Abstract:

As a typical unconventional gas reservoir with low pressure, permeability and water cut, deep coalbed methane needs effective support fracturing to achieve good development effects, leading to large difference of liquid production in the whole life cycle of gas wells. Based on the comparison of coalbed methane recovery effect of different well types in Yanchuan South coalbed methane exploration and development block, it is considered that although the L-shaped horizontal well has the construction cost similar to that of three directional wells, but its production is higher and post-operation and maintenance cost is lower. It is more suitable for coalbed methane development in mountainous areas. By comparing the characteristics of different lifting processes, the combination of pumping unit and forced closed spring inclined well pump is optimized, and the drainage and gas recovery in the whole life cycle of L-shaped horizontal well is realized. In the gas wells with low liquid production, the technology of water drainage gas recovery has achieved good stimulation effects in the gas wells with small deviation, and high influence of liquid accumulation and pulverized coal. The existing mechanical production equipments can realize the efficient utilization of assets, save the cost of purchased materials, reduce the energy consumption index, and provide referential significance for the further drainage gas production in low liquid production wells.

Key words: coalbed methane, life cycle, dewatering gas recovery, horizontal well, drainage