CN114350329B - A high temperature resistant intercalation modified nano-titanium carbide composite plugging agent and oil-based drilling fluid - Google Patents

Abstract

The invention discloses a high-temperature-resistant intercalation modified nano titanium carbide composite plugging agent and oil-based drilling fluid. The high-temperature resistant intercalation modified nano titanium carbide composite plugging agent comprises nano titanium carbide (50 nm), p-dodecyl styrene, a hexadecyl acrylate compound, a vinyl naphthene compound, an intercalating agent, a crosslinking agent and an initiator; the drilling fluid comprises the high-temperature-resistant intercalation modified nano titanium carbide composite plugging agent. The high-temperature-resistant intercalation modified nano titanium carbide composite plugging agent is used as a nano plugging agent, has the particle size distribution of 90-330nm, and can effectively plug nano-sized pores in a shale well wall, so that the well wall can be effectively stabilized and collapse can be prevented, and meanwhile, the preparation method is reliable in principle and has a wide market prospect; the oil-based drilling fluid used by the invention has good rheological property, stability, plugging property and other properties under the condition of the shale stratum.

Description

A high temperature resistant intercalation modified nano-titanium carbide composite plugging agent and oil-based drilling fluid

technical field

The invention relates to the technical field of oil and gas field drilling, in particular to the synthesis of a high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent and an oil-based drilling fluid containing the plugging agent.

Background technique

Oil-based drilling fluid refers to the drilling fluid that uses oil as the continuous phase. Compared with water-based drilling fluid, oil-based drilling fluid has the advantages of high temperature resistance, salt and calcium intrusion resistance, good borehole wall stability, better lubricity and good oil and gas formation. It has many advantages such as less damage, and has achieved excellent results in various complex formations, and has a broad application prospect.

In recent years, the exploitation of unconventional oil and gas in China has been continuously intensified, followed by the increasing difficulty of drilling. Although oil-based drilling fluid is widely used in shale gas development, it cannot effectively solve the problem of wellbore instability caused by liquid-phase pressure transmission, and accidents of drill sticking and instrument sticking occur from time to time. How to improve the plugging effect of oil-based drilling fluid, reduce the fluid loss of drilling fluid, and improve the stability of the wellbore wall has always been a difficulty and focus in the field of oil-based drilling fluid research. The key is oil-based drilling fluid plugging agent development. For shale formations with well-developed fractures or beddings, the existing plugging agents have achieved a good plugging effect in micron-scale shale pores and fractures, but in terms of plugging nano-scale pores and fractures, their plugging agents are not The effect needs to be further improved. Therefore, in view of the problem of wellbore instability caused by the inability to effectively plug nano-scale pores and fractures in shale, it will be a very important task to synthesize a nano-sized plugging agent to improve the plugging effect of oil-based drilling fluid. Good choice.

Contents of the invention

Aiming at the problem of well wall instability caused by the inability of conventional plugging agents to effectively plug nano-pores in shale, the present invention provides a high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent, the particle size of which is It is nanoscale and can effectively seal the nanopores and fractures in the shale formation, so as to achieve the purpose of stabilizing the well wall.

In order to achieve the above object, the technical solution of the present invention is: the raw material of the high temperature resistant intercalation modified nano-titanium carbide composite plugging agent is nano-titanium carbide (50nm), p-dodecyl styrene, hexadecyl acrylate Ester compounds, vinyl naphthenic compounds, intercalation agents, crosslinking agents, initiators, the preparation steps of the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent are as follows:

Place the nano-titanium carbide under the condition of 60-70°C for vacuum drying, take the dried nano-titanium carbide and add it to the dispersion liquid of deionized water for ultrasonic dispersion, then add the intercalation agent dropwise while stirring, and then place it at 40 Reaction at -50°C, cooled to room temperature, centrifugal separation, ultrasonic dispersion, suction filtration, and washing to obtain intercalated modified nano-titanium carbide, and then ultrasonically disperse the obtained intercalated modified nano-titanium carbide with deionized water, The dispersion liquid is placed in the reactor, and after 20-30min of nitrogen gas, add the comonomer p-dodecyl styrene, hexadecyl acrylate compound, vinyl cycloalkane compound in the reactor, and use 20% -25% NaOH aqueous solution to adjust the pH value of the system to 6.5-7.5, raise the temperature to 60-70°C, then add crosslinking agent and initiator to react for 4-5h, after the reaction is completed, cool to room temperature, and prepare the sample Washing with distilled water to neutrality, and then vacuum-drying at 50-60°C, grinding the dried samples to obtain high-temperature-resistant intercalation modified nano-titanium carbide composite plugging agent.

