Darryl Trcka

Applications of a New Multiple Sensor Production Logging System for Horizontal and Highly-Deviated Multiphase Producers

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.

Pulsed neutron hold-up gives imager three-phase hold-ups on the wellsite of horizontal holes

Multi-phase hold-up data is essential for remed ial action in oil wells that produce unwanted water and gas. Conventional logging tools often fail to give hold-ups in horizontal wells due to fluid segregation. Pulsed neutron logg ing tools can measure three different nuclear parameters: the thermal neutron capture cross-section of the borehole, the carbon over oxygen countrate ratio, and the near over far detector countrate ratio. These three parameters can be related to the gas, oil , and water volume fractions in the borehole.