Derek Neilson (MD, Endeavour Energy UK).

I have no hesitation in recommending Jeff Broad as an expert in all aspects of fluid sampling, PVT analyses and EOS development. This is based on the very significant contributions he made in the development of an extremely complex compositional simulation model. By means of his thorough review of the existing PVT dataset, we were able to accurately map the aerial and vertical variations in fluid compositions in a giant saturated carbonate oil reservoir for the first time. The resultant full field model has since been successfully used to investigate different production scenarios with a view to optimising economic recovery.

His approach was to critically review a data set of about fifty PVT studies. The reservoir had been producing for about fifty years and reservoir pressures had declined in some sectors. In addition to ensuring the reported PVT data was precise, we also examined pressure drawdown history, well conditioning prior to sampling and other factors to ensure that the sampled fluids had not been gas depleted. The conclusion of this review was that only six PVT studies were representative of the initial in place reservoir fluid. For some of the other more accurate PVT studies, we were able to confidently determine that the sampled fluids had been gas depleted due to production prior to sampling. The data set was extended to eighteen studies by re-saturating these fluid compositions at initial reservoir conditions.

A lumped EOS was then developed for use in the reservoir simulator based on the eighteen PVT studies. By working with a third party, the ten million grid blocks in the model were automatically populated with the fluid compositions. The resultant full field model was then initialised and successfully history matched. This was a breakthrough in our understanding of the reservoir and enabled us to proceed with predicting future production scenarios.