrifuge to 13000r/min, and centrifuge for 20 minutes to maximize the amount of solids in the solid obtained in step (c) Removal of unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds;

(e) Place the solid obtained in step (d) in an electric heated blast dryer at 105° C. to dry for 2 hours, grind into a powder, and pass through a 100-mesh sieve to obtain an anti-settling stabilizer.

Example 3

Prepare anti-settling stabilizer according to the composition of Table 1, including the following steps:

(a) Under continuous stirring, mix the lithium bentonite and attapulgite according to a certain ratio and slowly add them to water, stir to make the dispersion uniform to obtain a suspension, and then heat the suspension to 80°C;

(b) The organic cationic surfactant and the non-ionic amine-terminated polyether compound are mixed in a ratio of 3:1 and then heated to 80°C to dissolve the heated modifier mixture in the ethanol aqueous solution (by volume A ratio of 1:1 anhydrous ethanol and water is prepared), a 16 wt% ethanol aqueous solution with a mass fraction of the modifier is prepared, and then it is slowly added to the suspension obtained in step (a), and then Incubate for 5 hours at 80°C;

(c) After the reaction is completed, the reaction solution obtained in step (b) is cooled to room temperature, precipitated until the layers are clear, filtered and washed with distilled water to a neutral pH of 6;

(d) Add the washed filter cake obtained in step (c) to a high-speed centrifuge, set the speed of the high-speed centrifuge to 13000r/min, and centrifuge for 20 minutes to maximize the amount of solids in the solid obtained in step (c) Removal of unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds;

(e) Place the solid obtained in step (d) in an electric heated blast dryer at 105° C. to dry for 2 hours, grind into a powder, and pass through a 100-mesh sieve to obtain an anti-settling stabilizer.

The compositions of Examples 1 to 3 are shown in Table 1.

Table 1 Composition of anti-settling stabilizer

Example 4

(1) Formula of high temperature, high pressure, anti-settling and stable oil-based drilling fluid (oil-water ratio 80:20):

The base oil is 3# white oil; the water phase is 25% CaCl ₂ aqueous solution; the emulsifier is tall oil fatty acid polyamide and polyoxyethylene oleate; the wetting agent is calcium dodecylbenzene sulfonate The organic earth is sodium bentonite modified by didodecyl dimethyl ammonium chloride; the alkalinity regulator is calcium oxide; the fluid loss agent is oxidized asphalt; the anti-settling stabilizer is prepared in Example 1, and the weighting agent For barite.

(2) Preparation method of drilling fluid:

Add 8g tall oil fatty acid polyamide, 4g polyoxyethylene oleate and 4g calcium dodecylbenzene sulfonate into 320mL of white oil. Refers to the speed of 12000rpm) high-speed stirring for 5min; under high-speed stirring, add 8g didodecyldimethylammonium chloride modified sodium bentonite and 12g calcium oxide, high-speed stirring for 5min; continue under high-speed stirring Add 80 mL of 25% CaCl ₂ aqueous solution and stir at high speed for 20 minutes; then add 8 g of oxidized pitch and 2 g of the anti-settling stabilizer prepared in Example 1, and stir at high speed for 5 minutes; finally add barite to increase the density to 1.8 g /cm ³ , high-speed stirring for 20 minutes, to prepare oil-based drilling fluid.

(3) Performance evaluation of drilling fluid:

1) Before the aging performance test of the drilling fluid, the rheology, electrical stability, and high temperature and high pressure fluid loss properties of the prepared drilling fluid were first tested. The results are shown in Table 2.

2) Then put the drilling fluid into a high-temperature aging tank, stand for 72h at the set aging temperature, and cool to 65°C to test the performance of the drilling fluid after aging. The results are shown in Table 3.

