Seria Field, Brunei: 80 Years On - Near-Field Exploration Going Strong

Abstract

This article, written by Senior Technology Editor Dennis Denney, contains highlights of paper IPTC 15199, ’The Seria Field, Brunei: 80 Years on, Near-Field Exploration Going Strong,’ by John Church, SPE, and Bong Poh Yuk, Brunei Shell Petroleum, prepared for the 2011 International Petroleum Technology Conference, Bangkok, Thailand, 15-17 November. The paper has not been peer reviewed. [Note: Conference rescheduled to 7-9 February 2012.] Copyright 2011 International Petroleum Technology Conference. Reproduced by permission. The onshore Seria oil field in Brunei was discovered in 1929 and has produced more than 1.1 billion bbl. The field still has a large near-field-exploration (NFE) portfolio of undeveloped reservoir blocks on the northern flank. These blocks, under the shallow marine surf zone, have been difficult to access because of the very shallow water and shoreward-dipping nature of the fault blocks. However, the Seria North Flank (SNF) project has begun to unlock these volumes by implementing the fishhook-well concept, allowing these opportunities to be developed from land. Introduction The Seria oil field is a complexly faulted anticlinal structure with hydrocarbons trapped behind fault/dip structures in stacked deltaic sediments. The field straddles the coastline, with the northern half of the field offshore under shallow water. Early oil production was dominated by wells drilled on land. Production peaked at approximately 120,000 BOPD in 1956. The field production declined throughout the 1960s and much of the 1970s. Since 1990, the field has been producing approximately 20,000 BOPD. The northern flank of the Seria anticline was known to hold hydrocarbons, but the shallow surf zone made drilling rig access problematic. Poor-quality seismic data had limited development activity. Several penetrations had been made by use of deviated wells drilled from shore, which passed orthogonally through the shoreward-dipping fault blocks with only limited and suboptimal reservoir penetration. The potential was known, but underexploited. SNF Project (2004–09) New high-resolution 3D seismic over the shallow marine surf zone was acquired in 1998 that identified a large number of undrilled blocks on the north flank of the Seria anticline. Exploration drilling began in 2004, with the discovery of the first block on the SNF. Follow-up drilling led to further discoveries in adjacent blocks in 2005 and 2006.