摘要
深层页岩天然裂缝与层理缝发育,经体积改造后易形成“主缝+支缝+次微缝”的多级裂缝结构,但受高垂向应力和高水平应力差条件的影响,深层页岩压裂裂缝开度极窄且主次缝开度差异较大。为了明确多级裂缝内支撑剂运移机制与分布规律,搭建了大型可视化支撑剂输送实验系统,研究了泵注排量、液体黏度、支撑剂粒径、支撑剂浓度、裂缝特征参数对支撑剂运移与分布的影响规律,最后基于水电相似原理计算了裂缝整体导流能力并开展了评价分析。研究结果表明:①缝内支撑剂存在多种堆积模式,其形成由流体对支撑剂的携带能力决定;②支撑剂分流效率受多种因素影响,增大排量与减小支撑剂粒径均可提高分流效率;③多级裂缝内,增大排量与压裂液黏度均在一定程度上改善了支撑剂非均匀分布,但裂缝导流能力表现为先增大后减小;④综合支撑剂分流结果与多级裂缝内支撑剂分布规律,推荐坚持“大排量+低黏度”泵注思想,以保证大粒径支撑剂占比,适当混合小粒径支撑剂,构建“近井区高导流+远井区有支撑”的高导流裂缝体。结论认为,基于含多级裂缝的大型可视化支撑剂输送实验系统,全面系统研究了不同条件下多级裂缝内支撑剂运移与堆积的模式,研究成果可为深层页岩压裂泵注工艺参数设计与优化提供理论支撑。
The developed natural fractures and bedding fractures in deep shale facilitates the formation of the multi-scale fracture structure composed of main fractures,branch fractures and secondary microfractures after volumetric fracturing,but influenced by high vertical stress and horizontal stress difference,the apertures of the hydraulic fractures in deep shale are extremely small and the aperture difference between main fractures and secondary fractures is large.In order to figure out the migration mechanisms and distribution laws of proppant in multi-scale fractures,this paper establishes a large visual experiment system of proppant transport,and studies the influence laws of pumping displacement,liquid viscosity,proppant particle size,proppant concentration and fracture characteristics parameter on proppant migration and distribution.Finally,based on the water-electricity similarity principle,the overall fracture conductivity is calculated,evaluated and analyzed.And the following research results are obtained.First,the proppant in fractures accumulates in many modes,which is controlled by the proppant carrying capacity of fluid.Second,the proppant diverting efficiency is under the influence of multiple factors,and can be improved by increasing the displacement or decreasing the proppant particle size.Third,in multi-scale fractures,the non-uniform distribution of proppant can be improved to some extent by increasing the displacement or the fracturing fluid viscosity,but the fracture conductivity increases first and then decreases.Fourth,based on the proppant diverting results and the proppant distribution laws in multi-fractures comprehensively,it is recommended to follow the idea of"large displacement&low viscosity"pumping to ensure the proportion of large-particle size proppant with an appropriate amount of small-particle size proppant,so that a high-conductivity fracture body of"high conductivity near the wellbore&support far from the wellbore"is formed.In conclusion,the proppant migration and accumulation modes
作者
郭建春
唐堂
张涛
周航宇
刘彧轩
李明峰
杨若愚
GUO Jianchun;TANG Tang;ZHANG Tao;ZHOU Hangyu;LIU Yuxuan;LI Mingfeng;YANG Ruoyu(State Key Laboratory of Oil&Gas Reservoir Geology and Exploitation//Southwest Petroleum University,Chengdu,Sichuan 610500,China;Shale Gas Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China;Exploration Department of PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610051,China)
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2024年第7期1-11,共11页
Natural Gas Industry
基金
国家自然科学基金项目“湖相多岩相组合页岩油气储层成缝机制及有效开采机理研究”(编号:U23B6004)。
关键词
深层页岩
体积压裂
多级裂缝
水平裂缝
支撑剂运移
缝内分布
室内实验系统
Deep shale
Volumetric fracturing
Multi-scale fracture
Horizontal fracture
Proppant migration
Distribution in fracture
Laboratory experiment system
