Global Onshore Well Management Principles

Preserve and Conserve Water

During drilling activities, one of the most important objectives for us is to protect groundwater. To isolate and protect freshwater zones throughout the life of the well, we design and construct new wells with multiple barriers of steel casing and cement. We closely monitor system pressures during drilling and completion activities. When drilling through freshwater zones, we use air or freshwater-based fluids to prevent water contamination. We hold fluids recovered from hydraulic fracturing in tanks or lined pits and manage them in accordance with government-approved methods to ensure safety and environmental protection.

In the water-stressed Permian Basin in the U.S., we have worked to improve our treatment and use of produced water since 2012. Water supply, reuse, transportation, and disposal can average 20 percent of well completion costs and operating expenses and the area has limited surface and groundwater resources available. Since water-to-oil ratios are between 1:1 and 7:1 in the basin, produced water is abundantly available. Given the limited water in the area and resulting well cost implications, there is both an environmental and economic incentive to utilize produced water whenever feasible. Our solution in the western portion of the basin, called the Delaware Basin, is a central water gathering and distribution system with a portable treatment system that can accept water from the drilling site then return it for use in hydraulic fracturing. This infrastructure, tailored to the region, offers flexibility for water disposal or reuse, both reducing our surface footprint and eliminating emissions, dust, and road noise associated with truck transportation. The produced water pipelines took 300 trucks off the roads per day in 2016 and reduced disposal costs by over 50 percent.

In 2016, we also piloted technology to assure safety and environmental protection in open-top water storage, including:

• Use of green biocide to prevent water quality deterioration.
• Containment designed to exceed regulatory standards.
• Use of technology to significantly reduce evaporation.

At the end of a well’s productive life, we follow stringent site-closure requirements. These include setting cement plugs and/or mechanical barriers inside the well to isolate and protect freshwater sources.