Publications

The South Makassar Basin’s present day shape is the result of a multi-phase geological history. After the accretion of the Argo plate to the Sunda land during the upper cretaceous, the area is affected by extensional regime during the Eocene, resulting in the development of horst and grabens of various orientations. After a period of sag, initially marked by the development of Oligocene carbonate platforms, the Miocene is a period of slow sedimentation in a starved deep water basin. The sedimentation resumes and accelerates during Sulawesi compressive phase in late Miocene time. In the area of interest, exploration activity during the last decades has been concentrated on carbonate reservoirs, located on basement highs. Available well results, together with regional stratigraphic marker maps have been used to realize a detailed 3D model at the basin scale. Crustal modelling has been implemented in order to take in account the variations of basement depth and nature together with the thermal implication of its rifting history. Thermal calibration was realized by comparing calculated temperatures and heat flows with 1) the values measured in wells, 2) direct heat flow measurements at sea bottom and 3) indirect heat flow values derived from bottom simulating reflector (BSR) mapping. Important lateral variations of heat flow are observed at sea bed. Thermal simulations demonstrate that these variations of thermal regime are best explained when lateral conductivity variations induced by basement high are introduced in the model. This complete description of the present day thermal regime and of its past evolution allows the derivation of maturity maps for different intervals of interest at the basin scale. This result can be used as a guide for further exploration in the basin. As an example South Sageri PSC will be used to illustrate the implication of this regional assessment.