Research on Wellbore Quality Control Technology for Coalbed Methane Deviated Wells

Deviated well is one of the main well types to develop coalbed methane in China. It's been widely used by various coalbed methane companies in recent years. Compared with traditional oil and gas wells, coalbed methane wells are characterized by shallow depth and strict well spacing, which means higher wellbore quality control technology. Furthermore, coalbed methane wells are apt to produce coal dust during dewatering and coal dust causes serious abrasion of pipe and rod. It's required to improve wellbore quality. This paper analyzes the weakness of current wellbore quality control standard and technology for coalbed methane wells on the basis of the characterization of coaled methane wells and finds out the key factors that control wellbore quality of coalbed methane deviated wells. The technology is developed to improve wellbore quality of coalbed methane wells from trajectory design and real-time control. Through the on-site test in Baode block, Shanxi Province, the technology is further improved and it's confirmed by the test result that this technology can improve the wellbore quality of coalbed methane deviated wells. In addition, this paper also presents some good suggestions for compiling standard about wellbore quality control for coalbed methane deviated wells.