高频层序划分揭示断陷深湖层系源储共生发育规律——以北部湾盆地海中凹陷始新统流沙港组二段为例  

High-frequency sequence division reveals the intergrowth development regularity between source rocks and reservoirs of deep lake facies strata in the faulted depression:Taking the Eocene Liushagang 2 interval in Haizhong Depression,Beibuwan Basin as an example

作　　者：江东辉 JIANG Donghui(Sinopec Shanghai Offshore Oil&Gas Company,Shanghai 200120,China)

机构地区：[1]中国石油化工股份有限公司上海海洋油气分公司,上海200120

出　　处：《西北大学学报（自然科学版）》2024年第3期527-540,共14页Journal of Northwest University（Natural Science Edition）

基　　金：国家自然科学基金重大项目(41390451)。

摘　　要：以北部湾盆地海中凹陷始新统流沙港组二段断陷湖盆深湖沉积体系为例,以高分辨率层序地层学理论为指导,利用最大熵谱分析与小波变换分析技术对流二段进行高频层序划分,在对沉积体系发育规律分析的基础上,通过流二段各五级层序深湖相烃源岩及湖底扇重力流相砂岩发育规律的分析,探讨断陷湖盆深湖层系源储共生的发育规律。研究认为:INPEFA频谱分析与小波变换分析技术可有效地运用于断陷湖盆深湖层系高频层序划分;北部湾盆地海中凹陷深湖层系流沙港组二段可划分为1个三级层序、2个四级层序、5个五级层序,其中2个四级层序以最大湖泛面为界分为湖泊扩张体系域(TST)与湖泊收缩体系域(HST);断陷湖盆优质厚层烃源岩往往发育于湖泊扩张体系域四级层序下部初始湖泛面(Ts)的五级层序内,虽然湖泊扩张体系域四级层序顶部最大湖泛面(Mfs)上下紧邻的五级层序发育的烃源岩面积大,但厚度小,为次要烃源岩及良好的盖层;湖泊扩张体系域四级层序中部的五级层序往往发育湖底扇重力流相储层,其夹持发育于初始湖泛面及最大湖泛面附近的两套烃源岩之间,可共同组成良好的“三明治”式生储盖组合,该套“三明治”式生储盖组合应是下一步非常规油气勘探的重要区域。Taking the deep lake sedimentary system of the Eocene Liushagang 2 interval in the Haizhong Depression,Beibuwan faulted lacustrine basin as an example,guided by the theory of high-resolution sequence stratigraphy,the high-frequency sequence division of the Liushagang 2 interval was carried out by means of the utilization of the maximum entropy spectrum analysis and wavelet transform analysis techniques;further,the source-reservoir intergrowth regularity of the deep lake strata in the faulted lacustrine basin was discussed,on basis of the analysis of the development rules of sedimentary system,and also the analysis of the development regularity of deep lake facies source rocks and sublacustrine fan gravity flow sandstones in the high-frequency grade-5 sequence of the Liu 2 interval.The research suggests:INPEFA spectrum analysis and wavelet transform analysis technology can be effectively applied to the high-frequency sequence division in deep lake facies strata in the faulted lake basin;the Liu 2 interval in Haizhong depression of Beibuwan Basin can be divided into one grade-3 sequence,two grade-4 sequences and five grade-5 sequences,with the grade-4 sequence being divided into two system tracts of the lake expansional system tract(TST)and the lake contraction system tract(HST),which are interfaced by the maximum flooding lake surfurce(Mfs);High-quality thick source rocks in faulted lacustrine basins were often developed in the initial grade-5 sequence at the first lake flooding surface in the lower part of the lake expansional system tract of grade-4 sequence.Although the source rocks developed in the two grade-5 sequences closely under or over the maximum lake flooding surface at the top of the lake expansional system tract of grade-4 sequence are large in areal extent,but thin in thickness,which can thus be served as the secondary source rocks and most well cap rocks.The grade-5 sequence at the middle part of the grade-4 sequence in the lake expansion system tract often developed sublacustrine fan gravity flow

关 键 词：高频层序 深湖层系 源储共生规律 北部湾盆地 海中凹陷 流沙港组二段 

分 类 号：TE121[石油与天然气工程—油气勘探]