Enrichment law and development technology of deep coalbedmethane in South Yanchuan Coalbed Methane Field

South Yanchuan Coalbed Methane Field in the southeastern margin of the Ordos Basin has experienced nearly 10 years from exploration and discovery to benefit development；the whole process of capacity building and development and production has a strong representative and demonstration role in the exploration and development of deep coalbed methane in China. The gas field has broken the 800-meter development limit, and it has greatly realized the scale benefit development. Based on the comprehensive analysis of the geological characteristics and the enrichment law of the South Yanchuan coalbed methane field located in the southeastern margin of the Ordos Basin, the paper studied its enrichment and high production factors as well as exploration and development technologies. Abundant exploration and development practice has proved that CBM reservoirs in the study area have three main characteristics: ①deep burial, high coal rank, high gas content and favorable resource conditions; ②low porosity, low permeability and micro-pore development is conducive to adsorption, but poor pore connectivity is not conducive to production; ③low reservoir pressure coefficient makes development difficult.On the basis of in-depth analysis of the geological achievements of deep CBM geology, a five-factor synergistic control theory of deep CBM reservoir formation and high production is put forward, which includes sedimentary control, structural control, hydrodynamic control, insitu stress control and permeability control, and physical property control. Four key technical systems suitable for deep CBM exploration and development were formed:①the intensive large platform drilling and completion technology characterized by “series branching” and “well factory”;②an effective production and transformation technology for deep coal seam development;③an intelligent drainage and production control technology based on the desorption theory;④ground gathering and digital gas field technology, which provides technical support for the economic and effective development of the same type of deep seam methane productivity construction.