Expanded flexible well cementing grout and preparation method thereof

Abstract

The invention provides an expanded flexible well cementing grout and a preparation method thereof. The grout comprises the following components in parts by weight: 100 parts of cement, 6-14 parts of toughening material, 3-80 parts of reinforcing material, 8-120 parts of density modifier, 0.5-2.5 parts of suspension stabilizer, 20-40 parts of high-temperature stabilizer, 35-100 parts of distilled water, 0.5-2 parts of dispersant, 0.5-4 parts of fluid loss agent, 0.3-4 parts of retarder, 0.1-2 parts of foam inhibitor and 0.1-2 parts of defoamer. The invention further provides a preparation method of the expanded flexible well cementing grout. The grout has good sedimentation stability; and the set cement has the characteristics of micro expansion, high strength and low elasticity modulus, and can avoid the phenomena of micro cracks, micro annuluses, even fracture and the like caused by cement sheaths in subsequent operation of gas storage wells, shale gas wells, dense oil-gas horizontal wells and the like, thus realizing good zonal isolation and providing a technical support for long-term, safe and effective operation of oil-gas wells.

Description

technical field [0001] The invention provides an expansion toughness cementing cement slurry and a preparation method thereof, belonging to the field of oil and gas well cementing engineering. Background technique [0002] Ordinary Portland cement is a brittle, porous, and shrinkable material with congenital defects. Due to the alternating stress and temperature changes in the process of gas injection and production in gas storage wells, large-scale shale gas wells and tight oil and gas horizontal wells Volume fracturing can easily lead to microcracks or even breakage of brittle ordinary cement stones; and cement hydration shrinkage is an inherent characteristic of Portland cement, which can easily lead to cement sheaths in the well and micro-gap in the annulus; the above two Both of these situations will cause the cement sheath to lose its interlayer isolation, resulting in formation fluid channeling, annular pressure and other phenomena. Therefore, it is necessary to modif...

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Problems solved by technology

[0004] (1) The disadvantage of latex is that the environment is seriously polluted, the amount added is large, and the price is expensive. After adding latex, the degree of reduction of the elastic modulus of cement stone is difficult to meet the requirements of on-site application;

[0005] (2) Rubber powder with poor surface hydrophilicity such as waste tire rubber powder and silicone rubber powder has poor bonding ability to cement stone matrix, which affects the integrity of cement stone. Although some studies have proved that modification can be carried out to improve the bonding strength, the increase Reduced industrial production costs;

[0006] (3) The disadvantages of fiber are poor dispersion, difficult mixing, high price, poor bonding with cement stone matrix, and the elastic modulus of fiber cement stone alone is difficult to meet the requirements of on-site application

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