Geochemical quantification of mixed marine oils from Tazhong area of Tarim Basin, NW China
Geochemical quantification of mixed marine oils from Tazhong area of Tarim Basin, NW China
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DOI：
10.1016/j.petrol.2012.04.028
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发表时间：
2012-07
影响因子：
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通讯作者：
Yankuan Tian;Chupeng Yang;Z. Liao;Haizu Zhang
中科院分区：
文献类型：
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作者：
Yankuan Tian;Chupeng Yang;Z. Liao;Haizu Zhang
塔中地区位于塔里木盆地中部，油气资源十分丰富，主要来源于寒武系-下奥陶统烃源岩和中上奥陶统烃源岩。由于多期生、运、聚等沉积后改造作用的影响，该区油气藏多为混源油气藏。原油地球化学研究结果结合108个原油样品的稳定碳同位素数据表明，塔中地区海相原油主要为陆源-O1和O2 + 3混合源原油。根据原油稳定碳同位素数据，定量评价了不同烃源岩对混合油的相对贡献，结果表明，塔中地区主要由中上奥陶统烃源岩贡献，少数油藏主要由寒武系-下奥陶统烃源岩贡献。但对于塔中地区不同亚单元的油气藏，不同烃源岩的相对贡献并没有呈现出规律性的分布规律，表明塔中地区在地史上经历了多期生烃、运移和聚集。
Located in the center of the Tarim Basin, NW China, Tazhong area was found to be enriched in oil and gas resources, and the resources are mainly originated from two sets of marine source rocks, namely, the Cambrian-Lower Ordovician (ϵ-O1) source rocks and the Middle-Upper Ordovician (O2+3) source rocks. Due to complex post-depositional alterations such as multiple episodes of hydrocarbon generation, migration and accumulation, most oil reservoirs in this area occur as mixed oils. Results of geochemical studies of crude oils, combined with bulk stable carbon isotope data of 108 oil samples, indicate that most marine oils from Tazhong area are mixtures sourced from both the ϵ-O1and O2+3strata. Based on bulk stable carbon isotope data of the oils, quantification studies were made to evaluate the relative contributions of different source rocks to the mixed oils, and the results show that the Middle-Upper Ordovician source rocks are the main contributor for the oils in the Tazhong area, despite fewer exceptions that some oil reservoirs were mainly originated from the Cambrian-Lower Ordovician source rocks. However, for the oil reservoirs occurring in different subunits in the Tazhong area, the relative contributions from different source rocks do not show regular distribution patterns, implying that Tazhong area was subject to multiple episodes of hydrocarbon generation, migration and accumulation in geological history.