Introduction Kalimantan
In the last two decades of exploration activities in Kalimantan and Eastern Indonesia areas, the exploration campaign has found several significant discoveries with total hydrocarbon discovered around 12 BBOE. Generally, the play concepts have moved from classical target in the shallow zone to deeper targets and older ages. Unfortunately, most of the exploration activities have concentrated in the producing basins, only one activity conducted in non-producing basin, which is in the southern edge of the Aru Trough Basin-Malita Calder Graben which discovered hydrocarbon. Kalimantan area contains three Tertiary producing basins and four non-producing basins. Exploration activities in Kalimantan region can be grouped into three applied technology phases:
(1) traditional exploration,
(2) 2D seismic exploration period, and
(3) 3D seismic exploration period.
The activities also can be grouped into three exploration concepts:
(1) traditional play,
(2) Mio-Pliocene Deltaic system, and
(3) Mio-Pliocene Deepwater system.
Since the first 3D seismic run in Kalimantan, more than 370 exploration wells have been drilled; all of the wells were drilled in producing basins with average success ratio of 53%, and have been discovered around 6 BBOE reserves in place. The most promising play concept of the recent exploration in Kalimantan is Mio-Pliocene Deepwater sands of Kut ei-North Makassar Basin (West Seno, Gula, etc). Currently , the exploration in this area has applied CSEM technology to answer several pitfalls in interpretation. Eastern Indonesia contains five producing Tertiary basins and 33 non-producing basins. Almost all of the basins, mainly the producing basins, were explored by the seismic activities from 1967-2005. Most of them were triggered the discoveries of hydrocarbon fields. Discoveries in Eastern Indonesia can be grouped into three system:
(1) Miocene Carbonate System,
(2) Plio-Pleistocene system, and
(3) Mesozoic system.
There were more than 160 exploration wells drilled in the last two decades with average success ratio of 41% and discovered around 6 BBOE reserves in place. The most attractive and promising play systems are Jurassic Roabiba-Aalenian-Plover Play system (Tangguh & Abadi giant gas field), Jurassic carbonate play system (Oseil), and Miocene carbonate in collision zone play system (Tomori area). There are 57 PSC contract areas in Kalimantan and Eastern Indonesia, 41 of which contract area are still in the exploration phase. Most of the PSC areas are located in producing basins. High trend of the world’s crude oil price, high exploration success in Kalimantan & Eastern Indonesia and large new reserves discovered may boast hydrocarbon players to find next remarkable discoveries in both mature and frontier basins in Kalimantan and Eastern Indonesia area.
The exploration activity in Kalimantan has found 84 oil & gas fields in the Kutei Basin (~22 BBOE), 25 oil & gas fields in the Tarakan Basin (~1.9 BBOE), and 8 oil and gas fields in the Barito Basin (~0.82 BBOE). The evolution of the exploration activity is influenced by seismic activity. In the early exploration period from late 19th century to the 1960’s, exploration focused in the land of Kalimantan. Discoveries of the Lousie, Sesanip, and Tanjung Fields were in this period.
