Prediction
of Oil PVT Properties Using Neural Networks
E.A. Osman,
SPE, O.A. Abdel-Wahhab, and M.A. Al-Marhoun, King Fahd University of
Petroleum and Minerals, Saudi Arabia
Copyright 2001. Society of Petroleum Engineers
This paper was prepared for presentation at the
12th
SPE
Middle East Oil Technical Conference & Exhibition
held in Bahrain,
7-20 March 2001.
Abstract:
Reservoir fluid properties are very
important in reservoir engineering computations such as material balance
calculations, well test analysis, reserve estimates and numerical
reservoir simulations. Ideally, these properties should be obtained
from actual measurements. Quite often, however, these measurements are
either not available, or very costly to obtain. In such cases,
empirically derived correlations are used to predict the needed
properties. All computations, therefore, will depend
on the accuracy of the correlations used for predicting the fluid
properties.
This study presents Artificial Neural
Networks (ANN) model for predicting the formation volume factor at the
bubble point pressure. The model is developed using 803 published data
from the Middle East, Malaysia, Colombia, and Gulf of Mexico fields.
One-half of the data was used to train the ANN models, one quarter to
cross-validate the relationships established during the training process
and one quarter to test the models to evaluate their accuracy and trend
stability. The results show that the developed model provides better
predictions and higher accuracy than the published empirical
correlations. The present model provides predictions of the formation
volume factor at the bubble point pressure with an absolute average
percent error of 1.789%, a standard deviation of 2.2053% and correlation
coefficient of 0.988. Trend tests were performed to check the behavior
of the predicted values of Bob for any change in reservoir temperature,
Gas Oil Ratio (GOR), gas gravity and oil gravity. The trends were
found to obey the physical laws.
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