Optimization Challenge

Reservoir model: Olympus

After reviewing a number of available benchmark models, it was decided to create a new model that would satisfy all criteria for a good benchmark study and would more easily enable adjustments as desired during evaluation of the model. This new model, referred to as OLYMPUS, is described in detail in a separate document or download.

The following geological reservoir characteristics were identified as sources of complexity to be included in a reservoir model for a good FD optimization challenge:

  • - Faulting – The presence of faults makes regular well patterns suboptimal such that placement of individual wells needs to be optimized. Some compartmentalization would be preferred, but compartments should not be regular in shape, again to prevent the optimality of regular well patterns.
  • - Fault throws - Should be modest (e.g. 1/3 the reservoir thickness at most) but enable contact between at least an upper and lower reservoir zone with different properties, ideally separated by a horizontal barrier.
  • - Barriers – A completely sealing horizontal barrier would pose the question of how to best develop two separate reservoirs with a limited set of wells.
  • - Channels – Channels should be present in at least one of the reservoir zones to introduce the challenge of high-connectivity and fast water breakthrough (undesired), as well as the possibility to tap into multiple good sands with a single extended-reach well. The background flood plain deposition should have sufficient permeability for displacement of the oil present there.
  • - Coarsening/tightening – A lateral trend across the reservoir domain would require different well placement strategies (density of wells) to recover the oil from different ends of the reservoir.
  • - Upward coarsening – The presence of a high-perm layer at the top of the reservoir, with lower quality sands below would introduce a challenge of obtaining a good sweep in the vertical.

 Most of these geological characteristics have been incorporated into the OLYMPUS reservoir model. A detailed description is available in the following document.