Production logging sensors based on center-point measurements are not always successful in obtaining accurate flow profiles in triphase horizontal wells because of the effects of factors particular to these wells: fluid segregation, small changes in the well inclination, and the flow regime.

This paper presents a new tool designed specifically for highly deviated and near to completely horizontal wells. The tool provides a recording of holdup and velocity profiles along the vertical diameter of the borehole cross-section. Three sensor arrays consisting of six optical probes, six electrical probes, and five spinners are spread across the well bore on retractable arms that can be opened and closed with a hydraulic sub to better locate holdup interfaces. The optical probes use the fluid's reflectance to derive the gas holdup, and the electrical probes measure the fluid's impedance to derive the water holdup. The spatial location of the different sensors is accurately known through the use of an integrated relativebearing sensor and a caliper measurement. The direct measurement of the velocity and fluid holdup profile enhances the capability of the analyst to determine the downhole phase split and reduces the uncertainties associated with triphase flow interpretation.

This paper will discuss the problems mentioned and will illustrate through worldwide field examples the success of the new tool.

Keywords:
floscan imager, flow rate, well deviation, production control, production monitoring, horizontal well, vertical diameter, holdup, holdup profile, probe
Subjects:
Drilling Operations, Well & Reservoir Surveillance and Monitoring, Directional drilling, Production logging
Copyright 2004, Society of Petroleum Engineers
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