Among them, the static sedimentation stability test method is the static sedimentation factor evaluation method: After the drilling fluid sample is statically aged in the aging tank, the density ρ _top and bottom ρ _{bottom of} the column upper part (lower layer of the free body) are measured respectively. The calculation formula of static settlement factor SF is as follows:

According to the sedimentation factor SF of the drilling fluid, the static sedimentation stability of the drilling fluid is evaluated. When SF is 0.50 to 0.53, it means that the drilling fluid system has not statically settled, and when SF is greater than 0.53, it means that static settlement has occurred.

(4) Evaluation of anti-pollution performance of drilling fluid:

Prepare 3 parts of the same oil-based drilling fluid according to the method described in (2), numbered 1#, 2# and 3#, add 20ppb calcium soil to 1# oil-based drilling fluid, and add it to 2# oil-based drilling fluid The seawater which accounts for 15% of the oil-based drilling fluid volume is tested for pollution, and the isolation fluid which accounts for 15% of the oil-based drilling fluid volume is added to the 3# oil-based drilling fluid for pollution test, and then the polluted drilling fluid is put into high temperature aging In the tank, it was allowed to stand for 72h at the set aging temperature. After cooling to 65°C, the performance of the drilling fluid after aging was tested. The results are shown in Table 4.

Example 5

(1) Formula of high temperature and high pressure anti-settling and stable oil-based drilling fluid (oil-water ratio 90:10):

The base oil is Saraline185V gas-based oil; the water phase is 25% CaCl ₂ aqueous solution; the emulsifier is tall oil fatty acid polyamide; the wetting agent is calcium dodecylbenzene sulfonate and polyoxypropylene alkyl sulfuric acid Ester salt (the carbon chain contains 14 carbons and 8 propoxy groups); organic earth is sodium bentonite modified by hexadecyl dimethyl ammonium bromide; alkalinity regulator is calcium hydroxide; filter reduction The loss agent is octadecylamine modified humic acid, the anti-settling stabilizer is prepared in Example 2, and the weighting agent is barite.

(2) Preparation method of drilling fluid:

Add 16g tall oil fatty acid polyamide, 5g calcium dodecylbenzene sulfonate and 3g polyoxypropylene alkyl sulfate ester salt into 360mL white oil. ”Refers to the speed of 12000rpm) high-speed stirring for 5 minutes; under high-speed stirring, add 2g hexadecyldimethylammonium bromide modified sodium bentonite and 16g calcium hydroxide, and stir at high speed for 5 minutes; continue stirring at high speed Add 40 mL of 25% CaCl ₂ aqueous solution with a mass fraction of 25%, stir at high speed for 20 minutes, then add 16 g of octadecylamine modified humic acid and 0.8 g of the anti-settling stabilizer prepared in Example 2, and stir at high speed for 5 minutes; finally Add barite to increase the weight to 2.4g/cm ³ and stir at high speed for 20 minutes to prepare oil-based drilling fluid.

(3) The performance evaluation of the drilling fluid is the same as in Example 4.

(4) The evaluation of the anti-pollution performance of the drilling fluid is the same as in Example 4.

Example 6

(1) Formula of high temperature, high pressure, anti-settling and stable oil-based drilling fluid (oil-water ratio 95:5):

The base oil is Sarapar 147 gas-to-oil; the water phase is 25% CaCl ₂ aqueous solution; the emulsifier is tall oil fatty acid polyamide and polyoxyethylene stearate; the wetting agent is polyoxypropylene alkyl sulfate Salt (the carbon chain contains 12 to 13 carbons, 8 propoxy groups) and fatty alcohol polyoxyethylene ether (MOA-3); the organic earth is sodium base modified by dioctadecyl dimethyl ammonium chloride Bentonite; alkalinity regulator is calcium hydroxide; fluid loss agent is octadecylamine modified humic acid and sulfonated asphalt; anti-settling stabilizer is prepared in Example 3; weighting agent is barite.

