A review of fracturing fluid systems used for hydraulic fracturing of oil and gas wells

Abstract

Hydraulic fracturing has been used by the oil and gas industry as a way to boost hydrocarbon production since 1947. Recent advances in fracturing technologies, such as multistage fracturing in horizontal wells, are responsible for the latest hydrocarbon production boom in the US. Linear or crosslinked guars are the most commonly used fluids in traditional fracturing operations. The main functions of these fluids are to open/propagate the fractures and transport proppants into the fractures. Proppants are usually applied to form a thin layer between fracture faces to prop the fractures open at the end of the fracturing process. Chemical breakers are used to break the polymers at the end of the fracturing process so as to provide highly conductive fractures. Concerns over fracture conductivity damage by viscous fluids in ultra-tight formations found in unconventional reservoirs prompted the industry to develop an alternative fracturing fluid called "slickwater". It consists mainly of water with a very low concentration of linear polymer. The low concentration polymer serves primarily to reduce the friction loss along the flow lines. Proppant-carrying capability of this type of fluids is still a subject of debate among industry experts. Constraints on local water availability and the potential for damage to formations have led the industry to develop other types of fracturing fluids such as viscoelastic surfactants and energized fluids. This article reviews both the traditional viscous fluids used in conventional hydraulic fracturing operations as well as the new family of fluids being developed for both traditional and unconventional reservoirs.

Empirical Modeling of the Viscosity of Supercritical Carbon Dioxide Foam Fracturing Fluid under Different Downhole Conditions

“…Hydraulic fracturing of shales is a technique that is widely known to unlock these stored reserves [3] and the fracturing fluids that are commonly used are polymer-based aqueous solutions. However, the application of polymers can plug the nanopores, which becomes a crucial issue [4][5][6][7][8][9]. Moreover, the fracturing process requires a high amount of fresh water during its application, it is susceptible to formation damage in water-sensitive regions, and it provides a reduction in liquid recovery [7,9].…”

A review of biophysical and socio-economic effects of unconventional oil and gas extraction – Implications for South Africa

“…Review articles that were surveyed focused on the technical aspects related to fracking such as fracturing fluid systems and factors influencing fracture propagation (Mahrer, 1999;Rahman and Rahman, 2010;Vatsa and Wang, 2013;Barati and Liang, 2014;) and the economic aspects of these oil and gas resources such as resource availability, estimates and productivity (Clarkson et al, 2012 andMcGlade et al, 2013). These aspects are all important for the optimization of production from unconventional deposits.…”

Wellbore to fracture proppant-placement-fluid rheology

“…This is investigated by studying the fluid's rheological properties when undergoing extensional flow (such as that from perforation to fracture) and relating this rheology to expected proppant transport ability. In recent years viscoelastic surfactants (VES) have found increasing application in hydraulic fracturing owing to their high viscosity and elasticity and their polymer-free nature which eliminates residue associated with guar gums for example (Barati and Liang, 2014). A large body of literature is available covering a range of applicable studies for such fluids.…”

“…In recent years viscoelastic surfactants (VES) have found increasing application in hydraulic fracturing owing to their high viscosity and elasticity and their polymer-free nature which eliminates residue associated with guar gums for example (Barati and Liang, 2014). A large body of literature is available covering a range of applicable studies for such fluids.…”