Successful Field Surveillance Using Portable Multi-Phase Flow Meter in a High Gas-Volume Fraction and High Water-Cut Application in East Kalimantan, Indonesia

摘要

Total Indonesia had been finding it increasingly more difficult to obtain direct measurement of produced oil from some of their remotely located fields. The production wells that needed testing were in a mature field in a swamp location and had high water-cuts (WC) and extremely high gas-volume fractions (GVF). The WC and GVFs in these fields range from 80 to 100% and 90 to 100%, respectively. Moreover, most of the wells have low potential and are very sensitive to back-pressure. All these characteristics as well as their logistics made accurate measurement of production from the wells in this area extremely challenging. As a result, the time interval between the well tests was ever increasing (more than one month). In order to achieve more frequent performance data, and thus, enable more effective work-over decisions, the suggestion was made to evaluate use of a portable multi-phase flow meter (MPFM) to resolve the measurement problems. The initial well tests yielded MPFM total hquid flow-rate readings that were ±30% of the test separator readings; the MPFM gas rates were ±25% of the separator reading. The operator's requirement was for the MPFM to be within ±10% of the test separator readings. Since these disparities were attributed to the extremely high GVFs that had been encountered on these wells, modifications to the present MPFM system were needed to 1. Reduce the GVF going through the meter 2. Reduce the uncertainty of the meter measurements 3. Improve the accuracy of the meter 4. Increase the meter operating envelope. Subsequently, a gas knock-out (GKO) vessel was designed and constructed to address the above needs. The GKO vessel was designed within a predetermined set of constraints so as to achieve the desired results. The GKO vessel was installed immediately upstream of the multiphase meter. After incorporating the GKO vessel with the MPFM, the new "hybrid" system was used to test the same wells that had been tested earher. The results using the MPFM and the GKO vessel yielded liquid rates and gas rates that were within ±10% of the test separator.