Data-Driven Intelligent Optimization Design of Fracturing Stage and Cluster Locations: A Case Study

ABSTRACT: Jimsar shale oil represents a significant unconventional oil and gas resource within China's ultra-deep tight reservoirs. Multistage hydraulic fracturing with multi-cluster perforation in horizontal wells is one of the key technologies for developing Jimsar shale oil. However, due to the characteristics of Jimsar's reservoir, such as ultra-deep, low permeability, strong heterogeneity, and dispersed sweet spots, there are challenges including non-activation of some fracturing clusters and low production contribution. Therefore, it is crucial to comprehensively consider both geological and engineering sweet spots when optimizing the positioning of fracturing stages and clusters. In this paper, reservoir petrophysical properties were classified to characterize the geological sweet spots in horizontal wells, and a K-means clustering algorithm was applied to establish an intelligent optimization model for selecting fracturing stages. Additionally, the downhole mechanical specific energy was used to characterize the rock's mechanical strength, which served as the basis for selecting the optimal engineering sweet spot for fracturing cluster positioning. Finally, practical factors such as field operations, casing collar locations, and bridge plug positions were integrated to achieve balanced fracture initiation. The research results provide a new method for intelligent design of fracturing stage and cluster positioning in hydraulic fracturing, aiming to achieve uniform initiation of multi-cluster fractures and enhance production. 1. INTRODUCTION The Jimsar Sag is an important demonstration area for shale oil development in China (Hu et al. 2022), with horizontal wells combined with multistage hydraulic fracturing being the key technology for developing this reservoir. The Lucaogou Formation oil reservoir in the Jimsar Sag, a primary lacustrine mixed-type shale oil reservoir currently under exploration and development, represents a major oil and gas exploration area in the Junggar Basin (Chen et al. 2024). This reservoir is characterized by deep burial, low porosity, low permeability, strong heterogeneity, and dispersed sweet spots, leading to uneven stimulation effects during multistage hydraulic fracturing (Wu et al. 2024).