Mixing Oil and Water: Scenes from the Texas Oil Boom, Pt. 2
This post is the second in a two-part series from Monika Freyman, Manager in Ceres’ water program on hydraulic fracturing, water resources, and energy development. Read part one here.
This blog is also featured on www.nationalgeographic.com
In the morning, we drove from Midland into sparsely populated, brush-dominated country. My colleague Ryan Salmon and I were on our way to see active drilling and hydraulic fracturing in Texas’ oil-rich Permian Basin. Ryan and I are preparing a report on the range of regional water issues associated with hydraulic fracturing and its water lifecycle, and as part of our research, we were going to see the process firsthand.
Hydraulic fracturing requires an immense amount of water infrastructure. From lubricating drill bits, to carrying loads of sand and chemicals to fracture geological formations underground, water is critical in every step of the process. Each fracturing site requires an estimated 1,500 truckloads of equipment and water, and each site produces a large amount of wastewater as a byproduct. From sourcing to final disposal, the water hydraulic fracturing lifecycle presents many challenges.
Some developers and water resource managers are responding to many of these challenges; however, there are two unique features of the fracking business model that potentially complicate the process. The first is that most operators primarily play the role of financial enabler and supply chain coordinator for drilling operations, but rarely do they conduct field operations themselves. Second, each contracted service provider has a billable time rate, be it a daily rate for a drilling crew or an hourly rate for a trucker to haul water. This distribution of responsibility and underlying economic urgency can work against the more measured and cautious approach to water management that many stakeholders endorse.
When we arrived at the drilling site, our first stop was to investigate the vertical derrick used to bore down into the earth. The derrick is used much like a construction crane, feeding long sections of pipe down into the wellbore where a drill bit cuts a hole into the earth below. Getting down to the oil-rich shale deposits buried deep underground is gritty and tough work.
When the well is drilled, a new team comes on the scene– the frackers. The large standing rig is replaced with a 15-foot high vertical pipe with connections for the chemicals, sand and water used to coax oil out of the ground in the fracturing process. We walked by a crew that was disassembling pipes with special perforations that launched explosive charges, which created holes in the pipes deep underground and allows frac fluid to flow into the formation. From these perforations, the frac fluid is forced into the shale formation under extremely high pressure. This water, sand and chemical mixture creates fractures in the shale, allowing the oil, or in other cases natural gas, to flow.
Water usage varies, depending on the geological formation, technology used and type of well being drilled. The site we toured was a vertically-drilled well; however, through advanced drilling technologies, developers can also drill horizontally in order to open up additional deposits. A horizontal hydraulic fracturing well is estimated to use between 2-10 million gallons of water, while vertical wells like the one we toured uses only about 10-20 percent of that amount.
The water at this site was also recycled. This process greatly reduces the water footprint of hydraulic fracturing operations, but according to technicians, recycled water can be trickier to work with than freshwater. In some of my preliminary analysis of regional water use, the Permian basin exhibits lower water use on a per well basis prompting me to investigate further if there are operational lessons to be learned.
The nerve center of the fracking operation is a trailer packed with technicians who constantly monitor the pressure and the mixture of chemicals, water and sand pumped into the well. The frac fluid is frequently tested and monitored to ensure that it has the proper viscosity, similar to a loosely-set Jello. This is an ideal consistency for pumping enough sand—up to three pounds per gallon of water—down into the oil-bearing formation. If the frac fluid is too “loose,” the sand falls out of the fluid and does not make it into the fissures.
In the photo below, the cup held up contains the frac fluid that was being assessed for proper viscosity.
After the fracking crew has finished and packed up their gear, the well is converted into a ‘Christmas tree’ of pipes, which bring up and contain the oil and “produced water” used in the drilling process. After so many weeks of intense activity, little infrastructure remains.
The final stop on our tour was a water disposal well. Some of the produced water from wells can be treated, but in other cases, water deemed too contaminated is injected deep underground. Deep well injection sites are a growing source of seismic concerns in several regions.
Oil exploration is expected to continue growing in the Permian Basin, despite the region’s limited supplies of freshwater and recent devastating drought. These conditions will put additional pressure on ground and freshwater resources and challenge oil producers to create practical solutions and take a more holistic approach to water management. In our forthcoming report, Ryan and I will analyze regional water challenges and also bring to light new models and strategies that are evolving to protect this most precious of resources.