A drainage data-based calculation method for coalbed permeability

作者：Lai Feng peng^*; Li Zhi ping; Fu Ying kun; Yang Zhi hao

来源：Journal of Geophysics and Engineering, 2013, 10(6): 065005.

DOI：10.1088/1742-2132/10/6/065005

• coalbed methane
• permeability
• drainage data
• productivity equation
• material balance equation

This paper establishes a drainage data-based calculation method for coalbed permeability. The method combines material balance and production equations. We use a material balance equation to derive the average pressure of the coalbed in the production process. The dimensionless water production index is introduced into the production equation for the water production stage. In the subsequent stage, which uses both gas and water, the gas and water production ratio is introduced to eliminate the effect of flush-flow radius, skin factor, and other uncertain factors in the calculation of coalbed methane permeability. The relationship between permeability and surface cumulative liquid production can be described as a single-variable cubic equation by derivation. The trend shows that the permeability initially declines and then increases after ten wells in the southern Qinshui coalbed methane field. The results show an exponential relationship between permeability and cumulative water production. The relationship between permeability and cumulative gas production is represented by a linear curve and that between permeability and surface cumulative liquid production is represented by a cubic polynomial curve. The regression result of the permeability and surface cumulative liquid production agrees with the theoretical mathematical relationship.

• 出版日期2013-12
• 单位中国地质大学（北京）