Use of Critical Multiphase Flow Correlation for Bean Surveillance

ABSTRACT A simple technique for investigating choke erosion based on critical multiphase flow correlation has been developed. It utilizes the coefficient (C-constant) in the correlation for determining whether the bean is being eroded or plugged. The coefficient remains fairly constant for a given well but only deviates if the bean is being subjected to erosion or plugging or if the well's operating point is in the sub-critical flow region. Bean erosion and plugging were simulated using a surface facility-coupled well model constructed with Prosper software. The model showed that the C-constant decreased when the bean was being eroded and increased when the bean was experiencing plugging. Test performance for cases of bean plugging was not available and therefore, the study focussed on bean erosion alone. Actual production test data were used from different fields where choke erosion has been reported in verifying the concept. The technique was also used to back-calculate the effective bean sizes for the wells with eroded bean. It was evident that the wells have been produced with effective bean sizes outside the desired operating window with the attendant reservoir management consequences. This paper recommends the use of this technique for verifying production test to ascertain the integrity of the reported bean size for reservoir management. The analysis can also be used to advise on the priority wells for bean box checks/bean change out. It can also be used to expedite calibration of integrated production system models (IPSM) with the right bean sizes.