碳酸盐岩台地边缘沉积结构差异及其油气勘探意义——以川东北早三叠世飞仙关期台地边缘带为例

发布时间：2018-04-03 06:02

本文选题：沉积结构差异　切入点：碳酸盐岩台地边缘　出处：《岩石学报》2017年04期

【摘要】：随着研究的深入,逐渐认识到碳酸盐岩台地边缘带(简称台缘带)具有沉积结构和演化的差异性,其不但记录了古地理格局及其演化过程,同时也对相关油气储层的发育具有重要的影响。以四川盆地东北部早三叠世飞仙关期同期近平行的三排台缘带为研究对象,通过钻井、野外露头及地震等资料综合分析,揭示研究区早三叠世飞仙关早期台缘鲕粒滩带明显继承了晚二叠世长兴期台缘礁滩带的分布,并具有整体向东迁移的特点。不同台缘带之间具有明显差异,可识别出迁移型和加积型两种台缘结构样式,迁移型台缘带主要分布在元坝-龙岗-梁平台缘带(简称1号台缘带)、简池-鸡王洞-沙陀台缘带(简称3号台缘带),其具有台缘斜坡坡度缓、迁移明显,造成台缘带鲕粒滩整体分布宽但厚度薄、横向间互云化的特点;加积型台缘带主要分布在铁厂河-普光-罗家寨台缘带(简称2号台缘带),沉积结构总体上表现为加积特征,但晚期具有向东迁移特点,台缘带窄、台前滑塌普遍,鲕粒滩分布集中且厚度大、云化彻底。不同台缘带内部沉积和储层分布具有差异性,1号台缘带内部具有斜坡带陡缓相间,缓坡区台缘带鲕粒滩迁移明显,鲕粒滩累积厚度薄且云化弱或不发育,相对的陡坡区迁移幅度略小,鲕粒滩累计厚度略厚,且具有向上云化程度逐渐增强的特点;由于面对相对开阔的海域,3号台缘斜坡带风暴影响明显,具有横向上的云化间互及垂向云化增强特征明显,资料有限,横向地貌变化尚待进一步揭示;2号台缘带具有横向上的鲕粒滩厚薄变化,但加积和整体云化特征稳定。台缘沉积结构差异性明显受早期长兴期古地貌、海平面变化及古风向和沉积期差异沉降等因素的联合影响。研究建立了相关台缘带沉积和白云岩分布模式。
[Abstract]:With the deepening of the research, it is gradually recognized that the carbonate platform marginal zone (terrace) has the difference of sedimentary structure and evolution, which not only records the paleogeographic pattern and its evolution process,At the same time, it also has an important influence on the development of related oil and gas reservoirs.Taking the early Triassic Feixianguan period of the northeastern Sichuan Basin as the object of study, the three parallel platform margin zones were comprehensively analyzed by drilling, outcrop and seismic data.It is revealed that the oolitic beach belt of the early Triassic Feixianguan platform margin in the study area obviously inherits the distribution of the reef beach belt in the Changxing period of the late Permian and has the characteristics of overall eastward migration.There are obvious differences among different platform margin zones, and two types of platform edge structures can be identified as migration type and accretive type.The migrating platform margin zone is mainly distributed in the Yuanba Longgang Liangping platform margin belt (referred to as the No. 1 platform margin belt), and the Jianchi Jiwangdong Shatuo platform margin belt (referred to as the No. 3 platform margin belt), which has the slope of platform edge slope is slow and the migration is obvious.As a result, the oolitic shoal of the platform margin belt has the characteristics of wide distribution, thin thickness and mutual cloud formation, and the accretive platform margin belt is mainly distributed in the Tiechang River Puguang Luojiazhai platform margin belt (2 platform margin zone), and the sedimentary structure is characterized by accretion in general.However, the late stage has the characteristics of eastward migration, narrow margin of platform, widespread collapse in front of platform, concentrated distribution of oolitic beach, large thickness, and complete cloud formation.The deposits and reservoir distribution in different platform margin zones are different. There is a steep and slow interphase between slope zone and platform margin zone, oolitic beach migration is obvious, the accumulation thickness of oolitic beach is thin, and cloud formation is weak or undeveloped.The migration range of the relative steep slope area is slightly smaller, the accumulative thickness of oolitic beach is slightly thicker, and it has the characteristic of gradually increasing the degree of clouding up, because of the relatively open sea area, the storm in the slope zone of the third margin has obvious influence.It has obvious characteristics of horizontal cloud interaction and vertical cloud enhancement, limited data, and the lateral geomorphologic changes need to be further revealed, while the thickness and thickness of oolitic shoal in the No. 2 margin zone are changed laterally, but the accretion and overall clouding characteristics are stable.The difference of sedimentary structure in the platform margin is obviously influenced by the early Changxing paleogeomorphology, sea level change, paleo-eolian direction and differential sedimentation, etc.The sedimentary and dolomite distribution model of the relevant platform margin zone is established.
【作者单位】：油气藏地质与开发工程国家重点实验室(成都理工大学);成都理工大学沉积地质研究院;中国地质大学构造与油气资源教育部重点实验室;中国地质大学资源学院;中国石化勘探分公司;中国地质大学;中国石油西南油气田分公司川东北气矿;
【基金】：国家自然科学基金项目(41302089、41672103) 成都理工大学中青年骨干教师培养计划项目;成都理工大学引进高层次人才科研项目联合资助中国地质调查局项目(1212011220758)
【分类号】：P618.13

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