Volume expansion type efficient slug gel plugging agent and preparation method thereof

Abstract

The invention provides a volume expansion type efficient slug gel plugging agent and a preparation method thereof. The volume expansion type efficient slug gel plugging agent is prepared from the following raw materials in parts by mass: 10-35 parts of a polymerization reaction agent, 1-3 parts of a cross-linking agent a, 0.02-0.5 part of a suitable-temperature initiator, 0.5-5 parts of a water-soluble resin flexibilizer, 0.5-5 parts of a composite inorganic flexibilizer, 2-8 parts of modified starch, 2-10 parts of a volume expansion reaction agent and 2-8 parts of a rheological modifier, wherein the volume expansion reaction agent is prepared from the following raw materials through an inverse emulsion polymerization method: a water-soluble polymeric monomer, a dispersion medium, an emulsifier, an oil-phase initiator and a cross-linking agent b. The plugging agent disclosed by the invention has the advantages of capability of underground crosslinking gel forming, flexible and adjustable gel forming time, high pressure bearing capacity after gel forming, relatively high water absorption expansibility, excellent mechanical strength after water absorption and the like.

Description

technical field [0001] The invention relates to a body-expanding high-efficiency slug gel plugging agent and a preparation method thereof, belonging to drilling fluid plugging technology in the field of petroleum exploration and development. Background technique [0002] Lost circulation is defined as the effect of the working fluid (such as drilling fluid, cement slurry, completion fluid or other liquids, etc.) A downhole complex situation in which a large amount of inflow into the formation (percolation filtrate is not included) is one of the most common and common technical problems in oil drilling engineering. In lost circulation, fractured and karst caves account for a high proportion. When drilling in fractured zones and unconformity formations, the above-mentioned types of lost circulation are very likely to occur. If the tiny pores in the formation will not cause lost circulation, but due to some improper measures taken such as making the wellbore pressure greater t...

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Problems solved by technology

However, the temperature application range of the plugging agent of this invention is narrow, and the temperature conditions and time range for the self-cementation of the plugging agent have not been determined; the gel formed at the formation temperature has poor water absorption and expansion properties, and the gel plugging after gelation The agent has weak elasticity and toughness, and the pressure-bearing plugging strength is low

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