渤中凹陷西次洼烃源岩地球化学特征及油源对比

Geochemical characteristics of source rocks and oil-source correlation
in western sub-sag of Bozhong Sag

郝鹏 臧春艳 王波 罗程飞 李阔 曹洁

中海油能源发展工程技术分公司中海油实验中心，天津 300452

(CNOOC Experimental Center, CNOOC EnerTech-Drilling & Production Co., Tianjin 300452, China

根据渤中凹陷西次洼东三段、沙一段和沙三段烃源岩沉积环境和有机质母源的差异，总结了鉴别3套烃源岩的生物标志化合物组合参数，根据多种地球化学资料，对西次洼6个含油气构造的原油及油砂进行了油源对比。结果表明：C24/C26（S+R）、?酌蜡烷异常指数、4MSI、C29αββ/（ααα+αββ）等生物标志化合物参数可以有效区别不同的烃源岩。研究区原油分为4类：Ⅰ类原油来源于沙三段烃源岩，分布于渤中8￣D油田；Ⅱ类原油来源于东三段烃源岩，分布于渤中1￣A、渤中2￣A油田古近系，曹妃甸L油田中生界和曹妃甸5￣E构造；Ⅲ类原油来源于沙一段烃源岩，分布于曹妃甸6￣D油田古近系和曹妃甸L油田新近系；Ⅳ类原油为混合型原油，分布于渤中1￣A、渤中2￣A、曹妃甸6￣D油田新近系。渤中8￣D油田和曹妃甸5￣E构造整体为单源供烃，其余油田古近系为单源成藏，新近系为多源混合成藏。

According to the differences of depositional environments and organic matter of members E2s3, E2s1 and E3d3 of the western sub-sag of Bozhong Sag, the biomarker parameters for identifying the three sets of source rocks were revealed. On this foundation, applying various geochemistry data, a rigorous study on oil-source correlation in six oil fields in the western sub-sag was made. The result shows that using C24/C26(S+R), gammacerane index, 4MSI and C29αββ/(ααα+αββ) biomarker parameters can distinguish the different source rocks effectively. The crude oil in the western sub-sag of Bozhong Sag can be divided into four types. The first type comes from E2s3 source rock, which is distributed in Caofeidian 8-D oilfield. The second type is derived from E3d3 source rock, mainly distributed in Paleogene reservoir of Bozhong 1-A and 2-A oilfields, Mesozoic reservoir of Caofeidian L oilfield, and Caofeidian 5-E structure. The third type is from E2s1 source rock and distributed in Paleogene reservoir of Caofeidian 6-D oilfield and Neogene reservoir of Caofeidian L oilfield. The fourth type is a mixed type of crude oil supplied by multiple sets of source rocks, mainly distributed in the Neogene reservoir of Bozhong 1-A oilfield, Bozhong 2-A oilfield and Caofeidian 6-D oilfield. Caofeidian 8-D and Caofeidian 5-E structures are single hydrocarbon source reservoirs, while the Neogene reservoir of the other oilfields are accumulated by multi-sources and the Paleogene reservoir is supplied by a single source rocks.

10.6056/dkyqt201906001