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This paper focuses on the first applications of an improved, second-generation multiple sensor production logging system designed for use in horizontal and highly deviated multiphase producers. The system integrates several key measurements to provide a comprehensive analysis of well performance under a variety of conditions and flow rates. An expanded and improved 2-dimensional capacitance array is used to define flow regime and measure 3-phase holdup, velocities and flow rates. A new 3-detector pulsed neutron instrument provides an independent measurement of water velocity, 3-phase holdups, and formation water saturation. Auxiliary sensors include an acoustic transducer and distributed temperature sensors useful for gas entry, liquid entry, and behind-casing channel identification. A quartz-pressure gauge measurement is recorded which is also useful in mechanistic models of multiphase flow. While a brief description of the system components will be provided in order to familiarize readers with the measurement concepts, this paper will concentrate on field examples from the Middle East that demonstrate the first use of the improved logging system in horizontal openhole multiphase producing wells. Determination of multiphase holdups, cross-wellbore velocity profiling, and production inflow profiling is demonstrated. Openhole logs are also shown, including resistivity image data, which clearly differentiate the inflow points as producing bed layers or conductive fractures.

We are introducing a new 1-11/16-inch multi-function pulsed neutron instrument. The Reservoir Performance Monitor (RPM) has operating modes allowing pulsed neutron decay, pulsed neutron spectrometry, pulsed neutron holdup, neutron activation water flow, and radioisotope measurements. The tool is combinable with fluid density, spinner flowmeter, or more advanced production logging instruments. The new instrument includes three gamma-ray detectors arrayed above a new neutron generator that can be pulsed at different frequencies and modes for different types of measurements. The system employs short tool sections for ease in shipping and handling. In the pulsed neutron capture mode, the tool pulses at 1 kHz, and records a complete time spectrum for each detector. An energy spectrum is also recorded for maintaining energy discrimination levels. Time spectra from short-spaced and long-spaced detectors can be processed individually to provide traditional thermal neutron capture cross section information, or the two spectra can be used together to automatically correct for borehole and diffusion effects and produce results that are very close to intrinsic formation values. In the pulsed neutron spectrometry mode, the instrument pulses at 10 kHz, and records full inelastic and capture gamma ray energy spectra from each detector. These data are processed to determine critical elemental ratios including carbon/oxygen and calcium/silicon from the inelastic spectra and silicon/calcium from the capture spectra. The pulsed neutron holdup imager mode yields both energy spectra and time decay spectra from each detector simultaneously. Measurements can be used to determine holdups of gas, oil, and water, and when combined with other production logs can provide a comprehensive production profile picture, even in deviated or horizontal wells. The neutron activation mode provides water-flow measurements using one of several data acquisition methods. Stationary measurements are made in either of two modes, and measurements at different logging speeds can be used to segregate different flow rates in either an annulus or in an adjacent tubing string. With the neutron generator turned off, the RPM can also be used to detect the distribution of materials, tagged with radioactive tracers, that are injected into the well during well treatments. In this manner, the effectiveness of operations such as hydraulic fracturing or gravel pack placement can be evaluated.

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