Reservoir Modeling

Reservoir simulation model of a river-delta sandstone oil reservoir with three injectors and two producers. Tracers can be used to "colour" the injection water and track the water flood from producer to injector. The concentration is obtained from the numerical solution of tracer transport equations. 


Tracer simulation
Chemical or radioactive tagging of injected water or gas (reservoir tracing) have been used for several decades to gain information about hydrocarbon reservoirs. IFE has developed and used tracers for this purpose during the last 30 years, and is recognized as one of the leading laboratories in this area. Unfortunately, most tracer-tests are only evaluated in a qualitative manner, without any kind of comparison to simulation results. For gas tracers, one of the reasons for this is the lack of adequate gas-tracer modelling tools. To improve the petroleum industry's tracer modelling capabilities, the section has therefore developed a specialized tracer-modelling tool that can be linked to ordinary reservoir simulators.

Natural tracers
Natural tracers are natural variations in geochemical compounds and isotopes in reservoir fluids and can be used to obtain information about fluid movements in oil reservoirs. However, most applications of geochemical and isotope variations of the reservoir fluids have been limited to regional exploration activities. Quantitative evaluation of natural tracer data and applications to improve reservoir models and forecasts are hardly reported in the literature, and even qualitative reservoir applications of natural tracers are rare. This additional and unexploited source of data to reduce reservoir model uncertainty was introduced by the Section during previous EU-projects (Huseby et al., 2005). The activity is continued through currently running projects funded by the Research Council of Norway (RCN) and the oil industry (Tracer-EnKF).

Integration of data to improve reservoir models and forecasting
Contemporary modelling and visualization tools have improved the ability to understand complex reservoirs and thus helped to improve decisions regarding optimum reservoir development. Nevertheless, any reservoir simulation model represents one of many realizations of the real reservoir, and to reduce the inherent uncertainty of the models it is important to include all available data, such as tracer, production and (4-D) seismic data. Conditioning of reservoir simulation models to available data (history matching) is a challenging task, and different approaches have been used for this problem. The Section has previously been involved in projects with the objective of integrating seismic, tracer and production data (Huseby et al., 2005; Skorstad et al., 2006; Huseby et al., 2007) by manual matching of reservoir models. Recently, assisted history matching, using an ensemble of models to represent the uncertainty of the reservoir models has gained popularity. Natural and injected tracers have so far not been utilized in relation to assisted history matching techniques, and the Section is therefore currently leading a project where natural and "ordinary" tracer data are introduced in assisted history-matching procedures for the first time. This work is done in collaboration with the International Research Institute of Stavanger (IRIS) and several oil companies
(Tracer-EnKF).

CO2 sequestration and CO2 for IOR
CO2 storage in abandoned petroleum reservoirs or in subsurface aquifers in relation to petroleum production facilities is one suggestion to solve future needs for storage of CO2 captured from fossil fuel power plants. Another, related idea, is to apply captured CO2 to improve the oil recovery from oil-producing reservoirs. Investigation of CO2 and fluid movement, as well as monitoring of CO2 transport and migration involve solution of conservation equations in subsurface porous media, and are therefore related to the core competence and objective of the Section. Based on this the Section is therefore involved in two CO2-related projects, one concerning sequestration and one concerning CO2 for improved oil recovery.

In a feasibility study of a CO2 Field Laboratory, sponsored by Gassnova with contributions from nine Norwegian partners, the Section performed modeling work on transport of tracers within a supercritical CO2 phase. One outcome of the feasibility study was a plan and a budget for running full-scale projects at two selected sites, together with the associated modeling, monitoring and supportive experimental work.

In collaboration with IRIS, the Section is addressing the improvement of macroscopic sweep efficiency in CO2-flooding of North Sea reservoirs using polymers and foams. The Section's main task so far has been to simulate and evaluate forming and coalescence of foam in an CO2-flooding experiment. The project aims to stimulate oil production by improving macroscopic sweep efficiency (volumetric sweep) in carbon dioxide (CO2) –flooding of North Sea oil reservoirs. This will also delay CO2 breakthrough, reduce CO2 production, increase CO2 storage capacity for oil reservoirs and reduce CO2 emission to air. One of the objectives from the Section's work is to provide better description of sweep improving methods in computer models.

Geostatistics and multifractals
The Section is also engaged in modelling of heterogeneous reservoirs. In this context, we have developed our own geostatistical techniques for analysing petrophysical data from well logs and core samples. These techniques are based on recent advances in multifractal statistics which we have pioneered ourselves. The method is applied to extraction of textural information from dipmeter curves for improved predictions of lithological facies which cannot be obtained open-hole logs. Advanced geostatistics are also used in computation of single and multiphase petrophysical properties of reservoir rocks by employing Integrated Pore Space Reconstruction and Flow Property Simulation Tool for Core Analysis and Reservoir Simulation. This work is done in collaboration with Ecole Polytechnique de Montreal.

Geothermal Energy
The Section is engaged in two large European Projects dealing with Geothermal Energy: "European Deep Geothermal Energy Programme in Soutz" (www.soultz.net) and "Enhanced Geothermal Innovative Network for Europe - ENGINE"
(http://engine.brgm.fr). The contribution to these projects consist of studies in corrosion, scaling and trace flow. This is done in collaboration with relevant sections at IFE within the Petroleum Sector.

Hydrogen Storage and Nanotechnology
The Section collaborates with the Department of Physics at IFE on European project dealing with hydrogen storage in solid materials and nanotechnology projects dealing with porous materials such as membranes and their characterisation. This work has been recently extended to include nanostructured carbon materials (such as carbon cones and carbon discs) and molecular imprinted polymers (MIPs). These serve as important components (transducers and recognition element respectively) in novel (bio)sensors for rapid detection with very low detection limit of chemical and biological agents including tracers but also weapons including rapid diagnosis of their effect on people. Additional applications of MIPs development is foreseen for selective solid phase extraction (SPE) of environmental pollutants, water tracer compounds used in petroleum reservoir applications and chromatographic separation of steroids.