Subsurface oil field.
Up to 490 m thickness according to ref. 1244.
Mud rich.
16.5 % porosity.
Abstract ref. 1244:
Recent exploration activity in the Salawati basin, along the northwestern tip of Iran Jaya, Indonesia, resulted in significant oil discoveries. Reservoir and trap are provided by highly porous and permeable Miocene reef rocks which yielded oil at rates of up to 32,000 bbl/day from individual wells. The Salawati basin is a structural-stratigraphic basin containing more than 4600 m of marine Tertiary sedimentary deposits. The basin is bounded on the north by the Sorong fault zone which separates the Australian continental plate from the Pacific oceanic plate. Basin development was initiated in the Miocene when local downwarping and increased water depths resulted in the deposition of a basinal limestone and shale sequence in the area. Toward the east and south margins of the basin these sediments are replaced by shallow-water carbonate rocks which form a well-defined shelf and associated shelf margin. The productive reef belt is just basinward of the shelf and shelf-margin area. The reefs, which reach heights in excess of 490 m, range in areal extent from 5-124 km2. Porosities within the reefal carbonate rocks are as much as 43% and average 20-30%. Late Pliocene-Pleistocene normal faults which cut many of the reefs, combined with postreef structural tilt, modified considerably the original configuration of the reefs and the associated oil accumulations. The knowledge gained from the current exploration program concerning reef morphology, porosity variations, tectonic history, and other factors which control the oil accumulations should expedite future exploration efforts in the basin. The Foraminifera Globigerina, Globorotalia, Orbulina, Alveolinella, Marginopora, Sorites, Flosculinella, Rotalia, Elphidium, Cellanthus, Amphistegina, Operculina, Gypsina, Ammonis and Miliolids are mentioned, Coral, hydroxoan and algal (Amphilhoa, Lithophyllum, Aethesolithon, Corallina and Archeolithothamnium) debris are mentioned. 