The Barito Basin is the oldest carbon basin in Kalimantan with an area of around 70,000 square km and classified as a mature basin.

It is located in South Kalimantan and until 2000s more than 80 wells had been drilled for exploration and delineation by NKPM, BPM, SHELL, PERTAMINA, CONOCO, PEXAMIN, PHILLIPS, TREND ENERGY, AMOCO, TRIDENT, and PERMIN TRACER. The drilling activity resulted in one large field (Tanjung production), five small fields (Kambitin-Bagok-closed, South Warukin-production, Warukin Tengah-production, Tapian Timur-production and South Dahor-closed), and one structural discovery in the Tanta well that have been produced (Surantoko et al, 2000).

The stratigraphic of the Barito Basin are based on unconformity boundaries, namely The Cape Formation is divided into Upper Cape and Lower Cape in the Middle Eocene, The Berai Formation is generally divided into Upper Berai, Middle Berai and Lower Berai, The Warukin Formation is divided into Lower Warukin and Upper Warukin, and Pliocene formations.

The proven source rock in the Barito Basin originates from the Tanjung and Warukin Formations. Bedrock formation in the Barito Basin started emitting carbon at 9 ma. The potential volume of carbon content that can fill traps in the Barito Basin reaches 1656.36 MMBO. Hydrocarbons migrate vertically through fault channels and laterally through reservoir layers. The reservoir rock-bearing formations are the Lower Tanjung Formation, the Lower Berai Formation and the Warukin Formation. Based on test data, the reserve cut-off value of the Lower Tanjung Formation is PHIE more than 11 percent, Vsh less than 43%, the Berai Formation PHIE more than 5 percent, Vsh less than 35 percent and the Warukin Formation Phie more than 12.5 percent with Vsh less than 45 percent. Petrophysical characteristics taken into in this study include the Lower Tanjung Formation reservoir thickness of 69.5 - 104 feet and effective porosity of 14.2 - 16 percent, in the Berai Formation the thickness of the reservoir is around 21.5 - 423.5 feet while the effective porosity is 3 - 16.9 percent, Lower Warukin Formation, reservoir thickness 13 feet - 466.5 feet with an effective porosity of 17.2-25.8 percent. There are three candidate seals in the Barito Basin such as the Upper Tanjung Formation, the Upper Berai Formation and the Upper Warukin Formation. Two types of traps are in the basin are anticline and stratigraphic traps. Based on the analysis, the success of exploration wells in the Barito Basin is associated with two geological factors are structural (fault zones) and stratigraphic traps (coral limestone). For the fault zone around the Meratus Mountains while those far from that place using stratigraphic traps.