Drilling fluid with borehole cleaning function and preparation method thereof

Abstract

The invention relates to the technical field of drilling fluids, in particular to a drilling fluid with a borehole cleaning function and a preparation method thereof.The drilling fluid with the borehole cleaning function is prepared from, by mass, 70-80 parts of bentonite or clay, 20-30 parts of bentonite, 20-30 parts of bentonite, 20-30 parts of bentonite, 20-30 parts of clay and 20-30 parts of water. The drilling fluid is prepared from the following components in parts by weight: 2-6 parts of an emulsifier, 2-6 parts of a filtrate reducer, 2-6 parts of an alkalinity regulator, 2-6 parts of a blocking agent, 2-6 parts of a weighting agent, 12-20 parts of cottonseed hull particles, 12-20 parts of ultra-short fibers and 1000 parts of water. According to the drilling fluid with the borehole cleaning function and the preparation method, the preparation method and the use method of the drilling fluid, operation is convenient, the characteristics of porosity and roughness of the cottonseed hull particles and the higher specific surface area and the good flowing property of the ultra-short fibers are utilized, the good borehole cleaning effect is achieved, and the rock-carrying efficiency is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of drilling fluid technology, specifically to a drilling fluid with wellbore cleaning function and its preparation method. Background Technology

[0002] Drilling fluid is a general term for various circulating fluids that fulfill the needs of drilling operations through multiple functions. It is considered the lifeblood of drilling, also known as borehole flushing fluid. Drilling fluids can be classified by composition into water, mud, clay-free flushing fluid, emulsions, foam, and compressed air, among others. Water is the earliest type of drilling fluid used; it requires no treatment, is convenient to use, and is suitable for areas with intact rock formations and abundant water sources. Mud is a widely used drilling fluid, primarily suitable for unstable borehole formations such as loose, fractured, easily collapsing, or water-swelling rock formations.

[0003] However, existing drilling fluids lack wellbore cleaning capabilities in practical applications, failing to effectively carry and suspend cuttings, maintain wellbore cleanliness, and prevent wellbore collapse and repeated drill bit cutting. Therefore, there is an urgent need for a drilling fluid that combines both cleaning and cuttings-carrying abilities. Summary of the Invention

[0004] This invention provides a drilling fluid with wellbore cleaning function, which overcomes the shortcomings of the prior art and can effectively solve the problem of poor carrying and suspending of cuttings in existing drilling fluids.

[0005] One of the technical solutions of the present invention is achieved through the following measures: a drilling fluid with wellbore cleaning function, the raw materials comprising, by mass parts: 70 to 80 parts bentonite or clay, 2 to 6 parts emulsifier, 2 to 6 parts filtration loss reducer, 2 to 6 parts alkalinity adjuster, 2 to 6 parts plugging agent, 2 to 6 parts weighting agent, 12 to 20 parts cottonseed hull particles, 12 to 20 parts ultra-short fiber, and 1000 parts water.

[0006] The following are further optimizations and / or improvements to the above-mentioned technical solution: The emulsifier mentioned above is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and sodium dodecyl sulfate.

[0007] The aforementioned filtration loss reducer is one or more of carboxymethyl cellulose, sulfonated methyl phenolic resin, and sulfonated lignite resin.

[0008] The alkalinity regulators mentioned above are one or both of sodium hydroxide and potassium hydroxide.

[0009] The aforementioned plugging agent is a mixture of potassium humate, potassium fulvate, and sodium humate, with a mass ratio of 20 to 30: 10 to 15: 20 to 30 for potassium humate, potassium fulvate, and sodium humate.

[0010] The aforementioned weighting agent is barite.

[0011] The particle size of the cottonseed hull particles is 0.1 mm to 2 mm.

[0012] The aforementioned short fibers are one or both of polyester fibers and glass fibers, and the length of the short fibers is 1 mm to 3 mm.

[0013] The density of the drilling fluid with wellbore cleaning function is 1.1 g / cm³. 3 Up to 2.4 g / cm 3 .

