David Chace

Production Logging In Horizontal Gravel-Packed Highly Viscous Oil Producers In The North Sea

The highly viscous heavy oil in horizontal wells in ChevronTexacos Captain field in the North Sea presents difficult conditions for most horizontal production-logging instruments because of plugging and coating of the sensors. Recently, production profiles in three of the Captain field screened horizontal wells were determined by use of an advanced horizontal production-logging system. The system combines 2D parallel-plate capacitance-array measurements of three-phase holdup and velocity profiles, pulsed-neutron measurements of three-phase holdup and water velocity, and conventional production-logging measurements to determine the production profile.

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.