Comet Ridge samples Betts Creek coal

COMET Ridge has conducted an extended production test at the Gunn 2 well in the Gunn project area in central Queensland to provide information to test the completion methodology for a full pilot scheme and to obtain good quality water samples from Betts Creek coal.

Lou Caruana

The GPA is approximately 90km north-northeast of Aramac, 570km northwest of Gladstone and immediately west of a number of the very large proposed Galilee Basin coal mines which are located on the eastern edge of the basin.

During December 2012, surface facilities including water storage tanks, flowlines, metering facilities and power generation were installed onsite and very early in the March quarter these facilities were commissioned for operation.

The well had been perforated over a 4m interval from 952.5m to 956.5m which is bounded above and below by impermeable mudstone.

The EPT was designed in this manner to ensure water would only be produced from the Betts Creek reservoir coal.

By excluding water from other zones in the well, surface water handling requirements could be optimised and dewatering time could also be minimised.

The downhole pump was started on January 11, 2013 to commence the EPT.

The pump and other equipment performed as designed with no mechanical or electrical issues throughout the test.

The water rate was progressively increased over a period of a few weeks, with the well reaching a stabilised production rate of approximately 400 barrels of water per day, which is the limit of the pumping system under the current configuration.

Analysis of the pressure data showed that the 4m coal interval, which was the subject of the test, has even greater flow capacity.

Formation water samples from the coal were taken at regular intervals for very detailed laboratory analysis.

‘The progress of the EPT has been extremely pleasing, with this well an important milestone for the company in the Galilee Basin,” Comet Ridge said in a statement.

“This is the first test for the company on a completed well, where the well has been set up for long-term production.”

Another very important outcome from the EPT is that the simple completion style of the well (case, cement and perforate) has proved to be extremely effective in both connecting the wellbore to the fractures in the coal and also in isolating the coal from sandstones.

The design can subsequently be applied to a pilot scheme to access selected coals.

Comet Ridge is evaluating different methods of water treatment and plans to conduct a simple field trial at Gunn 2 during the current quarter.

The trial will form the basis of the design for the pilot scheme in the Gunn project area with the intention of achieving independently certified gas reserves, which would be available to power, LNG or domestic gas markets.