A borehole muon detector for muon radiography or geotomography is provided, the borehole muon detector including a substantially cylindrical housing, which defines a bore, a pair of end caps, each end cap sealing an end of the cylindrical housing and a plurality of sealed drift tubes which are longitudinally disposed in the bore of the housing to form a bundle of drift tubes, wherein each sealed drift tube comprises: a centrally located anode wire disposed on a longitudinal axis; an inner surface which is coated with a cathode coating, the cathode coating divided into a first cathode pad and a second cathode pad by a Vernier pattern; and a timer in electrical communication with the anode wire for measuring a drift time. A system and a method are also provided.

A borehole muon detector for muon radiography or geotomography is provided, the borehole muon detector including a substantially cylindrical housing, which defines a bore, a pair of end caps, each end cap sealing an end of the cylindrical housing and a plurality of sealed drift tubes which are longitudinally disposed in the bore of the housing to form a bundle of drift tubes, wherein each sealed drift tube comprises: a centrally located anode wire disposed on a longitudinal axis; an inner surface which is coated with a cathode coating, the cathode coating divided into a first cathode pad and a second cathode pad by a Vernier pattern; and a timer in electrical communication with the anode wire for measuring a drift time. A system and a method are also provided.

Methods, tools, and systems for determining porosity in an earth formation are disclosed. Neutrons are emitted into the formation to induce inelastic scattering gamma rays and thermal capture gamma rays in the formation. The induced gamma rays are detected at a proximal gamma detector and a far gamma detector, which are spaced at different axial distances from the neutron source. A measured proximal-to-far inelastic ratio (a ratio of inelastic scattering gammas detected at the proximal and far detector) and a proximal-to-far thermal capture ratio (a ratio of thermal capture gammas detected at the proximal and far detector) are determined and used to calculate the formation porosity. Techniques are disclosed for removing borehole and casing configuration effects from the measured proximal-to-far thermal capture ratio, leaving only porosity dependence.

The downhole tool may include an electrical power source, a positive and a negative electrode, and at least one sensor. The positive and negative electrodes may be configured to generate an electric field between the positive and the negative electrode with an electrical charge from the electrical power source and discharge the electric charge through a downhole formation. The at least one sensor may be configured to detect quantum particles dislocated by at least one of the electric field and the discharged electrical charge to determine downhole information from at least one of a travel time of the quantum particles, a composition of the quantum particles, a quantity of the quantum particles, and a charge of the quantum particles.

The downhole tool may include an electrical power source, a positive and a negative electrode, and at least one sensor. The positive and negative electrodes may be configured to generate an electric field between the positive and the negative electrode with an electrical charge from the electrical power source and discharge the electric charge through a downhole formation. The at least one sensor may be configured to detect quantum particles dislocated by at least one of the electric field and the discharged electrical charge to determine downhole information from at least one of a travel time of the quantum particles, a composition of the quantum particles, a quantity of the quantum particles, and a charge of the quantum particles.

The disclosure presents a process for sharpening an image data representation of collected measurements from a subterranean formation. The sharpening process utilizes an azimuthal filter applied to azimuthal radial ranges around a borehole to designate azimuthal bins. The azimuthal filter utilizes a set of filter coefficients to modify an azimuthal target bin. The set of filter coefficients is a devolution set as it contains at least one positive and one negative filter coefficient. The filter ratio of positive to negative filter coefficients can be adjusted utilizing the statistical uncertainty of the collected measurements and a targeted filter ratio. In some aspects, an axial filter process, also using a binning methodology, can be applied to the collected measurements, where the azimuthal and axial filtered values can be combined for the final image representation. The azimuthal and axial processes can be executed in serial or parallel process flows.

The disclosure presents a process for sharpening an image data representation of collected measurements from a subterranean formation. The sharpening process utilizes an azimuthal filter applied to azimuthal radial ranges around a borehole to designate azimuthal bins. The azimuthal filter utilizes a set of filter coefficients to modify an azimuthal target bin. The set of filter coefficients is a devolution set as it contains at least one positive and one negative filter coefficient. The filter ratio of positive to negative filter coefficients can be adjusted utilizing the statistical uncertainty of the collected measurements and a targeted filter ratio. In some aspects, an axial filter process, also using a binning methodology, can be applied to the collected measurements, where the azimuthal and axial filtered values can be combined for the final image representation. The azimuthal and axial processes can be executed in serial or parallel process flows.

The disclosure provides a well integrity monitoring tool for a wellbore, a method, using a nuclear tool and an EM tool, for well integrity monitoring of a wellbore having a multi-pipe configuration, and a well integrity monitoring system. In one example, the method includes: operating a nuclear tool in the wellbore to make a nuclear measurement at a depth of the wellbore, operating an EM tool in the wellbore to make an EM measurement at the depth of the wellbore, determining a plurality of piping properties of the multi-pipe configuration at the depth employing the EM measurement, determining, employing the piping properties, a processed nuclear measurement from the nuclear measurement, and employing the processed nuclear measurement to determine an integrity of a well material at the depth and within an annulus defined by the multi-pipe configuration.

A system for retrieving a source element from a well may include a logging tool made of a first material, a milling tool, and a control device. The logging tool may include a cylindrical housing having a central chamber housing the source element and extending through a portion of the cylindrical housing along a central axis thereof. The logging tool may include a first communication device mounted on the cylindrical housing. The milling tool may include a tubing mounting structure that secures the milling tool to a tubing of the well. The milling tool may include a drill bit head made of a second material, the drill bit head may be configured for milling through the first material. The control device may include a second communication device configured to communicate with the first communication device.

A method for obtaining a gas saturation value of a subterrain formation involves a tool having multiple dual-function detectors that detect neutrons and gamma rays. The method includes steps of emitting neutrons into the formation, detecting neutrons and gamma ray signals form the formation using the detectors, determining formation parameters including the formation type and formation porosity, and further determining parameters such as the ratio of thermal neutron count rates from at least two of three detectors, the ratio of capture gamma count rates from at least two of three detectors, and calculating the real-time gas saturation value using the determined parameters.