A kind of nano plugging agent for water-based drilling fluid and its preparation method and drilling fluid

A technology of water-based drilling fluid and nano-plugging agent, applied in the field of water-based drilling fluid, can solve problems such as poor plugging effect and wellbore instability, achieve good plugging, improve plugging performance, and improve dispersibility Effect

Active Publication Date: 2021-11-02
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art, and to provide a nano-sealing agent and a Its preparation method and drilling fluid

Method used

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  • A kind of nano plugging agent for water-based drilling fluid and its preparation method and drilling fluid
  • A kind of nano plugging agent for water-based drilling fluid and its preparation method and drilling fluid

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preparation example Construction

[0019] In order to achieve the purpose of the present invention, the first aspect of the present invention provides a method for preparing modified multi-walled carbon nanotubes, the method comprising the following steps:

[0020] (1) dissolving multi-walled carbon nanotubes and sodium p-styrene sulfonate monomer in deionized water;

[0021] (2) in step (1) solution, add potassium persulfate as radical polymerization initiator, continue to feed inert gas in the reaction process;

[0022] (3) centrifuging the solution obtained in step (2) to remove amorphous carbon and residual catalyst, and filtering the supernatant;

[0023] (4) drying to obtain multi-walled carbon nanotubes coated with polystyrene sodium sulfonate.

[0024] In the method of the present invention, the weight ratio of the amount of multi-walled carbon nanotubes, sodium p-styrene sulfonate monomer and potassium persulfate is 1: (90-120): (0.8-1.2), preferably 1: (95-105): (0.9-1.1).

[0025] In the method of...

preparation example 1

[0047] This preparation example is to illustrate the preparation method of the modified multi-walled carbon nanotubes.

[0048] (1) Weigh 0.05 g of multi-walled carbon nanotubes and 4.75 g of sodium p-styrene sulfonate monomer into a three-necked flask, add 45 mL of deionized water, and ultrasonically disperse for 45 minutes at 25 °C at an ultrasonic frequency of 2.5 megahertz;

[0049] (2) Add 0.0475 grams of potassium persulfate to the solution of step (1) as a free radical polymerization initiator, continuously feed argon during the reaction process, and react for 50 hours at 65° C.;

[0050] (3) Centrifuge the solution obtained in step (2) at 25°C at a centrifugation rate of 9000 rpm for 6 minutes, and then filter the supernatant;

[0051] (4) drying the mixture obtained in step (3) in an oven at 65°C for 11 hours;

[0052] That is, polystyrene sodium sulfonate modified multi-walled carbon nanotubes A1 were obtained.

preparation example 2

[0054] This preparation example is to illustrate the preparation method of the modified multi-walled carbon nanotubes.

[0055] (1) Weigh 0.05 g of multi-walled carbon nanotubes and 5 g of sodium p-styrene sulfonate monomer into a three-necked flask, add 50 mL of deionized water, and ultrasonically disperse for 40 minutes at 27 ° C at a frequency of 3 megahertz;

[0056] (2) Add 0.05 gram of potassium persulfate to the solution of step (1) as a radical polymerization initiator, continuously feed argon in the reaction process, and react for 48 hours at 65° C.;

[0057] (3) Centrifuge the solution obtained in step (2) for 6 minutes at a centrifugation rate of 9000 rpm at 25°C, and then filter the supernatant;

[0058] (4) drying the mixture obtained in step (3) in an oven at 72°C for 9 hours;

[0059] That is, sodium polystyrene sulfonate modified multi-walled carbon nanotubes A2 were obtained.

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Abstract

The invention relates to a nano-sealing agent for water-based drilling fluid, a preparation method thereof and drilling fluid. The nano-sealing agent for water-based drilling fluid is polystyrene sulfonate sodium covalently coated multi-walled carbon nanotubes, wherein the multi-walled carbon nanotubes have a diameter of 20-30 nm and a tube length of 10-30 μm; The number-average molecular weight of the sodium polystyrene sulfonate of described grafting is 75kDa, and degree of polymerization (DOP) is 900; Described drilling fluid contains the water of 100 weight parts, and bentonite is 1-8 weight parts, and flow regulator is 4-10 parts by weight, 0.2-1.2 parts by weight of viscosifier, 4-10 parts by weight of fluid loss control agent, 30-60 parts by weight of plugging agent, 10-50 parts by weight of weighting agent, and 0.1 parts by weight of lubricant -4 parts by weight, the content of the pH regulator is 0.1-0.4 parts by weight. The present invention uses sodium polystyrene sulfonate modified multi-walled carbon nanotubes as the plugging agent, which can effectively plug micro- and nano-sized pores on the well wall of mud shale, and is especially suitable for low-space and low-permeability, development of micro-pores and micro-cracks, and capillary Drilling operations in formations with outstanding effects.

Description

technical field [0001] The invention relates to the field of water-based drilling fluids, in particular to a nano-blocking agent for water-based drilling fluids, a preparation method thereof, and drilling fluids. Background technique [0002] With the continuous development of unconventional oil and gas resources in oil and natural gas, such as the exploitation of shale gas and tight oil, the wellbore instability of hard and brittle shale has become the first problem to be solved. Most of the mud shale has closed or open bedding and micro-fractures, and the capillary force is strong. Under the dual effects of positive pressure difference and capillary pressure, the drilling fluid is easy to invade, causing the shale to crack along the fracture plane or bedding plane, and continuously develop vertically and horizontally along the fracture plane. In addition, the intruded filtrate will reduce the friction coefficient between fracture surfaces or bedding surfaces, thereby incr...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/03C09K8/24
Inventor 王平全唐涛龙海锋谢刚任妍君王秋润何毅罗显粱王哲
Owner SOUTHWEST PETROLEUM UNIV
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