A Faster Cleanup, Produced-Water-Compatible Fracturing Fluid: Fluid Designs and Field Case Studies

Abstract

Natural gas reservoir development continues at a record pace in North America. Additionally, reservoir pressure depletion and declining quality of reserves have resulted in escalating drilling, completion, and workover costs per unit of gas produced. This in turn forced industry to focus on increasing efficiency by refining completion processes and field operations to make wells commercially viable. Strategies such as multiple-zone commingled completions, the selection of fluids and additives to maximize hydraulic fracture effective length and conductivity, and fluid recycling/handling are but a few strategies employed. Additionally, operating companies have been seeking other cost-control measures, including reducing the number of additives in fracture fluids and minimizing disposal costs of produced waters by recycling and by using them as the base for completion and fracturing fluids. Because of the uncertainty of the produced water impurity, composition, and concentration, it is extremely challenging to make a fracturing fluid compatible with produced water. Together with the need to gel produced water, the demand for more conductive fractures, along with the capacity to create sufficient fracture geometry, has led to the development of a unique surfactant-based system relatively insensitive to most produced waters, and even to some high-density brines. Fluid chemistry modifications employed to enhance performance allowed for reductions in mix-water and fluid-handling costs, shortened flowback/cleanup time, and provided equal or improved post-fracture production response. This paper focuses on a description of the fluid chemistry and performance along with numerous fracture treatment applications with a variety of mix-waters.

Reutilization of Fracturing Flowback Fluids in Surfactant Flooding for Enhanced Oil Recovery

“…19 In addition, the amount of viscoelastic surfactants present in flowback fluids is high with concentrations ranging from 3 to 8 wt %. 20,21 This fact provided the impetus for studying whether VESs in the flowback fluids can be used in surfactant flooding by decreasing the oil/water IFT. 22 This study focuses on the reutilization of fracturing flowback fluids in surfactant flooding.…”

Reusing Flowback and Produced Water with Different Salinity to Prepare Guar Fracturing Fluid

“…Since the late 1990s, viscoelastic surfactant (VES) clean fracturing fluid has been widely used in fracturing stimulations of low-permeability reservoirs due to the fact of its good sand-carrying, fracture-forming performance and low damage characteristics. Bulat et al [19] presented a new flowback water-based clean fracturing fluid system, NG-VES, consisting of an amphoteric surfactant and a rheology optimizer as the main formulation. When the polar ends of the amphoteric surfactants are equal in the anion and cation parts, the "internal salt" formed by the system is neutral.…”

Study of Thermal Variations in Wells During Carbon Dioxide Injection

“…Several recent studies show that the integrity of annular cement is difficult to maintain, and that annular-pressure problems in wells become more frequent as they age (Wojtanowicz et al 2001;Vignes and Aadnøy 2008). For a well-formed annularcement sheath, the permeability is typically as low as 1 Â 10 À5 md (Nelson and Guillot 2006), and annular fluid or pressure transmission is therefore dependent on the formation of leakage paths.…”