鄂尔多斯盆地吴起—定边地区延长组下组合油源对比研究

Oil and source rock correlation of lower assemblage of Yanchang Formation in Wuqi and Dingbian areas, Ordos Basin

王香增 任来义 张丽霞 贺永红 杨超 段昕婷

Wang Xiangzeng Ren Laiyi Zhang Lixia He Yonghong Yang Chao Duan Xinting

陕西延长石油(集团)有限责任公司研究院, 西安 710065

Research Institute of Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi'an, Shaanxi 710065, China

通过对延长组下部地层组合中的长7、长9、长10烃源岩及原油地化资料的对比分析认为,长7烃源岩碳优势指数CPI为1.2,长9和长10为1.09;3套烃源岩中碳奇偶优势比均消失;长7烃源岩中Ts相对含量高于Tm,而长9和长10烃源岩中Ts相对含量低于Tm,说明长7烃源岩的成熟度要高于长9和长10烃源岩成熟度;规则甾烷中其ααα20R构型C27、C28和C29甾烷的分布类型上,长7呈现为"V"和"L"型分布,长9呈现为近"V"字型和反"L"型分布,长10主体呈反"L"型分布。长8原油在研究区西部来源于长7烃源岩,在东部及南部既来源于长7又来源于长9烃源岩;长9原油在研究区西部来源于长10烃源岩,在东部及南部既来源于长9又来源于长10烃源岩;长10原油在研究区南部既来源于长10又来源于长9烃源岩。

The geochemical correlation of source rock and crude oil from the lower assemblage (Chang7, 9, 10, respectively) of the Yanchang Formation has indicated that, the carbon preference index (CPI) of the Chang7 source rock is 1.2, and that of the Chang9 and Chang10 source rocks is 1.09. The odd-even predominance (OEP) of carbon disappears in the Chang7, 9, 10 source rocks. In the Chang7 source rock, the relative content of Ts is higher than that of Tm, while in the Chang9 and Chang10 source rocks, the relative content of Ts is lower than that of Tm, indicating for higher maturity of the Chang7 source rock. The C27, C28, C29 ααα20R regular steranes of the Chang7 source rock distribute in "V" and "L" shapes, and those of the Chang9 source rock in nearly "V" and anti-"L" shapes, and those of the Chang10 source rock in anti-"L" shape. Crude oil in the Chang8 strata mainly originated from the Chang7 source rock in the west of the study area, and from both the Chang7 and Chang9 source rocks in the east and south. Crude oil in the Chang9 strata mainly originated from the Chang10 source rock in the west of the study area, and from both the Chang9 and Chang10 source rocks in the east and south. Crude oil in the Chang10 strata originated from both the Chang10 and Chang9 source rocks in the south.

国家自然科学基金(41172122)项目资助。

https://doi.org/10.11781/sysydz201304426