Lightweight proppants in unconventional oil and natural gas development: A review

In the hydraulic fracturing process, proppant is a crucial substance that holds a fracture open after creating and generating conduits for oil/natural gas movement in the wellbore. With the expansion of unconventional oil and natural gas development, hydraulic fracturing is rapidly becoming essential and fostering the growth of proppant. Historically, commercial proppants mostly consisted of quartz sand, coated quartz sand, and ceramic proppant. The newly designed lightweight proppant could lower the settling rate of proppant, the usage of chemical agents in fracturing fluid, and the possible cost of fracturing, thereby benefiting environmentally sustainable production. This research provides a thorough analysis of lightweight proppants. The paper covers the research advances made on lightweight proppants in the scientific literature and commercial proppants manufacturers. There are three varieties of lightweight proppants: hollow/porous proppants, surface-modified proppants, and proppants derived from low-density materials. Field application of lightweight proppant is also summarised in scale inhibition, gravel packing, and hydraulic fracturing. In addition, future research directions and obstacles of lightweight propellants are highlighted.