| 准噶尔盆地东南缘二叠系芦草沟组烃源岩有机地球化学特征 |
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| 引用本文： | 张韩静,李素梅,高永进,张林,柯昌炜.准噶尔盆地东南缘二叠系芦草沟组烃源岩有机地球化学特征[J].现代地质,2022,36(6):1538-1550. |
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| 作者姓名： | 张韩静 李素梅 高永进 张林 柯昌炜 |
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| 作者单位： | 1.中国石油大学(北京)地球科学学院,北京 1022492.中国地质调查局油气资源调查中心,北京 100029 |
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| 基金项目： | 国家自然科学基金项目(42073064) |
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| 摘 要： | 准噶尔盆地东南缘烃源岩演化与油气成因复杂,采用岩石热解、色谱-质谱、碳同位素等有机地球化学分析技术,对该区二叠系芦草沟组烃源岩地球化学及其成烃演化特征进行了详细调查。结果表明,不同成熟度的二叠系芦草沟组烃源岩有机质丰度和有机类型差异显著,烃源岩有机碳、生油潜量(S1+S2)分布范围分别为0.43%~12.89%(均值2.84%)、0.52~77.24 mg/g,烃源岩质量可从低熟时的“极好”级别降低至高成熟时的“中等-差”级别(Rc≈0.54%~1.93%);有机质类型可从低熟时的Ⅰ-Ⅱ1型变化为高成熟时的Ⅱ2-Ⅲ,指示对高-过成熟烃源岩的有机质类型与生烃潜能评价需要进行评价参数的适当恢复。二叠系芦草沟组烃源岩生物标志物特征显著:姥鲛烷相对于植烷有微弱优势,Pr/Ph值分布范围为0.92~1.81(均值1.22),指示弱还原的湖相沉积环境;C27-、C28-、C29-规则甾烷呈斜直线型分布;C28-规则甾烷丰度偏高(C28/C29-规则甾烷均值为0.96)、升藿烷系列丰度偏低、伽马蜡烷发育,反映二叠系芦草沟组烃源岩咸化和/或水体分层的原始沉积环境。油-油、油-源对比表明,芦草沟组原油主要来自芦草沟组烃源岩。烃源岩地质地球化学分析表明,深浅层不同成熟度芦草沟组烃源岩均有发育,该区具有较好的生烃物质基础,具有寻找不同埋深油气藏的重要勘探前景。
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| 关 键 词： | 芦草沟组 生烃潜力 生物标志化合物 准噶尔盆地 |
| 收稿时间： | 2022-03-20 |
| 修稿时间： | 2022-04-21 |
Organic Geochemical Characteristics of Source Rocks of Permian Lucaogou Formation in Southeastern of Junggar Basin |
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| ZHANG Hanjing,LI Sumei,GAO Yongjin,ZHANG Lin,KE Changwei.Organic Geochemical Characteristics of Source Rocks of Permian Lucaogou Formation in Southeastern of Junggar Basin[J].Geoscience——Journal of Graduate School,China University of Geosciences,2022,36(6):1538-1550. |
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| Authors: | ZHANG Hanjing LI Sumei GAO Yongjin ZHANG Lin KE Changwei |
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| Institution: | 1. State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum, Beijing 102249,China2. Oil and Gas Survey, China Geological Survey, Beijing 100029, China |
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| Abstract: | Thermal evolution and petroleum potential of the source rocks as well as origin of the hydrocarbons discovered in the southeast Junggar Basin are not clear enough. Geochemical methods including Rock-Eval, GC-MS and carbon isotopic analysis are used to unravel relevant issues. The results show that there are obvious differences in organic matter abundance and kerogen types of the source rocks form the Permian Lucaogou Formation (P2l) with varying thermal maturity. The total organic carbon (TOC) of the P2l source rocks is ranged in 0.43 %-12.89 % (averaged 2.84 %), and the petroleum potential of (S1+S2) is in the range of 0.52-77.24 mg/g. The source rock quality can be reduced from “excellent” grade at low maturity to “moderate-poor” grade at high maturity (Rc≈0.54%-1.93%). The type of organic matter varies from type Ⅰ-Ⅱ at low maturity to type Ⅱ2-Ⅲ at high maturity, indicating that it is necessary to properly restores the original value of the kerogen type and hydrocarbon generation potential for the high to over-mature source rocks. Distinguished characteristics of the biomarkers of the P2l source rocks were observed: a weak advantage of pristine over phytane was observed with the ratios of Pr/Ph ranging from 0.92 to 1.81 (averaged 1.22), indicating a weakly reduced lacustrine sedimentary environment; the relative abundance of C27-,C28-, and C29-regular steranes showed an ascending linear pattern. The source rocks are also characterized by high relative abundance of C28-regular steranes (with the mean value of the C28/ C29-regular steranes ratio to be 0.96), low relative abundance of homohopanes with gammacerane developed, while the abundance of hopanes is low and gammacerane is moderately developed in the source rocks,indicating saline and/or water stratified paleoenvironment of the P2l source rocks when deposited. Oil-oil and oil-source rock correlations showed that the crude oils from the Lucaogou Formation were mainly derived from the P2l source rocks. The geochemical and geological investigations of this study shows that the P2l source rocks with a relatively wide range of burial depth and therefore a wide range of maturity level were well developed, suggesting an excellent hydrocarbons generation potential in the area investigated. It indicates great petroleum exploration prospects for deep and shallow horizons. |
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| Keywords: | Lucaogou Formation hydrocarbon generation potential biomarker Junggar Basin |
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