Multiphase Choke Correlation Improving Matching Field Data on Vaca Muerta Formation

In Non-Conventional fields, wellhead chokes are widely used to regulate the flow rate of the well to impose sufficient back pressure on the face of the sand so as not to exceed values of excessive drawdown. Many authors describe and model flow through chokes, but only with laboratory data. These models work well, and their error range is acceptable for the oil industry, but they fail when extrapolate to field data or outside the range with which the calculation algorithm was trained.

The new model proposed is a modified version of the original Sachdeva⁽⁸⁾ correlation and uses workflow proposed by Hagedorn and Brown⁽¹¹⁾.

Usually, correlations used nowadays in the oil industry present big errors of at least 20% and such errors make it impossible to provide an accurate production forecast and make correct decisions when choke management is required.

The new workflow, based on Sachdeva⁽⁸⁾ (1986) and Hagedorn and Brown correlation⁽¹¹⁾ (1965), improves the existing models using real data from oil fields. This workflow makes it possible to predict mass flowrate through choke without parameters like "Discharge coefficients".

The multiphase choke correlation presented in this paper for both subcritical and critical flow was developed and trained with real field production tests with shale oil wells from different fields of "Vaca Muerta" Formation in Neuquén Basin.

This correlation was tested, and its performance was compared with published correlations.

This new workflow was correlated with 258 points (124 points for training purpose and 134 points for cross check). The average error was 11.67 % and R^2=0.945. In cases where historical data exists, this error can be reduced to an order of 2-5 %.

The new correlation is a modified Sachdeva⁽⁸⁾ correlation including slippage between phases and use Hagedorn and Brown⁽¹¹⁾ methodology to find "Discharge Coefficient".