Study of hydraulic fracturing fluid filtration in core samples. Generalization of Carter's model

Guar-based fracturing fluids and synthetic polymers based on polyacrylamide, along with water and friction reducers, are commonly used in the oil and gas industry. One of the most important issues of hydraulic fracturing application is to study the mechanisms of contamination of the created fracture with fracture gels and to build models of polymer filtration into the rock. Known models of gel filtration in porous media describe it linearly with respect to t0.5 at late times, but not adequately during for early times. The generalized Carter model presented here enables accurate description of gel filtration both at early and late times and for linear and cross-linked gels. This paper presents a generalization of the Carter model for filtering hydraulic fracturing fluid in core samples. It considers the nonlinear relationship between the thickness of the filter cakes formed and the volume of pumped fluid. To validate the model, a series of experiments were conducted and interpreted. According to the study conducted, the appropriate degree of time is approximately 0.31 with a guar concentration of 3 kg/m3, and at a guar concentration of 3.6 kg/m3 in the range of 0.245 to 0.305. The experiments employed natural core samples, formation fluids, and process fluids that are commonly utilized in hydraulic fracturing under thermobaric conditions of productive sediments in the Priobskoye oilfield of Rosneft. Keywords: fracturing fluid filtration; hydraulic fracturing; leak off coefficient; cross-linked gel; linear gel; Carter equation.