This session explored the complex factors influencing water management decisions related to well development and fracking.
Drill cuttings are generated in high volumes at fracking sites They are characterized as residual wastes in Pennsylvania. Landfills charge the full disposal cost for drill cuttings, and then use the cuttings as daily cover. Current DEP regs make it difficult to store or treat cuttings on site and discourage both the movement of cuttings from one pad to another and the disposal of cuttings on site. Drillers can obtain a permit for a beneficial use disposal. Unfortunately, there are a lot of permit application requirements, and it may take as long as 18 months to obtain a permit. The industry is working with the DEP to attempt to streamline the permit requirements and to authorize more flexible disposal options for drill cuttings.
Frack water is perhaps the largest disposal issue at fracking sites. Some sites generate 80 to 120 barrels of water per minute. Water should be reused where possible to limit both the amount of water disposed of and the amount of fresh water drawn from streams. Tools are available to test frack fluid to make sure it is compatible with treated water for reuse. These include sequential flow back analysis, where samples are taken every 500 barrels of flow back. The water is analyzed for compatibility with treated water. Incompatibility may scale up the formation and reduce efficiency, so for this reason and many others, it is important to keep the water as clean as possible. Water is treated using flocculation, sedimentation and filtration, as a precursor to other technologies such as oxidation and ozonation. The variety of secondary treatments continues to grow as consultants bring more technology to bear on this important issue.
When recycling is not an option, injection wells are often used to manage residual water. There is a huge need for brine disposal capacity in the Marcellus. EPA regulates brine disposal wells under the Clean Water Act. Injection wells are the lowest cost disposal option when they are nearby and available, but permit requirements are stringent in Pennsylvania, so Pennsylvania has very few injection wells. Many of the permitted brine disposal wells are in Ohio, some distance from Marcellus play development wells. The brine must be transported from the play to the disposal site, at an additional cost. There are only 5 brine disposal wells in Pennsylvania. West Virginia has 70 wells, and Ohio has 180. Given the quantity of brine being generated in Pennsylvania, more permitted brine disposal wells are needed. Engineers and consultants are currently looking at viable injection well formations. Depleted oil and gas wells are the most likely candidates, but it is important to consider fault lines and seismic issues. Permitting requires the wells to be installed below the lowest area of available drinking water. That is why oil and gas wells are often useful sites for brine disposal. Permitting in Pennsylvania is handled by the USEPA, and permits take up to 18 months to obtain. In Ohio and West Virginia, the states handle permits, and they take 2 to 3 months to obtain. Local Pennsylvania injection wells can lower disposal costs, when the cost of moving the water to Ohio or elsewhere can cost up to $9 per barrel. So brine well disposal capacity is a high priority in the Marcellus shale.
Strategic planning for water use and management is something producers should focus on. Shale gas uses 4 million gallons of water. Droughts are unpredictable and limit water availability. Water is part of the supply chain for shale gas production. Producers need to identify local limiting factors and assess risks to the supply chain in order to identify back up plans. There are a number of strategic decision making tools to accomplish this, such as decision trees, multi-attribute utility analysis, and dynamic simulation. Each of these will identify risks, opportunities, costs and alternatives.