Measuring oil production
rates of individual wells is important to evaluate a well’s
performance. Multiphase flow meters (MPFMs) and test separators have
been used to estimate well production rates. Due to economic and technical
issues with MPFMs, especially for high gas–oil ratio (GOR)
reservoirs, the use of a choke formula for estimating well production
rate is still popular. The objective of this study is to implement
different artificial intelligence (AI) techniques to predict the oil
rate through wellhead chokes. Support-vector machine (SVM) and random
forests (RF) were used to generate different models to predict the
production rates for high GOR and WC wells. A set of data (548 wells)
was obtained from oil fields in the Middle East. GOR varied from 1000
to 9351 scf/stb, and WC ranged from 1 to 60%. Around 300 wells were
flowing under critical flow conditions, while the rest were subcritical.
Hence, two cases were studied using each AI model. Seventy percent
of the data was used to train both RF and SVM models, while 30% of
the data was used to test and validate these models. The developed
RF and SVM models were then compared against the previous empirical
formulas. The RF model in both critical and subcritical flow conditions
was able to perfectly match the actual oil rates. SVM was able to
predict the general trend for the oil rates but missed some of the
sharp changes in the oil rate trend. The average absolute percent
error (AAPE) values in the subcritical flow for SVM and RF were 1.7
and 0.7%, respectively, while in the critical flow, the AAPE values
were 1.4 and 0.75% for SVM and RF models, respectively. SVM and RF
models outperform the published formulas by 34%. The results from
this study will help to estimate the real-time oil and gas rates based
on the available data from wellhead chokes without the need for field
intervention.