The problem

Being able to predict gas-oil ratio and bulk petroleum phase volumes ahead of drilling is a crucial yet very poorly constrained element of exploration strategy.

Predicting the composition of the liquid phase is also critical because sulphur contents, wax contents and TAN all directly affect viscosity, recovery and price per barrel.

The solution

Petroleum composition controls the phase behaviour of the fluid during secondary migration, entrapment and production. The ability to predict petroleum composition is of crucial importance in the assessment of hydrocarbon quality and producibility, and, hence, a pre-requisite for the economic evaluation of a prospect.

The PhaseKinetics approach allows the explorationist to link source rock organic facies to the petroleum type it generates. Then, using data from a combination of open and closed system pyrolysis techniques bulk kinetic and compositional information can be obtained, corrected and integrated into a compositional kinetic model which allows the prediction of hydrocarbon physical properties (GOR, saturation pressure and formation volume factor). The calculation of petroleum phase behaviour under the subsurface conditions of hydrocarbon migration and entrapment is possible using these models in combination with modern basin modelling software. Migration pathways can be recognised, daughter compositions predicted and gas- and oil-leg volumes quantified.

Available source rocks, stains and seeps are analysed in 4 sequential stages:

• Definition of Petroleum Type Organofacies
• Definition of Thermal Response
• Integration of Compositional Evolution into Thermal Response
• Tuning of Compositional Evolution to PVT Format

These steps are shown in the four coloured boxes on the lefthand side of the figure below:

At GeoS4, we do the job by integrating the Petroleum Systems Modelling platform of IES Petromod , the petroleum engineering software of PVTsim and our own pyrolysis methodologies into PhaseKinetics.

Contact us directly if you have questions concerning the types and numbers of analyses involved. IMPORTANT if no samples are available, for example in a frontier exploration area, the petroleum type, thermal response, evolving composition and tuned parameters for the nearest PETROLEUM FACIES are selected. We can help with this choice.