牛庄洼陷第三系古沉积环境及其控油气作用  

PALEOSEDIMENTARY ENVIRONMENT IN TERTIARY AND ITS EFFECT ON PETROLEUM DISTRIBUTION IN NIUZHUANG SUBSAG, DONGYING SAG

作　　者：李素梅[1] 李雪[2] 张庆红[3] 句礼荣[4] 马晓昌[2] 

机构地区：[1]石油大学盆地与油藏研究中心 [2]中国石化胜利油田分公司清河采油厂,山东东营262714 [3]中国石化石油勘探开发研究院,北京100083 [4]中国石化胜利油田分公司滨南采油厂地质所,山东东营256606

出　　处：《石油与天然气地质》2003年第3期269-273,共5页Oil & Gas Geology

基　　金：国家重点基础研究项目 (编号G199943 3 10 )资助

摘　　要：地质与地球化学分析结果表明 ,东营凹陷牛庄洼陷及其邻区的两套主力烃源岩即沙河街组三段中、下亚段与沙河街组四段上亚段具有不同的原始沉积环境。沙河街组四段上亚段烃源岩可溶物及其相关原油具有Pr/Ph小于 1、高含量伽马蜡烷、升藿烷“翘尾”及硫芴含量相对较高的还原相、咸化湖相成因特征 ;沙河街组三段中、下亚段烃源岩及相关原油具有Pr/Ph大于 1、藿烷和氧芴系列含量相对较高的淡水湖相成因特征。研究区甲基甾烷、甲藻甾烷分布具有重要的沉积环境与生物属种标定意义 ,沉积环境及相关生源指标显示沙河街组四段“咸水型”油气与南斜坡原地富藻类未熟 -低熟页岩没有直接联系。该区油气分布及其成因类型明显受控于烃源岩的性质及其展布。沙河街组三段“淡水型”原油主要分布于牛庄洼陷 ,属自生自储的“淡水型”透镜体油藏 ;沙河街组四段“咸水型”原油主要分布于偏离生油洼陷的南斜坡等周边地区 ,具有相对较远的油气运移距离。沉积环境指标反映广利洼陷是广利油田及八面河油田北部“咸水型”rock samples and 20 oil samples have been collected from Niuzhuang subsag and its southern slope for detail GC,andGC-MS analyses.The rocks have been sampled from Es 3 and Es 4 members, which are respecting the two main source rocks being deposited in freshwater lake and brackish to saline lake environments, respectively. The oils have been sampled from Bamianhe, Guangli and Shaziling oilfields in the southern slope of Niuzhuang subsag.Our oil-oil and oil-rock correlations show that there are two genetic types of oils in Niuzhuang subsag and its periphery.They are separately corresponding to the two major source rocks in middle to lower Es 3 and upper Es 4 members.Rock extracts of Es 4 member and the related oil are characterized by Pr/Ph<1, high gammacerane, sterane and dibenzothiophene contents, relatively low diasterane content,and high C 35/C 34 homohopane ratios, suggesting that they have been generated in a reduction and brackish to saline lacustrine paleoenvironment. However, rock extracts of middle to lower Es 3 and the related oil are characterized by Pr/Ph>1,and relatively high concentration of hopane and dibenzofuran contents,representing freshwater lacustrine genesis. It is found that methylsteranes including dinosteranes are of importance to indicating sedimentary environment and even specific species of organisms. The alge-rich Es 4 shales deposited in brackish water in the southern slope of Niuzhuang subsag are rich in C 28-30 4-methyl steranes and dinosteranes, and but very small amount of dinosterane in the Es 4 source rock buried at a depth over 2700 m. Similar phenomenon has been observed in Es 3 mudstones deposited in fresh water,i.e.C 28, C 29, C 30 4α methyl-ααα-20 Rsterane of Es 3 mudstone distribute in the shape of “V” in the m/z 231 mass chromatogram, while those in Es 4 source rock have a linear distribution, suggesting that they have apparently different paleoenviornment and related geochemical environment. Analyses of formation water and trace elem

关 键 词：牛庄洼陷 古环境 烃源岩 原油 生物标志物 

分 类 号：TE112.133[石油与天然气工程—油气勘探]