Predication of Oil Flow Rate through Choke at Critical Flow for Iraqi Oil Wells

Before the production leaves the well head, it passes through a choke which serves to stabilize the optimum or desired flow rate against variations in flow line pressure. In this paper, the aim is to develop new correlation to predict oil flow rate through chokes with critical flow for Iraqi oil wells. This study shows that there is a strict quantitative connection between three factors: upstream pressure, gas-oil ratio and choke size with oil flow rate at critical flow for one hundred production tests of Iraqi oil wells. Many forms have been tried using nonlinear regression analysis to obtain the optimum form of correlation that gives minimum differences between the calculated and field data. Here, based on Iraqi oil wells data; new correlation has been developed for predicting oil flow rate through chokes at critical flow. The proposed correlation exhibits more accuracy (only 4.523% average absolute error) than the existent correlations. The correlation coefficient of the new correlation is determined as 0.997. The cross plots of calculated and field data gives strong index of priority of new correlation for applying with Iraqi oil wells. The graphical presentation of the results of the new correlation for Iraqi oil wells states more matching with the field data that are not used in formulating the new correlation than Gilbert (1954),  Baxendall (1957), Ros (1959), Achong (1961), Secen (1976), Pilehvari (1981), Osman and Dokla (1990), Owolabi, Dune and Ajienka (1991), Elgibaly and Nashawi (1996), Mesallati, Bizanti and Mansouri (2000) and Alrumah and Bizanti (2007) correlations.