【作者】 王昌勇；

【导师】 郑荣才；

【作者基本信息】 成都理工大学 ， 沉积学， 2009， 博士

【摘要】 姬塬地区位于鄂尔多斯盆地西南部,长6油层组及长8油层组为该区现今主力产层之一,已有的钻井显示此两层位砂体厚度变化大、物性较差而且非均质性严重、油水关系复杂,需要对长8～长6油层组物源、沉积相进行系统的精细研究,进行构造-沉积演化史分析,在此基础上进行成藏规律分析,解剖层序地层格架中储层发育特征,探讨构造运动、沉积演化、成藏作用相互之间的关系及其对储层的影响,并预测有利储层发育的区带,取得如下几个重要的研究成果:1.通过大量岩芯观察、测井资料及岩矿资料的分析,结合前人的研究成果,首次提出鄂尔多斯盆地姬塬地区长8油层组属于浅水三角洲沉积体系,长7油层组为水下扇-半深湖沉积体系,长6油层组为水体较深的曲流河三角洲-浅湖沉积体系。2.应用高分辨率层序地层学理论及其技术方法,对长8油层组和长6油层组进行了高分辨率层序分析,详细描述和对比了长8油层组的浅水三角洲与长6油层组水体较深的曲流河三角洲层序的结构类型、叠加样式和分布模式。3.在精细的沉积-层序分析基础上,进行物源区分析和层序-岩相古地理编图,结果表明,研究区长8及长6油层组主要受北东、北西和西南方向3大物源区影响,沉积体系分别受不同时期盆地南缘和西南缘构造的活动控制。4.首次分析了鄂尔多斯盆地西南缘构造演化与长8～长6油层组沉积学响应特征的关系,认为:长8期距离研究区较远的盆地南缘秦岭开始进入隆升状态,而距离研究区较近的盆地西部尚无明显的构造活动事件,研究区构造环境相对稳定,因此以发育受南缘构造活动控制的浅水三角洲沉积体系为主;从长7期开始,盆地西南缘开始强烈的构造活动并伴有火山喷发,六盘山一带也进入隆升状态并挤压沉积基底,造成湖盆强烈坳陷,因此以发育同时受盆地南缘和西缘构造活动影响的半深湖-水下扇沉积体系为主;长6期火山活动减弱,但盆地西部断裂带的构造活动仍较强烈,沉积盆地处于持续坳陷沉降状态,以发育受盆地西缘构造活动影响的、湖泊水体相对较深的曲流河三角洲-浅湖沉积体系为主。5.根据构造演化的长8～长6油层组沉积响应特征和层序-岩相古地理编图成果,结合有机地球化学特征,总结归纳了研究区长8～长6油层组油藏类型,解剖了各层位油藏形成条件,指出了研究区内最有利的勘探区带,为下一步滚动勘探开发提供了重要的地质依据。更多还原

【Abstract】 Jiyuan area is located in the southwest of Ordos Basin. Interval 6 & 8 of Yanchang Formation are principally producing formations of the study area. The thickness of single sand body varies greatly with bad physical property and obvious anisotropies, and complex relationship between oil and water is the typical characteristics of the two layers. In view of the needs of exploration and development in the study area, provenance, sedimentary facies and evolution ofstructure-sedimentation history are studied. The laws of hydrocarbon accumulation were concluded, and the distribution of reservoir in the sequence stratigraphic frame was analyzed. By the study of the relationship between tectonic movement, sedimentary evolution and hydrocarbon accumulation and the affection to reservoir, favorable belts for the development of reservoirs were forecasted. The research have acquire following results:1. Based on the core observation, analysis of logging and debris and minerals data, and combined with the fruit of predecessors this paper points out for the first time that the Interval 8 of Yanchang Formation in Jiyuan area in Ordos Basin developed shallow water delta. Interval 7 of Yanchang Formation developed subaqueous fans -semi-deep lake facies sedimentation and Interval 6 of Yanchang Formation developed meandering-delta and meare deposition system that has deep water depth.2. Guided by the high-resolution sequence stratigraphy theories and methods, the authors studied the high-resolution sequence of the Interval 8 & 6 of Yanchang Formation. Distribution, structure and stacking pattern correlation of sequence of Interval 6 and 8 of Yanchang Formation in Jiyuan area have been described and compared.3. Provenance analysis and sequence-paleogeographic mapping based on the careful sedimentation and sequence analysis of the Interval 8 & 6 of Yanchang Formation indicated that the sedimentation was controlled by the northeast, northwest and southwest sources of the study area. The sedimentary system was controlled by tectonic movement of the southern margin and the southwestern margin of the Ordos Basin in different stage.4. This paper analyzed the relationship between tectonic evolution and sedimentary response from Chang-8 to Chang-6 sedimentary stage in the southwest of the Ordos Basin first time, and draw a conclusion that Qinling where is far from study area had uplifted in Chang-8 stage, while no obvious tectonic movement in the west of the Ordos Basin where is close to the study area, and developed shallow water delta that controlled by southern margin tectonic activity of the basin. The southwestern margin of the Ordos Basin began move intensely with strong volcanic activity in Chang-7 stage. Liupanshan began uplift and compress the base which led intensely depress of the lake basin, and the study area characterized by semi-deep lake that develops subaqueous fans in Chang-7 depositional stage. The volcanic action of Chang-6 depositional stage became weak, but the tectonic action of faulted zone in the west of Ordos Basin is also intense. The basin depressing continuously and develop meandering-delta with deep lake water in Chang-6 stage, which controlled by the tectonic movements of the western margin of the Ordos Basin.5. The paper concludes the reservoir types and hydrocarbon generation conditions of different layer on the base of sedimentary response of tectonic movement, sequence-paleogeographic mapping and organic geochemical characteristics of Interval 6 & 8 of Yanchang Formation. And favorable belts for hydrocarbon accumulation in the study area have been pointed out as basis of next exploration and development.更多还原