A cement slurry system for long sealing section and large temperature difference cementing

Abstract

The invention discloses a cement slurry system for cementing with a long sealing section and a large temperature difference, and relates to the technical field of cementing materials in oil and gas fields. The cement slurry of the present invention is composed of 74-88 wt% oil well cement, 4-8 wt% fluid loss agent, 1-3 wt% suspension stabilizer, 10-20 wt% high temperature strength stabilizer, 1-3 wt% % retarder; retarder is made up of ethylenediaminetetramethylenephosphonate sodium, borax and terpolymer; terpolymer is sodium methacrylate sulfonate, isopentene Alcohol polyvinyl ether and maleic anhydride are used as monomers and are prepared by free radical solution copolymerization. The cement slurry of the invention has a wide service temperature range, which can meet the setting retardation effect of the cement slurry in the entire temperature range of the upper and lower ends of the cement slurry well section in the cementing construction, which are respectively 50° C. and 180° C. Under the environment of high temperature and large temperature difference of 50 °C, it can have a certain strength and avoid the "super-retardation phenomenon" of the top cement.

Description

Technical field [0001] The present invention involves the field of oil and gas field solid well materials technology. It is more specifically involved in a long -sealing solid section large temperature difference. The cement slurry system is involved. Background technique [0002] With the continuous deepening of oil and gas exploration and development, the targets of exploration and development are becoming increasingly complicated. More than 40% of the remaining oil and gas resources in China are distributed in deep, and deep oil and gas resources must be used in oil and gas production. The number of deep well -deep well drilling is increasing. It brought severe challenges to Gujing's work. The complex stratum long section large temperature difference and solid well technology has become one of the bottleneck technology issues restricting exploration and development. [0003] High temperature and large temperature difference solid well requires cement slurry to ensure both safe...

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Problems solved by technology

[0005] In order to overcome the defects and deficiencies in the above-mentioned prior art, the present invention provides a cement slurry system for well cementing with a large temperature difference in the long sealing section. Influenced by the strength of the cement stone formed by it, the compressive strength develops slowly in the low temperature area at the top of the well section, and even cannot be condensed

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