Abstract

The Belida oil and gas field, in the South Natuna Sea Block "B" contract area is approximately 1,200 kilometers north of Jakarta. The field was discovered in December 1989 and contains about 190 million barrels of recoverable oil and 75 billion cubic feet of recoverable gas. First oil is scheduled for late 1992. The Belida structure is a broad low relief anticline some 10 kilometers long by 5 kilometers wide with 160 feet of vertical closure above the oil/water contacts. The five wells drilled indicate that a significant lateral variation in velocity occurs across the field. Given such a broad structure and the presence of velocity variations, depth conversion of the reservoir horizons seismic time maps is a key component of accurate reservoir description and development. To provide confidence in the reservoir maps, several depth conversion techniques have been used to check the results of each individual method. Final depth maps were further validated by using additional studies in full field seismic inversion and one dimensional synthetic modeling to support the depth conversion and the implied distribution of oil and gas. The result is a suite of maps which can be used with confidence to support reservoir modeling, reserves estimates, location of platforms and the placement of development wells.