On Forecast Method for Volcanics Gas Production Capacity Using Logging Data

It does not have a mature method to predict the production capacity of oil and gas reservoir by logging data.Because of acidic volcanic reservoir with strong heterogeneity,big change of productivity in the studied area,it is difficult to predict the reservoir productivity.Based on the study of the natural gas well logging response characteristics,we propose the method of neutron-density porosity combination, NMR-density porosity,transverse and longitudinal wave velocity ratio,comprehensive parameter to reflect gas reservoir characteristics.Combining with the comprehensive parameter and effective thickness,we get the productivity index to identify the reservoir productivity grade.Based on the difference of the contribution degree of the reservoir porosity,saturation,permeability and effective thickness,we establish reservoir productivity calculation model using different index.The method is applied to predict the volcanic reservoir productivity in Xushen gas field.The reservoir level prediction accuracy rate is 90%,the relative error is lower and the effect is better.It provides accurate data for layer selection of natural gas test.