A programmable integrated measurement while drilling (MWD) system is an integrated, ruggedized, and condensed MWD system configured to enable end-user customizable applications for downhole exploration and drilling. The integrated MWD system integrates a co-processor with a directional controller enabling execution of the end-user customizable applications without interrupting the real-time operations of the directional controller.

An apparatus and method for estimating at least one parameter of interest of an earth formation including an estimation of the parameter of interest using a time-dependent ratio of information obtained from at least one neutron detector through the exposure of the earth formation to a radiation source, particularly a pulsed nuclear source. The apparatus includes a processor and storage subsystem with a program that, when executed, implements the method. Also, an apparatus and method for estimating at least one parameter of interest of an earth formation including an estimation of the parameter of interest using a first component and a second component of an information set obtained using a single radiation detector.

A method for determining a material in an annulus between two objects disposed in a borehole includes positioning logging tools in the borehole, each of the logging tools being oriented at a different angle. The method also includes measuring a property of the material in the annulus using the logging tools and determining the material in the annulus based on the measured property.

A presence of cement may be identified based on a downhole tool that may emit neutrons into a wellbore having at least one cement casing. The neutrons may interact with the particular material via inelastic scattering, inelastic neutron reactions, capture of neutrons and/or neutron activation through one of these reactions and cause a material to emit an energy spectrum of gamma rays, and wherein the downhole tool is configured to detect an energy spectrum of the gamma rays that is specific to at least one of a plurality of elements and associated a region within the wellbore. An amount of elements, such as calcium and silicon, may be determined from the gamma ray spectra that may indicate a present of cement within the wellbore.

Systems and methods may utilize information collected by a pulsed-neutron logging tool along with modeling a characterization of a borehole to form a 3-stage correction algorithm. This algorithm may be used to find an oil, water, and gas holdup in the borehole. During operations, a pulsed neutron logging tool which emits neutrons to interact with nuclei inducing gamma radiation. The gamma radiation is detected into a response which may be correlated to the location of a holdup in a borehole by using the entire spectrum or ratios of selected peaks. In examples, a borehole density index may be implemented to complement the response and improve accuracy and measurement confidence.

An x-ray based cement evaluation tool for measurement of the density of material volumes within single, dual and multiple-casing wellbore environments is provided, wherein the tool uses x-rays to illuminate the formation surrounding a borehole, and a plurality of detectors are used to directly measure the density of the cement annuli and any variations in density within The tool uses x-rays to illuminate the casing surrounding a borehole and a plurality of multi-pixel imaging detectors directly measure the thickness of the casing The tool includes an internal length having a sonde section, wherein the sonde section further includes an x-ray source; a radiation shield for radiation measuring detectors; sonde-dependent electronics; and a plurality of tool logic electronics and PSUs. Other systems and subsystems appropriate for carrying out the foregoing are also disclosed, as are a plurality of example methods of use therefor.

A presence of cement may be identified based on a downhole tool that may emit neutrons into a wellbore having at least one cement casing. The neutrons may interact with the particular material via inelastic scattering, inelastic neutron reactions, capture of neutrons and/or neutron activation through one of these reactions and cause a material to emit an energy spectrum of gamma rays, and wherein the downhole tool is configured to detect an energy spectrum of the gamma rays that is specific to at least one of a plurality of elements and associated a region within the wellbore. An amount of elements, such as calcium and silicon, may be determined from the gamma ray spectra that may indicate a present of cement within the wellbore.

A method for obtaining nuclear measurement data includes measuring a burst gate source intensity. The method also includes measuring at least one of burst gate neutron count rate or a capture gate neutron count rate at a neutron detector arranged proximate a gamma ray detector. The method further includes determining, based at least in part on the burst gate source intensity and at least one of the burst gate neutron count rate or the capture gate neutron count rate, a normalized neutron count rate. The method also includes determining at least one of an inelastic spectrum or a capture spectrum. The method includes determining based at least in part on the normalized neutron count rate, at least one of a corrected inelastic spectrum or a corrected capture spectrum.

A method for obtaining nuclear measurement data includes measuring a burst gate source intensity. The method also includes measuring at least one of burst gate neutron count rate or a capture gate neutron count rate at a neutron detector arranged proximate a gamma ray detector. The method further includes determining, based at least in part on the burst gate source intensity and at least one of the burst gate neutron count rate or the capture gate neutron count rate, a normalized neutron count rate. The method also includes determining at least one of an inelastic spectrum or a capture spectrum. The method includes determining based at least in part on the normalized neutron count rate, at least one of a corrected inelastic spectrum or a corrected capture spectrum.

Elemental concentrations in subterranean formations may be determined using neutron spectroscopy. For example, neutrons may be emitted by a downhole tool into the formation and produce gamma rays via inelastic scattering of fast neutrons or capture of slow neutrons. The borehole surrounding a downhole tool may introduce artifacts in the neutron spectroscopy measurement. Embodiments of the present disclosure are directed to techniques that reduce artifacts signals in downhole tools that include one or multiple detectors based at least in part on the inelastic and capture measurements.