基于沉积实验的重力流沉积体系砂体分布特征分析

Gravity Flow Deposit Distribution Characteristics based on Sedimentary Experiment

重力流沉积体系砂体展布规律极为复杂,通过重力流流体实验,确定了重力流沉积不同岩相的成因及展布规律,并在此基础上,通过岩芯观察及测井、录井资料分析,在滨南油田古近纪沙三下亚段进行重力流砂体展布规律研究,研究结果表明:1)塑性流体在运动过程中被稀释,导致颗粒支撑机制发生复杂的变化,从而出现多种流态的流体,因此塑性流体被稀释到一定程度后会转换为液态流体; 2)重力流沉积层序的垂向演化及横向变化是流体性质演化的结果,即地质记录中的复杂重力流层序为流体性质转换后再沉积的结果; 3)重力流垂向层序与沉积模式的有机结合是进行砂体展布预测的关键。在该模式的指导下,明确了滨南油田沙三下亚段岩相的空间展布和变化规律。

The distribution law of sand bodies in gravity flow sedimentary systems is very complex.By gravity flow fluid experiments,the cause of formation and the distribution law of different lithofacies have been determined.On this basis,through core observation,logging,and logging data analysis in Binnan oilfield sand,three subsections of gravity flow sand-body distribution rules were identified.The results show that:1)Plastic fluid dilution and the particle support mechanism show complex changes in the process of movement,leading to a variety of fluid flows in which plastic fluid diluted to a certain extent will be converted into liquid;2)The vertical evolution and lateral variation of the sequence of gravity flow deposits are the result of fluid property evolution,or in other words,the complex gravity flow sequence observed in geological records is the result of fluid property transformation;3)The organic combination of gravity flow vertical sequence and a sedimentary model is the key to predicting sand distribution.Under the guidance of the model constructed in this research,the distribution of lithofacies was confirmed in in Binnan oilfield.