RESERVOIR CHARACTERIZATION ON THIN LAYER SANDSTONE OF MIDDLE-LOWER WARUKIN FORMATION, “AYU” FIELD, BARITO BASIN, SOUTH KALIMANTAN

• Main Author: Ayu Agatha, Silvia
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/42707
• Institution: Institut Teknologi Bandung

The Lower Warukin Formation was deposited in shallow marine (fluvio-deltaic environment) at the Early-Middle Miocene. During the Early-Middle Miocene, tectonic changes led the uplift and emergence of Meratus Range. It changed the setting from transgressive to regressive. Warukin Formation is widely exposed in the northern part of Barito Basin. The Lower Warukin consists of thin layer of fluvial sandstone, shale and coal. Pertamina EP has discovered and drilled the northern part of Barito Basin and it produced oil 222 BOPD. Turns out there is continuity of Lower Warukin in the southern part of Barito Basin so it needs to be explored in the southern area. There is one and only exploration well in southern area but the quality of log is not good. It happened because of washout effect.To minimize washout effect, it needs pre-conditioning process to the logs. Target zone is in transition zone so the reflector is not clear to be determined. So it needs Extended Elastic Method to identify thin layer reservoir. To characterize the thin layer reservoir, it needs elastic parameter that sensitive toward lithology and fluid changes. In this observation, elastic parameter that sensitives to litho changes is Mu-Rho and elastic parameter that sensitives to fluid changes is Lambda-Rho. Mu-Rho has the best correlation with log EEI when chi 90°and Lambda-Rho has the best correlation with log EEI when chi ?43°. When chi 90° EEI is equivalent with S-Impedance. So the model based inversion should be in EEI volume and SI volume to indentify sand that contains hydrocarbon fluid. To enhance the inversion result, it needs to create relative volume. In relative volume, reservoir has positive value of S-Impedance and negative value of Lambda-Rho.