Well cementing cement paste suitable for coal bed methane and preparation method thereof

Abstract

The invention provides well cementing cement paste suitable for coal bed methane. Compared with the prior art, a multi-size-fraction leaking stoppage material, an active filler and a resin material are added into the cement paste to form a leaking stoppage type cement paste system, in the multi-size-fraction leaking stoppage material, the first-stage particle leaking stoppage material serves as asupporting material, and the bridging effect can be achieved to support cracks; gaps are filled with a second-stage particle leaking stoppage material, cement particles and the like to form a leakingstoppage frame, and a hydrophilic fiber leaking stoppage material can form a fiber grid structure in a crack, so that the stability of a cement paste leaking stoppage structure is improved; a resin cementing material is used for further enhancing the mutual cementing among the crack surface, the leaking stoppage material and the cement; therefore, the compactness of the leaking stoppage structureis improved through multistage filling of the bridges, the elasticity, the nano materials and the cement particles, and meanwhile, the addition amounts of the modified multi-size-fraction leaking stoppage material, the active filler and the resin material are adjusted, so that the combined action of the modified multi-size-fraction leaking stoppage material, the active filler and the resin material has a remarkable synergistic effect on the leaking stoppage performance of the cement paste.

Description

technical field [0001] The invention belongs to the technical field of coal bed gas exploitation, and in particular relates to a well cementing slurry suitable for coal bed gas and a preparation method thereof. Background technique [0002] As an important supplementary energy to conventional oil and gas resources, coalbed methane is of great significance to the energy demand and development of my country and the world. The development and utilization of coalbed methane can optimize the allocation ratio and structure of conventional and unconventional oil and gas resources, so that energy can be used more effectively. At the same time, it can reduce gas leakage and explosion hazards in the coal mine production process, improve production safety, and protect the atmosphere. environment. The development of coalbed methane has become a new trend in the development of new energy in the world. [0003] Considering the accumulation conditions of coalbed methane, during the devel...

AI Technical Summary

Problems solved by technology

On the one hand, the intruded cement slurry will block the cracks and pores, and even cement in the cracks and pores, resulting in a decrease in permeability; Coal reservoir production stimulation effect

In 2010, Haidher Gaus et al. proposed in the article Coalbed Methane Cementing Best Practices-IndianCase History that cement slurry intrusion into coal seam cleats will seriously affect subsequent hydraulic fracturing and proppant filling. The average fracture pressure gradient of coal seams in this area is 2.01MPa / 100m, the well depth of a coal seam is 1019.50-1026.20m, and the normal fracture pressure is about 20MPa, but due to the intrusion of cement slurry, the fracture pressure is greater than 30MPa during the actual fracturing operation

[0008] To sum up, there are currently few researches on the damage mechanism of cement slurry to coalbed methane reservoirs at home and abroad, and there is still a lack of research on the damage mechanism, damage method and degree, resulting in a lack of pertinence in the cement slurry system.

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