Seawater well cementing slow release type fluid loss additive and preparation method and application thereof

Abstract

The invention discloses a seawater well cementing slow release type fluid loss additive and a preparation method and application thereof. The preparation method comprises the following steps: reacting a monomer comprising 2-acrylamide-2-methylpropanesulfonic acid, unsaturated carboxylic acid, acrylamide substances and allyl polyethylene glycol with an initiator to obtain a quaternary anionic copolymer; preparing a mixed nitrate aqueous deionized solution as a solution A; preparing a sodium mixture deionized water solution as a solution B; under N2 protection, dropwise adding the solution A and the solution B simultaneously dropped into deionized water respectively for reaction to obtain calcium-aluminum hydrotalcite; preparing a quaternary anionic copolymer aqueous deionized solution as a solution C; preparing a calcium-aluminum hydrotalcite aqueous deionized dispersion as a dispersion D; and under the N2 protection, mixing the C solution and the D dispersion for reaction to obtain the seawater well cementing slow release type fluid loss additive. The preparation method is simple and can obviously improve the filtration loss control effect of the seawater well cementing slow release type fluid loss additive, and the seawater well cementing slow release type fluid loss additive has the long-lasting cement slurry dispersing ability.

Description

technical field [0001] The invention relates to a seawater cementing slow-release fluid loss reducer, a preparation method and application thereof, and belongs to the field of oilfield cementing fluid loss reducer. Background technique [0002] Under the condition that recoverable and easy-to-recover oil in inland and offshore areas is gradually depleting, oil field exploration and development has developed into ocean and deep wells. However, some metal cationic electrolytes in seawater will affect the rheology of cement slurry, which will greatly reduce the performance of fluid loss reducer in fluid loss control, dispersion and early strength. Therefore, seawater cementing requires fluid loss reducer to have both dispersion and early strength functions while having a good effect in reducing fluid loss. [0003] In order to solve such problems, the commonly used method is to introduce carboxyl groups with strong adsorption with cement hydration particles, sulfonic acid grou...

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Problems solved by technology

However, this type of copolymer still has two obvious disadvantages: firstly, the introduction of carboxyl groups increases the adsorption capacity of the polymer to ensure the performance of water loss control, and at the same time, it has a strong retarding effect on the cement slurry, so that the early strength of the slurry is improved. Secondly, the long side chain groups can control the early fluidity of the slurry well, but as the hydration reaction of the cement slurry proceeds, the admixture is gradually consumed, making it difficult to control the fluidity of the slurry in the later stage, so it is difficult Meet the requirements of cement slurry dispersion in the whole cementing process

But although the preparation of known slow-release admixtures has made some progress, there are still deficiencies, which are mainly manifested in: the research on synthesis mainly focuses on slow-release dispersants, but the synthesis of slow-release fluid loss reducers is not enough. There are few reports; on the other hand, most of the slow-release admixtures are suitable for freshwater cement slurry, and there are few investigations on its seawater performance

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