The Tanggulangin-1 well, the first of a three-well program, discovered gas in several reservoir zones. A total of 33 meters net gas pay has been estimated from logs in the three shallow reservoir zones behind a 9-5/8-inch casing. The well also encountered additional reservoir zones with strong gas shows in the open-hole section (below the 9-5/8-inch casing). These lower zones have not been logged as the well encountered a strong gas influx at 916 meters and subsequently, due to engineering difficulties, the well has had to be plugged back. The section beneath the 9-5/8-inch casing is currently being abandoned in preparation for the well to be suspended. Pre-drill estimates are likely to be "significantly exceeded" since the well intersected three new reservoirs. In addition, the reservoirs are thicker than pre-drill estimates and, two reservoir units which were water wet in the adjacent Wunut gas field are gas bearing in the current well.
The company said preliminary estimates indicate around 40 billion cubic feet of reserves in the shallower section and that six reservoir units with strong gas shows exist in the lower, open-hole section, as far as it was drilled, indicating that further gas reserves are present, though as yet unquantified. After completing the Tanggulangin well, the rig is set to spud a well on the Carat prospect, located five kilometers south of Wunut. The third well in the drilling campaign is Grati-1, which will target Pilocene reservoirs in a fault closed structure with an estimated depth of 850 meters. Novus said the three wells are drilling the same play system as the nearby Wunut field.
Novus holds a 50% interest in the license together with partner Lapindo Brantas, which operates the field with a 50% interest.