Historical exploration targets in the Balingian Province, Sarawak, have been focused on the oil plays in the pre-MMU (“Mid Miocene Unconformity”) Cycle I – III clastic plays. These plays are mainly lower coastal plain sandstones interbedded with shales and coals that are deposited in an overall transgressive setting. Since the first oil discovery of the Temana field in 1962, more than 6 billion barrels have been discovered in the Balingian province. After more than 250 exploration wells and an exploration success rate of around 65% (source S&P Global), the Balingian Province still has much more to offer and remains as one of the main hydrocarbon destinations for Sarawak.

In October 2023, PETRONAS announced the Malaysia Bid Round+ (“MBR+”) where the DEWA Complex Cluster was offered (these were formerly known as the D Cluster and Spaoh & West Acis fields) under the Small Field Asset (SFA) PSC. The DEWA Complex Cluster is comprised of 12 gas discoveries in shallow waters (40–50meters) near to the D35 and Bayan platforms and amalgamation hubs off the coast of Sarawak. The 12 fields can be further divided into 3 sub-cluster: the Danau Sub-Cluster (Danau, D30, D30W, Daya & Daya North), the Dafnah West Sub-Cluster (Dafnah West, D41, D41W, Dana) and the Spaoh Sub-Cluster (Spaoh, West Acis, Darma). Two fields namely the D30 and Dana fields have been previously on production. The D30 field, developed as an oil field, came onstream in 2010 but was permanently abandoned due to gas processing limitations at the D35 platform. At the point of abandonment, the field was producing around 15 mmscf/d. Dana was brought onstream in 2011 but was shut-in in 2014 also due to the rapid decline in oil production and the high levels of produced gas. The field was producing 8–12 mmscf/d of gas prior to being shut in.

Of the remaining fields, the D41 and Dafnah West (Dafnah West Sub-Cluster) and Danau (Danau Sub-Cluster) were also discoveries but were left undeveloped despite the encouraging gas accumulations that had been discovered.

As an example, the Dafnah West gas discovery, in the Cycle II & I fluvial and lower coastal plain sands found up to 84 m of net gas pay in two separate hydrocarbon columns; each consisting up to 97m and 40m of gas column respectively. Wireline logs have interpreted good reservoir properties between 19%-22% while formation pressure tests indicate excellent permeabilities up to 1.6D. The Danau field and its 2 wells found 3 pressure-connected gas-filled Cycle II hydrocarbon columns. An average flow rate of 10.5mmscf/d of sweet gas and 680 bcpd was achieved in one of the DST’s in Danau-2.

With the excellent reservoir development and quality of the Cycle I-III reservoirs as evidenced in the 35 well penetrations, coupled with the encouraging gas columns and their overall proximity to gas facilities, DEWA is in many ways a “hidden gem”. Our initial evaluations estimate that the DEWA cluster contains over 500 Bcf of undeveloped in-place gas (GIIP). Each of the three identified subclusters and nearby gas discoveries can be developed from a single platform, delivering potentially a production plateau more than 100 mmscf/d to nearby gas facilities.

This presentation discusses the potential of the DEWA area fields and the further hydrocarbon potential of shallow water Sarawak.

Seascape Energy Asia plc, an E&P company focused on Southeast Asia, and is a joint venture partner in the DEWA Complex Cluster PSC with a 28% participating interest holding. EnQuest Petroleum Production Malaysia Ltd is the operator with 42% and Petroleum Sarawak Exploration & Production Sdn. Bhd holds 30%.