A new plotting technique for modeling critical flow through Multi-Orifice wellhead chokes

Well production rate is one of the most crucial parameters for reservoir modeling, management and surveillance. In most cases, this parameter is known by using empirical correlations to estimate the flow rate passing through fixed wellhead choke. However, in offshore and hostile environments, the multi orifice valve (MOV) choke is installed as a substitute to control the well production remotely. Due to complexity of flow in this type of restriction, theoretical choke modeling is impossible and the available empirical correlations for fixed chokes can’t be used for rate calculation. In this paper, a new, yet simple plotting technique is proposed for modeling the flow of gas condensate type fluid in MOV wellhead choke to estimate well gas rate. By using a set of test separator data including 164 well rate, choke opening and wellhead flowing pressure, gathered from an offshore gas condensate reservoir located in Middle East, the technique was developed and validated. The results revealed that proposed methodology can estimate well rate with an absolute average percent deviation of 5%. The critical need for rate data, make the findings of this paper attractive for petroleum industry.