Characterization of Multiple Transverse Fracture Wells Using the Asymptotic Approximation of the Diffusivity Equation
Abstract
Shale oil and gas remains a developing field of study because of the inherent complexities of producing fluids from ultra-tight media via wells with highly complex, uncertain geometries. Production analysis provides evaluators with powerful tools for the optimization of production from unconventional reservoirs, requiring only limited geologic and petrophysical data, given that certain assumptions are made. In this study, we present a new subset of analytic formulations for the production analysis of Multiple Transverse Fracture Wells (MTFW’s). These analytic models are based upon the asymptotic approximation of the diffusivity equation and are unique in that they apply the asymptotic solution in conjunction with the principle of superposition to represent the interactions between hydraulic fractures during reservoir drainage from MTFW’s. With these models we show that the interaction between hydraulic fractures during MTFW production will appear similar to boundary-dominated flow (BDF) on a diagnostic plot but is in fact a unique interference signature that results from the superposition of pressure drawdowns induced upon each fracture by its neighbors. In addition, we present our work on the explicit definition of the end of transient linear flow in MTFW’s. Previous authors have observed and defined the “end of linear flow”, however, we discovered that this definition remains ambiguous in industry literature. We present our own definition of the end of linear flow, based upon the core construction of the asymptotic approximation of the diffusivity equation, founded upon the concept of detectability. Our definition, dubbed the “limit of detectability” is intuitive, recognizable on classic pressure transient diagnostic and specialized plots, and independent of inner boundary conditions.
Subject
Unconventional reservoirsproduction analysis
rate transient analysis
pressure transient analysis
fluid flow in porous media
Citation
Malone, Andrew David (2019). Characterization of Multiple Transverse Fracture Wells Using the Asymptotic Approximation of the Diffusivity Equation. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /184431.