Petroleum Geology Conditions And Reservoiring Analysis, Malay Basin

Malay basin locates in center of the Sunda plate, which is one of the thickest tertiary basin in Southeast Asia. It has about 12.8×104km2 and quite abundant resource. Though the exploration and development lasted almost 30 years, most of the results which made by oil company are still not published, such as petroleum geology, reservoir characters etc. All of them are very scattered, up to now, no man research it systematically. Based on the base data , which provided by CNOOC, and mass document, we research on regional geology, tectonic features, basin evolution, oil geology, reservoir formed conditions, regularities of distribution, controlling elements, potential analysing and predict the advantaged area.Oil conditions are superior in Malay Basin: lake shale in early Oligocene and Eocene and deltaic river shale during Miocene. The former mainly contains formation K, L, M, the later is composed by formation I, H, F, E and D. The main reservoir contains river sand, deltaic-river sand in late Oligocene, braided-river sand during the late Oligocene and early Miocene, tide sand and neritic sand during the early Miocene and Medio-Miocene, river mouth and shore sand during early Miocene and late Miocene. The seal mainly grows in late Oligocene and late Miocene. Actually, many sandstones interbed with mud rock and shale, which may be as inner seal. Trap styles in Malay basin are tectonic trap and stratigraphic- structure trap. The main migration mechanism is lateral migration, especially the slope in northeast. In the centre, vertical migration is routine. The preserve condition is also quite well, overpressure benefits to the conservation in many respects.Through analyzing the maturity and tectonic activities, we realize regularities of distribu -tion of hydrocarbon: the source rock in deep in north is in gas window, while source rock is shallow and mainly generate oil in the south owing to swell in late Miocene. So oil fields are discovered in southeast and center area, while gas fields locate in north and southwest.By analyzing the conditions , controlling elements and the history of exploration and devel -opment, we can get the conclusion as follows: the western in the Malay Basin has a better reservoir formed conditions and lacks enough studies. So it’s a better goal in the future. the lithologic-stratigraphic trap in the centre of the Malay Basin and Southeast are also favourable area, Nature gas will be discovered in deepwater zone.