Predicting Frac Stage Differential Stress and Microseismicity Using Geomechanical Modeling and Time Lapse Multi-Component Seismic - Application to the Montney Shale

Abstract

This paper describes the application of a workflow that uses Geophysics, Geology, and Geomechanics (3G) for completion optimization. The 3G workflow relies on the modeling of the interaction between hydraulic and natural fractures to estimate key reservoir properties that could be used to better understand data such as microseismicity or to plan an engineering completion. The 3G workflow uses geomechanical simulation that combines the meshless Material Point Method (MPM) with Continuous Fracture Modeling (CFM). The distribution of the natural fracture density is estimated from G&G data and in this paper it uses a time lapse 3C seismic that was processed for Shear Wave Velocity Anisotropy (SWVA). The geomechanical workflow uses this as an input to predict quickly over a large area the Normalized Differential Horizontal Stress (NDHS) and the Maximum Horizontal Stress Direction (MHSD) maps. Both these properties are used to improve the interpretation of microseismicity and to provide valuable information for the completion engineer to optimize his frac design. When using this approach on a Montney two wells pad, it appears that high values of NDHS are directly correlated to the fracture density estimated from the shear wave splitting parameter. While the local direction of maximum horizontal stress generally follows the direction of the imposed regional stress, large stress rotations of up to 90 degrees could occur in areas where the NDHS is very high. This observation is validated with microseismic data that confirms the local development of axial fracs instead of the desired transverse hydraulic fractures. Combining the NDHS and MHSD maps will be a very valuable completion optimization tool that would assist the completion engineer in adapting his frac design and treatment to the local geomechanical environment. The same 3G workflow will also provide to the completion engineer with quantitative tools such as the strain distribution and the J integral to predict or evaluate the efficiency of multiple fracing sequences and understand what is happening in the field experiments frequently showing zipper fracs outperforming other fracing sequences.

Using geomechanical modeling to quantify the impact of natural fractures on well performance and microseismicity: Application to the Wolfcamp, Permian Basin, Reagan County, Texas

“…These data are used as input into FracPredictor™, a particle-based geomechanical computation tool (Aimene and Nairn, 2014; Aimene and Ouenes, 2015). This new 3G workflow provides multiple outputs including horizontal differential stress Aimene and Ouenes, 2015), local maximum horizontal stress directions and the related origins of where stress rotations occur, , and strain resulting from the stimulation process and its correlation to microseismicity Ouenes et al, 2014Ouenes et al, , 2015Aimene and Ouenes, 2015). Also included in the model is the J integral.…”

Coupled Fluid-Solid Geomechanical Modeling of Multiple Hydraulic Fractures Interacting with Natural Fractures and the Resulting Proppant Distribution

“…The initial development, known as CRAcks in the Material Points, or CRAMP (Nairn 2003, Bardenhagen et al 2011, enables the calculation of stresses and strains in the presence of a fracture and also allows the dynamic behavior of fractures, such as opening and propagation, to be simulated. A recent extension of the CRAMP algorithm allowing fractures interacting has been used to simulate the interaction of hydraulic and natural fractures to solve multiple completion optimization problems (Aimene & Ouenes, 2015, Ouenes et al 2015a, Ouenes et al 2015b, Ouenes et al 2015c.…”