215 / 2019-06-23 10:30:48

Quantitative 3D Outcrop Modeling of Carbonate Reef and Shoal Facies Based on UAV Oblique Photography Data

Unmanned aerial vehicle (UAV); Oblique photography; 3D outcrop geological modeling; Reef flat facies; Jiantianba

Current standard geostatistical approaches to characterizing subsurface and reservoir heterogeneity may not capture realistic facies geometries and fluid flow paths. Data acquisition approaches having many shortcomings for the high-steep outcrop area of carbonate rock, the outcrop area data of Jiantianba was collected by using the global perspective, high speed and agility, and high degree of quantification of the oblique photography of the UAV, which acquired was processed and interpreted geologically in detail to establish a geological knowledge database of the outcrop area, and on this basis, a 3-D geological modeling of the outcrop area was realized. The research shows that: (1) The data model from the UAV oblique image acquisition and processing of the high-steep outcrop area of the Jiantianba carbonate rock has 3-D coordinates (latitude, longitude, altitude) corresponding to the image information, allowing accurate location of coordinates of any point and measurement of the scale of the geological body, which laid a solid foundation for the study of the fine geological architecture of carbonate rocks and the establishment of a precise geological knowledge database. (2) Through fine dissection and statistical analysis of relevant geological parameters of the three sections in the outcrop area, the geological model and knowledge base of the typical outcrop area have been established, including the types of lithology, continuity and scale, vertical lithology combinations and evolution characteristics. (3) Under the guidance of virtual well location, lithology calibration, stratification setup, geological model and knowledge database, the 3-D stratigraphic-structural model and lithology model of the typical outcrop area were established by the method of sequential indication simulation(SIS). Subsequently, combined with the outcrop anatomy, the training image analysis of different microfacies was carried out, and the multi-point geostatistics was used to establish a 3-D geological model of reef-shoal facies that is more in line with geological understanding. The research shows that for the high-steep outcrop area of carbonate rock, and the 3-D modeling technology of outcrop based on UAV oblique photography has advantages like quantified data, good coordinate and lithology correspondence and good association of cross-section and plane than conventional field outcrop.