4 Sep 2020

PerGeos Process Based Modelling

Process Based Modelling modules for PerGeos


This technology, validated over the years with Oil&Gas companies, simulates the natural processes of forming sedimentary rocks, i.e. sedimentation, compaction and diagenesis. The calculation of petrophysical parameters, e.g. absolute permeability, formation factor, and NMR; and the calculation of multiphase flow properties are based entirely on the 3D numerical rock models, or
imported Micro CT volumes, combined with information on the fluid characteristics.
The 3D numerical rock models are generated through sedimentation, compaction and diagenesis simulation.

The Process Based Modelling comes as 4 fully documented new PerGeos modules, accessible from the Analysis workspace.

The sedimentation component in the process based modeling routine offers a set of model types to choose between; each model mimics the grain skeleton of known sedimentary rock
types. Each grain bed is characterized by a set of parameters, e.g. grain size distribution, grain shapes and information on mineralogy. These parameters are based on expert knowledge about the actual rock or information derived from thin section analyses (e.g. point counting or SEM analyses).
PerGeos also supports a set of sedimentation processes for the various rocks, e.g. low or high energy depositional environment.

The size of the grid and associated voxel size is defined under the Grain Bed Properties options.

The Sedimentation module outputs an implicitly defined dataset of type GrainBed. In order to visualize the GrainBed data, it is necessary to apply the Grain Bed Gridder, which transforms the implicit data to a Label data.

Compaction of the sediment due to vertical stress from the overburden, is an important agent for porosity reduction during burial. PerGeos emulates both vertical and horizontal compaction through bulk volume reduction.

The last step in the rock forming process is Diagenesis. PerGeos supports a set of relevant diagenetic processes, e.g. quartz cementation, clay coating, clay filling, clay bridging, carbonate cementation, pyrite growth, and feldspar dissolution. In addition the sheet silicate Muscovite mica may also be added during the diagenesis process.
The diagenetic modeling must be based on a selection of reliable rock parameters derived from Scanning Electron Microscope (SEM) images, point counting of thin sections, X-ray diffraction (XRD), or X-ray microtomography (Micro CT).