TN凹陷不整合结构及其油气地质意义

TN凹陷经历了侏罗纪至早白垩世裂谷盆地发育全过程,不整合面普遍发育。通过井震结合识别出不同级别不整合界面12个,以超覆不整合、截超不整合、平行不整合及褶皱不整合4种类型为主。研究不整合结构,明确了不整合界面的封闭或疏导作用,当不整合与构造、断层较好匹配时可形成有利圈闭。与不整合相关的油藏类型主要发育4种,分别为多层系叠加反向屋脊断块油藏、水下扇体的构造-岩性油藏、砂体尖灭油藏和潜山油藏。结合油田生产实际分析了不同油藏类型的特点,明确了不同油藏在凹陷的分布规律,对下步勘探具有一定指导意义。

UNCONFORMITY STRUCTURES AND THEIR SIGNIFICANCES IN PETROLEUM GEOLOGY FOR TN SAG

TN Sag has experienced Jurassic to Early Cretaceous rift basin during the process of its development,the unconformity interfaces are commonly developed.By means of the well and seismic combination,12 unconformity interfaces were identified,fourmain types of the unconformity are shown as follows:overlapping,truncated,parallel and foldunconformities.Through the research on the unconformity structures,the closing or transferringactions of the unconformity interfaces were made clear,when the unconformities well matched with their structures andfaults,the favorable traps can be formed.Four principal types of oil reservoir are developed when associated with the unconformities,they are respectively multi-strata superposed reverse ridge fault block reservoir,subaqueous fan-body structural-lithologic reservoir,sandbodypinchout reservoir and buried hill reservoir.Integrated with the practice of the oilfield production,the characteristics of different types of the reservoir were analyzed,thus the distribution laws of different reservoirs were ensured for the sag.All the achievements have provided a certain guiding significance for the next step exploration.