IDENTIFICATION AND CHARACTERIZATION OF RESERVOIR POTENTIALS IN TELISA FORMATION IN SRA FIELD IN CENTRAL SUMATRA BASIN

• Main Author: Reza Ananda, Syahli
• Format: Theses
• Language: Indonesia
• Subjects: Geologi, hidrologi & meteorologi
• Online Access: https://digilib.itb.ac.id/gdl/view/55790
• Institution: Institut Teknologi Bandung

SRA Field is an oil field that has been in production since 1982 and is located at Central Sumatra Basin. This study aims at seeking for reservoir intervals that have not been well identified in Telisa Formation. Some indications have been found in some reservoir intervals containing hydrocarbon based on data of marked log, test, and oil show from mud log. The objective of this study is to identify shaly sand reservoirs in Telisa Formation which could be then developed and expected to help production. This study uses primary data of sub-surface condition of drilling of fourty seven wells with wireline log data such as gamma ray log (GR), resistivity log, density log (RHOB), neutron log (NPHI), biostratigraphy data consisting of age and depositional environment, data of core rock (core), 3D seismic cube, checkshoot data, lithological description of rock cutting (mud log), marked log data or the validation of hydrocarbon existence, and the report of well drilling. Identification and characterization of the reservoir potentials in this study is the result of the mud log screening for resistivity value, analysis of lithostratigraphy which is an integration of data of correlations among various wells, biostratigraphy data, seismic and petrophysical data. Based on the analysis results, Telisa Formation, which serves as cap rocks of Central Sumatra Basin, is found by this study containing hydrocarbon potential on its reservoirs which have a character of shally sand and low resistivity. The reservoir intervals were deposited in an environment of estuarine intertidal bar facies and shallow subtidal facies with a characteristic pattern of gamma ray log of gradual funnel. This study finds various hydrocarbon potentials at Telisa Formation at reservoir A, the parameters cut off volume shale <0.62, effective porosity >0.05, water saturation <0.83, resistivity 2 - 5.7 Ohm and reservoir B cut off volume shale <0.6, effective porosity >0.05, water saturation <0.85, resistivity 2 - 5.6 Ohm. The results of the net pay map obtained an average shale volume value at reservoir A 0.48, porosity 0.11, water saturation 0.72, average net thickness 5.5 ft and reservoir B an average shale volume value 0.46, porosity 0.1, water saturation 0.76, thickness net averaged 2 ft. Then calculate by using volumetric formula, the resources of oil in place 1.11 mmstb.