Geology

Sabah has a proven petroleum system, within the Miocene-Pliocene fold and thrust belt, that is the location of numerous hydrocarbon discoveries and multiple producing fields.

The uplift in quality provided so far by the Sabah MC3D multisensor broadband seismic data, has allowed clear delineation of the seismic facies within the complex Miocene-Pliocene fold and thrust belt.  The deeper sections below the fold and thrust belt have been clearly imaged for the first time, enabling a better understanding of the basin development and deeper targets.

The Sabah Fold and Thrust Belt

The Sabah fold and thrust belt is an established circum-Borneo play with multiple commercial oil and gas fields located in this proven prolific geological province.

The thrusts likely formed from the combination of two geological processes. Firstly, as the result of subduction of the Dangerous Grounds beneath continental Borneo. Secondly, due to large-scale gravity sliding where up to seven kilometers of Miocene and younger clastic sediments were rapidly deposited via river deltas to the Sabah shelf and shelf-edge area.

To date, most of the exploration and development of hydrocarbon resources has taken place along the crests of individual thrusts within the inner fold-belt, however, the outer thrust-belt and inter-thrust areas remain largely unexplored. By studying current day geological processes acting on the seabed, it can be observed that sand transportation is achieved by straight turbidite channels that dissect thrusts and terminate as distal turbidite fans that pond in the inter-thrust areas. The new Sabah GeoStreamer 3D seismic data reveals that the same geological processes also occurred in the past and QI investigations imply the possible presence of hydrocarbons in these ponded turbidites.

The Sabah MC3D ensures that the Sabah fold and thrust-belt will remain a highly attractive oil and gas province for hydrocarbon explorers for many years to come.

Sabah fold and thrust belt
The current day seabed over the Sabah fold and thrust belt displays the syntectonic nature of the thrust-sheets while sand deposition occurs principally by turbidite channels and ponded distal turbidite fans.

 

Sabah Trough and Dangerous Grounds

Across the Sabah Trough and in the area of the Dangerous Grounds the new seismic reveals numerous potential prospects, many with direct hydrocarbon indicators (DHI) similar to that of a recent discovery well.    

3D Miocene carbonates
Superior resolution of untested top Miocene carbonate structures.

The high-quality broadband seismic images reveal, with rich clarity, the pre-rift and syn-rift sediments in multiple prospective basins. Basin opening carbonate and clastic plays are strikingly presented in 3D, offering a rare opportunity to observe complete petroleum systems, from deep-seated source rocks and migration pathways to potential reservoirs and competent seals. 

Closures at the carbonate build-up level are believed to be the same play targeted by the Tepat-1 well. Other potential basin opening leads include syn-rift and pre-rift clastics that exhibit typical extensional regime tectonics with tilted fault-block geometries. These clastics are thought to provide the main source rock interval for the area and additionally serve as potential for continental to shallow marine clastic reservoirs.

Shallower in the section, Miocene-Pliocene basin-floor fans are observed to trap stratigraphically against the outer most thrusts faults or display subtle roll-over anticlines, with only a short and direct migration path from the rifted kitchen depocenters.