The Effect of Coal Seam Gas saturation on CBM Well Productivity-A Case Study of Central Region of Hedong Area

摘要

Coal seam gas saturation is an important index of CBM evaluation, and it impacts CBM well productivity. The central region of Hedong area is one of the major CBM development block in Ordos basin. The coal seam gas saturation changes seriously in the target area. In this study, coal seam 8+9 was chosen as the study seam. And this study conducted simulation to investigate gas saturation effects on CBM well productivity. The sensitivity simulation results between different saturated coal seam and well productivity show that the higher gas saturation of the coal seam, the higher peak gas rate and the recovery factor. Coal seam permeability is the key parameter that affects CBM well gas productivity, in this study, a relationship between permeability and gas saturation was established to interpret the gas saturation affects on well productivity. Accoriding to the simulation results which show the reletionship betweent different saturated coal seam and peameability change intensity, the fundamental influence principle of gas saturation to CBM well productivity was that during the depleting, the higher the gas saturation was, the bigger the rate of the permeability increased, and ultimately the better the well productivity appeared.