The locations of subsurface hydrocarbon accumulation is of prime importance to the oil and gas industry. However, attempts have only recently begun to model the complete petroleum system within one interactive program, since the computing power required to achieve this has only recently arrived on the desktop. However, even with the latest computers, there is still a need to include some simplifications in the model in order to keep computing time down. Another objective of this program is to bring the process of basin modelling into the PC environment, thus making it more accessible to the non-specialist.
Several models for different aspects of the petroleum system are currently in use. The GALO model (Makhous et al., 1997) is a one-dimensional (1-D) model simulating basin heatflow and thermal regime, and hydrocarbon maturation. It shows how an integrated study of heatflow can be used in conjunction with geochemical data to give a good idea of how the hydrocarbon evolution of a basin may occur over long time and length scales. However, the fact that it is 1-D means that it has no constraints on the eventual fate of the hydrocarbons generated and cannot take into account lateral heatflow variations in the basin. Modelling petroleum formation without structural information, such as the location of traps and potential migration pathways, does not allow predictive accumulation modelling. A more complete model such as SEMI (Sylta et al.,1998), allows more realistic hydrocarbon modelling, although the effects of structural deformation by fault movement, compaction and sedimentation, are often treated superficially or ignored. In addition, there are several projects of this nature being undertaken at the major oil companies; unfortunately, due to the commercially sensitive nature of this work, there is little published data.
One example of such a model is Platte River/IFE's BasinMod software. This integrates the results of several different programs into a complete model similar to Migrate2. However, the whole process of modelling is not carried out within one program, which limits the interactivity of this approach. Details of the BasinMod project can be found on the web. For Migrate2, I have attempted to integrate every major feature of a petroleum system into one program, which also allows the visualisation of both input and output data. Due to the potential scale of such a project, some simplifications have had to be introduced. These have been chosen where there would either be minimal impact on the accuracy of the model, or where the modelling process could not be verified by any observation, and would therefore not be constrained.
The program Migrate2 models the formation, migration and accumulation of hydrocarbons through time in a three-dimensional (3-D) model of part of a sedimentary basin. The program is written in Visual C ++ for the Win32 environment, and allows visualisation of both the input data for the model during the model construction phase, and the results through all of the time steps in the model. Program input consists of 3-D interpretations of seismic data, together with physical data such as porosity and permeability, and geochemical data, which is used to predict hydrocarbon formation. Output consists of a series of 3-D models of the volume of rock through time, which can be freely scaled and viewed from any angle, and coloured to represent a variety of parameters. This program is a preliminary stage for the full predictive modelling of hydrocarbon accumulation evolution.
This project models the evolution of hydrocarbon movement and accumulation through time. Modelling involves reconstructing the positions of the rocks within the Earth Model at each time step, calculating the temperature field through time, and generating the paths taken by hydrocarbons as they move from their sources to their final traps due to bouyancy forces.
Stratal surface geometries in their present day
configuration are retro-deformed to their original configuration
Temperatures are calculated on a regular grid within the
Earth Model
Migration Paths are calculated using the surface geometry
of the base of a sealing unit
Oil (green) and gas (red) are generated and migrated via hydrocarbon
pathways to structural traps
Information provided by: http://www.bdrg.esci.keele.ac.uk