A example of history match is presented, for a reservoir which the original simulation model does not reflect the production behavior. The remaining uncertain attributes were evaluated through a dynamic procedure during the sensitivity analysis. The objective of this work is to present new approaches to improve history matches.

The methodology consists on a dynamic sensitivity analysis based on simulation of models where uncertain attributes are tested and compared with a base model. The sensitivity analysis must be performed for each well, and include pressure evaluation. Techniques were developed to analyze reservoir performance, like differential pressure maps between zones. New approaches to assess connectivity between zones were used, to give alternate structural models to the sensitivity analysis. The simulated value of each parameter may be compared with the base model or with the observed data. The attributes are selected and combined in a derivative tree. Parameters with opposite influence may be combined in order to fit the observed data and obtain the history match. This methodology may be helpful for reservoirs which simulation model does not reflect the production data, and with uncertainties on reservoir characterization.


History match is one of the most important activities during the development and management of petroleum reservoirs. Matched models are fundamental to ensure reliable future forecasts, and give an idea of the level of understanding of the geological and reservoir models. Petroleum reservoirs are very complex and there are great difficulties involved in building correct reservoir models. Depending on this level of knowledge, available production data, and complexity of a reservoir, this activity may be very time consuming. In order to achieve matched models, sometimes little changes can be made on the geological and reservoir models, mainly in those attributes with higher uncertainty, for example, relative permeability curves, its distribution through the reservoir, and other parameters with few samples. The use of numerical simulation has been a strong tool available to reservoir managers in the tasks of history match.

On the other hand, numerical simulation is also used in the appraisal phase, providing a preview for the reservoir performance considering geological models previously prepared from the first static data. At this stage, the use of numerical simulation is also appropriated for the planning of strategies for the development of petroleum fields. Usually it requires more time but it makes the process more reliable, leading to better results. In these early stages, uncertainty studies are based on the impact of geological attributes in the performance of oil and gas accumulations (discovery and appraisal), with main use focused on the influence of these attributes on recoverable and in place hydrocarbon volumes, and in preliminary economic evaluation of the accumulations (ex: Net Present Value) considering a defined time of production, in a static view. In this kind of studies, there is a previous stage (sensitivity analysis) when the influence of each attribute is assessed isolated in a basic model. So, there may be an idea of the relative influence of each attribute in the studied objective-function.

This content is only available via PDF.
You can access this article if you purchase or spend a download.