[0014] The drilling fluid with wellbore cleaning function described above is prepared according to the following steps: The first step is to add the required amount of bentonite or clay, emulsifier, and short fibers to water, mix and stir to obtain the first mixture; The second step is to add the required amount of cottonseed hull particles and filtration loss reducer to the first mixture, and then mix and stir to obtain the second mixture. The third step involves adding the required amounts of plugging agent, weighting agent, and alkalinity regulator to the second mixture, and then mixing and stirring to obtain a drilling fluid with wellbore cleaning function.

[0015] The second technical solution of the present invention is achieved through the following measures: a method for preparing drilling fluid with wellbore cleaning function, comprising the following steps: The first step is to add the required amount of bentonite or clay, emulsifier, and short fibers to water, mix and stir to obtain the first mixture; The second step is to add the required amount of cottonseed hull particles and filtration loss reducer to the first mixture, and then mix and stir to obtain the second mixture. The third step involves adding the required amounts of plugging agent, weighting agent, and alkalinity regulator to the second mixture, and then mixing and stirring to obtain a drilling fluid with wellbore cleaning function.

[0016] The drilling fluid with wellbore cleaning function and its preparation method provided by this invention are easy to operate and use. Utilizing the porous and rough characteristics of cottonseed hull particles, as well as the higher specific surface area and good flow properties of ultra-short fibers, it has a good wellbore cleaning effect and effectively improves rock carrying efficiency. Detailed Implementation

[0017] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0018] The present invention will be further described below with reference to embodiments: Example 1: The drilling fluid with wellbore cleaning function comprises, by weight, 70 to 80 parts bentonite or clay, 2 to 6 parts emulsifier, 2 to 6 parts filtration loss reducer, 2 to 6 parts alkalinity adjuster, 2 to 6 parts plugging agent, 2 to 6 parts weighting agent, 12 to 20 parts cottonseed hull particles, 12 to 20 parts ultra-short fiber, and 1000 parts water.

[0019] Example 2: As an optimization of the above example, the emulsifier is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate and sodium dodecyl sulfate.

[0020] Example 3: As an optimization of the above examples, the filtration loss reducing agent is one or more of carboxymethyl cellulose, sulfonated methyl phenolic resin, and sulfonated lignite resin.

[0021] Example 4: As an optimization of the above examples, the alkalinity regulator is one or both of sodium hydroxide and potassium hydroxide.

[0022] Example 5: As an optimization of the above examples, the plugging agent is a mixture of potassium humate, potassium fulvate and sodium humate, and the mass ratio of potassium humate, potassium fulvate and sodium humate in the plugging agent is 20 to 30: 10 to 15: 20 to 30.

[0023] Example 6: As an optimization of the above example, the weighting agent is barite.

[0024] Example 7: As an optimization of the above example, the particle size of the cottonseed hull particles is 0.1 mm to 2 mm.

[0025] Example 8: As an optimization of the above examples, the short fibers are one or both of polyester fibers and glass fibers, and the length of the short fibers is 1 mm to 3 mm.

[0026] Example 9: As an optimization of the above examples, the drilling fluid with wellbore cleaning function has a density of 1.1 g / cm³. 3 Up to 2.4 g / cm 3 .

[0027] Example 10: A method for preparing drilling fluid with wellbore cleaning function, comprising the following steps: The first step is to add the required amount of bentonite or clay, emulsifier, and short fibers to water, mix and stir to obtain the first mixture; The second step is to add the required amount of cottonseed hull particles and filtration loss reducer to the first mixture, and then mix and stir to obtain the second mixture. The third step involves adding the required amounts of plugging agent, weighting agent, and alkalinity regulator to the second mixture, and then mixing and stirring to obtain a drilling fluid with wellbore cleaning function.

[0028] In the specific preparation method described above, the stirring speed in the first to third steps is 30 r / min to 80 r / min, and the stirring time is 20 min to 60 min.

[0029] Example 11: The drilling fluid raw material with wellbore cleaning function includes, by mass parts: 78 parts bentonite, 4 parts sodium dodecylbenzenesulfonate, 4 parts carboxymethyl cellulose, 4 parts sodium hydroxide, 4 parts plugging agent, 4 parts barite, 18 parts cottonseed hull particles, and 18 parts ultra-short polyester fiber; wherein the mass ratio of potassium humate, potassium fulvate, and sodium humate in the plugging agent is 25:15:30.

