Production testing using portable Multiphase Flow Meters (MPFM) was implemented in ADCO Field "B" with objectives to quantify the water and gas production, evaluate the performance of slugging/intermittent wells for procurement actions, evaluate the production test data measured by the conventional test separators and improve the testing duration and strategy. The program included in addition a set of elements to qualify the multiphase meters results before use and considered parallel testing with conventional separators to allow fair comparison of results.
More than 50 wells were tested during this campaign. All these wells were selected carefully to represent anomalies that need to be investigated for possible proactive actions. Some of these wells were tested more than once to qualify and validate the production test results by the MPFM. Production test results were carefully analized and compared with the results of test separators for fair evaluation and interpretation of well's behaviour. The comparison indicated that the multiphase meter results were relevant and accurate.
In conclusions the water cut measured by MPFM was almost three times more than those measured by test separators. This ratio is matched well with the actual field water volumes. The GOR measurements were varying from one well to another but majority of wells showed more gas production by the phase tester compared with test separators specially for the low potential, unsteady wells. In terms of oil production rate, the difference between the phase testers and test separators was marginal in high potential wells and between 20–40% higher by MPFM in low potential wells. These findings helped in optimizing reconciliation and allocation of the water and gas production. In addition to the above findings, phase testers helped in reservoir management decisions and optimization of testing duration and frequency per well, testing remote wells, slugging/intermittent wells due to system back pressure, testing wells located on platforms not equipped with testing facilities, easy mobility of the phase meters between different locations, replacement of portable test separators and cost optimization.
This paper presents the experience gained using a mobile multiphase well testing unit for production testing. The challenges presented by the nature of these operations and the requirements for successful well tests are reviewed. The importance of well testing experience and multiphase flow metering expertise is highlighted. The paper also explains the unique benefits of the multiphase well test data in identifying and evaluating various well performance anomalies and how the measurements are used to monitor well production over time.
Accuracy of the flow test results performed by the existing test separators in ADCO fields was an issue rose long time ago. Field reports always indicated that the actual production volumes of oil, water and gas from ADCO- "B-field" do not match with the theoretical volumes calculated based on well test results measured by test separators. This mismatch of the actual and theoretical production data is reflected on the accuracy of reconciled production allocation per well and reservoir.
Productions performance and well's diagnostics analysis were other issues that affected the reservoir management decisions and proactive actions, especially for high water cut and high GOR wells. Monitoring of the slugging and intermittent wells was also a problem faced using test separators. Accuracy of production data in addition is a requirement for numerical simulation, reserves calculations, and optimization of reservoir data acquisition,...., etc.
In view of the above issues, ADCO took the lead early in searching the market for the use of Multiphase Flow Meter (MPFM) technologies. Several meters were tested and evaluated in different fields.