Logging Evaluation Methods And Applications Of Parameters In Shale Reservoir

As a new type of unconventional nature gas resources,shale gas has been successfully explored and exploited in the United States and Canada.Prospects for shale gas development in China are bright and broad.Both continental strata in North China and marine strata in South China show good geological conditions and great potential for producing large-scale shale gas.Using well logging to interpret and predict gas-content shale is a quick,low cost method providing systematic data.Therefore,building a quantitative model linking well logging information with geological conditions of shale reservoirs to calculating geological parameters is an effective way to make a complement to laboratory tests which are time-consuming,laborious and expensive,and provide a convenient,fast,as well as reasonable way to evaluate reservoirs of shale gas.This article analyzed geological characteristics of shale gas,and discussed the connections between geology and well logging evaluation.Reservoir parameters includes organic carbon content,porosity,thermal maturity of organic matter,adsorbed gas content,free gas content.Combing geological parameters of shale from different types of basins,applicability of shale gas logging evaluation of marine basin,continental rift basin and continental depression basin had been discussed.And Yanchang oil and gas region had been determined as demonstration area of shale gas.logging evaluation.Different well logging curves reflect different geological characteristics of shale.The article discussed the relationship of geological parameters and well logging curves,calculated and evaluated geological parameters of shale through acoustic,resistivity,density loggings,in order to solve problems of evaluating continuity in longitudinal direction of geological parameters in shale reservoir.Based on results from systematical laboratory tests,using multivariate analysis methods,relationship between loggings and different geological parameters had been simulated and a calculation model fit with shale reservoirs in study area had been established.Then use the model to calculate TOC,porosity,thermal maturity,adsorbed gas content and free gas content,modify the calculating results through laboratory tests results and finally make conclusions of continuous changes of geological parameters in longitudinal direction.Based on study of geological conditions in Yanchang petroleum province,particularity of geological conditions has been analyzed,and combing with laboratory test data,a calculation model for reservoir parameters of continental depression basin has been established.After verifying the reasonableness of this model,continuous change values of each parameter has been calculated.It should be noted that an advice of improved algorithm for thermal maturity of organic matters has improved the model.By analyzing several typical wells,detail interpretations for characteristics of both well logging and reservoir parameters of target layers have been provided,effective gas content layers have been identified after comprehensive analyses,and an effective prediction for distribution characteristics of reservoir parameters has been successfully made..Using these results,a fundamental for latter exploration and exploitation of shale gas in Yanchang oil and gas region has been established.