加拿大阿萨巴斯卡Kinosis区域下白垩统McMurray组内河口湾复合点坝砂体构型解剖*
Architectural analysis of compound point-bar sandbody in inner estuary of the Lower Cretaceous McMurray Formation in Kinosis area, Athabasca,Canada

河口湾可分为宽阔的外河口湾和较窄的内河口湾。内河口湾水动力条件表现为潮汐影响、河流主控的特征,主要发育点坝或者线状砂坝。加拿大阿萨巴斯卡Kinosis地区发育大量潮汐作用影响的复合点坝沉积,复合点坝内部构型研究直接影响油田的开发效果。基于该区测井及高品质三维地震(频带8~220 Hz,主频90 Hz)等资料,提出1套以解决油田开发问题为核心,基于以“轴变定界、样式定型、井点定面”为原则的内河口湾复合点坝砂体构型解剖方法,研究对象为达到地震可分辨尺度的“复合砂体”。通过岩心和地震相特征分析,刻画了不同级次构型单元内部沉积特征。利用倾角测井等资料,分析了侧积体和侧积层的规模及产状,实现了点坝内部构型解剖。结果表明,内河口湾点坝沉积发育倾斜非均质层(IHS)、生物扰动、泥砾等指示潮汐作用的沉积现象;侧积体倾斜角度为8°~12°,单一侧积体宽度为55~200m。通过复合砂体构型解剖,明确了构型单元内部隔夹层和层内水层的分布与构型单元的组合有直接关系,提出了针对单一河道单元部署井网的策略。
The estuary can be divided into widely outer estuary and narrowly inner estuary. The area of inner estuary was dominated by fluvial currents and influenced by tides,where the point bars and linear bars were developed. The tidal influenced compound point-bars were well developed in Kinosis area,Athabasca. Architecture of the compound point bars influenced the production effects of oilfield. Based on the log data and high quality 3D seismic(bandwidth 8-220Hz),a set of compound point-bar sandbody analysis method was put forward and the spatial distribution of compound bars were characterized. Through the core and analysis of seismic facies,internal sedimentary characteristics of the architectural units in different hierarchy were depicted. Using the dip log data,the size and occurrence of the lateral accretions were analysis and the anatomy of the internal point-bars were conducted. The results show: the inclined heterogenetic stratification (IHS),bioturbation and mud breccias were developed in inner estuary which were the marks of the tide. The mud plug breccias and seismic facies can help us to recognize the compound point bars. The dip angle of the lateral accretions are 8°-12° and the width are 55-200m.The results of the compound point-bars were applied in prediction of interlayer and intralayer water saturation, production plan design, and optimization