Efficient anti-pollution isolation liquid for well cementation and preparation method thereof

Abstract

The invention relates to an efficient anti-pollution isolation liquid for well cementation and a preparation method thereof, belonging to the technical field of well cementation. The isolation liquid comprises the following components in parts by weight: 100 parts of clear water, 4-29 parts of suspending stabilizer, 0.5-5 parts of fluid loss additive, 0.3-2 parts of tackifier, 0.1-5 parts of diluting agent, 0-5 parts of viscosity and shearing force increasing agent, 30-350 parts of weighting agent, 1-25 parts of pH value regulating agent and 0.1-0.5 part of defoamer. The isolation liquid provided by the invention has wide density regulation range, large temperature resisting range, strong anti-pollution capacity, wide applicability and strong maneuverability, can be conveniently subjectedto in-situ preparation, can be prepared by using a mud tank equipment base fluid method or cement vehicle equipment dry-mixing method, and can apply effective abrasion, scraping and carrying effects to attachments on an interface of a well wall; and by using the isolation liquid, the problems that in the well cementation operation, pollution is generated by fluid displacement, the adhering quality of a well cementation interface is poor and the like are effectively solved.

Description

Technical field [0001] The invention relates to a high-efficiency anti-pollution isolation fluid for cementing and a preparation method thereof, which is used in the technical field of oil cementing engineering prefluid. Background technique [0002] The ultimate goal of cementing engineering is to ensure the quality of cementing, ensure that the cement ring is effectively sealed and cemented with the casing and the stratum, and prevent the oil, gas and water between different stratums from passing through each other, so as to ensure the normal exploitation and long-term exploitation of oil and gas wells. Later acidification fracturing to increase production is convenient. [0003] When cementing, use cement slurry to displace the drilling fluid, and form a cement ring in the annulus to support the casing and seal the formation. In this process, the complicated situations are as follows: [0004] (1) Contact pollution of drilling fluid and cement slurry [0005] The drilling fluid sy...

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Problems solved by technology

[0011] The purpose of the present invention is to provide a high-efficiency anti-pollution spacer fluid for cementing to solve the problems of low efficiency of two-phase fluid contact pollution replacement and poor cement sheath cementation quality in cementing operations. 3 -2.60g / cm 3 The performance is controllable within the range, and the performance is stable in the temperature range of 40°C to 140°C; it has excellent anti-pollution performance, dilutes the drilling fluid and effectively isolates the drilling fluid and cement slurry, prevents contact pollution, and improves the displacement efficiency; Effective abrasion, scraping and displacement of attachments such as mud cake, dry dehydrated gelled and thickened drilling fluid, and improved cementing quality

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