Tracking Research Of Multi-branch Horizontal Well Technology At FanZhuang Coalbed Methane Region

Fanzhuang block located in the south of Qinshui coal-bed methane fields. The coal rock reservoir has very poor reservoir properties. The pressure, permeability and saturation of the field is very low. In the past 11 conventional vertical wells have been tested about production. The test result is not satisfactory. Traditional technology isn't applicable to Qinshui Basin high rank coal-bed methane reservoirs. Coal-bed methane multi-branch horizontal well sets of drilling, completion and stimulation in one, it can increase the desorption sweep area, enhance coal bed flow conductivity, add single well production. It also is benefit to environmental protection and it played an important role in the United States Coal-bed methane production. In order to increase the single-well production and economic efficiency, promote the industrialization of coal-bed methane to large-scale development, North China Oil Field decided to recommend multi-branch horizontal well technology to development Fanzhuang block's coal-bed methane after lots of pre-feasibility studies and analyses. In this paper, the Jingping-2 well group was studied, through drilling and completion technology assessment, adaptiveness analysis of production equipment, the speed of production analysis and bottom-hole pressure monitoring technology for the group link wells and cavity wells. In this paper,the author summarized experiences and lessons in the process of drilling, completion and production of coalbed methane multi-branch horizontal well. It provides experience and technical support for rationally and effectively exploiting Qinshui Basin coal-bed methane mining in the future. At the same time, it summarized the successful experiences and failures of implementing multi-branch horizontal well.The results show that the coal bed of Jinping-2 well group which was drilled is complex, with low permeability and lack of the geology awareness. As a result the rate of drilling is low and the drainage relief cannot effectively spread. In the course of drilling and completion, the selection of drilling rig, caves intersection, branch sidetracking and drill bits are reasonable. But restricted by well spacing, awareness of geological structure at that time, drilling accidents, unpredictability of complex cases and processing method, the well group failed to achieve the desired result in the end. Sand-flushing operations of Jinping-2 well group contaminated the coal bed, this affected the gas production to some extent. Bottom-hole pressure gauge played an important role in ensuring the fluid level to decline smoothly, and it created a favorable environment for the formation of pressure drop funnel.