摘要
渤海湾盆地南堡凹陷2号构造带具有多洼、多层系供烃的特征。为了揭示其复杂的油气来源,开展色谱-质谱等地化测试,分析原油地化特征,将原油分为3类,并确定每类原油的来源。结果表明:(1)Ⅰ类原油主要分布于西构造带沙三段储层中,原油中C27与C29规则甾烷相对含量接近,孕甾烷参数((孕甾烷+升孕甾烷)/规则甾烷)和甾烷异构化参数(C29甾烷20S/(20R+20S)、C29甾烷ββ/(αα+ββ))较高,具有水生生物和高等植物共同输入特征,原油成熟度高,来源于沙三段烃源岩;(2)Ⅱ类原油主要分布于西构造带东二段储层中,原油中C29规则甾烷含量具明显优势,孕甾烷参数和甾烷异构化参数均低,原油母质中高等植物具有明显优势,原油成熟度整体偏低,来源于沙一段—东三段烃源岩;(3)Ⅲ类原油主要分布于东构造带东三段和西构造带东一段和明化镇组储层中,原油中C29规则甾烷具有一定优势,孕甾烷参数较低,甾烷异构化参数较高,以高等植物输入为主,原油成熟度较高,为3套烃源岩的混合来源;(4)原油4-/1-MDBT和Ts/Tm指数具有沿断层向浅部层系减小的趋势,且原油甲基菲换算的镜质体反射率与下覆烃源岩镜质体反射率一致,表明研究区原油具有原地供烃的特点。本研究成果为研究区的浅层精细勘探及深层勘探提供理论指导。
The No.2 structural belt in the Nanpu sag of Bohai bay basin has the characteristics of multi-sag and multi-layer hydrocarbon supply.In order to reveal its complex oil and gas sources,geochemical tests such as chromatography-mass spectrometry are conducted to analyze the geochemical characteristics of crude oil.The crude oil is categorized into three types and the specific sources of each type are identified.The results show that:(1)Type I crude oil is mainly distributed in the third member of the Eocene Shahejie Formation(Es_3)reservoir of the western structural belt.The relative content of C_(27)and C_(29)regular steranes in the crude oil are similar,and the pregnane parameters((pregnane+homopregnane)/regular sterane)and sterane isomerization parameters(C_(29)sterane 20S/(20R+20S),C_(29)steraneββ/(αα+ββ))are relatively high,indicating a combined input from aquatic organisms and higher plants.The crude oil demonstrates high maturity and is derived from the source rock of Es_3.(2)Type II crude oil is primary distributed in the second member of the Eocene Dongying Formation(Ed_2)reservoir of the western tectonic belt.It is characterized by a noticeable predominance of C_(29)regular steranes,coupled with lower pregnane parameters and sterane isomerization parameters.The crude oil's source material is notably dominated by higher plants.This crude oil exhibits lower maturity and originates from the source rocks of Es_1-Ed_3.(3)Type III crude oil is predominantly distributed in the Ed_3 reservoirs of the eastern tectonic belt and the Ed_1 and Minghuazhen Formation of the western tectonic belt.There is a certain advantage in the C_(29)regular sterane content,with lower pregnane parameter and higher sterane isomerization parameter.The crude oil is dominated by higher plant input and with higher maturity,and be identified as a composite source originating from three sets of hydrocarbon source rocks.(4)The 4-/1-MDBT and Ts/Tm indices of the crude oil show a decreasing trend towards the shallow strata along the fault.Notably,the vitrinite reflectance values converted from the methylphenanthrene in the crude oil are consistent with the vitrinite reflectance in the underlying source rock,indicating that the crude oil in the study area is characterized by in-situ hydrocarbon supply.The findings in the study can provide theoretical guidance for both detailed exploration in the shallow strata and deep exploration in the area.
作者
刘华
魏鑫
欧阳冠宇
刘景东
陈蕾
刘海青
孟祥雨
LIU Hua;WEI Xin;OUYANG Guanyu;LIU Jingdong;CHEN Lei;LIU Haiqing;MENG Xiangyu(School of Geosciences,China University of Petroleum(East China),Qingdao,Shandong 266580,China;Jidong Oil field Company,PetroChina,Tangshan,Hebei 063004,China)
出处
《中国海上油气》
CAS
CSCD
北大核心
2024年第1期26-36,共11页
China Offshore Oil and Gas
基金
国家自然科学基金“富油凹陷压力梯度与油气运移方式量化表征(编号:41972141)”部分研究成果。
关键词
渤海湾盆地
南堡凹陷
2号构造带
原油类型
地化特征
生物标志化合物
油源对比
原地供烃
Bohai bay basin
Nanpu sag
No.2 structural belt
type of crude oil
geochemical characteristics biomarker
oil-source rock correlation
inn-situ hydrocarbon supply
