Abstract
Unconventional resources require fracture stimulation to achieve gas production at economic rates and recoveries. However, hydraulic fracture modeling in these resource plays, specifically in the Eagle Ford shale, is challenging and often reduced to rules of thumb and design concepts taken from other shale plays. Although there is a place for extrapolating best practices to the Eagle Ford shale from other reservoirs, the calcareous makeup of the rock and the complex geology resulting in condensate rich environments of this play presents unique completion challenges. Further, concepts of pressure dependent leakoff, process zone stress, hoop stress, stress dependent Young's modulus, and complex fracture propagation limit confidence in traditional fracture models and can result in early job terminations and less than optimal fracture stimulations. These challenges require a hydraulic fracture model and treatment design tailored specifically to the Eagle Ford shale.
This paper will focus on hydraulic fracture design for the Eagle Ford shale using a first-order discrete fracture network (DFN) model for predicting fracture geometry. Additionally, an approximate analytical production solution for multiple finite-conductivity, vertical transverse fractures will be used to production history match the well flow streams for DFN calibration purposes and to aid in fracture optimization. Fracture length, fracture conductivity and fracture spacing for multi-cluster, multi-stage completions along the horizontal wellbore are varied to illustrate the impact of improved hydraulic fracture design on well production and the effect of fracture interference on the resulting geometries and production. The advantage of using a discrete fracture networks for hydraulic fracture design in the Eagle Ford shale is the ability to model complex fracture behavior that may better predict fracture geometry.
Results will be presented which illustrate the impact of varying fracture/completion design, including the effects of stage and perforation cluster number/spacing as well as fracture length and proppant pack conductivity for Well A, which is a dry gas producer, and Well B, with a GOR of 200 bpd of condensate. Included will be treatment and production data, fracture diagnostics, and microseismic results. Readers of this paper will gain insight on how sound engineering and fracture modeling can increase recovery and optimize completions in the Eagle Ford shale.
