Fractures Identification and Reservoir Characterization of Gas Carbonates Reservoir from Merbau Field, South Palembang Basin, Sumatra, Indonesia

Ricky A. Wibowo¹, Wisnu Hindadari², Parada D. Silitonga¹, Rusalida Raguwanti¹, and Syamsu Alam^3
1EPTC - Upstream, PT PERTAMINA (Persero), Jakarta, Indonesia
²Sub Surface, PPDT, Bekasi, Indonesia
³Exploration, Pertamina Upstream, Jakarta, Indonesia

Merbau gas field situated on the southern part of South Palembang Basin at Sumatra Island, Indonesia. The field was discovered in 1975, but the delineation wells were drilled in 80’s. Recently, to support the high gas energy demand in vast growing economic area of Java and Sumatra, the South Sumatra Gas Project developed the field to fulfill commitment of 300 MMSCFD supply to energy demand of industry.

The gas project in the Merbau field has drilled 10 (ten) development wells already with significantly increase the calculated reserves. Application of borehole images data on two wells (MBU#6 and MBU#BA3) clearly show that fractures were developed and influenced the capacity of gas production of each well. The carbonate reservoirs in the field are heterogeneous laterally and vertically. The fault intensity were also produced several fractures that enhance the permeability and productivity of gas such as at MBU-4A and MBU-8. A further detailed sedimentary and structural study of borehole images data is thus required, including detailed facies and secondary porosity identification, and structural controls of carbonate reservoir layers in the field.

The determination of fractures density and orientation, porosity distribution of carbonate facies, altogether with seismic inversion and interpretation were proved as the main tools to help next development well location and reservoir zones.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas