This paper describes early UKCS experience of a new production logging sensor, the Digital Entry and Fluid Imager, or DEFT* tool.
Deviated and horizontal wells can cause complex flow regimes to arise that render interpretation of conventional production logging sensors difficult or sometimes impossible.
The DEFT tool is a new type of production logging tool which facilitates the understanding of the nature of wellbore flow and improves confidence in interpretation. The tool makes four independant measurements of the phase holdup, distributed in differring quadrants of the pipe cross section.
Results to date show that the DEFT tool gives a direct count of the dispersed phase bubbles. Each probe can give an indication of the flow type, the absolute velocity of the dispersed phase, and the bubble flow direction. As the four measurements are distributed at different locations within the pipe cross section, an image of pipe flow may be interpreted.
Early results also show how the DEFT tool can be used to define the location of oil entries and to pin-point circulatory flow.
The paper briefly describes the tool principles. Interpretation is illustrated with example logs made during its field introduction.