Handil field is located in the swamp area of the present delta of the Mahakam River in East Kalimantan, Indonesia, in the central part of the Tertiary Kutei basin. The anticlinal feature was found by seismic work in 1973, the discovery well being drilled in April 1974.

An east-west fault perpendicular to the axis of the anticline (10.5 km long, 4.5 km wide) divides the field into two blocks of equivalent area. Areal closure is 35 sq km. Vertical closure increases with depth through the hydrocarbon-bearing section. Most of the 120 reservoir sands between 500 and 2,900 m are tidal to fluvial delta-plain sediments (middle to late Miocene). Most of them are oil bearing with a gas cap. Their types of deposition can be identified as channel fills, offshore bars, etc.

A high pressure zone is encountered below 2,900 m, where deeper prospects remain for investigation. More than 50 significant markers (lignite, carbonate streaks) are used to correlate the sand bodies. Vertically, the field has been divided into six zones corresponding to

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changes in environmental conditions and/or oil characteristics.

Isobath maps show a displacement to the southwest (approximately 2.5 km) of the top of the anticline from deeper horizons to surface. In the upper and shallow zones, hydrocarbons are found in the south block only, divided into smaller blocks by an east-west fault pattern. Daily production is 160,000 bbl. Cumulative production is 125 million STB (October 1978).

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