ABSTRACT
A calculation method for predicting Bottom Hole Pressure (BHP) based on easily obtainable wellhead parameter has been the preferred method in the petroleum industry. But, the predictive capability of the existing correlations is a thing of concern to the oil industry operators. This is due to the inability of the existing models and correlations to account for the presence of the sand particles in the flow stream; also the requirement for the well to be shut-in for BHP predictions is counter productive. These inadequacies were corrected in the proposed model. Results showed that the average pressure drop in the multiphase fluid flow using the proposed model is higher than the pressure drops determined using existing models and correlations. The effects of the fluid density, viscosity and velocity on the sand particles lifting were also investigated and results showed that the sand particle lifting was improved by higher fluid velocity and density and lower fluid viscosity. Validation of the proposed model with field data showed that the model predicts the field BHP data better than any of the existing models and correlations, based on the Average Absolute Deviation (AAD) value of 6.53 returned by the proposed model compared to AAD value of between 13.56 and 24.67 returned by the existing models and correlations.
INTRODUCTION
Movement and deposition of sand particles inside the well-bore could have adverse effect on the productivity as the movement causes increased erosion of the installed wellbore equipment and additional pressure drop along the wellbore while the deposition causes sand to be collect in the low spot along the wellbore and thus constrict the flow of oil through the well at these points. Though sand removals techniques has been successful in fluidizing the settled sand particles and removing them from the wellbore, these operations are time consuming, expensive and require a knowledge of where the sand deposits are.
