COSL jack-up to drill Tambak wells offshore Indonesia

Coro Energy has issued an update on drilling plans for the Duyung production-sharing contract in the West Natuna basin offshore Indonesia, in which the company has a 15% interest.

The campaign will comprise one exploration well (Tambak-1), designed to test the Tambak prospect beneath the central area of the Mako gas field, and one appraisal well (Tambak-2), primarily investigating the intra-Muda sandstone reservoir in the southern area of the Mako field, also gathering stratigraphic data from the Lower Gabus interval.

China Oilfield Services Ltd’s jack-up Asian Endeavour 1 will drill the wells.

Tambak-1 well will appraise the Mako field’s central area and its intra-Muda sandstone reservoir, assumed to lie around 385 metres (1,263 feet) below sea level.

A full suite of wireline logs will be run before the well is deepened to test the Lower Gabus Tambak prospect beneath the base Muda unconformity. Planned TD is around 1,370 metres (4,495 feet) subsea.

Tambak is a three-way dip closed inverted anticlinal structure, around 15 square kilometres (5.8 square miles) in size.

The reservoir is prognosed to be early Oligocene-age fluvial and lacustrine sandstones of the Lower Gabus formation, and to be charged by the underlying syn-rift lacustrine source rocks of the Benua shale.

Potentially, the prospect could hold 250 bcf of gas.

Tambak-2 will be the most southerly test of the Mako field to date and will, Coro said, represent a significant step out from the Mako South-1 well, which is more than 13.5 kilometres (8.4 miles) to the north-east.

Gaffney Cline & Associates has assessed 2C resources at 276 bcf of recoverable dry gas in the Mako field with gross 3C resources of 392 bcf through additional field upside.

The Asian Endeavour 1 will soon mobilise for Singapore from the COSL yard in Shanghai, likely reaching the first well location in late September.

Source: Offshore Magazine