(2) Preparation method of drilling fluid:

Add 12g tall oil fatty acid polyamide, 12g polyoxyethylene stearate, 4g polyoxypropylene alkyl sulfate ester salt (containing 12-13 carbons in the carbon chain, 8 propoxy groups) and 2g fatty alcohol polyoxyethylene ether (MOA-3), stir in a high-speed mixer at a speed of 12000rpm ("high speed" in this example refers to a speed of 12000rpm) for 5min; add 1g double ten under high-speed stirring Sodium bentonite modified by octaalkyl dimethyl ammonium chloride and 16g calcium hydroxide, stir at high speed for 5 minutes; continue to add 40 mL of 25% CaCl ₂ aqueous solution under high speed stirring, and stir at high speed for 20 minutes; then Add 16g of octadecylamine modified humic acid, 16g of sulfonated asphalt and 4g of the anti-settling stabilizer prepared in Example 3, stir at high speed for 5 minutes; finally add barite to increase the weight to 2.5g/cm ³ , stir at high speed for 20 minutes to prepare Get oil-based drilling fluid.

(3) The performance evaluation of the drilling fluid is the same as in Example 4.

(4) The evaluation of the anti-pollution performance of the drilling fluid is the same as in Example 4.

Comparison

This comparative example is different from Example 5 only in that: no anti-settling stabilizer is added.

The performance test results of the oil-based drilling fluids of Examples 4 to 6 and the comparative example before and after aging are shown in Table 2 and Table 3, respectively.

Table 2 Oil-based drilling fluid system performance before aging

Table 3 Oil-based drilling fluid system performance after 72h standing aging

It can be seen from Table 2 and Table 3 that the high-temperature, high-pressure, anti-settling and stable oil-based drilling fluids obtained in Examples 4 to 6 of the present application have a density greater than or equal to 1.8 g/cm ³ , and an aging temperature greater than or equal to 180° C., belonging to high temperature and high pressure drilling fluids. , And the specific gravity of the drilling fluid can reach 2.5g/cm ³ at the highest, and the highest aging temperature can reach 232℃.

Comparing the data in Table 2 and Table 3, it can be seen that the rheological properties of the high-temperature and high-pressure oil-based drilling fluids in Examples 4 to 6 of the present application are still relatively stable after being left at high temperature for a long time for 72 hours, without abrupt changes, and the demulsification voltage (ES) High, low high temperature and high pressure filter loss (HTHP), and no sedimentation at the bottom, and the sedimentation factor SF is less than 0.53, indicating that the anti-sedimentation stabilizer of the embodiment of the present application forms a stable three-dimensional space grid structure with good sedimentation stability . However, in the comparative example, since no self-made anti-settling stabilizer was added, serious settlement occurred after 72 hours of standing at high temperature.

The application also tested the anti-pollution performance of the high-density oil-based drilling fluids obtained in Examples 4 to 6, and the test results are shown in Table 4.

Table 4 Anti-pollution performance of oil-based drilling fluid system

It can be seen from Table 4 that the high-temperature, high-pressure, anti-settling and stable oil-based drilling fluid obtained in the examples of the present application still maintains a relatively high level of demulsification voltage after being contaminated by external sources, and has stable rheological properties without sudden changes, indicating that it has relatively high performance. Good basic performance and anti-pollution performance.

The present disclosure is an example of the principles of the embodiments of the present application, and does not limit the present application in any form or substance, or limit the present application to specific embodiments. For those skilled in the art, it is obvious that the elements, methods, and systems of the technical solutions of the embodiments of the present application can be changed, changed, modified, and evolved without departing from the embodiments and technical solutions of the present application as described above. , As defined in the claims, the principle, spirit and scope. The implementation schemes of these changes, changes, modifications, and evolutions are all included in the equivalent embodiments of the present application, and these equivalent embodiments are all included in the scope defined by the claims of the present application. Although the embodiments of the present application can be embodied in many different forms, some embodiments of the present application are described in detail here. In addition, the examples of the present application include any possible combination of some or all of the various embodiments described herein, and are also included in the scope of the present application defined by the claims. All patents, patent applications and other cited materials mentioned in this application or anywhere in any cited patent, cited patent application or other cited materials are hereby incorporated by reference in their entirety.

