Halliburton Logging Services, Inc.

Michael L Gartner

Paul L Sinclair

Voldi E Maki, Jr

Larry L Gadeken

Christopher A Schnoor

A method and apparatus for determining the percentage of gas by volume in a well producing mixed phase fluids and flowing up the cased well. A low energy gamma ray source irradiates the flowing fluid and counts are measured by a detector crystal. A metal casing shields the surrounding formations from the gamma radiation so that the detector response is determined primarily by the mixed phase fluids flowing in the well. Calibration enables the determination of gas volume percentage for a specific diameter casing.

Gas hold up tool for use in cased well boreholes

A porosity measuring MWD system utilizing a source and two detectors is set forth. The source and two detectors are preferably mounted in a stabilizer fin on a drill collar. A standoff measuring device is also included. Dependent on dynamically measured standoff, output pulses from the two detectors are input to storage counters; different counters are selected for different ranges of standoff. Porosity measurements are determined from the counts for variations in standoff measurements; this provides a near/far ratio for ranges of standoff; as the standoff range varies, the counts are directed to different counters. Near/far ratios are determined and represent the apparent porosity; a corrected value of porosity is then determined for each particular range of standoff.

Method and apparatus for correcting MWD porosity measurement

Apparatus for measuring the volume of gas present in a multiphase flow regime in a cased oil or gas well borehole and the amount, if any, of stratification thereof at a particular borehole depth. The apparatus includes a low energy gamma ray source and a sodium iodide detector located a very short distance from the source and separated by shielding material. Low energy gamma rays, unable to leave the well casing and return, are emitted from the source and scattered back from the multiphase production fluid to a detector comprising a sodium iodide crystal and photomultiplier tube. Both the source and detector are surrounded by rotatable slit collimators to provide sensitivity to azimuthal variations in gas volume percentage in the flow.

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Austin, TX, United States of America

Michael L Gartner