Zhang, Lifu (2020-11). Solid and Soluble Products of Engineered Water/Rock Interactions in Shale Reservoirs. Doctoral Dissertation. Thesis uri icon

abstract

  • Hydraulic Fracturing (HF) is an effective technique for hydrocarbon extraction from low-permeability shale reservoirs. It involves injecting a mixture of pressurized water, sand, and small amounts of chemicals into wells to introduce fractures in rock formations, which allows hydrocarbons to flow. However, with significant increases in production of oil and natural gas, concerns about potential environmental impacts resulting from excessive freshwater usage and wastewater contamination were raised. The average water requirement for an unconventional well is 1-3 orders of magnitude greater than a conventional well. After hydraulic fracturing, 5-85% of the HF fluid returns to the surface and may cause groundwater and surface water contamination when improperly treated. To reduce consumption, transportation, and disposal cost of water, flowback water was commonly reinjected for subsequent hydraulic fracturing by industry. However, because of complex interactions between injected water and reservoir rocks, induced fractures may be blocked by impurities carried by flowback water and mineral precipitation by water-rock reaction. Therefore, knowledge of water-rock interactions during hydraulic fracturing provides important information about the changes within the formation and ways to effectively manage the flowback waters. My research focuses on investigating water-rock interactions during hydraulic fracturing in the lower Eagle Ford Formation and the Marcellus Formation. Simple interactions between deionized water and reservoir rocks and complicated interactions between flowback water and reservoir rocks were studied under static and dynamic conditions to understand basic interaction mechanisms and evaluate effects of reuse of flowback water on hydraulic fracturing performance. Moreover, interactions between pseudo Marcellus Formation rocks and water were conducted to simplify water-rock system and understand how water-rock interactions affect flowback water properties. Pertinent low-cost pre-treatment methods were investigated to better manage Marcellus Formation flowback water for reinjection purposes. The results of my PhD work have potential to be adapted to the field-scale application directly and will contribute to successful management of flowback waters.

publication date

  • November 2020