Operators have many options to consider and factors they must evaluate in developing a successful water management plan. The re-use and mixing of produced waters during fracturing operations to help mitigate the continued use of fresh water, or even simply for the disposal of produced water, is critical in maintaining the oil and gas industry's social license and streamlining operations. When recycling waters (especially when mixed together) there are a number of concerns that need to be assessed, including scale precipitation (barite, calcite, iron sulfides, etc.), the ability to effectively treat the water for re-use, reservoir compatibility, and the achievement of acceptable friction properties for pumping operations. All of these considerations require a series of laboratory tests and other engineering analyses to ensure the best chance for success.
This paper outlines the steps required to successfully implement a water management program from both the economic and technical perspectives, using a case study from the Marcellus and Utica Shales. It describes the reservoir analysis; the Friction Flow Loop experiments using synthesized versus actual produced waters; the modeling and subsequent Dynamic Tube Block (scale loop) experiments to optimize scale inhibition; and ultimately, the field results, which tie together the work required for optimal outcomes. Based on all of the testing and analysis done in the case study, it was determined that the use of fresh and Marcellus produced waters, when mixed with Utica water or individually, present no incompatibilities with the Utica formation, and with proper lab testing, a successful chemical suite can be achieved for fracturing treatments with these waters.