AN INTERPRETATION METHOD OF PRESSURE ATTENUATION WELL TEST IN NEW COAL BED WELL IN CONSIDERATION OF THE CHANG IN PERMEABILITY WITH PRESSURE
Zhang Gongshe(Jianghan Petroleum Institute)and Lin Tao,Wu Yahong,Fan Mingfu and Liu Changyin(Downhole Special Operation Department of Zhongyuan Petroleum Exploration Bureau).NATUR.GAS IND.v.20,no.2,pp.71～73,3/25/2000.(ISSN 1000 0976,In Chinese)
The matrix pores in coal play a little role in fluid flow,therefore the permeability derived from well test is the reflection of the percolation flow capacity in cleat system.The change in reservoir pressure may cause that in effective stress,which makes the change in both open size and permeability of the fissures in coal bed,the permeability decreasing with the falling of the reservoir.In light of such a condition that the coal bed permeability was influenced by the change in the reservoir pressure near well bore in the process of pressure attenuation testing,an interpretation method of analyzing the pressure attenuation testing data is derived in the paper by use of the Duhamel principle.In new coal bed methane gas well,the primary permeability,primary reservoir pressure and skin factor may be obtained by use of the method,so as to aviod the difficulty in need of pre estimating primary reservoir pressure in slug flow interpretation.Finally,the measured data and interpreted results of the coal bed methane gas wells in Shanxi Province are proposed in the paper also.
【CateGory Index】： TE27