【摘要】 古暗河作为岩溶体系研究的核心对象，其复杂的空间结构和充填规律是制约缝洞型油藏开发的重要地质难题。先期系统的地震描述已无法满足油田对暗河储层的科研需求，古暗河空间结构和储层模式认识模糊极大限制了塔河地区缝洞型油藏开发和井位部署。基于钻测井、常规地震、波阻抗反演、泥质反演及开发动态等资料，恢复了塔河地区的古地貌、水系和断裂系统等暗河发育的地质背景，剖析了不同地貌下的古暗河充填特征与规律。同时，结合过暗河井资料，分析探讨了落水洞、廊道和暗河扩容端等部位的储层成因，建立了不同地貌背景下古暗河储层发育模式。研究揭示：在相对高地貌(高地、缓坡)及陡坡补给区，落水洞发育角砾和砂岩叠置的大型溶洞，在陡坡排泄区则发育泥岩与角砾复合充填的大型溶洞；地貌从高地到陡坡的有序变化中，转折端储层类型从裂纹化围岩向砂岩/粉砂岩充填的溶洞过渡，最终转变为水平孔缝和粉砂充填的小型溶洞；暗河平直段储层发育模式存在分区特征，高地浅层补给区和排泄区储层物性较差，而高地深层补给区和径流区储层物性较好；暗河交汇部位和扩溶端多发育多期垮塌复合充填的溶洞或未充填溶洞，储层物性好；廊道处则发育泥岩及泥岩胶结角砾充填的溶洞，储层物性差。更多还原

【Abstract】 As a key research subject in karst systems,ancient underground rivers exhibit complex spatial structures and diverse filling patterns,posing significant geological challenges to the development of fracture and cavity reservoirs.Conventional seismic interpretation methods are no longer sufficient to support the research needs for these reservoirs.The unclear understanding of the spatial structure and reservoir models of these ancient underground rivers has severely limited the effective development of fracture and cavity reservoirs and well deployment in the Tahe area.Based on drilling data,well logging,conventional seismic interpretation,acoustic impedance inversion,shale content inversion,and production performance data,the study reconstructed the paleogeomorphology as well as the water and fault systems that controlled the development of underground rivers.It further analyzed the filling characteristics and patterns of ancient underground rivers under different geomorphic settings.Additionally,by integrating data of wells intersecting underground rivers,the study explored the genesis of reservoirs in sinkholes,corridors,and channel expansion areas,and established reservoir development models under various geomorphic contexts.The results indicated that:(1) In regions of relatively high topography (e.g.,highlands and gentle slopes) and in steep-slope recharge zones,large-scale caves filled with stacked breccias and sandstone are developed in sinkholes,whereas in steep-slope drainage zones,large-scale caves are predominantly filled with mudstone and breccia composites.(2) Along the geomorphic transition from highlands to steep slopes,reservoir types shift from fractured surrounding rocks to caves filled with sandstone or siltstone at geomorphic turning points,and eventually evolve into small caves filled with horizontal pores,fractures,and siltstone.(3)In the straight reaches of ancient underground rivers,reservoir development exhibits zonal differentiation:shallow recharge and drainage zones in highlands have poor reservoir physical properties,while deeper recharge and runoff zones demonstrate better properties.(4) At junctions and expansion zones of underground rivers,multi-phase collapse-filled or unfilled caves are mostly developed and exhibit favorable reservoir properties.In contrast,caves in corridors are typically filled with mudstone or mudstone-cemented breccia,resulting in poor reservoir quality.更多还原