苏北盆地溱潼凹陷断阶带油气运移路径综合分析  

Quantitative evaluation of the sealing capacity and identification of the preferred petroleum migration path in the Qintong subbasin, Subei basin

作　　者：陆黄生[1] 秦黎明[2] 刘军[2] 杨永才[2] 胡瑛 方朝合[4] 张枝焕[2] 

机构地区：[1]南京大学地球科学系,江苏南京210093 [2]中国石油大学石油天然气成藏机理教育部重点实验室,北京102249 [3]中国石油勘探开发公司,北京100034 [4]中国石油勘探开发研究院廊坊分院,河北廊坊065007

出　　处：《中国地质》2008年第1期67-78,共12页Geology in China

基　　金：国家重点基础研究发展规划项目(2001CB409800);国家自然科学基金项目(40802017、40212020)共同资助

摘　　要：溱潼凹陷断阶带断裂系统发育,控制油气聚集的断层主要有F1、Ⅲ、F2、F3及其相应的分支断层,将断阶带分为北部的草舍扭动断裂带与南部的祝庄扭动断裂带。在断层封闭性定量评价与封闭史研究的基础上,结合研究区生排烃史、油源分布特征、油气成藏期以及含氮化合物示踪分析研究表明,断阶带Ⅲ、F2、F3断层在不同的研究区封闭性存在明显的差异,祝庄断阶带Ⅲ号断层垂向封闭性较好,不能成为油气运移的通道,使得角墩子地区的原油主要来源于阜四段源岩,没有阜二段与泰州组源岩的贡献;而F3断层活动期短,侧向封闭性差,也不为油气的运移通道;相比之下,F2断层活动期长,断层垂向封闭性差,而侧向封闭性好,为祝庄地区主要的运移通道,与油气成藏期具有较好的匹配关系,流体包裹体分布与含氮化合物示踪分析也证明了这一点。研究还表明草舍断阶带F2断层活动期短,垂向封闭性好,侧向封闭性弱,不是油气运移的通道;相比之下,F3断层活动期长,垂向封闭性较弱,可以作为油气运移的主要通道,后期主要通过砂体和不整合面运移聚集成藏,与生排烃史、油气成藏期和含氮化合物示踪也具有较好的匹配关系。In the Qintong subbasin, the fault system is well-developed, and the faults controlling petroleum accumulation include faults F1, Ⅲ, F2 and F3 and their branch faults, which divide the fault steps into the Zhuzhuang wrench fault belt in the north and Caoshe wrench fault belt in the south. Based on the quantitative evaluation of the vertical and lateral sealing capacities of the faults, combined with the history of hydrocarbon generation and expulsion, distribution of oil sources, formation stage of petroleum accumulations and tracing analysis of pyrrolic nitrogen compounds, there is appreciable difference in sealing capacities of faults Ⅲ, F2 and F3 in different study areas. In the Zhuzhuang fauk bek, the vertical sealing capacity of fault Ⅲ is good and cannot act as conduits of petroleum migration; so in the Jiaodunzi area, the oil was mainly derived from source rocks of the fourth member of the Funing Formation, but there are no contributions from the second member of the Funing Formation and the Taizhou Formation. The activity of fault F3 is short-continued and its lateral is poor; so this fault is not a conduit of petroleum vertical sealing sealing capacity migration either. By contract, fault F2 is long-active and its capacity is poor while its lateral sealing capacity is good; so this fault is a main conduit of petroleum migration in the Zhuzhuang area and has a accumulations. The distribution of fluid inclusions and good match with the stage of formation of petroleum tracing analysis of pyrrolic nitrogen compounds also support this. Study also indicates that fault 2 in the Caoshe fault belt is short-active and has a good vertical sealing capacity but a poor lateral sealing capacity; so this fault is not a conduit of petroleum migration. Fault F3 is long-active and has a weak vertical sealing capacity; so it is a preferred conduit of petroleum migration. In the late stage, petroleum migrated and was accumulated mainly through sand bodies and unconformities, which also matches well with the the analysi

关 键 词：断层封闭性 运移路径 溱潼凹陷断阶带 苏北盆地 

分 类 号：P618.13[天文地球—矿床学]