Construction of typical facies models and the three-dimensional distribution of their petrophysical parameters - A foundation of understanding 3D seismic facies
Research output: Thesis › Master's Thesis › Research
For interpretation of 3D seismic the understanding of geological facies and seismic facies is important. Therefore, the geometry and properties of the facies are of importance. To improve this, a research study is done, which is dealing with the construction of three dimensional facies models. Furthermore the distribution of their petrophysical properties is discussed. This study is divided into two parts. In the first part, information about the geometry and about facies of different geological bodies (channel, fan, salt dome, reef, volcano and karst) were taken from literature. Based on this results, a three dimensional model with “Petrel software” (3D seismic interpretation and modeling software) of each depositional environment was constructed. To achieve an optimal model of the seismic facies two methods were used. Method I for fluvial systems and Method II, which is a newly created workflow, for complex structural or stratigraphic depositional systems. For Method I a predefined function, which is provided by a commercial software, was used. This function allowed the building of facies models with objects, which are generated and distributed stochastically. The basic idea of Method II is based on the creation of a classical geological model by interpretation of faults and horizons in 3D. Instead of a 3D seismic, profiles from real examples were used. The second part is dealing with petrophysical parameters (density, compressional- and shear wave velocity) on each geological body. Therefore, a range of typical petrophysical parameters of each facies were obtained from literature information. In addition, the influence of porosity, clay content, pore fluid change and depth on density and velocity were considered. The result of this study is summarized in form of fact sheets. For each geobody a fact sheet with all useful information was created. Such a fact sheet represents a geological body and shows the link between the major facies compounds, their measurements (used for modeling) and their petrophysical parameters. Finally, these facies models and their petrophysical properties can be used for seismic forward modeling.