Computing flow profiles and total flow rate with temperature surveys in gas wells
Additional Document Info
Distributed temperature sensing or DTS is gaining increasing popularity because of its potential to generate flow profiles over completed intervals. In fact, several studies have reported successful reproduction of field data, obtained with conventional production logs, in both vertical and deviated wells. One input that enters into typical DTS calculations is the total flow rate at surface. In absence of dedicated flowmetering, uncertainty normally creeps into assigned well rates. This study provides a methodology wherein both the total and individual layer rates can be computed independently with DTS, completion, tubular, and other related data. To do the entire suite of calculations, a wellbore model handling steady fluid flow and unsteady-state heat transfer estimates a production rate, given wellhead pressure and temperature. The same model is then used to compute the flow profile based on measured DTS data across the producing intervals. The model rigorously accounts for various thermal properties of the fluid and the formation, including Joule-Thompson (JT) heating or cooling. Examples from both gas and oil wells are shown to illustrate the application of the proposed methodology. Good correspondence between the measured and calculated results demonstrates the robustness of the proposed method. 2011 Elsevier B.V.