Seawater-Based Fracturing Fluid: A Review

Hydraulic fracturing uses a large amount of fresh water for its operation; conventional wells can consume up to 200 000 gallons of water, while unconventional wells could consume up to 16 million gallons. However, the world's fresh water supply is rapidly depleting, making this a critical and growing problem. Freshwater shortages during large-scale hydraulic fracturing in regions that lack water, such as the Arabian Peninsula and offshore operations, need to be addressed. One of the ways to address this problem is to substitute fresh water with seawater, which is a sustainable, cheap, and technically sufficient fluid that can be utilized as a fracturing fluid. However, its high salinity caused by the multitude of ions in it could induce several problems, such as scaling and precipitation. This, in turn, could potentially affect the viscosity and rheology of the fluid. There are a variety of additives that can be used to lessen the effects of the various ions found in seawater. This review explains the mechanisms of different additives (e.g., polymers, surfactants, chelating agents, cross-linkers, scale inhibitors, gel stabilizers, and foams), how they interact with seawater, and the related implications in order to address the above challenges and develop a sustainable and compatible seawater-based fracturing fluid. This review also describes several previous technologies and works that have treated seawater in order to produce a fluid that is stable at higher temperatures, that has a considerably reduced scaling propensity, and that has utilized a stable polymer network to efficiently carry proppant downhole. In addition, some of these previous works included field testing to evaluate the performance of the seawater-based fracturing fluid.