Methodological Research Of Lithological Identification And Calculation Of Porosity Of Reservoir In Bel Sag Using Logging Data

This paper presents the methods for the identification of lithology characteristics and the calculation of porosity with Logging data for Bel Sag in Hailar Basin. Considering the fact of the complicated lithology in the target reservoir, the principle of'sub-dividing blocks in horizontal and sub-dividing formations in vertical'is adopted based on the composite data from different sources for the target reservoir.Using the normal logging data with standardization, normalization, square-wave conversion, the basic model and also the U-TH-K identification chart is built up; after the reservoir lithology is identified, the lithology in the target reservoir is classified into three main groups of sedimentary pyroclastic rock, pyroclastic sedimentary rock and sedimentary rock and twelve sub-groups under them.The lithology identification method is applied for the logging data of 31 wells, and the conformity percentage is up to 86.1%, which builds up the reliable basis for the further calculation of more reservoir parameters. Using the identification results, two kinds of methods for porosity calculation, i.e.,by normal logging and nuclear magnetic resonance logging, are integrated with the result of core analysis. The calibrated porosity of tuffaceous pyroclastic rock in Tongbomiao sub-group is very close to the core analysis results, which indicates that the porosity calculation methods provided in this paper can meet the requirements of practical application.The methods of lithology identification and porosity calculation presented in this paper will contribute to both the breakthrough of exploration in the target region and the basic geologic research.