# Geological Modelling

## Objectives

Distinguish the concepts of conceptual model, deterministic model, stochastic model, estimated model, simulated model, implicit modeling and explicit modeling. Gather the necessary knowledge to generate (1) geological models, by implicit surface estimation, or cross-section interpretation and digitization; (2) fracture models and extract results such as porosity, permeability and ornamental stone maximum block size curves. Use geological modeling software such as Leapfrog Geo. Develop the ability to design data processing flowcharts, from surveys to models, choosing the best algorithms and specific solutions for each case. Learn the limitations of models and internalize that they are numerical and computational representations of reality and that as such they have associated uncertainty.

## General characterization

13250

3.0

##### Responsible teacher

José António de Almeida

Weekly - 2

Total - 34

Português

### Prerequisites

Geostatistical knowledge from a first cicle.

### Bibliography

[1] Caers, J. (2011) Modeling Uncertainty in the Earth Sciences. John Wiley & Sons.

[2] Wellmann, F., & Caumon, G. (2018). 3-D Structural geological models: Concepts, methods, and uncertainties. In Advances in Geophysics (Vol. 59, pp. 1-121). Elsevier.

[3] Orche, E. (1999) Manual de Evaluación de Yacimentos Minerales. Gráficas Arias Montano, Madrid

[4] Rossi, M.E. & Deutsch, C.V. (2014) Mineral Resource Estimation. Springer.

[5] Wellmann, F. & Caumon, G. (2018) 3-D structural geological models: concepts, methods, and uncertainties Advances in Geophysics., 59, 1-121.

[6] Leapfrog Geo, Manual de Utilizador.

### Teaching method

This course comprises classes for exposition of subjects with the support of PowerPoint and practical classes where students learn to work with Leapfrog Geo software.

### Evaluation method

The assessment is continuous and comprises one test and a summative assessment with the delivery of sets of questions resolved on the topics taught in class with the software’s. The test refer to "geological modeling subjects" and the "fracture modeling by objects". It last for 2 hours, and each weight 60% in the final grade. This component can be replaced by an exam on a scheduled date (60% of the grade). The summative assessment comprises the delivery of 6 questionnaires solved in class (5 with Leapfrog Geo and 1 Excel). The minimum rating for the 2 tests component is 8 in 20.

## Subject matter

Objectives of the 3D geological modeling. Morphological models and attribute models. Conceptual model. Deterministic models and stochastic models. Applications. Starting data (boreholes, GIS coverages, points and lines). Vector and block representation. Spatial resolution. Uncertainty. Realism. Estimation and simulation. Modeling with Leapfrog Geo. Modeling of stratified geological structures. Digital terrain model. Modeling top and bottom surfaces of layers. Faults. Deposition surfaces and erosion surfaces. Chronology. Modeling of intrusions, dikes and veins. Implicit and explicit modeling. Use of structural elements. Estimation of lithologies in grids of blocks. Nearest neighbor estimator. Fracture modeling by objects. Orientation, intensity, shape, dimension, opening and filling of fractures. Evaluation of block dimension curves in ornamental rock quarries. Evaluation of equivalent permeability and porosity. Cubic law and Oda approximation.

## Programs

Programs where the course is taught: