Full Life Cycle Approach Improves Water Management Economics
Sourcing water for the large-scale multifrac stimulations in West Texas shale formations, and the subsequent disposal of produced water in injection wells, can constrain the economics of hydraulic fracturing operations in the area. To help limit the costs associated with water management, operators must adopt an integrative strategy that addresses the full life cycle of a field, an expert said.
In a presentation held by the SPE Gulf Coast Section’s Waste and Water Management Study Group, Kristie McLin spoke about the challenges ConocoPhillips’ Permian unconventional water management team faced in developing a water management plan for Red Hills and China Draw, developing assets in the Delaware Basin. McLin is currently a senior advisor for supply chain sustainability at ConocoPhillips.
Located near the border of Texas and New Mexico, Red Hills and China Draw are stacked pay formations, with a water/oil ratio typically above 1:1 for each formation. McLin said that during the exploration and early development of the fields, minimal infrastructure was installed to support the water demand for completions and produced water disposal.
However, the minimal infrastructure was not an economically sufficient long-term solution. McLin said the company sought to develop a holistic water management program centered on the reuse of produced water for stimulation and the minimizing of the use of trucks to transport water to various wellsites. The goal of the program was to add maximum value to the field development plan by managing the water cycle in such a way that it helped ConocoPhillips meet its production targets.
“We needed to make sure that all the water was available for our operations on the day it was needed. We couldn’t hold up the frac because we’re waiting on water. We needed to make sure that whatever solution we designed would be able to supply and support our development plan in a timely manner,” McLin said.
Short-term infrastructure was a primary focus in the water management strategy. ConocoPhillips rented a temporary disposal facility and fracture tanks to use with its pumps, and it hired an outside company to operate the facility. McLin said the costs of renting a disposal facility were comparable to the costs it would have endured to operate its own permanent facility, minus the costs of construction and installation. The water management team also rented some of its infield gathering systems, particularly for wells that it did not anticipate operating for extended periods of time.
McLin said the success with rental facilities caused a significant paradigm shift in the company’s water management planning. The lack of permanent infrastructure costs made it easier for ConocoPhillips to develop the fields, but she said the short-term savings would not preclude the construction of company-owned facilities in the future if it is economically feasible.
“We were able to immediately enact strategies that save us money while saying, maybe, eventually we’ll get there with some ConocoPhillips-owned and operated infrastructure that will eventually save us money. But right now, it’s pennies compared to what we’re saving now,” she said.
In addition to examining the temporary storage and disposal facilities, the water management team also had to determine the best way to integrate produced water reuse into its program. McLine said its initial treatment pilot started off on a small scale, treating 5,000 bbl of water per well for select vertical wells. However, there were still concerns about scaling up the pilot to treat the required volume for a single horizontal well, approximately 250,000 bbl of water.
Beyond volume capabilities, the water treatment system had to meet additional criteria. It could not pose a safety risk to operational personnel. The water could not cause any long-term production issues over the life of the well. Also, it needed to be cost-effective and fit-for-purpose, and the produced water needed to perform comparably to the fresh water previously used in fracture stimulations.
McLin said the low oil price market forced greater creative thinking with regards to the consideration of treatment options, and if prices continue to stay low other operators will need to be even more creative in devising cheaper solutions.
"We need to think how clean does the water really need to be, and what treatment option is the best option? Even now, we must push the boundaries of what is the best blend of produced water and fresh water that doesn't require treatment," she said.
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