Integrated Analysis of the Coupling Between Geomechanics and Operational Parameters to Optimize Hydraulic Fracture Propagation and Proppant Distribution

Abstract

This paper presents an analysis of the interactions between stimulation design and two important geomechanical effects: the variation of least principal stress (S hmin) between lithological layers and the stress shadow effect that arises from simultaneously propagating adjacent hydraulic fractures. To demonstrate these interactions, hydraulic fracture propagation is modeled with a 5-layer geomechanical model representing an actual case study. The model consists of a profile of S hmin measurements made within, below and above the producing interval. The stress variations between layers leads to an overall upward fracture propagation and proppant largely above the producing interval. This is due to interactions between the pressure distribution within the fracture and the stress contrast in the multiple layers. A sensitivity study is done to investigate the complex 3-D couplings between geomechanical constraints and well completion design parameters such as landing zone, cluster spacing, perforation diameter, flow rate and proppant concentration. The simulation results demonstrate the importance of a well characterized stress stratigraphy for prediction of hydraulic fracture characteristics and optimization of operational parameters.

Numerical Simulation of Multi-Fracture Propagation Based on the Extended Finite Element Method

“…(2) Interactions between different hydraulic fractures within the same horizontal wellbore may inhibit further propagation of some fractures, especially if a fracture is subjected to additional stress from adjacent fractures. This phenomenon is known as the stress shadow effect, which can occur even in homogeneous reservoirs [11][12][13]. (3) The dynamic fluid distribution between hydraulic fractures is related to wellbore hydraulics and perforation characteristics, and is influenced by wellbore friction, perforation friction, and hydraulic fracture propagation control.…”

Triaxial Deformation of the Goldwyer Gas Shale at In Situ Stress Conditions—Part I: Anisotropy of Elastic and Mechanical Properties

“…Significant progress has been made over the past decade to extract gas from ultra-low permeable unconventional shale reservoirs (Guo et al 2015;Jarvie et al 2007;Rezaee 2015;Sone 2012), a cleaner and readily available energy resource to accelerate the transition towards a lower carbon economy. Rapid progress in technology, notably hydraulic fracturing, and horizontal drilling, made shale gas economically producible (Herrmann et al 2018;Rybacki et al 2017;Singh et al 2019;Sone and Zoback 2013a;Yang et al 2015;Yang and Zoback 2014). The success of North America's massive shale gas revolution allows other countries like China, Australia, Argentina, or Poland to seriously consider extraction of natural gas from the subsurface where economic and recoverable reserves are identified (EIA 2013).…”

“…Although hydraulic fracturing (HF) reopens and/or creates fractures at various scales (Norris et al 2016), and proppant is placed to keep them open, the rapid decline in production observed in such fractured reservoirs is mostly attributed to progressive (time-dependent) fracture closure (Al-Rbeawi 2018;Wang 2016). Fracture closure is controlled mainly by in-situ conditions such as confining pressure, temperature, stress orientation (Dewhurst et al 2015;Islam and Skalle 2013;Masri et al 2014;Niandou et al 1997;Rybacki et al 2015Rybacki et al , 2016Sone and Zoback 2013a, b;Villamor Lora et al 2016), compositional stress layering (Ma and Zoback 2017;Mandal et al 2021;Singh et al 2019;Xu et al 2019;Yang et al 2015), time-dependent deformation (Herrmann et al 2020;Rassouli and Zoback 2018;Rybacki et al 2017;Sone and Zoback 2014;Xu et al 2019), and the mechanical/petrophysical properties of the shale, e.g., porosity, minerology, brittleness, friction (Cerasi et al 2017;Kohli and Zoback 2013;Rybacki et al 2015Rybacki et al , 2016Sone and Zoback 2013a, b). Therefore, the detailed mechanical characterization of gas shales is essential, not only for the selection of favourable intervals for hydraulic fracturing stimulation, but also to better predict and mitigate post-stimulation fracture closure.…”