Preparation method of high-plugging-strength leaking-stopping agent for well drilling

Abstract

The invention discloses a preparation method of a high-plugging-strength leaking-stopping agent for well drilling, belonging to the technical field of preparation of leaking-stopping agents. The theory of the preparation method comprises the following steps: carrying out graft modification on butyl polyacrylate resin by utilizing oxidized cassava starch and taking methyl ethyl ketone peroxide as an initiator under the catalysis of ethylene glycol antimony, so as to enhance expansibility; then modifying bamboo fibers by virtue of maleic anhydride, and combining the bamboo fibers with modified cassava starch grafted butyl polyacrylate resin by virtue of a coupling agent, so as to enhance strength; and then adding expanded vermiculite, so as to enhance the swell capacity and plugging strength. By utilizing the theory, the defects of existing leaking-stopping agents that the swell capacity is relatively low, the water flushing resistance is relatively weak, the plugging strength is low, and the repeated leakage easily occurs are effectively solved; and by applying the leaking-stopping agent to complex formations with big crevices and multiple caves, the permeability of a blocked layer can be well decreased, and the high strength and pressure resistance of the blocked layer can be obtained.

Description

technical field [0001] The invention discloses a preparation method of a plugging agent for drilling with high plugging strength, and belongs to the technical field of plugging agent preparation. Background technique [0002] Lost circulation is a common problem in the drilling process, and may cause other downhole complex situations and major accidents such as well collapse, pipe sticking, blowout, etc., which is extremely harmful to drilling work, and may even lead to the scrapping of the wellbore, resulting in huge economic losses. There are dozens of existing plugging technologies, which are mainly divided into bridging plugging materials, high water loss plugging materials, temporary plugging materials, chemical plugging materials, inorganic gel plugging materials, soft and hard plugging materials according to different mechanisms and functions. Plugging materials, high temperature plugging materials, composite plugging materials. [0003] At present, a more effective ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem mainly solved by the present invention: aiming at the defects that the existing leak-stopping agent has small expansion, weak water erosion resistance, low plugging strength, and easy to cause repeated leakage, it provides a method of using modified cassava starch Graft copolymerization with butyl acrylate, under the action of coupling agent, through maleic anhydride, combined with bamboo fiber, and then adding expanded vermiculite to synthesize the method of high plugging strength drilling plugging agent, the invention first combines tapioca starch and hydrogen peroxide After mixing, stir and react with dodecyl mercaptan, remove the supernatant, react with butyl acrylate and ethylene glycol under nitrogen protection, then add methyl ethyl ketone peroxide to react, remove the ethylene glycol after the reaction, collect the residue and mix with Bamboo fiber, expanded vermiculite, etc. are placed in a high-pressure reactor for reaction, and then cooled and discharged to obtain a plugging agent for drilling with high plugging strength. Methyl ethyl ketone is used as an initiator to graft modified butyl polyacrylate to increase the expansion, and then use maleic anhydride to modify bamboo fiber, and combine it with modified tapioca starch grafted polybutyl acrylate through a coupling agent to increase The principle of adding expanded vermiculite to increase the expansion and plugging strength effectively solves the problem that the existing plugging agent has a small expansion, weak water erosion resistance, low plugging strength, and easy to cause repeated leakage. For the complex formation with large fractures and porous holes, the plugging agent can reduce the permeability of the plugging layer, obtain high plugging layer strength and high pressure bearing capacity of the plugging layer.