Publications

East Tuban Block is located at Northeast Java Basin that covers an area of 772 Km2. Current exploration activities are concentrating in Ngrayong Formation, a shallow clastic reservoir target. Enhancing 2D seismic processing shifts the play concept of East Tuban Block to deeper target, which are Kujung and Ngimbang Carbonate. Dutch drilled hydrocarbon discoveries in East Tuban Block noted in 1890. The well drilled on the pop-up structure of Sekarkurung Anticline, as the product of Late Miocene tectonics, and penetrated trough to Wonocolo and Ngrayong Formations. The current exploration target in East Tuban Block was defined by using 2D Seismic survey from 84, 91 and 92 vintages. The seismic reflection shows some multiple targets below the existing objectives. Based on this seismic signatures, 2 (two) wells drilled in Lengowangi and South Bungoh prospects and successfully found hydrocarbon from Ngrayong, Lower Ngrayong and Upper Tuban Formations. Those two discoveries contributed to the increasing reserve to 126 BCFG and 10 MMBO. In order to increase the resources, some methods to enhance improved subsurface imaging had been applied. The existing 2D Seismic survey has been reprocessed using pre-stack time migration in order to image the subsurface better and converted to depth domain seismic section. The processing result shows the strong reflection and predicted as the potential basement as of could be defined as the Kemandung Ridge which is extend on the NE - SW direction. Overlying this ridge, the seismic signatures show the reflection build - up that interpreted as carbonate from older formation of Ngimbang or Kujung Formations. Carbonate build - up extend NE and SW follow the Kemandung Ridge direction. This Ngimbang and Kujung Formation objectives will become the future target and believe will increase the resources of East Tuban Block.