Not all produced water can be recycled or reused for other drilling operations. In some cases, the salt content of the produced water is simply too high. For example, regardless of the formation, current
hydraulic fracturing technologies require the use of relatively low salinity water. High salt content makes the injection fluid difficult to pump downhole, thus increasing the power requirements and resulting in higher volumes of chemicals needed to reduce friction.
State regulations also play a major role in the industry’s ability to recycle or reuse produced water.
Another factor that influences produced water management is wellsite location. For instance, in some areas of
the Haynesville Shale, well locations are widely spaced. Due to this distance, the creation and operation of a centralized treatment facility would result in higher volumes of truck traffic than that associated with the disposal of the fluid in a nearby saltwater injection well (SWD).
To reclaim produced water as a way to conserve water, we developed Aqua Renew® in 2006 as a logical evolution of our involvement with the Barnett Shale Water Conservation and Management Committee in North Texas. In addition, we also collaborated with the City of Fort Worth, Texas, to explore possibilities of recycling produced water.
Our Marcellus and Utica Shale districts now treat and recycle a vast majority of the produced water from our operations. At each Marcellus and Utica wellsite, produced water is collected and stored in on-site holding tanks before being transferred to central locations where suspended particles are removed through filtration or gravitational separation. The water is tested for salt and other mineral content to determine the rate at which it can be blended with freshwater to ensure proper quality and quantity for reuse by Chesapeake operations. It is then stored in on-site tanks or transported to the next well scheduled for hydraulic fracturing. This process has allowed us to filter and reuse 97% of the wastewater associated with our operations in the Marcellus North, 52% of the wastewater in the Marcellus South and 89% of the wastewater in the Utica district.
Although we still must mix recycled produced water with some incremental supplies of freshwater to ensure the proper mixture for hydraulic fracturing, every gallon of produced water we filter and reuse is one less gallon of water that must be trucked to a disposal well and one less gallon of freshwater we must purchase and use, making this a win-win for our bottom line and our environmental conservation efforts.
Aqua Renew continues to expand across our operating areas. While freshwater is the preferred fluid, we are experimenting with newer additives and higher concentrations of salt in our base fluids. In fact, several wells in the Mississippi Lime play of northwestern Oklahoma were hydraulically fractured using 100% produced water. Chesapeake is monitoring these wells to determine if any long-term adverse production impacts occur from this process. We also are exploring the use of brackish, nonpotable aquifers as potential sources for fracturing fluids.
Produced water includes water trapped in the producing geological formation, and is a byproduct of natural gas and oil extraction. Generally, this water contains various salts, sand and silt found naturally in the Earth and travels from the producing formation through the wellbore to the surface with natural gas and oil during completion and production operations.
Not all produced water can be recycled or reused for other drilling operations due to water quality and state regulations.