What is LPG Fracturing
LPG fracturing is a process used to recover petroleum by fracturing rock at depth using a propane gel. This generates better flow of gas in tight formations, improving the economics of drilling operations.
BREAKING DOWN LPG Fracturing
LPG fracturing requires drilling operators to treat liquid petroleum gas, or LPG, chemically, making it a gel-like consistency. Well operators inject a mixture of the gelled LPG and particulate matter into the well at high pressure, generating fractures in the rock formation. The particulate matter in the gel, known as proppant, lodges in the fractures to keep them open. Heat and pressure in the drilling operation cause the gel to revert to petroleum vapor, allowing the drilling company to recapture virtually all of the injected LPG at the wellhead. This operation stimulates greater flow in tight plays, where pockets of gas or oil are trapped in relatively impermeable rock formations.
LPG fracturing compared to conventional hydraulic fracturing
Hydraulic and LPG fracturing methods employ similar methods. Both inject mixtures of liquid and proppant into a well to generate more efficient production. Hydraulic fracturing has existed since the late 1940s and has seen wider use among petroleum companies as they have undertaken broader development of tight shale formations such as the Bakken, Eagle Ford, Niobrara and Pierre.
GasFrac, a company based in Alberta, Canada, developed LPG fracturing in the early 2000s as a waterless alternative to hydraulic fracturing. The use of chemical-laden water in conventional hydraulic fracturing plays has made that process a frequent target for criticism due to its potential for environmental harm. For one thing, hydraulic fracturing uses large amounts of water which cannot be reintroduced to an existing aquifer once treated, so companies using the process compete for scarce water supplies in some areas. Second, hydraulic fracturing carries risk of groundwater pollution from storage or leakage, as well as from the introduction of heavy metals or salts pulled from the underground rocks to the surface.
By contrast, waterless fracturing allows better recovery of the fluids injected into the well, which typically commingle with natural gas at the wellhead. The propane gel also does not leach chemicals out of rock formations the way water does. Some early tests reported improved production over conventional hydraulic fracturing as well.
Risks of the process mainly revolve around propane’s flammability, which becomes an issue in the event of an undetected leak because propane is heavier than air and can settle in low-lying areas.
The use of LPG fracturing has grown but has not become widespread in the industry to date. Likely reasons for this include widespread infrastructure already in place for hydraulic fracturing, the relatively slow acceptance of new technologies within the energy industry and the mixture of expense and secrecy surrounding proprietary aspects of the technology.