Marginal Field Development Strategy, Kartini Field, Offshore Southeast Sumatra

Abstract

Kartini field was discovered in 1977 and was followed by the drilling of three delineation wells. The reservoirs are fluvial sandstones of the Gita member, Talang Akar Formation that contain gas, oil and water. Kartini-1 and −2 tested at 4,485 BOPD and 2,944 BOPD, respectively. Trapping is created by combination structure and stratigraphic pinch out along the channel edges. In 1992 the initial plans were to develop the field by installing a 9-slot platform and drilling 8 development wells. The well locations were based on 2-D seismic and un-migrated 3-D seismic data. The first two wells were drilled in the field and resulted in uncommercial wells. Maxus ascertained that the development risk was high and put the field's development on hold. Subsequently the seismic data was migrated which allowed Maxus to utilize the seismic attributes in conjunction with a new geological interpretation to remap the main productive reservoirs. During this hiatus period, Maxus's experience with caissons progressed from a simple design with a maximum three wells without workover capability to the current technology allowing up to eight wells with workover capability. This improved technology results in significant cost savings and allowed the Kartini field to be developed economically. In addition to the deviated wellbores, three horizontal wells will be drilled and are designed to drain reserves from thin oil-bearing sandstones that would be uneconomic otherwise. Based on new seismic and geological interpretations, installation of a low cost Guardian structure, and utilization of horizontal wells, Kartini field was developed as an economic field with production beginning in October 1998.