Inclined pipes financed by Statoil at the SINTEF multiphase flow laboratory.

 

Present

Multiphase flow simulators are currently based on one-dimensional,  ‘mechanistic’ flow models (i.e. the flow is described by mathematical equations that attempt to capture the physical mechanisms governing the various phases — gas, oil, water).

However, to solve these equations it is necessary to rely heavily on empirical correlations based on relevant experimental data. Having recognized this, Statoil co-funded the construction of well-instrumented flow facilities at IFE and SINTEF.

These loops are suitable for carrying out small-, medium- and large-scale experiments on model fluids and were extensively used by Statoil during the 1980s.

From 1993 onward, Statoil heavily invested in even more advanced facilities at IFE and SINTEF. Meanwhile, Hydro’s high pressure loop in Porsgrunn has been used for the study of live hydrocarbon systems (i.e. hydrocarbon systems as they occur in nature). 

Experimental loops cannot exactly reproduce field conditions, no matter how advanced they are. Flow models must therefore be thoroughly tested against reliable and representative field data.

In this way, Statoil has acquired an extensive body of information from our own fields, more recently supplemented by a shared field databank managed by Scandpower.

Over the years we have continually refined today's industry standard, known as OLGA (OiL and GAs simulator). The next simulator, PeTra (Petroleum Transport simulator), is about to be commercialized.

Future

With OLGA2000 having cornered the dynamic multiphase flow simulator market and its innovative successor PeTra about to be commercialized, we have a clear intention to maintain our lead together with new and existing partners who share the same goals.

One-dimensional flow models

So far, the greater majority of the modelling work has been based on one-dimensional pipe flow models and empirical relationships based on extensive laboratory experiments.

The experimental results have naturally been scaled-up to represent genuine field conditions, but this is a far cry from numerically capturing all of the fundamental governing mechanisms. Furthermore, the influence of flow conditions on other properties is still poorly understood.

Shorter-term priorities are to remedy some of these shortcomings in the one-dimensional domain. So far, the greater majority of the modelling work has been based on one-dimensional pipe flow models and empirical relationships based on extensive laboratory experiments.

Two- and three dimensional flow models

All multiphase flow phenomena, however, are interactive and completely dominated by three-dimensional effects. 

The longer-term aim is thus to extend our modelling capabilities by including 2 and 3D aspects to strengthen and supplement one-dimensional modelling — but not to supercede it.

This requires significant development of basic flow models, close interaction between experimental investigations and instrument development, and further work on empirical relations in conjunction with physical modelling.