[0030] According to the raw material ratio, bentonite, sodium dodecylbenzenesulfonate, and ultra-short polyester fibers were first added to the mixer and stirred at 40 r / min for 35 min to ensure thorough mixing. Then, cottonseed hull particles and carboxymethyl cellulose were added, and stirring was continued at 75 r / min for 35 min to ensure thorough mixing of the cottonseed hull particles with the other components. Finally, the plugging agent, weighting agent, and sodium hydroxide were added in sequence, and the mixture was stirred for 40 min to prepare a drilling fluid with wellbore cleaning function, denoted as A1.

[0031] Example 12: The drilling fluid raw materials with wellbore cleaning function include, by weight parts: 80 parts clay, 5 parts sodium dodecyl sulfonate, 5 parts sulfomethylphenol resin, 5 parts potassium hydroxide, 5 parts plugging agent, 5 parts weighting agent, 20 parts cottonseed hull particles, and 20 parts ultra-short glass fiber (1-3mm); the mass ratio of potassium humate, potassium fulvate and sodium humate in the plugging agent is 25:12:28.

[0032] According to the raw material ratio, clay, sodium dodecyl sulfonate, and ultra-short glass fibers were first added to the mixer and stirred at 30 r / min for 30 min to ensure thorough mixing. Then, cottonseed hull particles and sulfomethylphenol resin were added, and stirring was continued at 70 r / min for 35 min to ensure thorough mixing of the cottonseed hull particles with the other components. Finally, the plugging agent, weighting agent, and potassium hydroxide were added in sequence and stirred for 30 min to prepare a drilling fluid with wellbore cleaning function, denoted as A2.

[0033] Example 13: The drilling fluid raw materials with wellbore cleaning function include, by mass parts: 81 parts bentonite, 5 parts sodium dodecyl sulfate, 6 parts sulfonated lignite resin, 4 parts sodium hydroxide, 5 parts plugging agent, 6 parts weighting agent, 21 parts cottonseed hull particles, and 21 parts ultra-short polyester fiber; the mass ratio of potassium humate, potassium fulvate, and sodium humate in the plugging agent is 20:15:25.

[0034] According to the raw material ratio, bentonite, sodium dodecyl sulfate, and ultra-short polyester fiber were first added to the mixer and stirred at 45 r / min for 35 min to ensure thorough mixing. Then, cottonseed hull particles and sulfonated lignite resin were added, and stirring was continued at 75 r / min for 40 min to ensure thorough mixing of the cottonseed hull particles with the other components. Finally, the plugging agent, weighting agent, and sodium hydroxide were added in sequence and stirred for 30 min to prepare the drilling fluid with wellbore cleaning function, denoted as A3.

[0035] Example 14: The drilling fluid raw materials with wellbore cleaning function include, by mass parts: 82 parts clay, 6 parts sodium dodecylbenzenesulfonate, 6 parts sulfomethylphenol resin, 6 parts potassium hydroxide, 6 parts plugging agent, 6 parts weighting agent, 22 parts cottonseed hull particles, and 22 parts ultra-short glass fiber (1-3mm); the mass ratio of potassium humate, potassium fulvate, and sodium humate in the plugging agent is 28:10:22.

[0036] According to the raw material ratio, clay, sodium dodecylbenzenesulfonate, and ultra-short glass fibers were first added to the mixer and stirred at 50 r / min for 40 min to ensure thorough mixing. Then, cottonseed hull particles and sulfomethylphenol resin were added, and stirring was continued at 80 r / min for 40 min to ensure thorough mixing of the cottonseed hull particles with the other components. Finally, the plugging agent, weighting agent, and potassium hydroxide were added in sequence and stirred for 40 min to prepare the drilling fluid with wellbore cleaning function, denoted as A4.

[0037] Comparative Example 1: Unlike Example 1, no short fibers were added, denoted as D1.

[0038] Comparative Example 2: The drilling fluid formulation is as follows: 100 parts water, 3 parts bentonite, 0.2 parts soda ash, 0.5 parts sodium hydroxide, 2 parts filtration loss reducer, 3 parts emulsion thickener, 4 parts plugging agent, 0.2 parts oxygen scavenger, 2 parts dispersant, and barite. This drilling fluid is designated as D2.

