生烃期古构造在大油田形成中的作用探讨

发布时间：2018-04-07 15:26

  本文选题：鄂尔多斯盆地　切入点：延长组　出处：《西北大学》2015年硕士论文

【摘要】：本文以鄂尔多斯盆地中生界延长组为例,主要研究了古构造演化与油气成藏之间的关系,并结合烃源岩分布范围、大型有利储集体以及古构造演化预测了大型有利油气区的分布。本次研究主要取得以下认识：通过大量钻井地层对比和定量恢复各期地层沉积厚度和剥蚀厚度等,制作分析了延长组长7页岩生油时的储层顶面古构造形态。并在前人研究基础上开展了延长组烃源岩厚度展布分析、大型三角洲-重力流储集体展布分析和异常压力分析等,探讨了它们对大型含油区的控制作用。晚白垩世是延长组烃源岩大量生烃和油气运聚时期,本文主要恢复了长6、长8储层在中侏罗世末、早白垩世末和现今的构造面貌。将已发现油田与早白垩世末长6的顶面构造叠合,发现大油田分布主要受生烃岩范围和大型三角洲-重力流储集体的控制,而与早白垩世末长6的顶面构造关系不很明显。经过不同高低古构造位置的部分储量丰度和单井产量、原始含油饱和度统计比较可以看出,由于在成藏期存在较大的古构造高差和油气运聚动力,早白垩世末长6的顶面构造高部位的油藏含油饱和度、单井产量和储量丰度稍偏高。但总体而言,古构造与大油田的关系的密切程度不如烃源岩厚度和大型储集体分布那样明显。根据以上大油田形成与分布的控制因素,可以圈定预测大型有利含油区。在延长组湖盆三套烃源岩分布范围内,将不同时期的大型三角洲-重力流储集体分布区与古、今鼻凸轴线所圈定的重合区确定为Ⅰ类大型油田分布区；将湖盆内大型三角洲储集体单独发育区确定为ⅡA类油田分布区；将湖盆内古、今鼻凸轴线所圈定的有利油气聚集区确定为ⅡB类油田分布区,；其余生烃岩分布区为Ⅲ类油田分布区。
[Abstract]:Taking the Yanchang formation of Mesozoic in Ordos Basin as an example, this paper mainly studies the relationship between paleotectonic evolution and hydrocarbon accumulation, and combines with the distribution range of source rocks.Large favorable reservoirs and paleotectonic evolution predict the distribution of large favorable oil and gas regions.The main results of this study are as follows: through a large number of drilling strata correlation and quantitative recovery of sedimentary thickness and denudation thickness of each stage, the paleotectonics of the top surface of Yanchang No. 7 shale are made and analyzed.On the basis of previous studies, the thickness distribution analysis of source rocks in Yanchang formation, the distribution analysis of large deltaic gravity flow reservoirs and the analysis of abnormal pressure are carried out, and their controlling effects on large oil bearing areas are discussed.The late Cretaceous is the period of hydrocarbon generation and hydrocarbon migration and accumulation of source rocks in Yanchang formation. The structural features of Chang 6 and Chang 8 reservoirs in late Middle Jurassic, late early Cretaceous and present day are mainly restored in this paper.It is found that the distribution of large oil fields is mainly controlled by the range of hydrocarbon generating rocks and the large delta gravity flow reservoir, but not by the top structure of Chang6 at the end of early Cretaceous.Through the statistical comparison of reserves abundance and single well production at different positions of paleotectonics, the statistical comparison of original oil saturation shows that there are large paleotectonic height differences and hydrocarbon migration and accumulation dynamics in the reservoir forming period.The oil saturation, single well production and reserve abundance of the reservoir with high top structure at the end of the early Cretaceous are slightly higher.Generally speaking, the relationship between paleotectonics and large oil fields is not as close as the thickness of source rocks and the distribution of large reservoirs.According to the controlling factors of the formation and distribution of the large oil fields above, the large favorable oil bearing areas can be predicted.Within the distribution range of three sets of hydrocarbon source rocks in the lake basin of Yanchang formation, the distribution area of large deltaic gravity flow reservoir in different periods and paleo, the overlap area delineated by the present nose convex axis is determined to be the distribution area of type I large oil fields.The large delta reservoir development area in the lake basin is determined to be the distribution area of class 鈪，

本文编号：1719762