Bulletin of the Geological Society of Malaysia, Vol 47, Dec. 2003, pp. 165-179
Sabah Shell Petroleum Co. Ltd., Locked Bag No. 1, 98009 Miri, Sarawak
Abstract: This paper discusses the geology and development of the L reservoir unit in the Kinabalu field, Sabah and includes a description of the innovative water injection scheme being implemented for pressure maintenance to sustain oil production. Kinabalu field, situated 55 km west-north-west of Labuan Island was discovered in 1989 by KN-1 well with a total pay counts of 1,043 ft NOS, 113 ft NGS and 310ft NHS. The field contains some 500 MMstb oil-in-place, developed in 1997 and to date some 50 million barrels had been produced. The gas and oil are transported by pipelines through Samarang facilities and then onwards to Labuan Crude Oil Terminal for storage and export. The major producing reservoirs in the Kinabalu field are K and L units trapping hydrocarbons against the Kinabalu Growth Fault.
The intercalated sands and shales of L reservoirs were deposited in a shallow marine environment during Late Miocene time (Stage IVD). Production performance and a very fast pressure drop in these reservoirs suggested very limited to no water-drive. Several options were investigated to provide pressure support to this major oil reservoir, including injecting seawater and dumping of shallower formation water. In the Kinabalu field, water is produced from the shallower sand bodies (B & C Sands) and injected into the L reservoir unit through two horizontal wells. To date a natural dumping rates up to 1,200 barrels per day are experienced in these wells and electric submersible pumps will be installed soon to increase the injection rate up to 20,000 barrels per day. Some 16 million barrels oil are expected to be extracted by this pressure maintenance scheme thus adding some two to four thousand barrels oil per day to the Kinabalu field production.