Abstract:
A well logging instrument includes an instrument housing to traverse a wellbore penetrating subsurface formations. An electrically operated energy source that emits ionizing radiation is disposed inside the housing. An insulating sleeve is disposed between the energy source and an interior wall of the housing. The insulating sleeve comprises a thin dielectric film arranged in a plurality of tightly fitting layers of dielectric material disposed adjacent to each other and successively. A thickness of each layer and a number of layers is selected to provide a dielectric strength sufficient to electrically insulate the energy source from the housing and to provide a selected resistance to dielectric failure resulting from the ionizing radiation.
Abstract:
The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid, and determining a depth at which said fluid enters the wellbore.
Abstract:
The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid, and determining a depth at which said fluid enters the wellbore.
Abstract:
Systems and methods for measuring neutron-induced activation gamma-rays in a subterranean formation are provided. In one example, a downhole tool for measuring neutron-induced activation gamma-rays may include a neutron source and a gamma-ray detector. The neutron source may emit neutrons according to a pulsing scheme that includes a delay between two pulses. The delay may be sufficient to allow substantially all neutron capture events due to the emitted neutrons to cease. The gamma-ray detector may be configured to detect activation gamma-rays produced when elements activated by the emitted neutrons decay to a non-radioactive state.
Abstract:
An apparatus and method for determining the density and other properties of a formation surrounding a borehole using a high voltage x-ray generator. One embodiment comprises a stable compact x-ray generator capable of providing radiation with energy of 250 keV and higher while operating at temperatures equal to or greater than 125° C. In another embodiment, radiation is passed from an x-ray generator into the formation; reflected radiation is detected by a short spaced radiation detector and a long spaced radiation detector. The output of these detectors is then used to determine the density of the formation. In one embodiment, a reference radiation detector monitors a filtered radiation signal. The output of this detector is used to control at least one of the acceleration voltage and beam current of the x-ray generator.
Abstract:
Methods and related systems are described for the detection of nuclear radiation. The system can include a scintillator material that intrinsically generates radiation and a photodetection system coupled to the scintillator material and adapted to generate electrical signals based on light emitted from the scintillator material. A processing system adapted and programmed to receive the electrical signals, to generate a count rate reference value based at least in part on electrical signals generated in response to the light emitted from the scintillator material due to the intrinsically generated radiation.
Abstract:
An apparatus and method for determining the phase fraction of a fluid collected downhole is shown comprising an x-ray generator, a filter, a sample cell, and a radiation detector. The filter produces a radiation spectrum with a high energy portion and a low energy portion. Filtered radiation is passed through a sample fluid and the resulting attenuated radiation signal is used in calculating the phase fractions of oil, water, and gas in the sample fluid. In one embodiment, a second reference radiation detector measures the radiation directly from the x-ray generator and this measurement is used in normalizing the fraction result. The ratio of the high energy signal to low energy signal of the reference detector is used in controlling the input voltage of the x-ray generator thus ensuring a stable spectrum.
Abstract:
An X-ray downhole imaging tool is provided and includes an X-ray tube capable of operating at least at 50 KeV and emitting at least one hundred micro-amperes of continuous electron current and a radiation detector axially displaced from the X-ray tube, at least partially shielded therefrom and radially directed. In certain embodiments, the radiation detector includes a microchannel plate and a resistive anode. In certain embodiments, a second detector which is axially directed is also provided.
Abstract:
A method and apparatus for determining the density and phase fractions of well services fluids is shown including an x-ray generator, a sample cell, and a radiation detector. Radiation is passed through the sample cell and fluid and the attenuated radiation signal is used to evaluate the fluid. In one embodiment, a reference radiation detector measures a filtered radiation signal and controls the acceleration voltage and/or beam current of the x-ray generator using this information. The apparatus may be permanently affixed for long term monitoring or temporarily clamped on to a pipe in production.
Abstract:
The invention relates to methods and apparatus for determining a downhole parameter in an underbalanced drilling environment which include: selectively activating a first fluid flowing from the formation through a wellbore while under balanced drilled; detecting the activated first fluid; and determining a depth at which said fluid enters the wellbore.