Enhancing the Fracture Growth Uniformity of Perforation Clusters by Pre-injection of Cold Water.

Abstract

This study investigated how thermoelasticity impacts the uniformity of cluster stimulation and fracture initiation and growth in horizontal, multi-fractured laterals. Thermal cooling has previously been shown to lower the minimum principal stress and induce fracturing in conventional reservoirs. In the current study, cool fluid was injected prior to the primary stimulation to investigate whether the local minimum principal stress could be reduced. In the base case without pre-treatment, fractures were propagated in a non-uniform manner after the primary stimulation. This resulted in a few clusters being dominant, leaving the rest of the reservoir's hydrocarbon unstimulated. Thus, the pre-treatment period can be utilized to reduce in situ stress at the entry of the clusters. The simulation results showed that clusters with a pre-cooling period had more uniform fractures than did the base case. Utilizing thermally controlled fluid is a novel method for improving cluster uniformity and efficiency.