基于地质成因的走滑断裂带岩溶缝洞型储层连通性与剩余油分布模式

Connectivity and residual oil distribution patterns of fractured-vuggy karst reservoirs in strike-slip fault zone： A case study of the Tarim Basin

李凤磊 林承焰 任丽华 张国印 朱永峰 张银涛 关宝珠

Fenglei LI Chengyan LIN Lihua REN Guoyin ZHANG Yongfeng ZHU Yintao ZHANG Baozhu GUAN

塔里木盆地走滑断裂带超深层碳酸盐岩岩溶缝洞型储层的立体结构，是影响其连通性和剩余油分布的主要因素。优选具有典型缝洞体特征的一间房地质露头，通过无人机露头扫描、探地雷达分析和实际测量等手段，完成断裂、裂缝和溶洞的参数提取，依据露头大型溶洞、小型溶洞、断层核和破碎带的分布特征，建立断裂带露头区缝洞体发育模式。基于里德尔剪切机理与应力椭圆理论，分析走滑断裂结构特征；采用传统解释与智能识别结合手段，完成富满油田跃满井区三维地震资料的走滑断裂、缝洞体主体和裂缝带精细解释，以及不同结构储层地震响应正演验证；借助缝洞型井组的干扰试井，分析储层连通要素，建立以生产井单井产能、见水周期、油压变化和静压梯度等生产动态为依据的油藏单元划分思路，探讨了不同结构特征储集体对剩余油分布的影响。研究结果表明：①断裂走向为控制缝洞体发育的主要因素，可将其划分为单断面无溶蚀断-缝组合、单断面弱溶蚀断-缝-洞组合和单断面强溶蚀断-缝-洞组合3个发育阶段，建立单断面、平行断面和复杂断面3个岩溶缝洞体发育模式，用来指导研究区缝洞型储层立体结构刻画；②确立断裂面走向为核心连通要素，基于储层解释结果，划分了不同断裂面组合的顺向强连通、复合中连通和侧向弱连通3种连通类型；③建立同向单断裂组合、斜列断缝面组合和不同向多断缝面组合3种储集体连通性组合模式，以及与之对应的剩余油分布模式。基于这种认识，可以建立起一种油藏连通单元的分析思路，从而指导走滑断裂带岩溶缝洞型油气藏勘探与剩余油挖潜工作。

For ultradeep， fractured-vuggy carbonate karst reservoirs located in the strike-slip fault zone within the Tarim Basin， their three-dimensional architecture is identified as a primary factor influencing their connectivity and residual oil distribution. This study focuses on the geologic outcrop in the Yijianfang area within the basin that exhibits the characteristics of typical fractured-vuggy reservoirs. Using unmanned aerial vehicle （UAV）-based scanning of the outcrop， analysis of ground-penetrating radar （GPR） data， and the field measurements， we determine the parameters of the faults， fractures， and karst caves. By examining the distribution characteristics of the large and small karst caves， fault cores， and fracture zones exposed， we establish the developmental model of fractured-vuggy reservoirs in the outcrop area in the fault zone. Based on the mechanisms of Riedel shear structures and the stress ellipse theory， we analyze the structural characteristics of the strike-slip faults. Afterward， we conduct fine interpretations of the strike-slip fault， main body of fractured-vuggy reservoirs， and fracture zones in the Yueman well block of the Fuman oilfield based on 3D seismic data， while combining conventional interpretations with intelligent identification. With the help of interference tests of a well group， we identify the major factors controlling the connectivity of the fractured-vuggy reservoirs. Accordingly， we divide the reservoir units based on production performance including single-well productivity， water breakthrough cycle， changes in tubing pressure， and static pressure gradients of the wellbore. Additionally， we explore the impacts of reservoir architecture on residual oil distribution. The results indicate that the strike of the fault plane represents a primary factor governing the development of fractured-vuggy reservoirs. These fractured-vuggy karst reservoirs have evolved through three stages： the single fault-plane fault-fracture combination without karstification， single fault-plane fracture-karst cave combination with weak karstification， and single fault-plane fracture-karst cave combination with strong karstification. These evolutionary stages correspond to three combination patterns of fractured-vuggy karst reservoirs， namely the single， parallel， and complex fault-plane patterns. Data on production performance can serve as a basis for determining reservoir connectivity since single-well production， tubing pressure， and stratigraphic static pressure reflect the degree of reservoir connectivity. Fault-fractured-vuggy karst reservoirs with varying fault-plane combinations manifest three reservoir connectivity types： strong connectivity along the fault zones of the same strike， moderate connectivity via intersecting fault zones with different strikes， and lateral weak connectivity via non-intersecting fault zones with different strikes. The fractured-vuggy reservoirs with the oblique fault-fracture plane combination， manifest slightly weak connectivity， with fractures and reservoirs particularly well-developed at fault intersections. In contrast， the fractured-vuggy reservoirs with the single fault of the same strike exhibit strong internal connectivity， indicating great potential for oil exploitation.

10.11743/ogg20250122