Identification and characterization of Thermally Induced Fractures through integrated analytical and semi-analytical models

Abstract

Thermally induced fractures (TIFs) are common in waterflooded fields where the injection of (relatively) cold water leads to a cooling front that reduces a formation's in-situ stresses. Understanding TIFs is important since their existence impacts oil recovery potential, well injectivity, injection well integrity, and injector-producer well spacing in reservoirs under waterflooding. Identifying and characterizing dynamic TIF growth is a critical step in defining field development strategies and making daily reservoir management decisions. This research introduces a workflow that integrates analytical well monitoring and semi-analytical models to identify TIF onset, propagation properties, direction, and impact during dynamic reservoir events occurring at different levels. The practicality of the proposed workflow has been tested using synthetic data and its robustness confirmed by an analysis of actual field data. The novelty of the approach presented here is in its efficient integration of recent analytical and semi-analytical models to identify TIF onset, propagation, characteristics, and impact from generally available well injection production history data. This practical workflow will help engineers detect and monitor TIFs and evaluate the metrics describing waterflood performance, including flood efficiency, inter-well communication, and pressure maintenance.