Produced Water Faces Tougher Regulatory Environment
Produced water is one of the largest by-products from the oil and gas production process and is under increasingly stringent environmental regulations.
Very little of this water is actually left on the surface. Figures from the Produced Water Society show that of all the H20 produced by the oil and gas industry in the United States, just 5 percent is discharged into surface waters.
Much of the produced water (65 percent) is injected back into the producing formation, while 30 percent is placed in deep saline formations.
Thanks to the recovery of unconventional reserves and carbon reduction targets, natural gas is looking to be one of the greatest sources of energy in the years to come. In response, the oil and gas industry is always searching for new ways to treat or utilise natural gas and drive down costs.
Coal Bed Methane Water Management
In recent years, coal bed methane (CBM) has emerged as a major domestic source of energy in the United States.
As the process often involves pumping water from the coal beds to release gas,
higher levels of waste can be produced as opposed to other methods. Coal beds are also likely to contain large numbers of pores and fractures which are capable of storing water.
While there are many possible uses for produced water, they are all highly regulated.
In a report on coal bed methane production in Colorado, Wyoming, Montana, New Mexico, Utah and North Dakota, the National Research Council of the National Academy of Services identified why the industry has been placed under increased scrutiny in terms of waste water.
Due to rapid and relatively new development in certain regions, there has been little time to assess the environmental impact.
Applications for waste water considered in the report included site-specific irrigation and concluded that further in-field study was needed to judge the impact of produced water from coal bed methane on water chemistry and ecological effects.
Furthermore, the report said efforts should be made to make better use of produced water resources. Currently, produced water is considered only fit for reinjection through water treatments however regulations make this method unappealing.
"Careful management of non-renewable 'fossil' water, after extraction, for best non-renewable resource use should be considered a priority," the report said.
Developments in Treatment of Produced Water
Among those looking to enhance their operations through treatment of produced water is Petroleum Development Oman (PDO).
The company has recently embarked on a pilot project in collaboration with Japan Cooperation Center Petroleum (JCCP) and Sultan Qaboos University, which will use both chemical and mechanical methods to treat produced water for use within enhanced oil recovery.
Although the project is currently only in the pilot stage, if it proves successful, PDO plans to enact it on a larger scale. The plant will be capable of treating 50 cubic-metres of produced water per day.
Raul Restucci, managing director of PDO, said, "The production of oil often leads to the production of water that is too saline for human consumption and is polluted by chemicals and oil."
"The issue has gained more significance at PDO in recent years because as our fields mature, more water and steam injection is required, and the volumes of produced water increase accordingly," he added.
Morihiro Yoshida, managing director of JCCP, also said, "Development of appropriate water treatment technology would augment scarce water resources as well as protect the environment. The processes on which this pilot plant is based comprise a promising system for such water treatment."