Evaluasi Petrofisika Pada Zona Reservoir Low Resistivity Low Contrast (LRLC) Di Lapangan Talang Jimar, Cekungan Sumatra Selatan

Abstract

The Talang Jimar field is located in the South Sumatra Basin and was first produced in 1947. However, over time, this field experienced a decrease in the rate of oil production due to a decrease in reservoir pressure. The study reviewed in this final project is that petrophysical evaluation in the Low Resistivity Low Contrast zone can increase the amount of oil production and cumulative oil production in the Talang Field. In the Talang Jimar Field, there is a hydrocarbon reservoir zone that is experiencing conditions. The Low Resistivity zone can be interpreted as a hydrocarbon layer containing oil and gas that has experienced special conditions, because of its hidden location which can be misinterpreted as a layer of water. This results in the value of the calculation of water saturation being Low Contrast as the fluid in the rock is known as a water layer despite the fact that the zone has a hydrocarbon layer. This condition occurs because the geological diagenesis in the area is complex and data from resistivity logs are limited when identifying hydrocarbons in the zone. The presence of shale in a reservoir will cause the resistivity value to decrease, but on the contrary, the water saturation value will increase so that it can cause uneconomical analysis results in the identification of hydrocarbons. So, to overcome this, it can be done by analyzing routine core analysis data from the company to find out the cause of the well experiencing Low Resistivity Low Contrast conditions in the reservoir zone which probably should have contained hydrocarbons, but when the petrophysical analysis was carried out normally no hydrocarbon content was found in the reservoir. the well. The method used in this study consisted of four stages, namely the preparation stage, data collection stage, data processing, and analysis stage, and the last stage was the data presentation stage. In the preparation stage, data is collected from the literature, then at the data collection stage, data is collected from the company, namely well-logging data, mud log data, DST data, routine core analysis data, and also rock analysis data in the form of data. Petrography, XRD data, and SEM data. Before conducting a petrophysical analysis, it is necessary to do a stratigraphic sequence correlation to determine the depositional environment in the study area, after that a 3D depositional model is made for easy understanding. At the analysis stage, petrophysical analysis was carried out using primary data in the form of Gamma-Ray Log, Resistivity Log Porosity Log, and Permeability Log which aims to show reservoir rock characteristics covering four main aspects, namely shale volume, porosity, permeability, and water saturation. The characteristics of the reservoir rock that have been obtained are then used in determining the potential hydrocarbon zone, with the final result in the form of a net pay zone thickness value.