The above disclosure is provided as illustrative rather than exhaustive. For those skilled in the art, this description will suggest many changes and alternatives. All these alternatives and variations are intended to be included within the scope of the claims, where the term "including" means "including, but not limited to."

This completes the description of the alternative implementations of the present application. Those skilled in the art may recognize other equivalent transformations of the embodiments described herein, and these equivalent transformations are also encompassed by the claims attached herein.

Claims (16)

1. A preparation method of anti-settling stabilizer, comprising: using lithium bentonite and attapulgite as raw materials, and using organic cationic surfactants and non-ionic amine-terminated polyether compounds as modifiers to modify the raw materials , To obtain the anti-settling stabilizer.
2. The method of claim 1, comprising:

   (a) adding the lithium bentonite and the attapulgite into water, stirring and dispersing to obtain a suspension, and heating the suspension to a first set temperature;

   (b) Mixing the organic cationic surfactant and the nonionic amine-terminated polyether compound to obtain a modifier, and the modifier is heated to a second set temperature and then dissolved in an aqueous ethanol solution to obtain The ethanol aqueous solution of the modifier is slowly added to the suspension obtained in step (a), and then the reaction is kept at a third set temperature;

   (c) After the reaction is completed, the reaction solution obtained in step (b) is cooled to room temperature, the precipitate is separated into layers, filtered, and the filter cake is washed with water to neutrality;

   (d) removing unreacted organic cationic surfactants and non-ionic amine-terminated polyether compounds in the solid obtained in step (c);

   (e) Dry the solid obtained in step (d), grind it into a powder, and sieve to obtain the anti-settling stabilizer.
3. The method according to claim 2, wherein, in step (a), the weight ratio of the lithium-based bentonite to the convex clay is 1:1 to 5:1;

   Optionally,

   The first set temperature is 70°C to 85°C, the second set temperature is 70°C to 85°C, and the third set temperature is 70°C to 85°C. Preferably, the first set temperature The fixed temperature, the second set temperature, and the third set temperature are all the same;

   The cation exchange capacity of the lithium bentonite is 40 meq/100 g to 50 meq/100 g, and the cation exchange capacity of the attapulgite is 25 meq/100 g to 40 meq/100 g;

   The lithium-based bentonite and the attapulgite are added to the water under continuous stirring.
4. The method according to claim 2 or 3, wherein, in step (b), the reaction time of the reaction is 2 hours to 6 hours;

   Optionally,

   The organic cationic surfactant is selected from the group consisting of octadecyl trimethyl ammonium chloride, dioctadecyl dimethyl ammonium chloride, dihydrogenated tallow dimethyl ammonium chloride, dihydrogenated tallow methyl ammonium chloride Benzyl ammonium chloride, cetyl trimethyl ammonium bromide, didodecyl dimethyl ammonium chloride, ditetradecyl dimethyl ammonium bromide and ditetradecyl dimethyl ammonium Any one or more of ammonium chloride;

   The non-ionic amine-terminated polyether compound is selected from any one or more of amine-terminated polyether D230, D400, M600 and M1000;

   The total amount of the cation in the organic cationic surfactant and the amine group in the non-ionic amine-terminated polyether compound is the cation exchange capacity of the mixed lithium bentonite and attapulgite in step (a) 80% to 120% of the total amount, wherein the weight ratio of the organic cationic surfactant to the nonionic amine-terminated polyether compound is 2:1 to 5:1;

   The ethanol aqueous solution is prepared from absolute ethanol and water in a volume ratio of 1:1 to 1:2.
5. The method according to any one of claims 2 to 4, wherein in step (c), the neutral pH is 6 to 7; optionally,

   In step (d), the unreacted organic cationic surfactant and non-ionic amine-terminated polyether compound in the solid obtained in step (c) are removed by centrifugal separation;