The intercalation agent is one of tetramethylammonium hydroxide (TMAOH), dimethyl sulfoxide (DMSO);

The cetyl acrylate compound is one of cetyl acrylate and cetyl methacrylate;

The vinyl cycloalkane compound is one of p-vinyl cyclopentane, vinyl cyclohexane, vinyl cyclooctane;

The crosslinking agent is one of N, N-methylenebisacrylamide (MBA), dicyclopentadiene acrylate (DCPA);

Described initiator is the one in ammonium persulfate, potassium persulfate;

The molar mass ratio of the intercalation modified nano-titanium carbide, p-dodecylstyrene, hexadecyl acrylate compound, and vinyl cycloalkane compound is 2:2:1:3;

The added amount of the crosslinking agent is 1%- 3%;

The dosage of the initiator is 1%- 3%.

Another object of the present invention is to provide an oil-based drilling fluid, which is added with the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent of the present invention.

In parts by weight, the composition of the drilling fluid is as follows: 225-227 parts of 3# white oil, 3.6-3.8 parts of main emulsifier TYODF-301, 9.8-10.2 parts of auxiliary emulsifier TYODF-401, wetting agent TYODF-501 is 3.2-3.3 parts, cutting agent TYODF-701 is 0.7-0.8 parts, organic soil TYODF-601 is 7-8 parts, fluid loss additive TYODF-101 is 14.5-15.5 parts, 25-35% Calcium chloride solution is 24-26 parts, calcium oxide TYODF-801 is 7.3-7.7 parts, high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent is 1.25-3.75 parts, barite powder is 250-600 parts, density It is 1.5-2.2g/cm3.

The beneficial effects of the present invention are as follows:

The particle size distribution of the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent prepared by the invention is between 90-330nm, which can effectively plug the nano-pores and cracks in the mud shale formation, so as to achieve stable wells The effect of the wall; the oil-based drilling fluid used in the present invention has good performance in terms of rheology, stability and plugging performance under the condition of mud shale formation.

Description of drawings

Fig. 1 is the particle size distribution diagram of the high temperature intercalation-resistant modified nano-titanium carbide composite plugging agent in Example 1;

Fig. 2 is a particle size distribution diagram of the high temperature intercalation-resistant modified nano-titanium carbide composite plugging agent in Example 2.

Detailed ways

The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In this embodiment, unless otherwise specified, the stated parts are parts by weight.

1. Synthesis of high temperature resistant intercalation modified nano titanium carbide composite plugging agent:

Example 1:

Put 0.60g of nano-titanium carbide under vacuum drying at 65°C, take the dried nano-titanium carbide and add it to the dispersion liquid of 50ml deionized water for ultrasonic dispersion for 30min, then add 10% dimethyl 30ml of sulfoxide, then reacted at 45°C, cooled to room temperature, centrifuged, then ultrasonically dispersed, suction filtered, washed to obtain intercalated modified nano-titanium carbide, and then the obtained intercalated modified nano-titanium carbide was used 60ml of deionized water for ultrasonic dispersion, the dispersion is placed in the reactor, after 20-30min of nitrogen gas, add 2.72g of p-dodecylstyrene, 1.48g of cetyl acrylate, 1.44g of vinyl cyclopentane In the reactor, adjust the pH value of the system to 6.5 with 22% NaOH aqueous solution, raise the temperature to 60°C, add 0.13g dicyclopentadiene acrylate and 0.13g potassium persulfate to react for 4h, after the reaction is completed, cool To room temperature, the prepared sample was washed with distilled water to neutrality, and then placed at 55°C for vacuum drying, and the dried sample was ground to obtain a high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent.

