Evaluation of Fracturing Effect and Mechanism of Casing Deformation Weakening for Ultra-Long Section Fracturing
Hao Yuexiang
Yin Chen
Li Yizhen
Jiang Yumeng
Zeng Chao
Zhao Xueqin
Liu Chen
Abstract：Due to the modification by ultra-long section and multi-stage complex geological tectonic processes,pre-existing fractures and faults are extremely developed in the southern Sichuan shale,which not only reduce fracturing efficiency but also cause casing deformation and increased economic losses;therefore,for high-risk well segments with extremely developed natural fractures,a multi-stage merged ultra-long stage fracturing mode is implemented to avoid fracturing risks and improve fracturing effectiveness.This study focuses on a well with highly developed fractures in the Weiyuan shale of the Sichuan basin,where pre-existing fractures of various scales are extremely developed throughout the wellbore,indicating significant casing deformation risk during hydraulic fracturing,and after actual casing deformation occurred during hydraulic fracturing,the fracturing plan was adjusted immediately by merging 18 stages into an ultra-long segment of 1 168 m,with 18 fracturing and temporary plugging operations performed on this segment.Based on large-array surface microseismic monitoring,this study characterizes the spatiotemporal propagation characteristics and focal mechanisms of fracture activities,and combined with integrated geological-engineering analysis of microseismic data,3D seismic data,geological surveys,and logging data,clarifies the implementation effect of ultra-long stage hydraulic fracturing,demonstrating that ultra-long stage hydraulic fracturing can reduce the risk of casing deformation in high-risk areas to a certain extent,though highly fractured zones may act as leakage channels for fracturing fluids in ultra-long stages,leading to insufficient stimulation,while adjusting real-time segmentation and fracturing plans for ultra-longsection fracturing based on microseismic responses is beneficial for both reducing casing deformation risks and improving fracturing stimulation effectiveness.
Keywords：shaleultra-long section hydraulic fracturingfocal mechanismcasing deformationpre-existing fracturepetroleum geology
Publication Date：2025-12-30
Online Publishing Date：2026-01-26(First online date of this platform, not the publication date of the document)
Pages：13( 4751-4763 )