Optimizing Hydraulic Fracturing in the Paradox Formation: Geomechanical Study of the Cane Creek Play
Authors: Dvory N. Z. , McLennan J. D. , McPherson B. J 
Published: August 2024

The Cane Creek Play, known for its potential in unconventional tight oil extraction, presents drilling challenges. This study revisits its viability in modern horizontal drilling techniques, focusing on the interplay between hydraulic fracturing, stress states, and existing fractures/faults. While historical views emphasize the role of natural fractures in productivity, our results indicate that their stimulation may not be inherently linked to well output. The planar fracture modeling approach adopted here advances our understanding by providing a granular view of the shear potential of geological features, revealing that significant stress alterations are necessary to initiate slip. The study proposes a redefined approach to hydraulic fracturing that prioritizes detailed characterization of stress states and fracture dynamics, with implications for sustainable and economically viable extraction practices. Future research should further explore the interplay between pore pressure and stress shadow dynamics in unconventional reservoir stimulation.

1. INTRODUCTION

The Cane Creek Play in the Pennsylvanian-age Paradox Formation in southeastern Utah is regarded as a promising yet challenging, unconventional tight oil play in the US, with a history marked by drilling and completion difficulties. Initially identified nearly a century ago, substantial exploration resumed only in the early 1990s with the advent of horizontal drilling technology. Despite some successful wells, achieving substantial production remained elusive. Research, sponsored by the US Department of Energy, aims to leverage the basin's geomechanics knowledge and develop sustainable and economic stimulation strategies. A common hypothesis that local operators hold is that the main challenge in developing Cane Creek Play is successfully accessing natural fractures. Yet, studies such as Walton & McLennan (2013) have shown that natural fractures may not significantly contribute to productivity. We acknowledge that the natural fractures stimulation approach is valid when there is a tractable number of relatively large conductive fractures or faults or possibly when their orientation relative to the stress field is optimal for slippage. Considering slippage-related conductivity, we recognize two mechanisms that might trigger slip: (1) the decrease in the effective stress due to pore pressure rise in the vicinity of the propagating hydraulic fracture and (2) the increase of the differential stress over the fracture surface due to stress shadow propagation. The two mechanisms depend on the hydraulic fracture propagation and the stimulation fluids leakoff into the rock – the latter will be relatively small from a matrix perspective. Recent Eagle Ford, Permian, and Junggar Basins studies reported a detailed characterization of hydraulic fracture propagation. These studies showed, from slant core fracture characteristics and fiber optic studies, that hydraulic fractures in those plays typically spread in strands of fracture swarms that are oriented in the direction of the maximum horizontal stress (Gale et al., 2018, 2021; Raterman et al., 2017, 2019; Shi et al., 2022; Ugueto et al., 2021). Specifically, Ugueto et al. (2021) showed broadly linear fracture hits in offset wells, which implies that fracture propagation behaviors such as branching and stepovers are limited to a small scale. Those findings suggest that in a permeability range representing tight reservoirs (0.01-0.1md), the effect of pore pressure distribution in the far field is localized and, therefore, levels up the potential for slip triggered by the stress shadow distribution. Microseismicity, specifically for multi-stage hydraulic fracturing in horizontal wells, is primarily attributed to shear slip on pre-existing fractures and faults.