A NEW HYPOTHETICAL APPROACH TO PROTECT FRESH WATER AQUIFER QUALITY FROM CONTAMINATION BY HYDRAULIC FRACTURE INITIATED CONTAMINATION: FRACTURE ADVANCE CESSATION BY PLUGGING ACTION

Ground and surface water contamination associated with the current high volume-high pressure hydraulic fracturing (HF) applications for unconventional reservoirs is now well recognized. The current technology has become a global threat that endangers water resources with the added consequence of damaging earthquakes induced by the water disposal practice. Mitigation of this threat has been attempted through governmental regulation, treatment and recycling of water used in the process and produced water, as well as closer scrutiny of well permitting, well casing design and more open disclosure of chemicals used in fluids. Major threats introduced by hydraulic fracturing include the use of chemicals and biocides in HF fluids. Some additives are proprietary and not disclosed. The long list of known chemicals used in HF includes 2-Butoxyethanol, Methanol, and highly toxic biocides used to kill micro-organisms that may compromise productivity. Remedies such as the addition of new biological agents or chemicals to counter adverse effects have not been successful. A wide range of filters and purification systems have been used to remove radioactive materials, metals, and other contaminants. Hypothetical data were input to computer models and bench tests for fluid movement through fractured rock to simulate transmission of compounds through pore throats and fracture complexes within petrophysical characteristics potentially encountered in unconventional reservoir systems. Examples of these hypothetical models included materials including gum arabic, tragacanth, (derived from tree sap) etc. that might form adhesive colloidal gels to seal fluid passageways upon encountering fresh water after moving through fractures filled with brine water and petroleum. Hypothetically, such a system would use differential permeability and plugging to stop induced fractures from invading fresh water aquifers. This kind of HF modification may show some promise for protection of fresh water aquifers but will require extensive testing. The processes preliminarily tested herein are designed in order to impose some degree of assurance toward maintaining water quality in an industrial environment of ongoing widespread hydraulic fracturing practices in unconventional oil and gas reservoirs around the world.