Mature oil fields are a reality that producers world over have to wake-up to every morning. Newer technologies, scientific methods and new areas of study may all facilitate oil recovery from ageing wells, but never reverse the ageing process.
One of the major problems a mature field throws up is produced water. At 98% of the total waste generated, produced water stands as the largest waste on an oil and gas field. The Produced Water Society, formed in the US, recently made a presentation in Oman aimed at understanding the problem the gulf state faces owing to its large percentage of mature assets. A conference in Muscat discussed various cost-effective methods for handling the waste, which is not only useless, but also toxic.
According to the Produced Water Society, the treatment of produced water is a major component of the overheads involved in producing oil and gas. Wells may start out producing little water, but sooner or later all oil wells produce a much larger volume of water than oil. The ability to efficiently and economically dispose of this water is critical to success in the oil production business.
A mixture of performance standards for disposal processes and regulations limiting discharges mandates the standards for treatment of produced water. Produced water can be used as a source of water for waterfloods or pressure maintenance projects. If reuse is not an option, produced water is disposed of by discharge into the sea or injection under ground.
Standards of treatment for reuse are set by industry technical organisations, such as the American Petroleum Institute (API) and its member companies, the Oil Producers Association (OPA) and other industry groups. Standards for produced-water disposal are determined by state, national and international regulatory bodies.
One of the widely accepted definitions of produced water is the brine brought up from the hydrocarbon bearing formation strata during the extraction of oil and gas, and can include formation water, injection water, and any chemicals added downhole or during the oil/water separation process.
According to industry insiders, produced water in places like Oman has reached up to 80% of the fluid extracted. The disposal of this water is becoming a mammoth task, as in the Middle East the water has to be disposed onshore, unlike the North Sea, where it is disposed of into the sea/ocean after treatment.
Onshore disposal of produced water is a lot tougher, as regulations are more stringent. The disposal is also energy intensive. The water has to be pumped back into the ground after it has been processed until it contains only five parts per million (ppm) of oil.
The core of this problem is absence of cost-effective technology for the environmentally friendly disposal of water. However, Singapore may well provide the technology that the Middle East needs. As a country, Singapore fought its way from being water-starved country to one that is self-sufficient in its water needs solely through effective recycling.
Keeping in line with its ‘clean water solution provider’ image, a group of Singaporean companies, as part of an environmental services mission, has been visiting Middle East producers offering technologies to solve oilfield and water-related problems. Dayen Environmental is one of the companies with a technology to solve the produced water problem and has entered the Middle Eastern market to provide the much-needed technology to oil producers.
Though many large companies are offering various methods of water purification, Dayen believes it will make a mark as its process offers low-operative cost. Dayen is well-recognised in water treatment and solutions in the Middle East as well as in China. While working on a sewage treatment plant Dayen came across the challenge that producers are faced with to dispose the produced water cost-effectively, given the increase in the quantity with every operation.
Dayen worked with a team of scientists in Singapore to come up with a customised treatment process for produced water. The result of the research is a novel treatment process, which combines electrolytic treatment with physical separation – under the umbrella of a technology termed Decore and Poreflon.
“With our technology we can reduce the oil content in water to almost one ppm, while the need is only five ppm for safe disposal. I am confident we are the only ones who can reduce the content so effectively and drastically,” says Ang Kwee Huat, director, Dayen Environmental Limited.
Dayen has a pilot plant at an oil field in Middle East and has carried out successful pilot operations.
“We are awaiting patent, and since our technology is cutting-edge, we do not wish to give much details but we believe that in a few months, the result of our research will become evident,” he adds.
Ang says that traditionally produced water was used to flood wells to get out more oil or used for enhanced oil recovery. But today with polymers serving better purpose, the water is disposed into another well, dug for this purpose. The produced water must be pumped 700-800 meters into the ground for safe disposal. The energy used for this pumping is obviously saved with treating the water with the Decore and Poreflon technology.
The treated water can be put to a number of uses like irrigation for bio-fuel crops, salt-tolerant poplar forest and in production of mineral products, claims Dayen.
Treatment of produced water is the Dayen’s first step into the oil and gas business. However the company believes that this step has been taken at a time when the industry is hard-pressed for technology and as representatives of Singapore, the country which won the Stockholm Water award for 2007, Dayen believes it can make a difference to the oil and gas industry.
