Abstract
This paper describes how the integration of basic, analytical and numerical reservoir engineering techniques in the Salema Field, and to really "understand reservoir dynamics". Because Salema is a mature field with a water injector, it was even more important to determine the presence of additional opportunities.
The application of traditional techniques such as conventional production analysis, diagnostic and Chan plots, material balance, Build-ups/Fall-off tests allowed the confirmation of different key events and water production mechanisms, to characterize the basic description of reservoir dynamics. The understanding gained was incorporated into the simulation model.
The methodology helped to minimize the number of uncertainties, narrowing down the variables that had a considerable impact on the history match, diminishing the number of potential realizations, and more importantly ended up in a more consistent and better understanding of the production behavior of the field.
Previous models were not able to reproduce the water production/reservoir pressure observed in some of the existing wells, clearly suggesting that the injected water volumes were not represented correctly in the reservoir.
The methodology can be considered as an integrated workflow towards the construction of any 3D reservoir simulation model, as it is simple and easy to follow. The 4D results obtained six months later, confirmed the results obtained from what the model predicted.
This case study is another example that success in subsurface disciplines depends more on the correct understanding of the reservoir than the degree of complexity with which it is modeled, using reservoir simulation to confirm the achieved understanding rather than just getting a history match.
All the integrated work resulted in the identification of two additional opportunities that will increase the final RF to close to 40% and contributed to extend the field life until 2022. Such opportunities have later been confirmed by the 4D seismic interpretation.
Due to Brazilian regulations the original well names are omitted in this document, instead generic well names have been used.
