沉积物重力流流体转化沉积-混合事件层

随着浊流和碎屑流理论体系日臻成熟，重力流的流体转化过程逐渐受到重视，而与其相关联的混合事件层概念也应运而生。混合事件层是单次碎屑流或浊流流体转化中的沉积记录，是多种流变学特征的垂向沉积组合。典型混合事件层沉积序列具有五段式的特征（即纯净砂岩段H₁、条带状砂岩段H₂、黏性碎积岩段H₃、波状层理段H₄、块状泥岩段H₅），其内部通常存在岩性突变界面。混合事件层发育于粗粒三角洲内部、海底扇和水道与舌状体过渡区、舌状体侧缘、远端及限制性的微型盆地边缘地区，其垂向叠置厚度可达数十米。混合事件层的发现对重力流流体转化、重力流沉积物空间流变学性质研究具有重要意义，同时也推动了油气储层构型和非均质性研究，为进一步寻找深水有利储集砂体提供了新思路。混合层地球物理识别方法的建立及其相关概念在湖泊重力流研究中的灵活应用将是下一步的研究方向。

The Flow Transforming Deposits of Sedimentary Gravity Flow-Hybrid Event Bed

With the maturity of theoretical systems of turbidity current and debris flow, gravity flow transformation has gradually drew more attention, and its related concept-hybrid event bed is also aroused at this time. The hybrid event bed is a depositional record of flow transformation from a single-period debris flow or turbidity current event, which is manifested by vertical depositional combination of various rheological characteristics. The sequence of a typical hybrid event bed contains five divisions:clean sand internal H₁, banded internal H₂, cohesive debrites internal H₃, ripple-laminated internal H₄ and massive mud internal H₅, and obvious lithological interfacies are well identified in this bed. Hybrid event beds are well distributed in the coarse-grained deltas, the distal and lateral area of submarine fans and lobes, the transitional zone of channel-lobe and confined mini-basin margin with the vertical stacking thickness up to several meters. The recognition of hybrid event bed is extremely meaningful for further study on flow transformation of gravity flow and spatial rheological characteristics. Also, it promotes corresponding studies on the heterogeneity of hydrocarbon-bearing reservoirs and provides new thoughts for favorable deep-water reservoir sandbodies. The geophysics identification of hybrid bed and the flexible application of this new concept to the study on lacustrine gravity flow will be the next research direction.