PetroleumBRUNEI awarded Block M to a consortium comprising ChinaOil USA (Macao) Co. Ltd (now known as China Sino Oil Co. Ltd), Valiant International Petroleum Ltd (now known as Triton Borneo Ltd) and Jana Corporation Sdn Bhd on 6 February 2006. The Block M Production Sharing Agreement was later signed on 28 August 2006 between the parties. On 21 September 2007, PetroleumBRUNEI appointed Tap Energy (Borneo) Pte Ltd (Tap) as the new operator for its onshore Block M.

Tap currently has a 39% equity interest in Block M. The remaining interests are held by Triton Borneo (36%), China Sino Oil (21%) and Jana Corporation (4%).

Block M covers an area of 3,011 sq. km. It comprises of onshore acreage relinquished to the Government at the end of 2003, as well as an area lying at the southern part of the Belait District. Block M has been explored since the beginning of the last century with the first successful well, Belait-2, drilled in 1913. The Belait-2 well produced a total of 33,000 barrels of oil between 1924 and 1931. Ten wells were drilled before the Second World War. Eight more wells were drilled later - Belait 11 to 14 in the mid 1950’s and Belait 15 to 18 in the 1970’s and 1980’s. Many of these wells were drilled in the Talingan area and encountered good oil and gas reservoirs. Nevertheless, a huge portion of Block M remains unexplored.

Seismic reprocessing of old seismic data and remapping work is underway to select optimal drilling sites and the first exploration well is expected to be drilled at the end of 2008. An airborne gravity and magnetic survey over the block will also be conducted in the third quarter of 2008. Both 2D and 3D seismic programmes will begin in the fourth quarter of 2008.