What is Produced Water
Produced water refers to waste water generated during the production of oil and natural gas. Produced water contains a mixture of organic and inorganic chemicals, which are dissolved or in particulate form. The water itself may have started as fresh water, but can also come from non-freshwater sources such as brine.
BREAKING DOWN Produced Water
Produced water starts as water is often found trapped underground in impermeable rock formations, including formations that serve as reservoirs where oil and natural gas is found. When a well is drilled during exploration, this trapped water can enter the reservoir. Because the water was not intentionally injected it is considered formation water.
This water will mix with any chemicals used during the drilling process, as well as with the oil and natural gas. Another way produced water is created is through the intentional injection of water into a reservoir to aid in the recovery process. This water may contain chemicals used during the production process.
When oil and natural gas are extracted from the well, production water that makes its way into the production zone will also be extracted. This water has to be dealt with. Produced water represents one of the largest waste streams in production.
When it's created during offshore extraction operations may be discharged into the open ocean, where it becomes diluted by seawater. Because onshore operations do not have a large body of water to disperse produced water, waste must be treated. Most regulatory bodies place limits on the chemical composition of produced water being discharged.
Wells that are nearing the end of their productive lives may contain a large proportion of produced water relative to oil equivalents. This is because produced water has been continuously injected into the reservoir in order to aid in resource recovery, and as the amount of available resources diminishes, the reservoir becomes predominantly wastewater.
Produced Water in the news
Produced water has found itself in the headlines in recent months, as the Trump Administration's Environmental Protection Agency has sought to explore potential ways to loosen rules around its disposal – and potential repurposing
In May 2018, the EPA announced that it is launching new study that "will take a holistic look at how EPA, states and stakeholders regulate and manage wastewater from the oil and gas industry."
A press release announcing the new research explained that with the volumes of wastewater are generated by the oil and gas industries "will only increase" but that most of the produced is currently disposed via underground injection, "where that water can no longer be accessed or used." The EPA noted that stakeholders have asked "whether it makes sense to continue to waste this water, particularly in water scarce areas of the country, and what steps would be necessary to treat and renew it for other purposes."
EPA Administrator Scott Pruitt said the study "will take into consideration the expertise of states and stakeholders in developing effective options and alternatives to better manage wastewater from the oil and gas sector."
The agency quoted New Mexico Energy, Minerals and Natural Resources Department Cabinet Secretary Ken McQueen, who noted that in that state's arid environment, "conserving our resources by recycling produced water for more beneficial uses presents a significant economic development and water supply opportunity.
"For years New Mexico has advocated recycling of produced water in oil and gas completion activities," he added. "Continued collaboration with EPA on this issue will no doubt encourage even greater recycling and additional reuse opportunities."