Reservoir Geometry Identification of Reef and Carbonate Platform Deposits and Its Implication to Reservoir Quality Prediction Case Study of Baturaja Formation, Halimeda Field, South Sumatra Basins

Bagus, Dinawan¹; Ardianto, Candra Dwi²; Arham, M. Aidil³
¹ Geology, University of Pembangunan Nasional "Veteran"
² Geology, University of Pembangunan AAPG UPN Student Chapter Yogyakarta, Indonesia
³ Petroleum Geoscience, PT Medco E & P Indonesia, Jakarta, Indonesia

Halimeda Field is one of Hydrocarbon Field which located in South Sumatra Basin. It’s located in the central part of the Musi Platform, an area known for its gas production from the Baturaja Formation. The field lies on the southern rim of an elongate Pre-Tertiary basin high, the Bungur High, which trend NE-SW and transects the Musi Platform. This reservoir is composed of Early Miocene carbonates that are developed on a rugged basement terrain.

The production in platform carbonate in this field identified is still not optimum. Because of this term, need a geological understanding of reservoir to understand the condition of reservoir such as geometry distribution, and quality of reservoir for proper plan / method in the future development and production. The method that are being used in this study are depositional environtment interpretation by interval core data in reef and platform carbonate in Baturaja Formation. Understanding geometry and distribution of carbonate reservoir ny analisis from carbonate fasies map and distribution of reservoir by sequence stratigraphy correlation to determined the distribution of reef and platform carbonate. Core plug data is also help to determined reservoir that has good and excellent quality.

This study is using conventional core data from 4 well and well log data from 5 well. Conventional core data show that early Miocene Carbonate Baturaja Formation reservoir consist of highly variable carbonate succession. Callibration of wireline log data with sedimentological fasies interpretation allows subdivision of the carbonate into lithofasies on the basis of log response bedding scale and contained sedimentary fabrics. Core detail description was end up with 2 fasies group that are reef and carbonate platform fasies ( Friedman and Reeckman, 1982 ).

A correlation between Zeit Bay Field crude oil analysis and different rock samples had been performed to relate the crude oil to its proper source rock.

Anlysis carbonate fasies map based on sequence stratigraphy correlation and comparing with core plug data shown that excellent porosity and permeability not only in reefal fasies but also platform fasies. The process of diagenetic also influences formation of pore and destruction of pore. Reservoir characteristics indicate that platform fasies has oportunity to become good quality reservoirs. Laboratory analysis from core plug data result show the porosity range from 4 well 1,2 – 37,3 % and the permeability range from 0,01 – 2297 mD.

AAPG Search and Discovery Article #90155©2012 AAPG International Conference & Exhibition, Singapore, 16-19 September 2012