Modeling and Analysis of Temperature Transients Caused by Step-Like Change of Downhole Flow Control Device Flow Area

摘要

Evolution and wide-spreading of downhole monitoring systems has increased a lot over the last few years. Particularly downhole temperature data has been recognized as an important input for real-time production optimization. Whereas distributed temperature analysis and interpretation are the only methods used now, temperature evolution with time offers an excellent new source of information not yet fully understood. Simulation and analysis of temperature transients in wells are therefore a promising research area at the initial stage of development. Near wellbore multiphase flow simulation considering heat transfer is not a simple task. There are aspects as well-reservoir mutual influence where transient analysis needs to be considered. Neglecting thermal effects and completion design will result in inaccuracies of the physical phenomena representation. This paper describes a non-isothermal dynamic well-reservoir simulator taking into account the presence of flow control valves in the wellbore. A simultaneous and fully implicit approach was used to solve the coupled problem. The geometry studied is two dimensional for the reservoir and one dimensional for the well. The reservoir is considered homogeneous, anisotropic and two-phase (oil/water or gas/liquid) saturated with the initial pressure above the bubble point. The well is vertical and the multiphase flow model in the wellbore is drift-flux considering the radial influx. Case studies for three-zone intelligent wells are analyzed from transient temperature profiles generated by the simulator. A single phase is used as a base case for the two-phase case. This paper will prove that temperature transients from a step-change in production rate are able to provide full well-test equivalent information about each production zone. A downhole flow control valve step-change is also analyzed as a feasibility study of a well test without zonal shut-in. Restrictions of the simulator are presented and discussed for an appropriate use of the results.