苏北盆地海相地层残存状况及成藏类型分析

Residual strata and hydrocarbon accumulation model of marine sediments in Subei Basin

潘文蕾 彭金宁 翟常博 李海华 邱建华 曹倩 李风勋 陆永德

PAN Wenlei PENG Jinning ZHAI Changbo LI Haihua QIU Jianhua CAO Qian LI Fengxun LU Yongde

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 中国石化 石油勘探开发研究院, 北京 100083

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China SINOPEC Petroleum Exploration and Production Research Institute, Beijing 100083, China

基于前人研究认识和勘探成果，结合区域地球物理剖面解析和钻井资料分析，探讨了苏北地区海相地层在经历了印支—燕山期挤压构造与喜马拉雅期伸展构造迭加改造下的变形及分布面貌。在此基础上，综合成藏组合分析，总结了研究区可能的油气成藏类型及其主控因素。研究认为：(1)苏北地区以淮阴—东台断裂为界，西侧残留地层以下古生界为主，纵向上基本表现为地层倒转，由北往南逐渐由老变新；东侧残留地层以上古生界为主，纵向上正常分布，同样由北往南地层逐渐变新。(2)苏北地区存在四类与海相地层有关的油气成藏类型，即早期原生残留型、晚期新生古储型、晚期古生新储型和晚期古生古储型。早期原生残留型必须同时具备早期成藏有利区及燕山期改造破坏程度弱两大要素；晚期新生古储型必须具备陆相烃灶与海相储层对接的良好配置要素；晚期古生新储型残留海相地层必须具备晚期生烃烃灶及垂向运移到陆相储层的通道两要素；晚期古生古储型残留海相地层必须具备晚期生烃烃灶及纵向区域盖层封盖良好两要素。晚期古生新储型油气藏是近期海相勘探突破的有利类型，晚期古生古储型油气藏应是海相勘探拓展的有利类型。

Based on the understandings of previous studies and exploration results, with the analyses of regional geophysical profiles and drilling data, it was discussed in this paper the deformation and distribution of marine sediments in the northern Jiangsu area under the superimposed transformation of Indosinian-Yanshanian compressional structures and Himalayan extensional structures. On this basis, the possible types of hydrocarbon accumulation and their key controlling factors of the study area were summarized by comprehensive analysis of accumulation assemblage. Results indicate that: (1) Bounded by Huaiyin-Dongtai fault, the Lower Paleozoic strata dominate the remaining strata of the west side, which basically show a stratum inversion in vertical direction and gradually change from old to new from north to south. The remaining strata of the east side are dominated by the Upper Paleozoic, which are normally distributed vertically and gradually change from old to new from north to south. (2) There are four types of hydrocarbon accumulation related to marine strata in the northern Jiangsu area, including early-stage primary-generation and residual type, late-stage new-generation and ancient-storage type, late-stage ancient-generation and new-storage type, and ancient-generation and ancient-storage type. For the early-stage primary-generation and residual type, two factors must be occurred: the favorable area for early accumulation and the weak degree of reconstruction and damage in the Yanshanian period. For the late-stage new-generation and ancient-storage type, the connection between continental hydrocarbon kitchen and marine reservoir is needed. For the late-stage ancient-generation and new-storage type, there must be late hydrocarbon generation kitchen and vertical migration channel to continental reservoir. For the late-stage ancient-generation and ancient-storage type, there must be late hydrocarbon generation kitchen and vertical regional cap rocks. The late-stage ancient-generation and new-storage type is a favorable target for recent breakthroughs in marine exploration, and the late-stage ancient-generation and ancient-storage type is favorable for further exploration.

中国石化油田部项目“苏北—南黄海盆地中古生界成藏条件与有利区评价” YTBXD-01-SKY21-2020

https://doi.org/10.11781/sysydz202202231