石油科学通报2026，Vol.11Issue(3)：690-706,17.DOI:10.3969/j.issn.2096-1693.2026.02.026
超深页岩储层水力压裂邻井光纤监测远场应变响应特征研究
Far-field strain response analysis of hydraulic fracturing in an ultra-deep shale reservoir using offset-well fiber-optic monitoring
摘要
Abstract
As a new strategic replacement for shale gas development in China,the Cambrian Qiongzhusi Formation shale gas reservoir in the Southern Sichuan Basin is characterized by great burial depth,high in-situ stress,well-developed natural fractures,and notable inter-well interference.These characteristics pose severe challenges to the evaluation and optimization of hydraulic fracturing performance in new production platforms.Meanwhile,conventional hydraulic-fracturing monitoring methods are limited in spatial continuity,inter-well-scale characterization,and quantitative evaluation of stage-to-stage stimulation differences,making it difficult to continuously monitor complex fracture behaviors such as fracture propagation,fracture-offset-well interaction,and communication with natural weak planes in ultra-deep shale reservoirs.Address these challenges,this study conducted cased-hole offset-well fiber-optic strain monitoring using low-frequency Distributed Acoustic Sensing(DAS)during zipper fracturing oper-ations on a production pad in this area.Strain-rate data were acquired throughout the complete treatment process of 52 fracturing stages from two treatment wells,and the far-field strain-response characteristics associated with hydraulic-fracture propagation were systematically analyzed.A field-data interpretation workflow was established,including raw DAS data quality control,low-fre-quency information extraction,synchronized analysis of strain-rate waterfall plots and treatment parameters,fracture-arrival-time statistics,shut-in response analysis,and cumulative-strain-based evaluation of reservoir stimulation effectiveness.The results show that the monitoring responses are generally characterized by widespread response,clear depth correspondence,complex response patterns,and significant differences between earlier and later treatment stages.Hydraulic fracture propagation mainly exhibits three dominant modes:competitive propagation of multiple fractures,coexistence of vertical and inclined fractures,and large-scale communication with bedding-parallel fractures.The fracture propagation velocity toward the offset well and the strain response characteristics at shut-in are closely correlated with fracture propagation behavior.The average fracture propagation velocity is jointly controlled by local in-situ stress and natural fracture conditions,the vertical offset between the treatment well and the mon-itoring well,the degree of communication with previously created fractures,and local stress-field modification induced by zipper fracturing.The strain response during shut-in reveals differences in closure behavior among different fracture types.Fracturing stages dominated by opening-mode vertical fractures commonly exhibit obvious strain reversal after shut-in,indicating relatively sufficient fracture closure.In contrast,intervals affected by bedding-plane communication or shear slip along weak planes generally show slowly decaying tensile strain that is difficult to fully reverse,suggesting that residual fracture opening or shear displacement may remain on the fracture surfaces.This study pioneers the use of hydraulic-fracturing far-field strain monitoring results for quantitative evaluation of reservoir stimulation effectiveness,enabling quantitative assessment of stimulation intensity and the spatial extent of stimulation for different fracturing stages.Furthermore,it documents the monitoring of seismic events during operations and discusses their impact.The study provides a data-driven framework for optimizing fracturing design,mitigating well interference risks,and enabling collaborative development in deep shale reservoirs,while establishing a foundation for future fracture parameter inversion and quantitative evaluation.关键词
超深页岩储层/水力压裂/光纤监测/低频分布式声波传感/储层改造Key words
ultra-deep shale reservoir/hydraulic fracturing/fiber optic/low frequency distributed acoustic sensing/reservoir stimulation effectiveness分类
能源科技引用本文复制引用
宋毅,曾波,孙玉铎,马维臻,杜广浩,郭欢,宋佳忆,隋微波..超深页岩储层水力压裂邻井光纤监测远场应变响应特征研究[J].石油科学通报,2026,11(3):690-706,17.基金项目
中国石油天然气股份有限公司科技专项"非常规储层改造关键技术研究"课题五《页岩气复杂防控及高效压裂技术与试验》(项目编号2023ZZ28YJ05)资助 （项目编号2023ZZ28YJ05）
