The Application of Clastic Grain-size Analysis to the Genetic Study of Sand Bodies in Upper Es4 Submember of Xin176 Area in Dongying Sag
碎屑颗粒粒度分析在东营凹陷辛176块沙四上亚段砂体成因研究中的应用

The utilization of grain-size data to analyze the structure characteristics of the sediment grains can effectively determine the transport mode of sediments, judge the hydrodynamic conditions, distinguish the sedimentary environments, and analyze the genetic mechanism of sediments. Based on a large number of grain-size frequency curves, probability cumulative grain-size curves and grain size-standard deviation curves, the authors studied in detail grain-size components in sediments and characteristics of these components, extracted the grain components sensitive to the change of environment, and determined the corresponding hydrodynamic conditions. In combination with the sedimentary facies and structural setting, the genesis of sand bodies in the Cs5 sand group within Upper Es4 submember of Xin176 block was discussed. The result shows that the sand bodies in wx583 and x176x1 of Xin176 area are beach-bar sand bodies transported from Guangrao Salient and formed by fluvial and wave, whereas the sand bodies in n114x1 and w587 were transported from the Qingtuozi Salient in the form of gravity flow and mixed with clastic materials transported from Guangrao Salient, and then transformed by wave after the deposition of mixed sediments. The sand body in w58 is a channel sand body transported from Qingtuozi Salient in the form of gravity flow.