The key challenge in unconventional gas plays covering vast geographical areas is locating the regions in the reservoir with the highest combination of reservoir and completions quality. This allows operators to evaluate not only the richness of their resource but also the ability of the reservoir to produce hydrocarbons in commercial quantities.
This paper discusses hydraulic fracturing designs targeting tight gas in horizontal wells drilled in the Apollonia tight chalk formation in the Abu-Gharadig basin, Western Desert, Egypt through the integration of laboratory, geological, petrophysical, geomechanical, fracture simulation, and diagnostic fracture injection test (DFIT) analysis.
Laboratory testing, which included scanning electron microscopy (SEM) and X-ray diffraction (XRD), was conducted to determine mineralogy and potential damage mechanisms. Fracturing fluid chemistry was tested and optimized using core plugs from representative reservoir rock (fracture conductivity, fracturing fluid compatibility, surfactant type, fracture regain permeability, and scale tendency).
Geomechanical rock properties derived from advanced petrophysical analysis of newly acquired high-definition triple-combo full-wave sonic logs and core samples were combined with geological parameters and potential treating schedules to develop sophisticated fracture simulation models. These models were then refined with in-situ reservoir data obtained from DFIT analyses to derive the final fracturing treatment design.
The stimulation model was built using a three-dimensional (3D) geological model with multidisciplinary inputs, including formation properties, in-situ stresses, natural fractures, and completion parameters (i.e., well orientation, stage and perforation cluster spacing, fluid volume, viscosity, and proppant volume, size, and ramping schedule).
The integration of all available data resulted in an optimized fracture design that helped reduce both cost and formation damage, thus improving flowback, long-term productivity, and profitability from this tight formation.