The Identification of Condensate Banking With Multiphase Flowmeters—A Case Study

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThe identification of condensate banking has always been a challenge. Furthermore, large productivity losses can result from the absence of early detection of a condensate bank in the near well bore area of the well. The traditional means of detecting a condensate bank range from comparison of the dew point to downhole pressure measurements, identification of composite radial models and quantification of skin using pressure transient analysis. One of the methodologies that have been more theoretical than practical has been the detection of a leaner stream of effluent at the well head during production. This type of approach has been quite challenging in the past, as a high resolution measurement of the condensate to gas ratio is essential to a successful diagnostics of condensate banking.The paper presents a case of analysis of the development of a condensate bank during a well test. The multiphase flowmeter identified a gradual reduction of the condensate to gas ratio with increasing choke sizes. The methodology of diagnostics is demonstrated, in particular with the discrimination against liquid loading issues.The PVT compositional analysis provides a verification of the analysis, and the observation of the evolution of the phase diagram leads a further understanding the downhole and near well bore thermodynamic phenomena.The degradation of the productivity of the well is also analyzed, with a significant drop of gas productivity observed even on smaller choke sizes at the end of the test.Finally the paper presents a numerical simulation match of the data and provides a number of recommendations for the utilization of single well -near well bore compositional models to help interpreter to obtain better and simpler matches.This paper provides a new methodology to make full use of the benefits of the dual energy gamma Venturi multiphase flowmeters in the evaluation of gas wells. Operational issues related to gas well testing with traditional test separatorsThe test of gas wells has always been a challenge compared to testing oil wells. The high level of energy contained in the stream in the form of compressible fluids, the higher pressure usually encountered at surface due to the lower hydrostatic head in the tubing and the potential presence of toxic components such as H2S in the effluent contribute to increase the Health and Safety risks inherent in the handling of gas wells.On the operational side, the presence of water in the stream combined with a large temperature drop across restriction or the choke can lead to severe plugging issues with hydrates.Erosion can also be a serious risk encountered with the combination of high fluid velocities (in particular at low pressure) and a bit of sand. Perforation of the walls of the surface piping can present very serious risk to the operational personnel and the facilities.However, the main difficulty of testing gas wells comes from the determination of accurate gas, condensate and water flow rate measurements. The sh...

Field Validation Processes for Multiphase Wet Gas Surface Well Testing Solutions: Example from the Yamburgskoe Arctic Gas Condensate Field, Russia

“…Early work about the deployment of Dual-Gamma Venturi multiphase flowmeters in the Yaburggazdobycha operating area has been presented by Theuveny, Zinchenko and Shumakov ( [5], [6]). During the production metering campaign, all the wells demonstrated some level of unstable production behaviour, which could be retrospectively inferred from small fluctuations of pressure and temperature.…”

Testing Gas Condensate Wells in Northern Siberia With Multiphase Flowmeters

“…The importance to manage differently the multiphase well testing operation in the gas environment gas been illustrated before (Theuveny et al [1]. The principal challenge can be summariezed as follows:…”

“…• Mitigation of the carry over in gas line out of conventional separator • Increasing need for high resolution of GCR measurements to determine changes in fluid properties on choke changes • Higher repeatability measurements to confirm slow trends • Circumventing hydrate formation issues downstream of surface production chokes plugging up controls in separators • Remote unmanned operations • Lowering of risk associated with well testing in gas well operations through elimination of active control systems and reduction of the volumes of pressurized hydrocarbons contained in the testing systems • Permanent monitoring requirements More of these requirements for wet gas well testing have already been presented in Theuveny et al [1]. The basics of the gas well testing with dual energy gamma -venturi multiphase flowmeters have been shown by Pinguet et al [2], Hopman et al [3] and Guiese et al [8].…”

Testing Gas Condensate Wells in Northern Siberia with Multiphase Flowmeters

“…• Mitigation of the carry over in gas line out of conventional separator • Increasing need for high resolution of GCR measurements to determine changes in fluid properties on choke changes • Higher repeatability measurements to confirm slow trends • Circumventing hydrate formation issues downstream of surface production chokes plugging up controls in separators • Remote unmanned operations • Lowering of risk associated with well testing in gas well operations through elimination of active control systems and reduction of the volumes of pressurized hydrocarbons contained in the testing systems • Permanent monitoring requirements More of these requirements for wet gas well testing have already been presented in Theuveny et al [1]. The basics of the gas well testing with dual energy gamma -venturi multiphase flowmeters have been shown by Pinguet et al [2], Hopman et al [3] and Guiese et al The importance to manage differently the multiphase well testing operation in the gas environment gas been illustrated before (Theuveny et al [1]. The principal challenge can be summariezed as follows:…”