Much has been said over the years about the Energy–Water nexus, meaning that it takes energy to develop water for consumption and it takes water to develop energy resources. Whether it is coal mining, copper mining, or oil and gas drilling, it seems that water and energy development must coexist.
At a recent Uinta Basin Oil and Gas Collaborative Group (UBOGCG) meeting held in Duchesne, the theme of the meeting was oilfield produced water. Several qualified speakers gave presentations on the management of water that is produced from oilfields in Utah during the process of extracting hydrocarbons from deep petroleum reservoirs in the Uinta Basin. The meeting was well attended, illustrating the interest garnered by the topic. For me, the meeting highlighted how little attention has been given in the past to putting this water to some kind beneficial use.
Oilfield water is produced in abundance out of petroleum reservoirs. For Utah oil wells, the production ratio of water to oil is 6:1 or higher – meaning that for every barrel of oil produced, there are six barrels of water. This is water that has remained in place with the hydrocarbons for eons, and it is generally brackish or mineral-laden, so for the most part it is unusable for human consumption or agriculture.
In the past, it has been a waste management problem for oil producers with most operators either disposing of the produced water or recycling the water for enhanced recovery operations or injection stimulation of oil production in other wells. But recycling has only accounted for a portion of the produced water and historically, much of it has been reinjected back into underground formations that already contain unusable water.
In Utah, there might be over 20,000 acre-feet of produced water that must be managed and/or disposed. If even a small portion could displace fresh water use in industrial or residential processes not requiring fresh water, then there could be great benefit by allowing fresh water to move toward other consumptive purposes.
There have been efforts in the recent past to characterize the quantity and quality of produced water, most relevant to Utah operators is the report by the Utah Geological Survey entitled “Produced Water in the Uinta Basin, Utah: Evaluation of Reservoirs, Water Storage Aquifers, and Management Options.” This report was described at the recent UBOGCG meeting, and it should serve as a valuable tool to the petroleum industry for operations in Utah.
Another study underway is being led by the Groundwater Protection Council (GWPC) based in Oklahoma City, Oklahoma, representing state government interests across the U.S. for groundwater regulation and protection matters. This study was initiated in July 2017 with a kickoff meeting in Salt Lake City and subsequent discussions in Oklahoma City; Boston, Massachusetts; and an upcoming meeting in Tulsa, Oklahoma. The purpose of the study is to provide the current regulatory landscape and state of scientific knowledge relative to produced water management and re-use. It is organized in three modules: (1) the legal and regulatory framework; (2) industry infield re-use; and (3) re-use opportunities outside of the oilfield. The leaders of the individual modules are proceeding to use subject matter experts to draft portions of the study that is expected for publication in early 2019.
Clearly, some of the best minds in the country are pondering this situation, and it is my greatest hope that better uses for oilfield produced water can be found for the benefit of all Utah citizens.