Applied study on modern gas production decrease analysis of coalbed methane well

Cui Bin; Fu Yutong

doi:10.13199/j.cnki.cst.2017.03.018

Abstract：In order to discover the application of the modern production decrease analysis to the coalbed methane well,based on the systematic statement on the development of the modem production decrease analysis method,according to the production data of the coalbed methane well group in Yanchuan South Block,the four modem production decrease analysis charts of the Blasingame,Agarwal-Gardner,NPI and Transient were applied to quantitatively evaluate the reservoir permeability,effective crack half length and drainage radius and to study the relationship between the drainage radius and reservoir permeability,the effective crack half length as well as the effective crack haff length and the total hydraulic volume and added sand quantity of the fracturing hydraulic.The results showed that the reservoir permeability of the well group was (0.008～0.064)× 10-15 m2 and the heterogeneity was strong.The effective crack half length of the fracturing was 27～ 72 m and the fracturing total volume and the added sand quantity were in a positive correlation relationship.The drainage radius of a single well was 36～ 103 m and the average was 56 m as well as was in a positive correlation relationship to the reservoir permeability and the effective crack half length.When the effective crack half length was longer than 50 m and the permeability was over 0.06× 10-15 m2,the drainage radius would be over 100 m.