HORIZONTAL DRILLING AND COMPLETION FALL SYMPOSIUM
Denver, Colorado, October 23, 2012
Niobrara Water Use and Reuse
At the Horizontal Drilling and Completion Fall Symposium in Denver, John Jaffee, the Water Manager for Anadarko Petroleum Corporation’s Rocky Mountain region operations, gave a presentation on the Niobrara Wattenberg Field’s water treatment plan. His presentation focused primarily on water use in shale play horizontal slickwater fracing and water sourcing challenges.
Jaffee started his presentation by explaining that the same general rules for drilling a vertical well apply to horizontal drilling, except horizontal wells require more water and larger production casings. Each horizontal well operation requires a total of 48,000 to 120,000 barrels of water, as opposed to 2,400 to 24,000 barrels for each vertical well. “Slickwater” refers to fracing solution that contains surfactants, which decrease surface tension, thereby increasing the fracing rate into the formation. Hydraulic fracturing (“fracing”) injects highly pressurized frac fluid into the wellbore to create small cracks or fractures in the shale formation. These cracks release hydrocarbons such as oil or gas trapped within the formation. Water is the most effective frac solution solvent because it is inert. Approximately 20% of the total water injected into a formation returns to the surface as flowback. Multiple layers of cemented steel casings in the wellbore protect ground water from the migration of injected frac fluid, returned backflows, and hydrocarbons.
Jaffee next addressed water-sourcing issues in Colorado. Slickwater fracing is a completely consumptive use because flowback is briny and contains too many frac fluid contaminants to allow the water to return to the water cycle. While fracing consumes only 0.08% of Colorado’s total annual water use, many communities are sensitive about sourcing water to oil and gas producers because fracing is controversial. Accordingly, industry considers community sensitivities when sourcing water.
There are currently many water sourcing limitations. For example, in Colorado, different types of water sources implicate different laws, regulations, and water availability. Almost all surface water supplies in Colorado are over-appropriated. Tributary well water withdrawals affecting an over-appropriated stream system require augmentation plans. Designated basins are rapidly depleting and the state is currently in a drought. Therefore, while fresh water is preferred, Anadarko entered into a five-year water lease for effluent water from a municipal waste treatment facility.
Jaffee then explained that water-transporting issues are also very controversial. Onsite water storage systems are difficult to deliver and manage because each platform requires up to 900 truck trips for water delivery and waste removal. People criticize the fracing industry for the cumulative impacts of its noisy, high-volume, big truck traffic because it causes severe road damage, consumes excessive amounts of fuel, and increases carbon emissions. Moreover, winter compounds these problems. Iced-over roads complicate travel. Stored water freezes and expands, requiring complicated heating mechanisms. Accordingly, Anadarko is exploring alternatives to onsite storage.
Recently, Anadarko installed twenty miles of 24 in. diameter high-density polyethylene pipe through the heart of its operations to deliver water directly to the Wattenberg Field. Their onsite gathering system supplies water at an effective fracing rate of 60 barrels/minute (“fracing rate”), utilizing a pressure-rated mine hose. This change significantly decreased truck traffic and water stored onsite. This system, however, still requires large vessels for post-fracing storage and requires enough horsepower to deliver the water at a fracing rate along the length of the entire system.
Anadarko is also investigating enclosed ferrocement storage systems. These modular containment units consist of grout walls built around gravel where the porosity of the grout holds the water in place. This method prevents the contaminated water from evaporating, is inexpensive, and has a sand filtration effect.
Jaffee summed up by noting in 2011, Anadarko recycled 95% of its total flowback water from the Wattenberg Field. Although Jaffe did not spend much of his presentation on water reuse or recycling, he discussed preventative measures Anadarko is taking and investigating to address current water issues in this industry.