砂泥岩薄互储层缝控压裂力学机理及穿层判别准则  

Mechanical mechanism of fractures controlling fracturing in sandstone-mudstone thin interbedded reservoirs and criteria for layer penetration

作　　者：李润森 侯冰[1,2] 周长静 何明舫[3] 刘欣佳[3] LI Runsen;HOU Bing;ZHOU Changjing;HE Mingfang;LIU Xinjia(State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum,Beijing,Beijing 102249,China;College of Petroleum Engineering,China University of Petroleum-Beijing at Karamay,Karamay,Xinjiang 834000,China;PetroChina Changqing Oilfield Company Oil&Gas Technology Research Institute,Xi’an,Shaanxi 710021,China)

机构地区：[1]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [2]中国石油大学(北京)克拉玛依校区石油学院,新疆克拉玛依834000 [3]中国石油长庆油田分公司油气工艺研究院,陕西西安710021

出　　处：《中国海上油气》2025年第1期156-166,共11页China Offshore Oil and Gas

基　　金：国家重点研发计划-中美政府间国际合作项目“深部含煤岩系超临界CO_(2)穿层压裂-驱替-封存评价技术研究(编号:2022YFE0129800)”;中国石油天然气集团有限公司-中国石油大学(北京)战略合作科技专项“鄂尔多斯盆地致密油-页岩油富集、高效开发理论与关键技术研究(编号:ZLZX2020-02)”部分研究成果。

摘　　要：苏里格盒8段砂泥岩双向薄互储层裂缝两翼纵向非对称延伸、穿层不充分、改造效果差,选取同层位砂泥岩露头开展真三轴压裂物理模拟实验,探究砂泥岩薄互储集层水力裂缝起裂-交互-穿透的扩展规律,考虑垂向应力差、层间应力差和簇间应力干扰构建全局嵌入内聚力单元数值模型,揭示多簇裂缝间/人工裂缝与层界面间的竞争扩展作用机制,建立多簇裂缝差异性穿透、激活层界面准则及图版。研究结果表明:垂向应力差能抑制簇间干扰诱导的相斥扩展特性,有利于提高缝高,针对垂向应力差异系数高于1.5的储层可适当缩短簇间距;层间应力差和簇间干扰易诱导人工裂缝沟通层界面,并发生剪切破坏,抑制缝高纵向增长,二者分别倾向于形成工字形和共轭T形裂缝形态;提高前置液排量和黏度有助于减小近井区域和层界面处压裂液滤失,提升裂缝穿层致裂能力,最终形成十字和米字为主的复杂缝网形态。本项研究成果可为砂泥岩双向薄互层控近穿远压裂施工参数优化提供理论指导。The sandstone-mudstone thin interbedded reservoir in He 8 member of the Sulige Gas Field is facing issues such as non-symmetric longitudinal extension of fractures on both sides, insufficient layer penetration, and poor effectiveness of reservoir stimulation. Therefore, physical simulation experiments of true triaxial fracturing were conducted on sandstone-mudstone outcrops at the same stratum level, so as to investigate the initiation-interaction-penetration propagation principle of hydraulic fractures in sandstone-mudstone thin interbedded reservoir layers. By considering vertical stress differences, interlayer stress differences, and stress interference between clusters, a numerical model of the global embedded cohesive element was constructed, revealing the competitive propagation mechanisms between multiple clusters of fractures/artificial fractures and interfaces between layers. In addition, criteria and diagrams for differential penetration of multiple clusters of fractures and activation of layer interfaces were established. Research results indicate that the vertical stress difference can suppress the repulsion propagation characteristics induced by interference between clusters, which is beneficial for increasing the fracture height. For reservoirs with a vertical stress difference coefficient exceeding 1. 5, it is advisable to appropriately reduce the inter-cluster spacing. Interlayer stress difference and interference between clusters can easily induce artificial fractures to communicate with the layer interface, leading to shear failure and inhibiting vertical propagation of fracture height. They tend to form H-shaped fractures and conjugate T-shaped fractures, respectively. Increasing the displacement rates and viscosity of pre-fracturing fluid helps reduce fracturing fluid loss near the wellbore and layer interfaces, enhance the ability to create fractures that penetrate layers, and ultimately form a complex fracture network dominated by cross-shaped and asterisk-shaped patterns. Research results c

关 键 词：砂泥岩薄互层 真三轴物理模拟 非对称扩展 簇间干扰 穿层判别准则 

分 类 号：TE357[石油与天然气工程—油气田开发工程]