Dynamic Evaluation Of Coalbed Methane Field Development Of A Block In Panzhuang

In recent years, surface CBM development grows quickly in China. Low average gas production of single well is the major challenge to CBM industry. The most important reason is the unknowns of fluid parameters and reservoir physical property parameters changes in coalbed methane well drainage process, as well as the lack of recognition on how these parameters changes affect gas productivity.A CBM block in Panzhuang, Qinshui Basin was chosen as the object of study. The drainage results of single wells were analyzed, reservoir simulation of single well and whole coalbed methane field were performed, and also the further analysis and discussion were conducted. The following achievements were got.Firstly, according to the history matching results, the precision of parameters from injection/fall off well testing are at lower level; in coalbed methane vertical well development, reservoir pressure, water saturation and gas content drop continuously and extend out and down in the form of a funnel; if initial reservoir pressure is larger than critical desorption pressure, porosity and permeability decrease firstly and then increase, but if initial reservoir pressure is smaller than critical desorption pressure, porosity and permeability mostly increase. Secondly, the geological model of research area was build, with the 437 imported wells information. A proper drainage working system of 4.18 m3/d water drainage rate was chosen to simulate the coalbed methane field development. Thirdly, in coalbed methane field development, fluid and reservoir property characteristics in study area change dynamically and are of horizontal partition. With the effect of porosity and permeability dynamic change, the total gas production capacity of coalbed methane field increases. The affecting process can be divided into three stages. The study area are divided into three units. Development scheme are adjusted based on the geological characteristics and simulation results of every unit. The new scheme reduces 38 wells and brings a bigger production capacity. Fourthly, the coalbed methane field dynamic evaluation method includes four steps—geological modelling, parameter correction and optimizing, coalbed methane field dynamic process and rules, CBM field development forecast and evaluation. Advices to optimize drainage working system is proposed from different point of view.