Gas-water Identification of Volcanic Layer Reservoir in Xushen Gas Field

The lithology of deep volcanic layer reservoir in Xingcheng District,Daqing,is complex,and parameters of rock matrix of it are difficult to be determined,so it is almost impossible to distinguish gaswater formation based merely on fluid type,but synthesized application of multiple logging information could be effective to identify gas reservoir.The gas-bearing identification method described in this paper includes synthetic application of 3-porosity method,cross-plot method,and new logging technologies.The supplements for 3-porosity method are the calibration of responses of 3 kinds of porosity logging with local core data,and the selection of 3 compositive parameters for enlarging characteristics of gas reservoir.The concrete jobs for applying cross-plot methods are plotting cross-plot of deep laterolog resistivity R_(LLd)～density ρ,and cross-plot of R_(LLd)～gas logging ratio,as well as determining corresponding gas-bearing criterions.New logging technologies used now are 2: the density～NMR porosity cross-plot and the sonic compression～transverse wave velocity comparison.These methods were applied in more than 20 wells,the gas-bearing interpretation accordant rate verified by gas test reaches up to 88%.Field logging cases are shown.