[0039] The drilling fluids A1 to A4 with wellbore cleaning function prepared in Examples 1 to 4 of this invention, and the drilling fluids of Comparative Examples 1 and 2, were subjected to performance tests, including tests on density, viscosity, filtration loss (test temperature 150℃, test pressure 3450kPa), suspension, and rock-carrying capacity at different well depths. Relevant experimental data are shown in Table 1. As can be seen from Table 1, the drilling fluids of Examples 1 to 4 of this invention exhibit good apparent viscosity, plastic viscosity, and rock-carrying efficiency at different well depths, generally above 20%, while filtration loss is also reduced to a certain extent. Furthermore, the quantity, size, and sharpness of returned sand reflect the cleaning effect of the drilling fluid on the wellbore; when there is less returned sand, the returned sand is small and thin, and the sharpness is relatively distinct, it indicates a good wellbore cleaning effect.

[0040] In summary, this invention provides a drilling fluid with wellbore cleaning function. By utilizing the porous and rough characteristics of cottonseed hull particles, as well as the higher specific surface area and good flow properties of ultra-short fibers, it solves the problem of poor wellbore cleaning effect in the actual use of existing drilling fluids and effectively improves rock carrying efficiency.

[0041] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A drilling fluid with wellbore cleaning function, characterized in that... The raw materials, by weight, include: 70 to 80 parts bentonite or clay, 2 to 6 parts emulsifier, 2 to 6 parts filtration loss reducer, 2 to 6 parts alkalinity regulator, 2 to 6 parts sealing agent, 2 to 6 parts weighting agent, 12 to 20 parts cottonseed hull granules, 12 to 20 parts short fiber, and 1000 parts water.

2. The drilling fluid with wellbore cleaning function according to claim 1, characterized in that... The emulsifier is one or more of sodium dodecylbenzenesulfonate, sodium dodecyl sulfonate, and sodium dodecyl sulfate.

3. The drilling fluid with wellbore cleaning function according to claim 1 or 2, characterized in that... The filtration loss reducer is one or more of carboxymethyl cellulose, sulfonated methyl phenolic resin, and sulfonated lignite resin.

4. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 3, characterized in that... The alkalinity regulator is one or both of sodium hydroxide and potassium hydroxide.

5. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 4, characterized in that... The plugging agent is a mixture of potassium humate, potassium fulvate and sodium humate, with a mass ratio of 20 to 30: 10 to 15: 20 to 30.

6. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 5, characterized in that... The weighting agent is barite.

7. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 6, characterized in that... The cottonseed hull particles have a particle size of 0.1 mm to 2 mm; or / and the short fibers are one or both of polyester and glass fibers, with a length of 1 mm to 3 mm.

8. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 7, characterized in that... The density of drilling fluid with wellbore cleaning function is 1.1 g / cm³. 3 Up to 2.4 g / cm 3 .

9. The drilling fluid with wellbore cleaning function according to any one of claims 1 to 8, characterized in that... Prepared according to the following steps: The first step is to add the required amount of bentonite or clay, emulsifier, and short fibers to water, mix and stir to obtain the first mixture; The second step is to add the required amount of cottonseed hull particles and filtration loss reducer to the first mixture, and then mix and stir to obtain the second mixture. The third step involves adding the required amounts of plugging agent, weighting agent, and alkalinity regulator to the second mixture, and then mixing and stirring to obtain a drilling fluid with wellbore cleaning function.

10. A method for preparing a drilling fluid with wellbore cleaning function according to any one of claims 1 to 8, characterized in that... Includes the following steps: The first step is to add the required amount of bentonite or clay, emulsifier, and short fibers to water, mix and stir to obtain the first mixture; The second step is to add the required amount of cottonseed hull particles and filtration loss reducer to the first mixture, and then mix and stir to obtain the second mixture. The third step involves adding the required amounts of plugging agent, weighting agent, and alkalinity regulator to the second mixture, and then mixing and stirring to obtain a drilling fluid with wellbore cleaning function.

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