   In step (e), the sieving is a sieve of 80 to 200 mesh, and optionally, a sieve of 100 mesh.
6. An anti-settling stabilizer prepared by the method of any one of claims 1 to 5.
7. An oil-based drilling fluid, comprising the anti-settling stabilizer according to claim 6;

   Optionally, based on the total volume of the base oil and the water phase being 100ml, the oil-based drilling fluid includes: base oil 80ml to 95ml, water phase 5ml to 20ml, emulsifier 3g to 6g, wetting agent 0.5g to 2g, viscosity modifier 0.25g to 2g, filtrate reducer 2g to 8g, alkalinity modifier 2g to 4g, the anti-settling stabilizer 0.2g to 1g and weighting agent.
8. The oil-based drilling fluid according to claim 7, wherein the base oil is selected from any one or more of diesel, white oil, and gas-to-liquid.
9. The oil-based drilling fluid according to claim 7 or 8, wherein the aqueous phase is an inorganic salt solution, optionally selected from any one of calcium chloride aqueous solution, sodium chloride aqueous solution, and potassium chloride aqueous solution Or more; optionally, the mass fraction of the solute in the inorganic salt solution is 20 wt% to 30 wt%.
10. The oil-based drilling fluid according to any one of claims 7 to 9, wherein the emulsifier is selected from the group consisting of fatty acid polyamide emulsifiers, fatty acid polyoxyethylene ester emulsifiers and fatty acid polyoxyethylene ether emulsifiers Any one or more of them, optionally, are selected from any one or more of tall oil fatty acid polyamide, polyoxyethylene oleate and polyoxyethylene stearate.
11. The oil-based drilling fluid according to any one of claims 7 to 10, wherein the wetting agent is selected from the group consisting of alkylbenzene sulfonate wetting agents, polyoxyethylene alkyl sulfate ester salt wetting agents , Polyoxyethylene alkyl sulfonate wetting agent, polyoxypropylene alkyl sulfate ester salt wetting agent, polyoxypropylene alkyl sulfonate wetting agent and polyoxyethylene alkyl alcohol ether wetting agent Any one or more of the agents.
12. The oil-based drilling fluid according to any one of claims 7 to 11, wherein the viscosity modifier is an organoclay, and optionally, the organoclay is selected from the group consisting of sodium bentonite modified by a long-chain quaternary ammonium salt Any one or more of them, wherein the number of carbon atoms in the long chain is twelve, fourteen, sixteen and eighteen, and the number of the long chain is one or two.
13. The oil-based drilling fluid according to any one of claims 7 to 12, wherein the fluid loss agent is selected from the group consisting of organic amine-modified humic acid, oxidized asphalt and Any one or more of the sulfonated asphalt, optionally, the number of carbon atoms of the organic amine in the organic amine-modified humic acid is fourteen, sixteen or eighteen;

    Optionally, the alkalinity regulator is selected from any one or two of calcium oxide and calcium hydroxide;

    Optionally, the weighting agent is selected from any one or more of barite, limestone powder and galena powder.
14. The oil-based drilling fluid according to any one of claims 7 to 13, wherein the oil-based drilling fluid has a density of 1.8 g/cm ³ to 2.5 g/cm ³ .
15. The preparation method of oil-based drilling fluid according to any one of claims 7 to 14, comprising:

    (1) Add the emulsifier and the wetting agent to the base oil, stir and mix;

    (2) Add the viscosity modifier and the alkalinity modifier to the mixture obtained in step (1), and stir and mix;

    (3) Adding the aqueous phase to the mixture obtained in step (2), stirring and mixing;

    (4) Add the fluid loss control agent and the anti-settling stabilizer to the mixture obtained in step (3), and stir and mix;

    (5) Add the weighting agent to the mixture obtained in step (4) and stir to adjust the density of the drilling fluid to a desired value to obtain the oil-based drilling fluid.
16. The preparation method according to claim 15, wherein the stirring and mixing time in step (1) to step (4) is 5 min to 30 min, and the rotation speed of the stirring and mixing is 8000 rpm to 12000 rpm.