Fracture optimization study in the Montney tight sand play

Abstract

Encana Corporation has employed several completion techniques over the past decade to successfully develop the unconventional Montney tight gas reservoir. Optimizing fracture stimulation and design has been an important focus for improving productivity and overall well economics. This paper outlines several factors that could influence hydraulic fracture propagation behaviour in the Upper Montney formation. Commercial fracture modeling software and microseismic surveys were used to improve understanding of fracture geometry and propagation. Sensitivities around elastic moduli, closure pressure, pore pressure and composite layering were used to highlight the range of possible geometries. This study revealed several potential fracture barriers in the Montney package which could impede vertical fracture growth. Production data was also investigated for the selected wells to examine the relationship between frac size, fluid volume, and productivity. Production analysis revealed that cumulative gas production has a linear relationship with injected water volume and the gradient of the least squares fitted line to the relationship varies by target zone. Increasing injection volume twice increased cumulative gas production by 1.81 time. Fracture modeling suggested that increased fracture surface area may be one possible explanation for increased productivity for the Upper Montney 1 zone in this study area.