Raptor Cased-Hole Reservoir Evaluation Tool

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The Weatherford Raptor cased-hole reservoir evaluation (CRE) tool is a pulsed-neutron wireline logging device that provides advanced analysis of oil, water, and gas saturation behind the casing.

The Weatherford Raptor cased-hole reservoir evaluation (CRE) tool is a pulsed-neutron wireline logging device that provides advanced analysis of oil, water, and gas saturation behind the casing.The Raptor CRE tool uses enhanced sigma and carbon-oxygen (C/O) techniques for oil-water saturation measurements in saltwater and freshwater formations, and a new N-vision technique that enables a quantified gas-liquid saturation measurement.

The Raptor CRE tool consists of a pulsed-neutron generator, a five-gamma-detector array, and processing, control, and telemetry electronics. It has two physical sections: the cased-hole reservoir measurement (CRM) unit that contains the generator and detectors, and the cased-hole reservoir processing (CRP) unit that contains the processing and control electronics. The telemetry cartridge includes the casing-collar locator. The addition of a gamma-ray, pressure, and temperature sub completes the standard operating configuration.

The Raptor CRE tool is suited for formation evaluation, production logging, and well integrity measurements. For formation evaluation, the tool has three different data-acquisition modes—sigma, C/O, or N-vision—to suit the logging objective. The Raptor CRE tool probes the formation with pulsed high-energy neutrons. During neutron-nuclei interactions, the neutrons are either absorbed (captured reactions), scattered (inelastic), or both (as in N-vision mode).

The Raptor CRE tool detects the resulting radiation, which is analyzed to yield information about the formation and its fluids.

For production logging and well integrity operations, the detected radiation is a result of momentary artificial radioactivity of oxygen in water, which is produced by high-energy neutrons. This brief radioactivity helps determine the velocity and direction of water flow inside and outside the casing.

Applications

  • Formation fluid saturations (oil-water, liquid-gas, and 3-phase)
  • Oil-water saturation measurements in freshwater formations using advanced C/O techniques
  • Oil-water saturation measurements in saltwater formations using advanced sigma techniques
  • Gas-liquid saturation measurements using N-vision logging
  • Saturation measurements in wells without openhole logs
  • Identification of pressure-depleted zones
  • Identification of fluid contact (gas-oil and oil-water)
  • Differentiation between gas and tight zones

Features, Advantages, and Benefits

  • The lanthanum-bromide detectors provide bright emission, small temperature degradation, high resolution, and faster emission decay, which results in greater count rates, improved temperature stability, and more reliable spectroscopy
  • The high-speed, cased-hole telemetry enables the Raptor CRE tool to combine with Weatherford production logging and cement evaluation tools for greater versatility
  • The Raptor CRE tool is compatible with Weatherford Compact™ logging tools for simultaneous neutron-gamma density and cross-dipole acoustic measurements in memory mode