Buttress-1 site: production
The Buttress-1 Well
The well was drilled in 2002 with the intention of producing natural gas. When it was found rich in CO2 it was decommissioned.
Production well tests to confirm suitability as the production site for the Otway Project were carried out by CO2CRC in June 2006.
Gas Processing and Compressor
When the Buttress‐1 well tests revealed a higher methane (CH4) content (20%) than expected (7% to 15%), the initial purification plant design to purify the extracted gas (to a 97% CO2 stream) was decommissioned. It was established that injection of this Buttress gas mixture (approximately 80% CO2 and 19% CH4) would not compromise the research objectives of the Otway Project. The confirmed absence of mercury and hydrogen sulfide (H2S) allows the injection of the produced Buttress gas straight into the depleted Waarre Formation, which already contains residual methane.
The Buttress production wellhead is connected to the Buttress-1 Surface Plant which comprises three different units:
- the process skid includes a ‘suction scrubber’ to remove free liquids, filters to remove solids and water bath heater to prevent hydrate formation;
- a small single stage reciprocating compressor overcomes pipeline pressure losses and provides additional pressure; and
- an after cooler limits the temperature of the process stream downstream from the compressor to fit pipeline temperature requirement (max of 50oC).