Abstract: An apparatus for estimating at least one property of an earth formation is disclosed. The apparatus includes: a carrier configured to be disposed in the formation; a neutron tube disposed at the carrier and located on an axis; a high voltage power source disposed in the carrier and electrically connected to the neutron tube, the high voltage power source located remotely from the neutron tube; and at least one detector disposed in the carrier and located proximate to the neutron tube.

Abstract: A method of estimating formation porosity using a neural network for neutron porosity tools. In the training stage, the near-to-far ratio, environmental variables, such as mineralogy, borehole size, standoff etc., are fed to the inputs and the neural network is trained for obtaining the related true porosity (the output). The trained neural network is implanted into tool's firmware for the real time porosity measurement, accounting for the environmental effects considered during training.

Abstract: An apparatus for irradiating an earth formation is disclosed. The apparatus includes: a carrier configured to be disposed in the formation; a neutron tube disposed at the carrier and located on an axis; and a high voltage power source disposed at the carrier and electrically connected to the neutron tube, the high voltage power source being offset from the axis.

Abstract: A downhole instrument for estimating density of sub-surface materials includes: a neutron source, a source monitoring detector, a near detector and a far detector. Each of the detectors may be coupled to an electronics unit adapted for receiving a detection signal from each of the detectors and compensating the detection signal for at least one of the near detector and the far detector according to the detection signal of the source monitoring detector. A method for estimating density is provided.

Abstract: An apparatus for measuring radiation in a borehole penetrating the Earth, the apparatus includes: a downhole tool having a structure defining a cavity; and one or more radiation detection components integrated into the cavity and configured to measure the radiation. An apparatus conveyable through a borehole for measuring radiation downhole and a method of producing a downhole apparatus for measuring radiation are provided.

Abstract: An apparatus for estimating a property of an earth formation penetrated by a borehole, the apparatus includes: a carrier configured to be conveyed through the borehole; a neutron source disposed at the carrier and configured to irradiate the earth formation with neutrons; a neutron detector disposed at the carrier and configured to detect neutrons reflected by the earth formation to the detector; a neutron reflector disposed partially around the detector, an area of the detector not covered by the reflector being configured to admit the reflected neutrons; and a neutron absorber disposed at least around the reflector.

Abstract: A method of estimating formation porosity using a neural network for neutron porosity tools. In the training stage, the near-to-far ratio, environmental variables, such as mineralogy, borehole size, standoff etc., are fed to the inputs and the neural network is trained for obtaining the related true porosity (the output).

Abstract: An apparatus for estimating at least one property of an earth formation is disclosed. The apparatus includes: a carrier configured to be disposed in the formation; a neutron tube disposed at the carrier and located on an axis; a high voltage power source disposed in the carrier and electrically connected to the neutron tube, the high voltage power source located remotely from the neutron tube; and at least one detector disposed in the carrier and located proximate to the neutron tube.

Abstract: An apparatus for irradiating an earth formation is disclosed. The apparatus includes: a carrier configured to be disposed in the formation; a neutron tube disposed at the carrier and located on an axis; and a high voltage power source disposed at the carrier and electrically connected to the neutron tube, the high voltage power source being offset from the axis.

Abstract: An apparatus for measuring radiation in a borehole penetrating the Earth, the apparatus includes: a downhole tool having a structure defining a cavity; and one or more radiation detection components integrated into the cavity and configured to measure the radiation. An apparatus conveyable through a borehole for measuring radiation downhole and a method of producing a downhole apparatus for measuring radiation are provided.

Abstract: A downhole instrument for estimating density of sub-surface materials includes: a neutron source, a source monitoring detector, a near detector and a far detector. Each of the detectors may be coupled to an electronics unit adapted for receiving a detection signal from each of the detectors and compensating the detection signal for at least one of the near detector and the far detector according to the detection signal of the source monitoring detector. A method for estimating density is provided.

Abstract: An apparatus for estimating a property of an earth formation penetrated by a borehole, the apparatus includes: a carrier configured to be conveyed through the borehole; a neutron source disposed at the carrier and configured to irradiate the earth formation with neutrons; a neutron detector disposed at the carrier and configured to detect neutrons reflected by the earth formation to the detector; a neutron reflector disposed partially around the detector, an area of the detector not covered by the reflector being configured to admit the reflected neutrons; and a neutron absorber disposed at least around the reflector.

Abstract: A photodiode whose long-wavelength cutoff is in the short-wavelength range (preferably, between ultraviolet and yellowish-green) having reduced temperature sensitivity is used in downhole applications. It may be matched with scintillation devices having an output matched to the response curve of the photodiode for use with nuclear logging devices. The photodiode may also be used in gyroscopes in which light from an LED matched to the photodiode is reflected from a spinning mass.

Abstract: A photodiode whose long-wavelength cutoff is in the short-wavelength range (preferably, between ultraviolet and yellowish-green) having reduced temperature sensitivity is used in downhole applications. It may be matched with scintillation devices having an output matched to the response curve of the photodiode for use with nuclear logging devices. The photodiode may also be used in gyroscopes in which light from an LED matched to the photodiode is reflected from a spinning mass.

Abstract: An electromagnetic coupling system is disclosed which includes a first electromagnetic transducer sealingly disposed in an outer wall of a tool mandrel, the mandrel adapted to be positioned in a drill collar. A second electromagnetic transducer is sealingly disposed in an interior of a port in the drill collar. The second transducer is positioned so that it is proximate the first transducer when the mandrel is positioned in the drill collar. A third electromagnetic transducer is sealingly disposed in an exterior of the port in the collar. The second and third transducers define a sealed chamber in the port. The second and third transducers are electrically coupled to power conditioning and signal processing circuits disposed in the chamber. A fourth transducer is positioned proximate the third transducer. The fourth transducer is electrically coupled to at least one of a sensor, an external communication line and an external power line.

Abstract: A load cell for sensing deformation in a drill collar is provided. The load cell comprises a disc member having one or more arcuate apertures and a deformation sensing element disposed on a side surface of the arcuate apertures. The load cell is capable of sensing such drilling parameters as weight and torque on a drill bit during the drilling operation.

Abstract: A load cell for sensing deformation in a drill collar is provided. The load cell comprises a disc member having one or more arcuate apertures and a deformation sensing element disposed on a side surface of the arcuate apertures. The load cell is capable of sensing such drilling parameters as weight and torque on a drill bit during the drilling operation.

Abstract: An electromagnetic coupling system is disclosed which includes a first electromagnetic transducer sealingly disposed in an outer wall of a tool mandrel, the mandrel adapted to be positioned in a drill collar. A second electromagnetic transducer is sealingly disposed in an interior of a port in the drill collar. The second transducer is positioned so that it is proximate the first transducer when the mandrel is positioned in the drill collar. A third electromagnetic transducer is sealingly disposed in an exterior of the port in the collar. The second and third transducers define a sealed chamber in the port. The second and third transducers are electrically coupled to power conditioning and signal processing circuits disposed in the chamber. A fourth transducer is positioned proximate the third transducer. The fourth transducer is electrically coupled to at least one of a sensor, an external communication line and an external power line.