收稿日期: 2015-05-20
修回日期: 2015-08-28
网络出版日期: 2015-09-20
基金资助
国家自然科学基金(编号:41402127)资助.
Formation Mechanism and Characteristics of Sandy Conglomerate Diagenetic Trap: A Case Study of the Triassic Baikouquan Formation in the Mahu Sag,Junggar Basin
Received date: 2015-05-20
Revised date: 2015-08-28
Online published: 2015-09-20
成岩圈闭是重要的油气圈闭类型之一,其成因类型较多,在准噶尔盆地玛湖凹陷三叠系百口泉组中发育的受沉积相和成岩相共同控制而形成的砂砾岩成岩圈闭是其中一种重要的成因类型。玛湖凹陷百口泉组发育扇三角洲沉积体系,在顺物源方向上,有机酸溶解扇三角洲前缘砂砾岩中的长石而形成次生溶解孔隙储层,其上倾方向上压实作用和胶结作用使扇三角洲平原砂砾岩致密化而形成圈闭遮挡层;在垂直物源方向上,次生溶解孔隙储层分布在由通源断裂和古鼻状构造构成的有机酸优势运移通道上,通道两侧前缘相砂砾岩较致密,其与水下分流河道间泥岩、其他物源体系的扇三角洲平原砂砾岩致密层构成圈闭侧向遮挡带;圈闭底板由百口泉组底部不整合面风化黏土层或平原相砂砾岩致密层或湖泛泥岩构成,圈闭顶板由湖泛泥岩构成。百口泉组砂砾岩成岩圈闭主要分布在由通源断裂和古鼻状构造构成的流体优势运移通道上,具有成藏优势,同时圈闭在横向上集群、纵向上叠置分布,具备了形成规模油气聚集的圈闭条件,是玛湖凹陷规模油气勘探的主要对象。百口泉组砂砾岩成岩圈闭的发现对中国东部裂谷盆地和中西部前陆盆地冲断褶皱带一侧陡坡冲积扇、扇三角洲的圈闭勘探具有借鉴意义。
潘建国,王国栋,曲永强,唐勇,齐雯,谭开俊,尹路,魏彩茹 . 砂砾岩成岩圈闭形成与特征——以准噶尔盆地玛湖凹陷三叠系百口泉组为例[J]. 天然气地球科学, 2015 , 26(S1) : 41 -49 . DOI: 10.11764/j.issn.1672-1926.2015.S1.0041
The diagenetic trap with many genetic types is one of the most important types of hydrocarbon traps.Sandy conglomerate diagenetic trap of the Triassic Baikouquan Formation in the Mahu Sag,Junggar Basin is an important genetic type,which is genetically controlled by sedimentary facies and diagenetic phases.The Baikouquan Formation is dominated by fan-delta deposition.In direction of provenance,secondary pore reservoirs of diagenetic trap consist of fan-delta front sandy conglomerate,of which the feldspars are dissolved by organic acid,and the fan delta plain tight conglomerate seals of diagenetic trap are formed by strong compaction and cementation in the upper direction.In perpendicular direction of provenance,secondary pore reservoirs of diagenetic trap distribute in the dominant migration pathway of the organic acid,which is comprised of source-faults and ancient nose structures.The lateral seals of diagenetic trap consist of interdistributary mudstone,fan delta plain tight sandy conglomerate of other provenances,and fan delta front tight sandy conglomerate distributing on sides of the pathways.The base seals consist of weathered clay layer,fan delta plain tight sandy conglomerate,and transgressive shallow lake mudstone,and the top seals consist of transgressive shallow lake mudstone.Distributing in the dominant migration pathway of the organic acid,stacking and clustering laterally,the Baikouquan sandy conglomerate diagenetic traps have the advantages of forming large-scale hydrocarbon accumulation,becoming the most important exploration target in the Mahu Sag.The finding of Baikouquan sandy conglomerate diagenetic traps could provide a model for trap exploration of the steep alluvial fan and fan delta in the eastern rift basins and foreland basins in the central and western China.
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