乌伦古坳陷东北侧油苗地化特征及其意义  

Geochemical Features and Geological Significance of Oil Seepages in Northeastern Wulungu Depression

作　　者：王千军[1] 曹高社[2,3] 邢舟 王金铎[1] WANG Qianjun;CAO Gaoshe;XING Zhou;WANG Jinduo(Research Institute of Exploration and Development Shengli Oilfield Company,Sinopec,Dongying,Shandong 257015,China;Institute of Resources ＆ Environment,Henan Polytechnic University,Jiaozuo,Henan 454000,China;Collaborative Innovation Center of Coalbed Methane and Shale Gas for Central Plains Economic Region,Jiaozuo,Henan 454000,China)

机构地区：[1]中国石化胜利油田分公司勘探开发研究院,山东东营257015 [2]河南理工大学资源环境学院,河南焦作454000 [3]中原经济区煤层(页岩)气河南省协同创新中心,河南焦作454000

出　　处：《新疆石油地质》2018年第4期376-382,共7页Xinjiang Petroleum Geology

基　　金：国家科技重大专项(2016ZX05002-002);中国石化股份公司科技攻关项目(P1700-4)

摘　　要：准噶尔盆地东北缘乌伦古坳陷尚没有实质性的油气勘探突破,缺失准噶尔盆地普遍具有的二叠系生油岩,被认为是其主要原因,尽管乌伦古坳陷的基底石炭系被认为是最有可能的潜在烃源岩,但能否形成具有现实意义的油气源,仍有疑问。在乌伦古坳陷东北侧地表露头上,发现了固体沥青油苗,油苗呈侵染状、火焰状和树枝状,侵入第四系土黄色未固结的沙土沉积物和花岗岩风化壳中。利用有机碳含量、岩石热解、氯仿沥青A、镜质体反射率、干酪根碳同位素和甾烷、萜烷类生物标志化合物分析,确认了油苗的存在,并与研究区烃源岩和已发现原油进行了对比。研究表明,油苗中有机碳含量高,具有典型的煤成油碳同位素比值,油源为油苗分布区的石炭系黑色泥岩;与准东地区以二叠系、中—上三叠统和侏罗系为烃源岩的原油差异较大,而与石炭系原油具有较好的类比性。根据区域构造分析,乌伦古坳陷所在区域的基底是中亚巨型复合造山系的一部分,与油苗所在位置石炭系的组成和构造特征相似,因此,油苗的发现及研究,不仅对研究区的油气勘探具有重要意义,同时也可为准噶尔盆地东北缘乌伦古坳陷的油气勘探提供参考。Exploration breakthrough has not been achieved in Wulungu depression in the northeastern margin of Junggar basin, this shouldbe attributed to the absence of Permian source rock which is commonly found in Junggar basin. Although the Carboniferous basement ofWulungu depression is considered as the most likely potential source rock, it is still doubtful whether reservoirs can form here. Flame-like,disseminated and dendritic solid bitumen seepages which intrude into the earthy yellow, unconsolidated sand sediments and weatheringgranites of Quaternary are found in the outcrops of northeastern Wulungu depression. On the basis of the analysis of total organic carboncontent, rock pyrolysis, chloroform bitumen A, vitrinite reflectance, carbon isotope of kerogen and biomarkers of steriod and terpenoid, thepaper verifies the presence of the oil seepages and compares them with the source rocks and discoverded crude oil in the study area. Thestudy shows that the oil seepages have high total organic carbon contents which indicate typical carbon isotope values of coal formed oil andthe oil source is the Carboniferous black mudstone distributed in the oil seepage area; this oil is greatly different from the oil sourced fromPermian, Middle—Upper Triassic and Jurassic rocks in Zhundong area, but it can be well correlated with the Carboniferous oil. The region-al structural analysis indicates that the basement of Wulungu depression is a part of Central Asia Orogenic Belt, which has similar composi-tions and structural features with the Carboniferous strata in the areas where the oil seepages are located. Therefore, the discovery andstudy of the oil seepages not only have important significance for oil and gas exploration in the study area, but can provide references for oiland gas exploration in Wulugu depression in the northeastern margin of Junggar basin.

关 键 词：准噶尔盆地 乌伦古坳陷 石炭系 油源对比 油苗 

分 类 号：TE112.113[石油与天然气工程—油气勘探]