Semi-interpenetrating network gel plugging material for oil and gas fields and preparation method thereof

Abstract

The invention discloses a semi-interpenetrating network gel plugging material for oil and gas fields and a preparation method. The plugging material comprises, by weight, 2-5% of a polyacrylamide polymer, 0.1-10% of polyvinylpyrrolidone, 0.1-3% of a cross-linking agent, and 0.1-0.3% of an antioxidant, with the balance being water. The preparation method comprises the following steps: dissolving the antioxidant in water to form a solution A; dispersing the polyacrylamide polymer, the polyvinylpyrrolidone and the cross-linking agent into the solution A according to a ratio, and uniformly mixingto obtain a semi-interpenetrating network gel plugging material base solution; and reacting the semi-interpenetrating network gel plugging material base solution for 8-12 hours, and crosslinking to obtain the semi-interpenetrating network gel plugging material. According to the plugging material disclosed by the invention, a chemical blending network system is formed after the polyvinylpyrrolidoneand a polyacrylamide polymer cross-linked network are interpenetrated or entangled, and the plugging material has high gelatinizing strength and high shear toughness under a high-temperature condition, and has higher pressure-bearing capacity and an excellent plugging effect.

Description

technical field [0001] The invention relates to the technical field of oil and gas field development, in particular to a semi-interpenetrating network gel plugging material for oil and gas fields and a preparation method thereof. Background technique [0002] Lost circulation is a common well-complex situation in drilling engineering, and most drilling processes have different degrees of lost circulation. Severe lost circulation will lead to a drop in pressure in the well, affecting normal drilling, causing wellbore instability, and inducing formation fluids to pour into the wellbore and blow out. Once lost circulation occurs during drilling, it is necessary to carry out plugging operations. The plugging operation usually involves pumping the plugging material to the leaky zone through pumping equipment, and after the plugging material forms an effective seal in the lost zone, the follow-up drilling work is carried out. [0003] At present, the most widely used plugging te...

AI Technical Summary

Problems solved by technology

However, for malignant formation loss, the success rate of conventional bridge plugging is very low; the bridge plugging material is difficult to stay in the lost zone around the wellbore, and it is easy to mix with formation fluid and flow away after being diluted, thus plugging It is difficult for the slurry to form a tight seal of sufficient strength around the wellbore

At present, many R&D institutions at home and abroad have developed a variety of cross-linked polymer-based plugging materials and processes, but no breakthroughs have been made in the treatment of fractures and karst cavities.

In particular, the cross-linking time of cross-linked polymer-based plugging materials is difficult to control, and the gel strength after gelation is difficult to meet the requirements of effective plugging, so polymer plugging materials still need a lot of research work

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