Sedimentary characteristics of reef, shoal and lime mud mound, and their seismic identification
He Yongyao1, Wang Yingmin1,2, Xu Cuixia3, Li Dong4, Wu Yuxiang5, Zhao Peng5
1. College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China;
2. State Key Laboratory of Petroleum Resource and Prospecting, PetroChina, Beijing 102249, China;
3. Sinochem Petroleum Exploration & Production Co., Ltd, Beijing 100031, China;
4. CNOOC Research Institute, Beijing 100027, China;
5. Shenzhen Branch, CNOOC Ltd, Shenzhen, Guangdong 518067, China
Abstract：Seismic identification marks are established by analyzing domestic and overseas cases of reef, lime-mud mound, and shoal. According to their sedimentary and geophysical characteristics, ‘trigonometric classifications' is proposed. Accordingly, a new comprehensive recognition method, named ‘point, line, plane, volume and time', is adopted for identification of reef, lime-mud mound, and shoal. ‘Point' represents seismic reflection configurations of single geologic body; ‘line' represents sedimentary environments; ‘plane' corresponds to plane distribution; ‘volume' corresponds to three-dimensional distribution; and ‘time' represents longitudinal cyclicity. Using this method, we recognize totally five types of reefs, three types of carbonate mud mounds, and two kinds of shoals in South China Sea. Located at structure tops in high energy environment and controlled by transgression-regression cycles, reefs are characterized by low frequency, middle and high amplitude, moderately continuous mound reflections. Located at structure slopes in high energy environment, shoals are represented by low frequency, middle and high amplitude, moderately continuous mat reflections. Located at structure lower slopes in low energy environment, carbonate mud mounds are characterized by low frequency, high amplitude, discontinuous mound reflections. Application results show that our approach can effectively identify reef, lime-mud mound and shoal in the study area.
