Seismic reprocessing contributes to development success at the Elang Field, Northern Bonaparte Basin

Abstract

The 3D data set over the Elang Field, Northern Bonaparte Basin, was reprocessed to provide greater confidence in mapping the structural configuration of the field and to investigate infield development opportunities. The original (1994) data set, which was acquired and processed in the inline (strike) direction, suffered from poor resolution and reflection coherency and multiple contamination at the reservoir level. The reprocessing strategy included rebinning and horizon velocity analysis (HVA) in the dip direction followed by radon demultiple applied close to the HVA velocities. The result was a significant improvement in resolution of reservoir horizons and faults. Interpretation of the reprocessed data yielded a simpler structural picture of the Elang Field with the crestal area interpreted as a simple rollover with little or no erosion of the reservoir section. The fault interpretation, aided by edge detection and coherency cube results, differs from the original 3D interpretation and is now characterized by a simple east-west fault pattern at the reservoir level. Reservoir mapping confirmed significant attic oil potential in the vicinity of Elang-1. This potential was tested in January 2000 by Elang-1/ST1 which intersected the reservoir 28 m up dip of Elang-1 and close to the prognosed depth. Production from the well has exceeded pre-drill predictions and added substantial incremental reserves to the field. This has increased value to the project and extended the life of the Elang production facility.