鄂尔多斯盆地东部上古生界储层热液蚀变作用

发布时间：2018-02-01 00:38

本文关键词： 热液蚀变作用蚀变矿物组合自生矿物储层物性上古生界鄂尔多斯盆地　出处：《天然气地球科学》2017年01期 　论文类型：期刊论文

【摘要】：鄂尔多斯盆地东部上古生界为典型的致密储层,为阐明储层致密化成因,应用岩相学和地球化学方法,对砂岩成岩作用进行研究。结果表明,上古生界储层砂岩除了正常埋藏成岩作用外,还经历了强烈的热液蚀变作用,形成了早、晚2期蚀变矿物组合。早期蚀变矿物组合为高岭石+细鳞片状伊利石+绢云母+石英等,代表了早成岩阶段煤系有机质热演化形成的有机酸流体进入储层发生的蚀变作用。晚期蚀变矿物组合为伊利石+绿帘石+铁白云石+自形晶黄铁矿+晚期硅质胶结物,其中铁白云石的δ13CPDB值介于-1.18‰~-11.97‰之间,平均值为-5.57%;δ~(18)O_(PDB)值介于-2.28‰~-15.10‰之间,平均值为-12.57%。晚期伊利石和高岭石表现为LREE富集、HREE亏损,稀土配分模式为右倾型,δEu和δCe异常特征明显。晚期成岩矿物流体包裹体均一温度峰值为170℃,远高于地层处于最大埋深时的成岩温度。结合盆地构造演化过程分析认为,早白垩世时鄂尔多斯盆地发生区域性快速沉降的同时,盆地出现了一次大规模热异常事件,导致上古生界煤系烃源岩大规模生烃,形成的含烃流体与热异常事件伴随的热液流体进入储层,使储层砂岩发生热液蚀变作用,形成大量晚期热液矿物组合,充填孔隙使储层致密成为超低渗储层。热液蚀变作用对油气储层的影响值得关注。
[Abstract]:Upper Paleozoic in East Erdos basin is a typical tight reservoir, in order to clarify the causes of reservoir densification, using petrographic and geochemical methods, the diagenesis of sandstone were studied. The results show that the upper Paleozoic Sandstone Reservoir in normal burial diagenesis, has experienced intense hydrothermal alteration. The formation, early, late 2 altered minerals. Early alteration mineral assemblage of kaolinite + flake illite + + sericite quartz, organic acid fluid represents the early diagenetic stage of coal thermal evolution of organic matter formation into reservoir alteration. Late alteration mineral assemblages for Yili stone + epidote + ankerite + euhedral pyrite + late siliceous cement, the delta 13CPDB ferrodolomite value between -1.18% ~-11.97%, the average value is -5.57%; 8 ~ (18) O_ (PDB) values between -2.28% ~-15.10%, the average value is -12.57%. Late illite and kaolinite showed enrichment of LREE, HREE loss, REE patterns for the right type, Delta Eu and delta Ce anomaly. Late diagenetic mineral fluid inclusions peak temperature is 170 DEG C, is far higher than the formation temperature in the rock into the maximum depth. Combining with the basin tectonic evolution process analysis believe that the early Cretaceous Erdos basin regional rapid subsidence basin at the same time, there is a large thermal anomaly, resulting in the upper Paleozoic coal measure source rock mass hydrocarbon, forming hydrothermal fluid containing hydrocarbon fluid and abnormal thermal events associated with into the reservoir, the reservoir sandstones occur hydrothermal alteration effect of the formation of a large number of late hydrothermal mineral assemblage, pore filling the reservoir become dense low permeability reservoir. The influence of hydrothermal alteration of oil and gas reservoir is worthy of attention.

【作者单位】：长安大学地球科学与资源学院;国土资源部岩浆作用成矿与找矿重点实验室;中国石油长庆油田分公司勘探部;陕西省地质调查院;
【基金】：国家自然科学基金项目“单个流体包裹体CO2碳同位素显微激光拉曼光谱分析研究”(编号:41173055);国家自然科学基金项目“热年代学约束下鄂尔多斯盆地西南缘构造复合带的古地温及抬升冷却历史恢复”(编号:41602128) 中央高校基金项目(编号:310827151062)联合资助
【分类号】：P618.13
【正文快照】： 3.中国石油长庆油田分公司勘探部,陕西西安710021;4.陕西省地质调查院,陕西西安710065)2017,28(1):43-51.[覃小丽,李荣西,席胜利,等.鄂尔多斯盆地东部上古生界储层热液蚀变作用[J].天然气地球科学,2017,28(1):43-51.]0引言热液流体是指来源于地壳深部、温度比所经围岩地层温度

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