A novel stimulation technique named Liquefied Petroleum Gas (LPG) based fracturing which can be an alternative to conventional water based fracturing technique or hydraulic fracturing.
In conventional hydraulic fracturing treatments, it is observed that effective fracture length contributing to the production is fraction of the propped fracture length. In LPG fracturing effective fracture length is more than conventional fracture length hence increasing productivity. If we use gelled LPG as a fracturing fluid, it is highly soluble with the formation hydrocarbon. If natural gas formations are present, then propane and methane will combine to create unique liquid vapour saturation and returns to the surface at ambient conditions which can be separated easily. LPG fracturing eliminates the need of flowback water disposal, which is currently major problem in hydraulic fracturing. In LPG fracturing, a stream of gelled LPG or a mixture of propane and butane is injected into the well. Proppant is supplied in this stream and carried into the formation at frac pressures causing fractures though some precautions are must for the safety issues. It has been observed that with less viscosity, less surface tension and less density, LPG can rapidly and efficiently clean up while reducing the pressure needed to mobilize fracturing fluids.
In this paper, effective fracture lengths and rapid cleanup are demonstrated with the help of post fracture pressure transient analysis. Comparison of LPG fracturing with conventional fracturing has been explained critically. Complete recovery of the LPG has also been demonstrated here. Major advantages and disadvantages of this technique along with economics are included in this paper. We can use this technique in order to protect the environment and to increase the productivity. This paper briefly reviews the previous work and explains an overview and applications of LPG fracturing.