Page 36 - Petroleum and Gas Field Processing

The spaces between wells and the production rate from each well are
determined with the objective of recovering the maximum volume of
petroleum in the most economical way. This is not an easy task and
requires extensive reservoir simulation studies. Such studies continue after
the development stage and, as more data become available, there studies
may result in having to drill additional wells (infill wells) for higher
recovery.

1.7.3 Reservoir Simulation

The complexity of the reservoir structures and the large number of
nonlinear equations governing the flow of fluids in the reservoir make it
impossible to obtain analytical solutions to the fluid flow problem.
Reservoir simulators implementing various numerical techniques are
constructed for solving such a problem. Running a simulator requires
inputting of many parameters that are related to the reservoir rock and
fluids. The majority of these parameters may either be known with various
degrees of certainty or may have to be assumed. Therefore, the accuracy of
the simulation results depends, first, on the accuracy of the input data.
Simulation studies are first conducted during the development stage
to predict and evaluate the performance of the reservoir for the life of the
field. Once production starts, data are collected and the actual reservoir
performance is checked against the simulation-predicted performance. In
almost all cases, the actual and predicted results do not match. Therefore,
reservoir (simulation) engineers modify the simulation by changing some
or all of the input data using either newly acquired data or making new
assumptions, or both. This is done until a match between the simulation
results and the actual results, obtained from the producing field, is
obtained. This process is known as history matching. The modified
simulator is then used to predict the field performance and direct the
production strategy for better management of the reservoir. The whole
process is repeated on a continuous basis for every specified period of
production.

1.7.4 Reservoir Management
The aspects of reservoir management are numerous and involve extensive
and complicated studies. In simple terms, however, the role of reservoir
management is to specify specific producing strategies that will control the
movements of the various fluids within the reservoir in order to achieve
maximum recovery of the hydrocarbon materials while minimizing the
production of undesired fluids. The production strategies may include

Copyright 2003 by Marcel Dekker, Inc. All Rights Reserved.