The Alvheim field is located offshore Norway and consists of several oil and gas discoveries which contains hydrocarbons in good quality Paleocene sandstones. In the early phases of the development the in-place oil and gas volumes were to a large degree uncertain. Nevertheless, the partners needed to work on the concept selection issues.
The model described in the paper includes a tool for displaying important upside potential seen in geological and geophysical evaluations and parametric model for the production profiles. This results in a "fast model" that could be applied as part of a Monte Carlo model handling all essential elements in the cash flow for various field development concepts.
One of the challenges was to make a model that realistically accounted for the information we knew would appear during production. This was solved using an optimizing inside the Monte Carlo simulation.
The developed model proved useful. Running the model would quickly give comparable economic figures for various concepts. The upside potential and risk associated could also be studied. Another important property of the model was the ability to incorporate the results of the appraisal wells and narrow the uncertainty range in the modeling as soon as the information became available.
Introduction
An offshore field development will go through several decision phases. Even with positive results in the exploration phase the risk may be overwhelming and field development decisions may not be possible. In the appraisal phase the owners will have to decide on more drilling or not, to reduce uncertainty.
The search for possible field development solutions starts as soon hydrocarbons are indicated. The first phase of the field development work will be conceptual, i.e; all options should be considered without digging into details. The result of the conceptual phase should be a small number of possible development solutions. In the next phase, the feasibility phase, the selected concepts are examined and the accuracy of the cost estimates is improved, leading up to the concept selection decision. In the next phase, the definition phase, the concept details and cost estimates are refined preparing for the final go or no-go decision and governmental approval followed by the implementation phase where the plans become reality and investments start.