Example 2:

Put 0.90g of nano-titanium carbide under vacuum drying at 65°C, take the dried nano-titanium carbide and add it to the dispersion liquid of 75ml deionized water for ultrasonic dispersion for 30min, then add 10% dimethyl methoxide dropwise while stirring. 45ml of sulfone, then placed in 45 ℃ for reaction, cooled to room temperature, centrifuged, then ultrasonically dispersed, suction filtered, washed to obtain intercalated modified nano-titanium carbide, then, the obtained intercalated modified nano-titanium carbide was mixed with 90ml Ultrasonic dispersion was carried out with deionized water, the dispersion was placed in the reactor, and after 20-30 minutes of nitrogen gas, 4.08g of p-dodecylstyrene, 2.32g of hexadecyl methacrylate, 2.48g of vinylcyclohexyl Put alkanes in the reactor, and use 22% NaOH aqueous solution to adjust the pH value of the system to 6.5, raise the temperature to 60°C, then add 0.20g dicyclopentadiene acrylate and 0.20g potassium persulfate to react for 4h, after the reaction is completed, After cooling to room temperature, the prepared sample was washed with distilled water until it was neutral, and then dried in vacuum at 55°C. The dried sample was ground to obtain a high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent.

2. Preparation of oil-based drilling fluid:

The present invention is mainly illustrated by the application of the following specific formula to resist high-temperature intercalation modified nano-titanium carbide composite plugging agent. Based on 225 parts by weight of base oil, the specific base slurry formula is: 225 parts of 3# white oil + 3.75 parts of main emulsifier TYODF-301 + 10.00 parts of auxiliary emulsifier TYODF-401 + 3.25 parts of wetting agent TYODF-501+ 0.75 parts of cutting agent TYODF-701+7.50 parts of organic soil TYODF-601+25 parts of 30% calcium chloride solution+7.5 parts of calcium oxide TYODF-801+15 parts of fluid loss reducer TYODF-101+500 parts of barite powder .

The specific preparation process is as follows:

Dosage: Take 225mL3# white oil, add it to a 1000mL mixing cup, then add 3.75g primary emulsifier TYODF-301, 10.00g secondary emulsifier TYODF-401, 3.25g wetting agent TYODF-501, 0.75g cutting agent TYODF- 701, stirred at a high speed of 12000r/min for 10min, then added 7.50g organic soil TYODF-601, stirred at a high speed of 12000r/min for 10min, slowly added 25mL of calcium chloride aqueous solution (30% concentration of calcium chloride by mass), and stirred at a high speed 20min; add 7.5g of calcium oxide TYODF-801 and 15g of fluid loss reducer TYODF-101 and stir at high speed for 20min, continue to add 500g of barite and stir at high speed for 30min to obtain the base slurry of oil-based drilling fluid. The density of the prepared drilling fluid is 2.0 g/cm ³ .

Prepare 4 parts of the same base slurry according to the above slurry preparation, and add 1.25g, 2.5g, and 3.75g of high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent to 3 parts of the base slurry to obtain 3 parts of plugging 0.5%-1.5% of different oil-based drilling fluids, in order to further illustrate the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent and the effect of oil-based drilling fluids of the present invention, the preparation of Example 1 and Example 2 The high temperature resistant intercalation modified nano-titanium carbide composite plugging agent and oil-based drilling fluid were tested for performance.

1. Particle size test of high temperature resistant intercalation modified nano-titanium carbide composite plugging agent

Using the BI-200SM laser scattering instrument produced by Brookhaven Instruments in the United States to test the particle size of the anti-high temperature intercalation modified nano-titanium carbide composite plugging agent, the high-temperature intercalation-resistant modified nano-titanium carbide prepared in the two examples The particle size test results of the composite plugging agent are shown in Figure 1 and Figure 2, respectively. The high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent of the present invention has a plurality of different nanometer sizes from 90 to 330 nm, and has a wide particle size distribution, and can be used for plugging different nanometer pores.

