Case History: Challenges Using Ultraviolet Light to Control Bacteria in Marcellus Completions

摘要

Covering nearly 60 million acres in New York, Pennsylvania, West Virginia, Ohio, and Kentucky, the Marcellus formation is a proven gas resource for years to come. The keys to unlocking the hydrocarbons trapped in this deep shale are horizontal drilling and high-volume water fracturing. Large amounts of water are needed to perform the completions and must be treated to control bacterial growth. Previously, the only method available was the use of chemical aids, which could represent a health hazard during operations in storage, addition, and recovery of returned fluids. The use of a new, environmentally acceptable process that has shown the ability to kill 99.9% of the bacteria in fracturing water is presented. Disinfection is accomplished on-the-fly while pumping downhole at normal job rates as required by design. Conditions for optimum kill are detailed, along with case histories from jobs that used the process. In addition, a solution is detailed for locations with substandard makeup water to accomplish high kill rates when pumping on-the-fly. The units used were truck-mounted to help ensure access to any locations that fracturing equipment could access.