Publications

The North Belut Oil and Gas Field is located in the Block B PSC, South Natuna Sea. The primary hydrocarbon producing intervals are the Oligocene Udang and Gabus formations. Field development started in late 2008. Two production platforms were utilized, with a total of 60 well slots with 32 wells drilled to date. Produced gas is contracted to Malaysia. The Udang formation is characterized by an interbedded sand-shale interval comprising five subzones separated by shale breaks. Individual sand thicknesses range from a few inches to several feet. The Udang is interpreted to have been deposited in a deltaic environment, with thin distributary channel and associated mouth bar sands.. The critical production risks for developing the Udang reservoir were identified as vertical and lateral reservoir continuity along with porosity and permeability. To address these risks, conventional coring together with advanced logging tools such as multi-component resistivity and image logs were acquired in several wells located in the crestal area of the structure. Petrophysical analyses incorporating advanced logging tool data identified some previously unrecognized pay. This analysis together with mud gas data was a key to identifying pay intervals and determining which zones to perforate. Production logging tool data were acquired in some wells, and supported the interpretation that the additional pay intervals identified by the advanced logging tool were contributing to production. * ConocoPhillips Indonesia With the various challenges in accurately calculating porosity, Sw and permeability associated with the Udang reservoir, this paper will focus on the integration of data and petrophysical methods implemented to optimize the petrophysical analysis for reservoir characterization.