Significant progress has been made to the development of multiphase flowmeters over the last few years, and a number of manufacturers now have prototypes in the final laboratory and field testing stage. However, most of these meters are flow regime dependent and very costly. This paper describes a different type of multiphase flow metering system that has been specially adapted and successfully tested by Saudi Aramco. The paper describes the results of the first successful onshore field test of a complete multiphase meter for measuring the production rates of oil, water, and gas flowing from a producing oil well in Saudi Arabia. The meter was located at a remote onshore site. The paper presents the current status of the metering unit developed by Saudi Aramco and discusses the test results and evaluation program. The test results obtained from the multiphase meter are compared against those of a conventional test separator.
Production tests are run routinely to measure oil, gas and water produced by a well under normal producing conditions. Test results are needed for reservoir management, forecasting purposes and for the monitoring of individual well and total field production. In addition, they provide periodic physical evidence of well conditions. Unexpected changes, such as extraneous water or gas production may signal well or reservoir problems. Abnormal production declines may be caused by artificial lift problems, fill-up in the casing, scale build-up in the perforations, etc.
Selecting the proper testing equipment for production testing is of preeminent importance if the best possible results are to be obtained. Conventional well testing requires a test trap, test lines and field personnel all of which are very costly. Over the past few years, emphasis has been placed on developing technology for metering of multiphase wellhead fluids to replace conventional well test systems. The oil industry has recognized the large potential for economic savings if dependable multi-phase well test meters could replace conventional test separators, portable test units and well testlines. The advantages could be very significant to operations in offshore and remote onshore areas. Several multiphase testing units have been introduced to the oil industry in the last few years to measure oil, water and gas rates.
The development of multiphase metering technology for oil/gas/water flow started in the early eighties. Over these years there have been several attempts to develop a suitable multiphase flow meter. As a result of this massive effort, the industry is now beginning to see the first multiphase meters becoming commercially available.
Saudi Aramco has acknowledged the potential benefits if dependable multi-phase well test meters could replace conventional test traps, test barges and well testlines. The benefits are very important to operations in offshore and remote onshore areas. A multiphase metering system utilizing two coriolis mass flow meters was developed for this purpose.
Installation of the multiphase metering unit was completed and the unit was used to test an onshore wet producer at southern area in Saudi Arabia. The first direct comparison test between the multiphase well test unit and the plant's conventional test trap was conducted on February 16, 1996. P. 365
