The Perth-based company said yesterday it had secured the Ensco-1 barge to drill the shallow-water appraisal well, with drilling expected to take one month to reach a total depth of 2900 metres.

Earlier this month, Cooper was forced to abandon its first Indonesian well, Kurnia-1, due to difficult hole conditions, but remained optimistic the prospect could one day deliver a commercial result.

Five other wells have been drilled to date on the Gurame gas discovery, all of which confirmed the presence of gas in a number of vertically stacked reservoirs.

Gurame-1X well is designed to further delineate the gas, demonstrate that it can flow at commercial production rates and acquire modern data from reservoirs for field development planning purposes.

Recoverable reserves for the Gurame field, in which Cooper has a 22.5% stake, are estimated to be between 400 billion cubic feet of gas and 20 million barrels of liquids and up to 2.7Tcf and 150MMbbl.

Cooper director Mike Scott said the well had a "high chance" of delivering a company-making addition to the company's portfolio.

"Following our recent exploration and development success in the Cooper Basin, Gurame-1X will add significant growth momentum to our company," he said.

"Importantly, this is a relatively low-risk appraisal well in a discovered gas field, which is designed to assist in maturing the substantial discovered but undeveloped recoverable hydrocarbons into development and then ultimately into production."

Gurame is located about 50km from the supergiant Arun gas condensate field and LNG plant and close to gas infrastructure and markets.