Our regional water management strategy is designed to reduce the impacts of our water use on stakeholders and the relevant watersheds, and to minimize risks associated with produced water disposal, supply sourcing and business interruption.
We use the water scarcity evaluation tool, Aqueduct, to align our water management with baseline water stress levels and availability in the areas where we operate. According to Aqueduct, baseline water stress measures the ratio of total annual water withdrawals to total available annual renewable supply, accounting for upstream consumption.
We evaluate our water management and target opportunities to conserve fresh water. Water use is tracked by both quantity, quality (fresh, brackish, recycled) and source (groundwater, surface). Produced water disposition is tracked by volume, transport and disposition method. All produced water in our U.S. onshore operations is either recycled for use in the oilfield or disposed of via salt water disposal wells. We don't discharge treated, produced water to surface. Tracking water use and disposal is mandated by our Environmental Management Standard and the Regulatory Compliance element of our Responsible Operations Management System (ROMS).
- ᵃ Improved source water testing in the Permian as operations have matured post-acquisition has allowed for better classification of water quality.
To facilitate sustainable water sourcing opportunities in our U.S. resource plays, we have a manager of sustainable operations with leadership accountability. Our ROMS system requires assets to conduct a risk assessment addressing local and regional sourcing constraints, capacity limitations, operational needs, and disposal and infrastructure alternatives. While we seek alternative sources to fresh water, such as brackish or grey water, opportunities are very limited in areas such as Oklahoma. Our ability to recycle produced water is highly dependent on proximity between supply and demand, local constraints/regulations and continuity of acreage position. While we strive to use more produced water, we must balance the benefits of reuse with the higher spill risk associated with handling larger volumes of produced water.
We provide industry leadership in trade groups that share lessons learned and best practices for sustainable water management. For example, Marathon Oil is a founding member of the Energy Water Initiative, a group that focuses on sustainable water management practices in the U.S. In addition, we’re an active participant in the New Mexico Produced Water Research consortium and in the National Alliance for Water Innovation (NAWI)-led Department of Energy desalination grant project. These projects study environmental risks and technological developments associated with discharging or beneficially using produced water outside of the oilfield. Through our involvement, Marathon Oil seeks to mitigate environmental risks of produced water, while providing additional management options to deepwell disposal.
The vast majority of our water consumption, typically more than 95%, is used in completions during hydraulic fracturing. Water consumption in our U.S. resource plays was 98 million barrels in 2019, compared to 82 million barrels in 2018. Of this amount, approximately 3 million barrels was recycled, a decrease from the previous year. This was the result of using another operator’s treated water in Oklahoma in 2018. No similar opportunities were identified in 2019. Some of the increased water consumption in Oklahoma in 2019 was offset by improvements in water recycling rates in our Bakken operations.
In our Eagle Ford asset, productive saline aquifers and company-owned supply infrastructure are available. They allow us to make significant use of water resources that are otherwise of no or limited use, so we can conserve high-quality water resources and reduce the risk of constraints on our operational water use. We continue to search for options that conserve fresh water and have been able to capitalize on specific opportunities in Oklahoma and the Permian. These opportunities are often situational and short-term, leading to fluctuations in recycled water use from year to year.
Competitively Advantaged Multi-Basin Model¹
Marathon Oil wants to preserve fresh water for drinking and other community needs while reducing business risk linked to access to water resources. Three primary drivers of alternative water usage are the availability of alternative water sources, including commercial solutions; the ability of our assets to develop contiguous acreage; and the regulatory environment, including local governments’ flexibility in transporting and storing produced, brackish and alternative water. As our assets mature and the subsurface qualities are better understood, we’re able to make data-driven decisions about alternative water source viability and infrastructure.
Marathon Oil has significantly increased the percentage of produced water we move via low-carbon transportation. In 2019, approximately 50% of produced water in our U.S. operations was disposed of using pipelines, eliminating approximately 460,000 truckloads and associated emissions of 30,000 MT of CO2, and also improving road safety. We achieved this through strategic use of water midstream providers and internal development of produced water handling infrastructure in our Eagle Ford and Bakken assets.
Water Usage by Resource Play
In 2019, more than 80% of our sourcing water in the Eagle Ford was brackish, with limited or no agricultural or livestock applications and unsuitable for human consumption. We developed water-sourcing infrastructure that mainly taps available brackish groundwater, leading to a long-term sustainable system with minimal risk of volume curtailment. While total water use in the Eagle Ford increased due to optimized well completion design, most of this increase was sourced from these brackish groundwater sources.
Our efforts since 2018 to develop a minimal footprint treatment system that allows us to cost-effectively treat high volumes of produced water on demand for internal use proved effective. We used this system to provide the majority of recycled water for the asset. In addition, the process mitigates risk of well curtailment due to logistics constraints as produced water from one pad is used as supply for another. On-demand treatment also reduces hauling of flowback water and waste management costs.
Concentrated efforts to establish strategic, flexible contracts with midstream water management companies allowed us to increase the volume of produced water using low-carbon transport from 14% in 2018 to 66% in 2019, while retaining the ability to recycle water for operations. Using midstream solutions enabled us to minimize internally owned/operated impoundment ponds saving capital and reducing surface impacts of operations.
In Oklahoma, we established commercial midstream partnerships to convert more produced water transport to pipeline and conducted a successful trial reusing produced water for drilling mud systems that we implemented in 2019. As a result of this work, produced water transported using low-carbon transport methods increased from 24% in 2018 to 51% in 2019.
Produced water in the Bakken region typically has a high saline content. We continue evaluating the technical viability of using this higher-saline produced water in our Bakken operations. In 2019, the asset conducted several completions using produced water and is evaluating other opportunities. These efforts have resulted in an increase in recycled water use in the Bakken of approximately 300%, resulting in an 8% reduction in fresh water usage, and reducing fresh water demand, truck transport distances and costs.
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