WIRELINE LOG BASED ASSESSMENT OF SHALE VOLUME AND POROSITY: A CASE STUDY

Abstract

Wireline log is one of the most popular method for reservoir characterization as well as reservoir quality assessment in oil and gas industry. This study shows the assessment of shale volume and reservoir porosity using wireline log data of anonymous field (well no. X). The reservoir lithology, resistivity and porosity have been estimated using lithology log, resistivity logs, and porosity logs such as sonic log and density-neutron logs. The shale volume is calculated from gamma ray and true resistivity methods. The effective porosity is estimated from neutron-density logs considering clay content. Based on log data analysis, lithology is mainly sand, and several hydrocarbon (gas) bearing zones are detected. Among them, one of the major hydrocarbon bearing zone is in the depth of 2588 to 2599 meter in this field. Shale volume ranges from 18.52 to 21.46 API. The average value of true resistivity is 9.17 ohm-m. The effective porosity (average) estimated using neutron-density combination formula is 18.65% and corrected sonic porosity is 18.35%. Results shows that the quality of reservoir porosity is good. The analyzed results may be used for reservoir pore fluid estimation, further reserve estimation and geo-statistical reservoir properties analysis.