Pre-treatment by disk filtration to remove algae followed by microfiltration to remove fine solids; desalination by reverse osmosis
Surat & Bowen Basins, Queensland
Challenge Santos, one of Australia's leading producers of coal seam gas, is exploring and developing a number of sites in Queensland's Bowen and Surat Basins. Vast volumes of water known as 'produced formation water' are displaced during coal seam gas production. Strict Queensland Government regulations govern the disposal of this water. Total Dissolved Solids (TDS) in the water can vary by a factor of 10 or more from well to well. Desalination by reverse osmosis (RO) is necessary before the water can be discharged or reused. Adding to the challenge, typically the flow rate of the water from a coal seam gas well is at its greatest immediately after commencement of gas extraction and gradually reduces over the life of the well. Santos required a water treatment solution that was flexible enough to be moved to different sites to maximise the efficiency of well operation.
Solution While some of Osmoflo's desalination plants are mounted in tailored containers, some equipment such as storage tanks or parts of pre-treatment systems is usually provided as permanent civil works. In an Australian first, Osmoflo designed this system so that on site civil works would be minimal. All equipment essential to plant operation including tanks, control rooms and even a small office, is located within containers, some with curtain sides for easy access to equipment and chemicals. Quick release hose fittings for all process water and inter-connecting chemical lines, retractable cable trays, industrial plugs and sockets for all supply & controls mounted within recessed panels thus ensuring all equipment is flush with containers for ease of transport. Capable of treating 1,500 kilolitres of water a day, the plant's initial location is at Roma. The pre-treatment system has been designed to remove algal blooms which occassionaly occur in the dams where produced water is stored and includes disk filtration and microfiltration. Operating at 85% recovery, the RO desalination plant operates in two or three stages depending on TDS content of the feed water. A full scale simulation of the entire system was run at Osmoflo's Burton facility to fine tune operational issues prior to delivery. Treated water can be released for irrigation, environmental flows or reused as process water.
Result Santos has a unique Australian first - a fully relocatable RO desalination plant capable of treating water of varying quality and salt content. This plant can be decommissioned from one site, relocated to another and be fully operational within five working days.
Santos is a leading Australian oil and gas exploration and production company. It is one of the CSG indutry's most experienced operators.