The upstream oil and gas industry generates large quantities of produced water during exploration and production. We’re talking about 3 to 15 barrels of water for every barrel of oil.
The challenge for operators has long been what to do with all this water. The water generated is highly saline, which means it cannot simply be released into rivers and streams, and it is not suitable for fresh or waste water treatment facilities.
The question is: how can upstream oil and gas operators dispose of this water in a way that is cost effective, compliant with regulations, and environmentally sustainable? There are three ways that it can be accomplished currently, but only one creates the most positive, lasting environmental impact.
Currently, the majority of water generated by the upstream oil and gas industry is injected underground. Also known as saltwater disposal wells, this method entails placing the produced water deep in the Earth beneath the water table. About 90% of operators currently use saltwater wells to dispose of their water.
There are several problems with this method.
First, there are capacity limitations. There are only so many areas with the necessary geological formations and conditions where you can safely dispose of the water. Once a current well is full, you must find a new one to continue disposal.
The second is seismicity. There is a potential connection between high volume fluid injection and increased seismic activity. Areas in Texas, Oklahoma, and New Mexico have recently experienced higher instances of earthquakes potentially due to injection of produced water into SWD’s in the surrounding region.
The third is that the produced water is injected into the ground and essentially forgotten about when it may still have value to give us. In other words, the water byproduct could be put to further productive use. instead of sitting sealed deep underground.
That’s where the next two environmentally sustainable disposal methods come into play.
One alternative disposal method for produced water is treating it for further use in drilling and completions. Reuse involves removal of particulates (oil, TSS, bacteria), scale formers (iron) and dissolved gas (H2S). The way this process works is by using oxidation, flotation, and filtration technologies to clean the water and make it suitable for reuse in hydraulic fracturing completion operations.
Treatment for reuse is valuable, because it minimizes SWD injection volumes substantially and the water is put to further use, lessening the industry’s dependence on freshwater for oil and gas exploration and production operations.
The drawback for this method is that it is only cost effective when you have active drilling operations in close-by locations with access.
A reliable alternate solution for produced water disposal method from an environmental standpoint is treating it for discharge.
There are wide reaching benefits of treating water for discharge:
If the goal is long-term sustainability and minimize dependency on SWD then treatment for discharge is the best commercial solution for disposal of produced water. The highly saline water starts as a byproduct but can then be treated and converted into fresh water for further productive use in a way that meets regulations, is safe for the environment, and helps replenish water in areas where it may be scarce.
There are three principal technologies used to treat produced water for discharge into the environment. Which one is used depends on the level of salinity in the water measured as total dissolved solids or TDS.
New innovations are creating new opportunities for oil and gas producers to make a positive environmental impact. And the best part is that these new disposal methods don’t just make environmental sense from a long term sustainability and ESG standpoint, but also minimizes risk significantly for O&G producers. Instead of disposing of a potentially valuable resource through SWDs, treating produced water for reuse or discharge generates a new water source for beneficial use and reduces the stress on the natural sources for freshwater.
Huge volumes of water can be treated and disposed of in an environmentally compliant way and even create potential new revenue streams. The sustainable path forward is here!
To learn more about produced water reuse and discharge, check out our upstream oil and gas brochure. It explains all the details and how you can implement these solutions for your operation.