Intelligent nanometer blocking agent for water-based drilling fluid

Abstract

The invention discloses an intelligent nanometer blocking agent for water-based drilling fluid and a preparation method thereof. The intelligent nanometer blocking agent is prepared from, by weight, 20-82 parts of intelligent polymer-modified magnetic nanoparticles, 3-45 parts of polyethylene glycol and 0.5-24 parts of polytetramethylene glycol. The preparation method includes the steps that the intelligent polymer-modified magnetic nanoparticles are added into water, polyethylene glycol is added with constant stirring, the mixture is subjected to a reaction for 3-5 hours, polytetramethylene glycol is added, the mixture is subjected to a reaction for 4-7 hours, water is evaporated, the product is dried for 4 hours at 60-75 DEG C, and then the intelligent nanometer blocking agent for the water-based drilling fluid is obtained. The preparation method has the advantages that the hydrophilia and hydrophobicity of the intelligent nanometer blocking agent can change correspondingly along with different formation temperatures and drilling fluid pH values, so that in the shale formation drilling process, while micro pores in the well wall are physically blocked, a water molecule repelling effect is achieved, water is chemically restrained from approaching the well wall, and then the water blocking performance of the drilling fluid is significantly improved.

Description

Technical field [0001] The invention relates to a multifunctional nano plugging agent for water-based drilling fluid, which belongs to the field of oil and gas field nano materials. Background technique [0002] In recent years, the development of domestic shale gas has received more and more attention. Shale gas is stored in shale formations, which are easy to absorb water and expand. During the drilling process, in order to prevent drilling accidents such as instability of the well wall and collapse of the borehole caused by shale water absorption and expansion, oil-based drilling fluids are currently used for drilling in the shale gas development process. However, oil-based drilling fluids have high costs, high risk factors during drilling, serious environmental pollution, and cumbersome post-processing. It is an inevitable trend to use water-based drilling fluids instead of oil-based drilling fluids to drill shale gas reservoirs. [0003] The pore size of shale formation is a...

AI Technical Summary

Problems solved by technology

However, the cost of oil-based drilling fluid is high, the risk factor is high during drilling, the environment is polluted seriously, and the post-processing process is cumbersome. It is an inevitable trend to replace oil-based drilling fluid with water-based drilling fluid for drilling shale gas reservoirs.

[0003] The pore size of the shale formation is about nanometer scale. At present, the particle size of conventional plugging materials is large. After the water-based drilling fluid is modified, the shale formation cannot be effectively sealed.