Managing And Quantification Geophysical Uncertainty In The Faulted Area: Study Case Stupa Field, South Mahakam Indonesia

Abstract

Stupa Field is one of gas fields in South Mahakam area. This field has complex structure with faulted area and limited seismic data quality. One of the major fault is Sepinggan fault which is located western part of Stupa field. This fault plays significant contribution for hydrocarbon traps and control sedimentation in South Mahakam Area. Echelon faults of Sepinggan fault as evidence of right lateral displacement of Sepinggan fault. Moreover this echelon faults divide Stupa into different panels and each panels have different development strategy. Geophysical interpretation on this area are more challenging due to the fact of limited data quality beside the nature of seismic data acquired is limited due to narrow seismic acquisition parameter which impacted difficulties for interpret exactly fault and horizon position in the main target of reservoir in this field. This situation will tend to give more uncertain in reservoir geometry. Next question will be arise such as how big the level of uncertainty, how to measure the uncertainty, is it accepted and confident enough to be used as one element of geomodel and how geophysical method can de-risk the next drilling target? In this paper we will demonstrate how to calculate lateral and vertical reservoir geometry uncertainty which is including Gaussian simulation on horizon uncertainty, fault uncertainty calculation with kinematic modeling and area depth strain (ADS) methodology and reservoir contact uncertainty with triangular simulation. Which one is the biggest factor for geometry uncertainty will be simulated too. GRV calculation and simulation of the reservoir geometry give impression that all of structural uncertainty source have similar effect for GRV computation on this field. Moreover structural uncertainty simulation can be used for putting the next drilling target which the result will be seen on the next coming well drilling campaign.

AAPG Datapages/Search and Discovery Article #90354 © 2019 AAPG Asia Pacific Technical Symposium, The Art of Hydrocarbon Prediction: Managing Uncertainties, Bogor, (Greater Jakarta), Indonesia, August 7-8, 2019