Controllable cross-linked gel plugging agent and preparation method thereof

Abstract

The invention relates to a controllable cross-linking type gel plugging agent and a preparation method thereof. The controllable cross-linking type gel plugging agent is prepared from a vinyl monomer,N,N-methylene bisacrylamide and a cross-linking agent. The preparation method comprises the steps: 1, under the action of an initiator, the vinyl monomer and the N,N-methylene bisacrylamide react toobtain a polymer main agent; and 2) the polymer main agent is mixed with a cross-linking agent, and a reaction is carried out at a certain temperature to obtain the gel plugging agent. The controllable cross-linking type gel plugging agent is controllable in cross-linking time, has the advantages of being good in liquidity, easy to pump and the like, and can be extruded into a leakage layer to form an integral immobile gel at the formation temperature and pressure, so that the pressure bearing strength and the plugging effect are improved, and repeated leakage is not likely to happen. Comparedwith a conventional plugging agent, the plugging agent is simple in formula and easy to construct on site.

Description

Technical field [0001] The invention belongs to the field of oil field chemistry and relates to a controllable cross-linked gel plugging agent and a preparation method thereof. [0002] technical background [0003] Lost circulation, especially malignant leakage, is an important technical bottleneck restricting the safe and efficient development of my country's oil and gas exploration. In view of the problem of malignant leakage, the current domestic and foreign processing technologies mainly include bridging and plugging technology (sawdust, mica and other materials), composite plugging technology (combining hard nut shells, fibrous materials and flake-like materials) , High water loss plugging technology, cement slurry plugging technology, gel plugging technology, etc., but technical measures such as bridge plugging, composite plugging, high water loss plugging, etc. are difficult to stay in the malignant leakage channel, and the fractures are developed in the formation. , The p...

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Problems solved by technology

For the problem of vicious leakage, the current treatment technologies at home and abroad mainly include bridging plugging technology (sawdust, mica and other materials), composite plugging technology (combining materials such as hard fruit shells, fibrous materials and sheet materials) , high water loss plugging technology, cement slurry plugging technology, gel plugging technology, etc. However, technical measures such as bridging plugging, composite plugging, high water loss plugging and other technical measures are difficult to stay in the malignant leakage channel, and the formation with fractures , The problem of poor plugging effect in broken formations; cement slurry plugging technology has: (1) it is not easy to stay in the leakage channel, and it is easy to be diluted by formation water, resulting in poor coagulation effect; (2) it is difficult to accurately control the coagulation time, On-site construction is difficult; gel plugging technology has: (1) low pressure bearing capacity, easy to leak again; (2) injection time is difficult to accurately control, on-site construction is difficult; gelling time is difficult to accurately control, on-site construction is difficult

Patent CN105778874A discloses "Cross-linked gel plugging agent and its plugging method for drilling downhole". Cross-linking time, the gel plugging agent has a good plugging effect, and has a certain residence and pressure bearing capacity, but the composition of the formula is complicated, and it is inconvenient to use on site

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