Halliburton Energy Services, Inc.

Moustafa E Oraby

Roland Edward Chemali

Jerome Allen Truax

Various micro-sonic density imaging-while-drilling systems and methods are disclosed. In at least some forms, the micro-sonic logging tool is embodied in a drill collar having at least one stabilizer blade. One or more acoustic transmitters are set in a distal face of the stabilizer blade to generate acoustic waves. One or more receivers can also be set in the distal face of the stabilizer blade to detect P-waves and S-waves that have propagated through the formation making up the borehole wall. Processing circuitry measures the velocity or slowness of the acoustic waves and optionally associates the measured values with a spot on the borehole wall as identified. Multiple transmitters can be used if it is desired to obtain compensated measurements. The tool can further include a fluid cell to measure acoustical properties of the borehole fluid, which can be used to convert the formation slowness measurements into density measurements.

Micro-sonic density imaging while drilling systems and methods

Systems and methods that provide relaxivity-insensitive permeability logs. At least some logging system embodiments include a logging tool assembly that measures spin-spin relaxation time distributions of formation fluid nuclei at different positions along a borehole. A processor operates on the measurements to provide a permeability log that is relatively insensitive to relaxivity coefficient changes and hence insensitive to changes in formation fluids. Thus, permeability logs will be relatively unaffected by invasion of the borehole fluids into the formation, even if surfactants in the borehole fluid cause large changes in formation wettability. For each position logged within a borehole, the processor may process the measured relaxation time distribution to determine a Swanson parameter value; adjust the Swanson parameter value to reduce dependence on relaxivity; and convert the adjusted value to a permeability measurement. Examples are included below to demonstrate the markedly increased permeability measurement accuracy.

Relaxivity-insensitive measurement of formation permeability

Formation fluid salinity is an important parameter in water saturation and formation porosity measurements. Systems and methods are disclosed herein to provide accurate water saturation and/or formation porosity measurements in the presence of unknown or highly variable salinity levels. Some logging tool assembly embodiments include a resistivity tool and an augmented neutron porosity tool. The neutron porosity tool is augmented with a gamma ray detector configured to measure the rate at which hydrogen nuclei capture neutrons from a neutron source. A processing system coupled to the logging tool assembly provides a salt compensated formation porosity log and/or a water saturation log. The logging tool assembly can also include a density logging tool and a natural gamma ray logging tool to provide a salt independent triple-combo log.

Systems and methods for evaluating formations having unknown or mixed salinity

Water salinity and water saturation measurements are enhanced by systems and methods for logging salt concentration in formation fluids. Some tool embodiments augment a neutron porosity logging tool with a gamma ray detector configured to measure the rate at which hydrogen nuclei capture neutrons from a neutron source. The ratio of the hydrogen-capture gamma ray count rate to the neutron flux can be combined with a porosity measurement to derive the salt concentration in the formation fluids. When the salt concentration is further combined with resistivity measurements, the water salinity and water saturation can be derived. Some tool embodiments employ a continuous neutron source, Helium-3 filled neutron detectors, and a gamma ray detector that is the same distance from the source as one of the neutron detectors.

Salt concentration logging systems and methods

Formation density is calculated from acoustic logging measurements. This technique does not require a radioactive source and in fact it may offer better precision particularly in rugose boreholes. In at least some embodiments, the technique exploits an observed relationship between a transmission coefficient T(p, V, pV) and a breakdown resistance &#x3bc;B(p, V, V) to enable determination of the formation density pb from measurements of the formation's compressional wave velocity V, the formation's shear wave velocity Vs, and the borehole fluid's acoustic impedance pV. The desired measurements can be acquired by attaching or integrating a fluid cell with an acoustic logging tool that measures acoustic wave propagation velocities. Real-time density logs can be obtained from both wireline and logging-while-drilling implementations.

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Cairo, Egypt

Moustafa E Oraby