The impact of pertinent parameters on the design of hydraulic fracturing in gas condensate reservoirs

Fracturing is the most common well stimulation technique in gas condensate reservoirs.Flow of black oil and dry gas in induced fracture systems has been widely studied by numerical simulation, core-flood and well tests.However, the flow behavior in fractures surrounding a gas condensate well, which could be significantly different to that of conventional systems, has not been fully understood.Most of the available literature has quantified the negative effect of condensate banking and inertial (non-Darcy) flow on well productivity, giving a pessimistic view of the gas rate in these systems. The above studies have neglected improvement in the gas and condensate relative permeability by increasing rate due to positive coupling of the two phases.

In this work, measured values of permeability, single-phase inertial factor and relative permeability of a propped fracture were used to evaluate the effect of pertinent parameters on fracture performance more realistically.A reservoir simulator was used to develop realistic models of flow in fractured systems. A comprehensive sensitivity analysis on the impact of fracture characteristics on well productivity for different fluids and rock properties was conducted. The results demonstrated that not only inertia was important but also positive coupling strongly affected the flow performance.In particular for a tight formation, whereby fracturing is most effective, positive coupling in the matrix can overcome negative inertia in the fracture region.The results also reveal the important contribution of the fracture width, as wide fractures reduce the inertial effect significantly.Furthermore, we will show that increasing the fracture length does not necessarily lead to higher gas well productivity as there are optimum values for any given set of parameters.