A New Production Logging Tool Allows A Superior Mapping Of The Fluid Velocities And Holdups Inside The Well Bore

Abstract

Abstract Drawing the flow profile of the three phases (oil, water and gas) downhole is the ultimate goal of production logging. However the flow regimes that develop inside the well bore can be very complex (e.g. stratification, mist, annular, recirculation, etc) and the mapping of the fluid velocities and holdups inside the well bore is key to the proper evaluation of the individual phases flowrates at every depth level along the survey interval. The mapping ability of the present production logging tools is somewhat limited; consequently difficulties are encountered when interpreting data sets that were acquired in such complex downhole conditions at the present time. Flow Scan Imager is a new tool which comprises five mini-spinners, six electrical and six optical probes that get deployed downhole once the tool is across the survey interval. Each mini-spinner will evaluate the localized fluid velocity that is passing by it, whilst each electrical and optical probe will respectively evaluate the localized water and gas holdup that prevail around its place. When deployed, these sensors will be positioned in such a way that their measurements will constitute a map of the fluid velocities and holdups along a vertical cross section of the well bore at every depth level thus enabling a superior estimation of the individual phases flow rates in complex flow regimes downhole. The use of this tool in deviated and horizontal wells will undoubtedly enable the users to better understand their production regimes, to define a more accurate flow profiles and consequently plan more efficient remedial works or production strategies, which will inevitably improve their ultimate hydrocarbon recovery. Introduction Zakum Development Company (ZADCO) in Abu-Dhabi led the initiations of running Flow Scan Imager tool for the first time in one of its deviated wells. It has allowed the clear visualization, for the first time, of water re-circulation downhole in an oil producer where the water cut at surface is zero. This has given the company a better insight into the down-hole conditions. In this paper we will 1) talk about the complexity of the flow regimes that has lead to the development of the FSI*, 2) explain the FSI* tool design features and advantages over previous generations of production logging tools and 3) review the logging results in ZADCO well # 1. Complexity of flow regimes Laboratory experiments have shown that flow regimes that develop downhole in highly deviated wells can be very complex. Figure-1. This is an illustration of the various flow regimes that could develop downhole in horizontal wells