2. Drilling fluid plugging performance test

Artificial cores are used to simulate nano-porous formations, and the average flow rate of the drilling fluid system in the artificial cores is measured, and the Darcy formula is used to calculate the permeability of artificial cores before and after adding high-temperature-resistant intercalation-modified nano-titanium carbide composite plugging agents. , so as to calculate the plugging rate of the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent on the artificial core, so as to evaluate its plugging performance. The effect is shown in Table 1. From the results shown in Table 1, it can be seen that the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent can effectively reduce the permeability of the artificial core, and the plugging effect is very good. When the amount of plugging agent added is 0.5%, the permeability of the core decreases by 86.0% and 86.3%, respectively. With the increase of the amount of high-temperature-resistant intercalation-modified nano-titanium carbide composite plugging agent, the plugging effect is better, while When the amount exceeds 0.5%, the permeability still decreases, but the decrease is almost insignificant, indicating that the optimum amount of the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent of the present invention is 0.5%.

Table 1 Artificial core plugging experiment table

name Artificial core permeability/10 ^-3 mD Blocking rate% Base slurry 6.79 / Base slurry+0.5% embodiment 1 0.95 86.0 Base slurry+0.5% Example 2 0.93 86.3 Base slurry+1% embodiment 1 0.88 87.0 Base pulp+1% embodiment 2 0.87 87.2 Base slurry+1.5% embodiment 1 0.82 87.9 Base slurry+1.5% embodiment 2 0.81 88.1

Note: The length of the core is 5cm, and the diameter is 2.5cm.

3. Drilling fluid rheological properties and fluid loss performance tests

According to the configuration of the base slurry of the previous oil-based drilling fluid, according to the standard GB/T16783.2-2012 "Petroleum and Natural Gas Industry Drilling Fluid Field Test Part 2: Oil-based Drilling Fluid", the high-temperature resistant prepared in Example 1-2 The oil-based drilling fluid prepared with the intercalated modified nano-titanium carbide composite plugging agent was compared with the base slurry, and the performance test of the oil-based drilling fluid before and after aging was carried out under the same conditions. The results are shown in Table 2 and Table 3. From the results shown in Table 2 and Table 3, it can be seen that the oil-based drilling fluid prepared by the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent prepared in Example 1 and Example 2 has good rheology, and the performance changes before and after aging are unchanged. The oil-based drilling fluid is characterized by its high rock-carrying ability and temperature resistance at a low viscosity. In addition, its API and high-temperature and high-pressure fluid loss are lower, and the demulsification voltage is higher. Therefore, the performance of the drilling fluid prepared by the high-temperature intercalation modified nano-titanium carbide composite plugging agent synthesized by the present invention is better.

Table 2. Drilling fluid rheological properties and filtration performance records before aging

Table 3 Rheological properties and filtration performance records of drilling fluid after aging

Note: AV—apparent viscosity, unit is mPa s; PV—plastic viscosity, unit is mPa s; YP—dynamic shear force, unit is Pa; API—normal temperature medium pressure filtration loss, unit is mL; HTHP— High temperature and high pressure filtration loss, the unit is mL; ES—emulsification voltage, the unit is V.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solutions of the present invention.

Claims (7)

