Research On Geophysical Logging Evaluation Method For Shale Gas Reservoir

Shale gas is an unconventional gas resource, which exists in the shale with adsorption and freedom state. Due to the characteristics of the lithology and reservoir type of shale gas reservoir, it is different from the conventional oil and gas reservoir.The research of the logging response mechanisms and the interpretation and evaluation of shale gas is still weak.Therefore, An urgent need to carry out the research of the logging response mechanisms and interpretation evaluation technology of shale gas.This article is based on the large number of surveying the domestic and foreign materials. We completed the following work by consulting a large number of foreign literature.We carried out the research of the reservoir identification and the response characteristics of shale gas, and we summed up the conventional logging response characteristics of the shale gas reservoir. We also carried out the study of the evaluation method of shale gas reservoir in the ability of hydrocarbon, that is, the study of the evaluation method of the abundance of organic matter and maturity.We studied and proposed some computational methods of the organic carbon content of the shale that based on the logging information.It including a single empirical formula method, the method of ?lgR and the sensitive logging comprehensive empirical formula method,and so on.We suggest that these methods are practical for the quantitative evaluation of TOC. These methods are feasible for the quantitative evaluation of organic carbon content. The calculated organic carbon content is in good agreement with the actual test results. However, these methods have certain regional limitations, the scope of application is limited. The logging evaluation methods of the maturity including maturity index(MI) and vitrinite reflectance (Ro).We Carried out the study of the shale gas reservoir interpretation model,established the reservoir volume model, and use the Geolog software to research and apply the optimization logging interpretation method of the multi-mineral model.We got the mineral content in the study area, and the calculated results and the core distraction results are in good agreement. The paper also studied the reservoir parameter calculation method of the shale gas reservoir. It mainly including porosity, permeability, free gas content and adsorbed gas content, and the total content of gas, and so on. The paper implements the calculation method of porosity that based on the combination method with three porosity and resistivity logging information. We calculated the adsorbed gas content by combining with isothermal experiment result of core Langmuir after obtaining the organic carbon content in formation, or analyzing organic material with core and running linear regression by logging parameters to calculate the adsorbed gas content. The calculated results and the core distraction results are in good agreement.