石油钻采工艺2026，Vol.48Issue(2)：187-198,12.DOI:10.13639/j.odpt.202512036
低渗砾岩储层缝网形成及影响机制模拟
Simulation of fracture network generation and impact mechanisms in low-permeability conglomerate reservoirs
摘要
Abstract
Conglomerate reservoirs exhibit complex lithology,extreme heterogeneity,high gravel content,cross-scale particle-size distributions,and spatially irregular gravel occurrence.In hydraulic fracturing,these characteristics strongly interfere with hydraulic fracture propagation path,resulting in complex fracture geometries and low predictive accuracy of fracture parameters,thereby limiting the theoretical support for fracturing design in such reservoirs.To address this challenge,a hydro-mechanically coupled numerical model was established for fracturing in conglomerate reservoirs based on the extended finite element method,in which adaptive mesh refinement method was introduced to explicitly capture centimeter-sized gravel clasts.The model enables accurate cross-scale simulation and characterization of fracture propagation from centimeter to hectometer size and was validated using available fracture propagation data for conglomerate formations.On this basis,meter-sized simulations were performed to clarify the m echanisms and controlling factors of fracture-gravel interaction,and these results were subsequently extended to reservoir-scale simulations to investigate fracture propagation patterns in conglomerate reservoirs.The results indicate that fracture-gravel interaction can be categorized into four main modes:bypassing,arresting,penetrating,and induced branching.Injection rate,fluid viscosity,horizontal stress differential,and gravel content are identified as the dominant factors governing interaction mode and fracture propagation geometies.Reservoir-scale simulations further reveal that natural fractures primarily determine the propagation path and geometies of hydraulic fractures,whereas gravel clasts exert only a minor influence on the overall fracture pattern.Key geological factors controlling fracture network development,in descending order of significance,are natural fracture density,natural fracture length,horizontal stress differential,injection rate,fluid viscosity,and gravel density.This study provides a theoretical foundation for the optimization of hydraulic fracturing parameters in conglomerate reservoirs and offers valuable engineering guidance for enhancing stimulation performance and development efficiency in these complex formations.关键词
砾岩储层/水力压裂/流固耦合/裂缝扩展/跨尺度模拟Key words
conglomerate reservoirs/hydraulic fracturing/hydro-mechanical coupling/fracture propagation/cross-scale simulation分类
能源科技引用本文复制引用
丁超,宋考平,程龙,季焕成,王苏天,杨顺..低渗砾岩储层缝网形成及影响机制模拟[J].石油钻采工艺,2026,48(2):187-198,12.基金项目
国家自然科学基金面上项目(编号:42472382). （编号:42472382）
