Research and application of cementing technology for coal bed gas wells

China is very rich in coal bed gas resource, but its development and utilization is still in the initial stage. As compared with the conventional oil- and gas-bearing beds, coal bed has a shallow buried depth, well-developed micropores and fractures and low mechanical strength and porosity, so it is easy to collapse and easy to be polluted. In this paper, based on the characteristics of coal bed gas well, the difference between the cementing of common oil and gas wells and that of coal bed gas wells and the characteristics and difficulties of coal bed gas well cementing are presented, the main problems existed in coal bed gas well cementing are summarized and the cementing technology and additives suitable to the characteristics of coal bed are proposed. Above-mentioned technology was adopted in the three wells in Jincheng area, Shanxi Province, obtaining an all-excellent cementing quality and solving the problem of poor cementing quality in this area on the main. The problems to be solved in the coal bed well cementing at present are discussed also in this paper.