关键词: 煤层气, 水平井, 井身结构优化, 分段压裂, 精细化排采

Abstract: The practical development experiences of CBM horizontal wells more than 15 years for major CBM blocks in China shows that there are wide variation in development effectiveness and poor repeatability among the same technology of horizontal wells under the different geological conditions. Therefore, the optimal technology of horizontal wells needs to further be investigated. Based on typical cases data statistical analysis of CBM horizontal wells technology application. The optimized methods of horizontal wells on the well types, the well structure, the completion method, the stimulation method and the drainage equipment & technology were studied. The results show that the well types and well structure play a decisive role on the efficiently and economically developing CBM. U-type wells and L-type wells are the most valuable for extension and application among all well types. The optimization of horizontal well structure should maintain smoothing of horizontal borehole, horizontal borehole down-dip of U-type wells, horizontal borehole up-dip and setting pocket for sinking coal powder of L-type wells. The completion method is selected according to the data of ground stress, the buried depth and permeability of coal-bed. The screen completion method should be adopted for lower ground stress, relatively shallow buried depth and high-permeable coal-bed. Otherwise, The technology of “casing cementing + segmented dense multi-cluster perforation + large-scale fracturing” should be adopted in the horizontal borehole. The drainage equipment combined “Rod pump + pumping unit ” should be selected in preference. The intelligent drainage and fine drainage should be implemented to strictly control the drainage rate of the stepwise up-production stage and stable production stage of coalbed methane, in order to ensure the sustainable high production of coalbed methane wells.