1. A kind of anti-high temperature intercalation modified nano-titanium carbide composite plugging agent, it is characterized in that, the raw material of described anti-high temperature intercalation modified nano-titanium carbide composite plugging agent is the nano-titanium carbide of 50nm, to dodecane Styrene, cetyl acrylate compound, vinyl cycloalkane compound, intercalation agent, crosslinking agent, initiator; it is prepared by following steps: S1. Intercalation modified nano-titanium carbide: place the nano-titanium carbide under the condition of 60-70°C for vacuum drying, take the dried nano-titanium carbide and add it to the dispersion liquid of deionized water for ultrasonic dispersion, and then drop while stirring Add an intercalation agent, then react at 40-50°C, cool to room temperature, centrifuge, then ultrasonically disperse, suction filter, and wash to obtain intercalation-modified nano-titanium carbide; S2. First, ultrasonically disperse the intercalated modified nano-titanium carbide obtained in S1 with deionized water, place the dispersion in a reactor, and add comonomer p-dodecylstyrene after passing nitrogen for 20-30 minutes. Hexadecyl acrylate compounds and vinyl cycloalkane compounds are placed in the reactor, and the pH value of the system is adjusted to 6.5-7.5 with 20%-25% NaOH aqueous solution, and the temperature is raised to 60-70°C, and then added The cross-linking agent and the initiator react for 4-5 hours. After the reaction is completed, cool to room temperature. The prepared sample is washed with distilled water until it is neutral, and then placed in vacuum drying at 50-60°C. Grind the dried sample. Obtain a 90-330nm anti-high temperature intercalation modified nano-titanium carbide composite plugging agent; The molar mass ratio of the intercalation modified nano-titanium carbide, p-dodecylstyrene, hexadecyl acrylate compound, and vinyl cycloalkane compound is 2:2:1:3; The added amount of the crosslinking agent is 1%- 3%; The added amount of the initiator is 1%-3% of the total weight of the four monomers of intercalation modified nano-titanium carbide, p-dodecylstyrene, hexadecyl acrylate compound and vinyl cycloalkane compound. %; The cetyl acrylate compound is one of cetyl acrylate and cetyl methacrylate; The vinyl cycloalkane compound is one of p-vinyl cyclopentane, vinyl cyclohexane and vinyl cyclooctane. 2. The high-temperature-resistant intercalation-modified nano-titanium carbide composite plugging agent according to claim 1, wherein the intercalation agent is tetramethylammonium hydroxide (TMAOH), dimethyl sulfoxide (DMSO ) in one. 3. The high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent according to claim 1, wherein the crosslinking agent is N, N-methylenebisacrylamide (MBA), dicyclopentadiene One of vinyl acrylate (DCPA); the initiator is one of ammonium persulfate and potassium persulfate. 4. An oil-based drilling fluid, characterized in that, the high-temperature intercalation-resistant modified nano-titanium carbide composite plugging agent according to claim 1 is added in the drilling fluid. 5. The oil-based drilling fluid according to claim 4, characterized in that, the drilling fluid comprises the following components: base oil, main emulsifier, auxiliary emulsifier, wetting agent, shearing agent, organic soil, reducer Fluid loss agent, aqueous phase, calcium oxide, weighting agent, plugging agent. 6. oil base drilling fluid according to claim 5, is characterized in that, described base oil is 3# white oil, and described main emulsifier is TYODF-301, and described secondary emulsifier is TYODF-401, and described The wetting agent is TYODF-501, the cutting agent is TYODF-701, the organic soil is TYODF-601, the fluid loss control agent is TYODF-101, and the water phase is 30% calcium chloride solution , the calcium oxide is TYODF-801, the weighting agent is barite powder, the plugging agent is the anti-high temperature intercalation modified nano-titanium carbide composite plugging agent according to claim 1, the main emulsifier , Co-emulsifier, wetting agent, cutting agent, organic soil, fluid loss reducer, and calcium oxide come from Chengdu Xiyou Huawei Technology Co., Ltd. 7. oil base drilling fluid according to claim 6, is characterized in that, by weight, the composition of described drilling fluid is as follows: 3# white oil is 225-227 parts, and main emulsifier TYODF-301 is 3.6-227 parts. 3.8 parts, co-emulsifier TYODF-401 is 9.8-10.2 parts, wetting agent TYODF-501 is 3.2-3.3 parts, cutting agent TYODF-701 is 0.7-0.8 parts, organic soil TYODF-601 is 7-8 parts, Fluid loss reducer TYODF-101 is 14.5-15.5 parts, 30% calcium chloride solution is 24-26 parts, calcium oxide TYODF-801 is 7.3-7.7 parts, high temperature intercalation modified nano-titanium carbide composite plugging agent 1.25-3.75 parts, barite powder 250-600 parts, drilling fluid density 1.5-2.2g/cm ³ .

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