3D Sesimic Reprocessing for Geophysical Analysis of Sea Bottom, Seabed Mapping and Geohazard Clarification

Abstract

This paper presents a case study from the ENI operated Muara Bakau PSC (Jangkrik) on the East Kalimantan shelf edge and the west slope of the Makassar straits. The paper discusses the resolution and accuracy of Short-Offset Processed 3D Seismic Data (SOPS) and the applicability of the resulting Digital Terrain Models (DTM) for seabed mapping and initial field development planning. For this case study a SOPS DTM of 12.5x12.5m grid spacing was generated covering a total area of 330 Km². A somewhat smaller area was later surveyed utilising an Autonomous Underwater Vehicle (AUV). The resulting AUV DTM was of 1x1m grid spacing. A number of exploration wells were already drilled within the area and accurate water depth measurements were performed from three of those wells. This provided the opportunity to evaluate the SOPS DTM accuracy and resolution. The results of the evaluation are presented in this paper. In the Jangkrik Project development, the SOPS DTM execution at early stage (during Concept Selection) allowed to: Progress the subsea system design of a "fast track" project without waiting for site geophysical survey (AUV) Make key decisions at early stage avoiding the cost and time impact of later changes such as: One well (JK 7) was relocated because initially positioned within a canyon