Cement paste system for long-cementing-section large-temperature-difference cementing

Abstract

The invention discloses a cement slurry system for long-cementing-section large-temperature-difference cementing, and relates to the technical field of oil and gas field cementing materials. The cement paste consists of 74-88 wt% of oil well cement, 4-8 wt% of a fluid loss agent, 1-3 wt% of a suspension stabilizer, 10-20 wt% of a high-temperature strength stabilizer and 1-3 wt% of a retarder. The retarder is formed by mixing and compounding sodium ethylene diamine tetramethylene phosphonate, borax and a ternary polymer. The ternary polymer is prepared by taking sodium methallyl sulfonate, isopentenol polyvinyl ether and maleic anhydride as monomers and adopting a free radical solution copolymerization method. The cement paste provided by the invention has a wide use temperature interval, can meet the retarding effect on cement paste in the whole temperature interval that the temperatures of the upper end and the lower end of a cement paste injection well section in cementing construction are 50 DEG C and 180 DEG C respectively, the cement paste is ensured to have certain strength in a 50-DEG C high-temperature large-temperature-difference environment at the top, and the super retarding phenomenon of top cement is avoided.

Description

technical field [0001] The invention relates to the technical field of cementing materials for oil and gas fields, in particular to a cement slurry system for cementing wells with large temperature differences in long sealing sections. Background technique [0002] With the deepening of oil and gas exploration and development, the objects of exploration and development are becoming more and more complex. More than 40% of the remaining domestic oil and gas resources are distributed in deep layers. Deep oil and gas resources must be developed to increase oil and gas production. The number of deep wells and ultra-deep wells is increasing, and the complexity of cementing is increasing, especially with long open holes, large temperature differences, and multiple pressure systems. , has brought severe challenges to the cementing work. The large temperature difference cementing technology for long sealing intervals in complex formations has become one of the bottleneck technical p...

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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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