古地理图的编制是恢复不同地质历史时期古地理面貌的重要手段。具有不同规模的构造运动、不同周期或级次的全球海平面升降或基准面旋回、沉积作用和气候等因素相互作用影响下耦合成的沉积层序常常表现出不同时间跨度和空间分布范围的旋回特点。不同级别和规模的沉积层序为不同驱动机制下不同规模的沉积响应。为了与油气紧密结合,通常选择Ⅱ级、Ⅲ级层序体系域和中期基准面旋回相域为编图单元,分别在大的块体、单盆地或盆地内大的区域和重点区块编制具有等时性、成因连续性和实用性的小、中、大比例尺层序/岩相古地理图,不同尺度地刻画出古地理面貌,从不同规模和尺度上反映物质的聚集和分布规律,为优选勘探区、预测有利区带和确定储集体提供有利的理论和实际依据,从而为油气勘探各个阶段服务。
Drawing paleogeography is an important method to reconstruct paleogeography of different geological history.Sedimentary sequence often manifests the cycle characteristic of different temporal and spatial distribution,which is coupled by the interaction of tectonic movement of diverse scale,global eustasy or base level cycle of different period or order,sedimentation and climate.Sedimentary sequence of different order and scale responds differently to varying driving mechanism.To link with hydrocarbon exploration closely,usually selecting the second-order,third-order and medium-term base level phases as compilation unit,to draw sequence lithofacies paleogeographic of small scale,medium scale and large scale on large plot,basin or large area inside basin,and important block.They are marked by the advantages,such as isochronisms,succession of the sedimentation process and practicability.The sequence lithofacies paleogeographic can manifest detailedly paleogeography in varying degrees and represent the combination and distribution regulation of material from diverse scale.And they can provide the theoretical and practical proofs for selecting exploration target area,predicting favorable zone and ascertaining reservoir,then provide service for every stage of hydrocarbon exploration.