IMPLICATION OF RESERVOIR CHARACTERISTICS BASED ON OVERVIEW OF STRUCTURE AND SEDIMENTOLOGY OF OUTCROPS ALONG BINTULU-NIAH-MIRI AREAS

Abstract

Six-day fieldwork was conducted in the north-west coast of Sarawak to examine the outcrops along Bintulu- Niah- Miri areas which cover southern part of Balingian Province and Baram Delta Province. The aim of this fieldwork is to synthesize the observations of structure and sedimentology of outcrops along Bintulu-Niah-Miri areas and discuss the implication of reservoir characteristics based on observation. The study was conducted by sketching the main structural elements of outcrops followed by detailed sedimentological analysis which include observation and facies description were conducted on different outcrops along Bintulu-Niah- Miri areas using sedimentary logs. The findings show that Bintulu- Niah- Miri areas outcrops consists of mixed-environment deposited succession with tidal and wave characteristic. This resulted in reservoir architect will be different and result in different in reservoir properties included horizontal and vertical permeability of fluids. Niah Cave is a good place to study the distribution of the types of breccia due to collapsed paleokarst at reservoir scale and also good analog for Central Luconia Platform where large resources of hydrocarbon have been discovered due to the its environment setting or forming process is same as Central Luconia Platform. In addition, Miri Airport Outcrop succession consist of Type 4- Fracture Create Flow Barriers which could lead to potential production problems.