Lembangan Enapan Senozoik Sarawak

Sarawak Cenozoic Sedimentary Basin (Part 1)

Sarawak Cenozoic sedimentary basin (Sarawak 'Greater' Basin) is one of the three important petroleum regions in Malaysia. It is located mainly in the offshore area of Sarawak. It also covers some parts in the onshore area.
The history and background of the Sarawak Basin (SB) in very much unknown. The earliest known document to use SB is an internal report prepared by Sarawak Shell Berhad (SSB) in 1971. The report does not defined what SB is, instead dividing it into several areas called 'Provinces'. The identified Provinces are Tatau, Balingian, Tinjar, Luconia and West Luconia. They are defined based on particular structural trap associated with hydrocarbon accumulation. Now, there are seven Provinces in SB.
In many maps, the extent of SB outline/boundary is somehow defined by the international border: Indonesia to the west, Vietnam to the north and Brunei to the east, except for the southern limit.
SB architecture is generally divided into three, one basement high (SW) and two depocentres located in the SE and NW respectively (Mat-Zin and Swarbrick, 1997).
The offshore geology is correlatable to onshore Miri Zone which mainly consists of Cenozoic sequences.
The offshore SB stratigraphy used 'Cycles' while onshore has rock formation names (e.g. Nyalau, Buan, and many more).

Figure 1– Sarawak Basin division of 7 geological provinces (tectonostratigraphically defined) (Madon, 1999)