摘要
鄂尔多斯盆地西南部马岭-乔川地区延长组长6油层组发育规模不等的各种储集砂体。为明确其砂体叠置关系及展布规律,通过岩芯观察、测井综合解释等手段探讨砂体的叠置类型和展布规律,并分析砂体成因与油气储集性能。研究认为:(1)砂体叠置类型可分为多期厚层型、厚砂-薄泥型、砂泥互层型和薄砂-厚泥型4类;(2)砂体叠置关系与重力流类型相关,多期厚层型砂体指示连续型砂质碎屑流沉积,厚砂-薄泥型砂体表明具有事件停顿的多期砂质碎屑流沉积,停滞期发生湖相泥质沉积和明显的浊积韵律层,砂泥互层型砂体主要是牛顿流体状态的浊流沉积的结果,牛顿流体湍动的特性和强度多变的水动力导致流体内悬浮的不同粒级沉积物交互沉积,薄砂-厚泥型砂体则体现浊流搬运末期水动力减弱,流体内泥质细粒沉积物增多的沉积结果;(3)4类砂体的纵向连通性是控制油气运聚的关键,多期厚层型砂体的纵向连通性最好,厚砂-薄泥型次之,砂泥互层型较差,厚泥-薄砂型最差,多期厚层型和厚砂-薄泥型砂体的油层、差油层厚度远高于后两种纵向连通性稍差的砂体。长6_(3)亚段康岔-华池以及Luo225等井区域此两类砂体连片展布,是有利于油气富集的优势区域。本研究对马岭-乔川地区长6油层组砂体叠置关系和分布做出了系统解释,亦可为深水湖盆区重力流致密储层的评价提供参考。
The Maling-Qiaochuan area in the southwestern Ordos Basin hosts stacking sand bodies within the sixth oilbearing interval of the Yanchang Formation(designated as the Chang 6 Member).Through integrated analysis of drilling cores and curves logging data combined with sedimentological observations,this study systematically investigates the architectural configuration and spatial distribution patterns of gravity flow deposits,while evaluating their genetic mechanisms and hydrocarbon storage potential.Three principal findings emerge:(1)Sandbody stacking patterns can be categorized into four distinct types based on core-log integration-multi-stage amalgamated sandstones,thick sand-thin mud sequences,sand-mud alternations,and thin sand-thick mud complexes,with multi-stage amalgamated sandstones demonstrating superior reservoir quality through petrological analysis.(2)Genetic analysis reveals these stacking patterns correlate with specific gravity flow processes:continuous sandy debris flows form multi-stage amalgamated units,while thick sand-thin mud sequences record intermittent sandy debris flows intercalated with lacustrine mudstones and turbidite rhythmites.Sand-mud alternations originate from turbulent Newtonian flows where fluctuating hydrodynamic energy facilitates alternating deposition of suspended sediments,whereas thin sand-thick mud successions reflect waning turbidity currents with enhanced mud deposition during flow attenuation.(3)Vertical connectivity analysis demonstrates multi-stage amalgamated sandstones possess optimal migration pathways,followed sequentially by thick sand-thin mud,sand-mud alternations,and thin sand-thick mud configurations.This connectivity hierarchy directly controls hydrocarbon accumulation efficiency,evidenced by significantly greater effective thickness in the first two types compared to latter configurations.Strategic mapping identifies the Kangcha-Huachi,Li-308,and Ba-95 regions within the Chang 6_(3)submember as prime exploration targets due to extensive development of these favorable sand architectures.This systematic characterization of sandbody architecture not only clarifies reservoir heterogeneity in the study area but also provides a methodological framework for evaluating tight gravity flow reservoirs in deep lacustrine basins.
作者
张晓磊
唐玮玮
李继宏
赵凱莉
时孜伟
王梓烨
ZHANG Xiaolei;TANG Weiwei;LI Jihong;ZHAO Kaili;SHI Ziwei;WANG Ziye(Exploration and Development Research Institute of Changqing Oilfield Company PetroChina,Xi’an,Shaanxi 710018,China;Chengdu University of Technology,Chengdu,Sichuan 610059,China;National Engineering Laboratory of Exploration and Development of Low Permeability Oil and Gas Fields,Xi’an,Shaanxi 710018,China;The 7th Geological Brigade of Sichuan,Leshan,Sichuan 614000,China)
出处
《矿物岩石》
北大核心
2025年第2期186-199,共14页
Mineralogy and Petrology
基金
国家科技重大专项项目(编号:2017ZX05036-004-006)。
关键词
马岭-乔川地区
长6油层组
砂体叠置关系
砂体展布规律
Maling-Qiaochuan area
Chang 6 Member
Sandbody stacking relationship
Sand body distribution pattern
