Surface welltesting of Gas-Condensate with multiphase flowmeters is still considered a challenge for production metering. Traditional means of well testing have been deployed for years and used consistently for reservoir and production management. However, it can be difficult to compare data sets obtained with different measurement devices.
Multiphase flow meters have been proved for multiphase production metering by many operation companies worldwide. However, in artic environmental conditions like those of Yamburgskoe gas-condensate field, with low ambient temperature and production rate regulation restrictions, this process had to be revalidated and the operational capabilities confirmed with all of the logistical challenge of this environment. A number of recommendations to prevent and mitigate the impact of the hydrate and document major benefits of multiphase well testing are based on the accumulated operational experience from the operations of various multiphase flowmeters in the area.
Most of the gas condensate wells in the Yamburgskoe gas-condensate field are flowing with liquid unloading issues in a slug flow regime that can be observed and monitored accurately with multiphase flow meters. The importance of slug flow regime identification relates to the selection of stable flow intervals for surface sampling and further recombination factor determination. This information is also extremely important for well completion design. There is good agreement between the slug frequencies obtained with nodal simulations and the actual dynamic measurements from the meter - an impossible task for conventional measurements based on separator or batch processing of the liquid.
Surface well testing to control changes of reservoir parameters, PVT composition, and production back-allocation performance is one of the key parts of gas-condensate field development in Russia. A number of multiphase welltesting operations have been successfully performed recently that show acceptable performance capability and the benefits of this methodology compared to the parallel production measurement with a traditional gas separator. This novel comparison and qualification process of multiphase flow meters also provides a better understanding of the aptitude of conventional means to collect rate in the case of wet gas wells in Northern Siberia.