Abstract: A method for optically sampling characteristics of subsurface fluids within a wellhole using continuous, non-pulsed light transmitted downhole in optical fibers for both sampling and reference light channels for accurate attenuation compensation.

Abstract: An apparatus for recording and displaying images of and identifying material types in a target object in a fluid carrying conduit includes a downhole unit. The downhole unit includes a controllable light source, the controllable light source structured to emit high energy photons. The downhole unit further includes a sensor unit structured to detect the high energy photons that are backscattered from the target object and to generate signals in response to the detected high energy photons. The apparatus also includes a control and display unit that includes a signal transmitter and a viewing screen structured to display at least one two-dimensional image that is generated using the signals from the sensor unit.

Abstract: A downhole fluid analysis tool capable of fluid analysis during production logging that includes a phase separator and a plurality of sensors to perform analysis on the fluids collected at a subsurface location in a borehole.

Abstract: Apparatus for imaging the wall of a borehole drilled through an underground formation, comprising: a light source; an optical detector device such as a CCD camera; a sensor head including a window for application against the wall of the borehole, the light source being connected to the sensor head so as to illuminate the region of the borehole wall when the sensor head is applied to the wall; and an optical fiber bundle connecting the window to the optical detector device so as to pass optical signals from the wall to the optical detector device; wherein the optical fiber bundle comprises a coherent bundle, each fiber of the coherent bundle providing one pixel of a two-dimensional, multi-pixel image of the borehole wall.

Abstract: Apparatus and method for estimating a downhole parameter include a high-gain semiconductor device having a plurality of semiconductor layers forming an active region, the active region having a bandgap offset that provides device operation through at least the temperature environment of a downhole location, the high-gain semiconductor device being used at least in part to estimate a downhole parameter.

Abstract: An x-ray tool for determining a characteristic of an oilfield fluid. The tool may include a generator portion housing a collimator about a target from which x-rays are emitted. In this manner x-rays may be attenuated right at the target such that a majority of shielding otherwise necessary for safety concerns may be eliminated. Rather, by employing the target within the collimator, shielding of the generator may be limited to a single shielding plate within the generator portion that is positioned parallel to the target at the opposite end of an x-ray tube therebetween. As a result of this configuration, an x-ray tool for analysis of oilfield fluids may be provided with a minimum weight of shielding material. Thus, hand-held user friendly embodiments may be safely employed at the oilfield.

Abstract: Formation strontium concentrations are measured utilizing a borehole tool. A log may be provided as a function of depth or distance. The strontium measurements can be correlated chronostratigraphically to provide a depth to absolute time correlation. Measures of strontium made in the borehole can be correlated to information obtained via seismic exploration of the formation traversed by the borehole. Measures of strontium in multiple boreholes of a single formation can be correlated.

Abstract: A dual neutron-gamma ray source comprises a compact neutron generator, a shield, a collimator, and an internal gamma target. The shield surrounds the compact neutron generator. The collimator traverses the shield from the compact neutron generator to a collimator port. The internal gamma target is positioned within the collimator to generate gamma rays from the neutrons.

Abstract: A variable-ratio neutron-gamma ray source comprises a neutron generator, a shield, a collimator, and an external gamma target. The neutron generator generates neutrons and the shield reduces external radiation exposure. The collimator collimates the neutrons into a neutron beam that traverses the shield. The external gamma target generates a dual neutron-gamma ray beam from the neutron beam, wherein the dual neutron-gamma ray beam has a variable neutron-gamma ratio as a function of a thickness of the external gamma target.

Abstract: Elemental analysis of an earth formation is obtained using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the Calcium, Magnesium and Carbon content of the formation is determined. The amount of organic carbon in the formation is estimated from the total Carbon content and the inorganic carbon associated with minerals in the formation. An indication of source rock may be obtained from the Th/U ratio.

Abstract: An apparatus for performing real-time analysis of a subterranean formation fluid includes a light source configured to transmit at least a sample signal through a sample of the subterranean formation fluid and a reference signal, at least one photodetector configured to continuously detect the sample and reference signals, and an electronics assembly configured to compensate for drift in the detected sample signal in real-time based on the value of the detected reference signal.

Abstract: A method for measuring optical properties of a fluid downhole, the method comprising measuring intensity of light interacting with the fluid downhole for each of one or more wavelengths; integrating each intensity of light for each wavelength for an integration time; and estimating the optical property from a difference between a starting value and an ending value for the integral of the intensity of light over time divided by the integration time for the wavelength. An apparatus is disclosed for measuring an optical property of a fluid downhole, the apparatus comprising one or more photodiodes that measure an intensity of light interacting with the fluid downhole for each of one or more wavelengths; and one or more integration circuits that each integrates an intensity of light for one wavelength for an integration time.

Abstract: In accordance with one exemplary embodiment, the present invention provides a sensor system for detecting a change in condition. The system includes a radioactive source. This system also includes at least one radiation detector configured to detect radiation from the radioactive source. Furthermore, the system includes a displacement assembly configured to physically displace in response to the change in condition and configured to change the radiation levels detected by the radiation detector in response to such displacement. Advantageously, this system facilitates non-intrusive communication of information across a physical barrier, via the measurement of changing radiation levels that change in response to a change in condition, for example.

Abstract: A method for estimating a property of a fluid downhole is disclosed, the method including but not limited to exposing the fluid to light downhole; directing different wavelengths of light that have interacted with the fluid light toward a first optical grating; measuring light at different wavelengths reflected from the first optical grating; and estimating a property of the fluid from the measured light. An apparatus for estimating a property of a fluid downhole is disclosed, the apparatus including but not limited to a downhole tool for estimating a property of a fluid downhole, including but not limited to a light source that illuminates the fluid downhole; a first optical grating having a plurality of elements that selectively light that have interacted with the fluid; and a sensor that measures the light reflected from the first optical grating elements.

Abstract: A method and apparatus are provided for determining a property of a fluid downhole by using a tunable optical grating to collect a fluid's spectrum over a wavelength region of interest. A property of the fluid is estimated from spectra that are obtained from light that has interacted with the fluid and then been reflected off of the tunable optical grating onto a photodetector.

Abstract: A photoelectric factor (PEF) that is corrected for standoff effects is obtained from measurements made with a single detector. A first PEF is obtained using a first pair of soft and hard windows and a second PEF is obtained using a second pair of soft and hard windows. Additional correction to the PEF may be made using a formation density measured by the logging tool.

Abstract: Methods, systems, and computer program products for measuring the density of material. According to one aspect, a nuclear density gauge is disclosed for measuring the density of a sample construction material. The gauge includes a radiation source positioned in an interior of a sample construction material and adapted to emit radiation from the interior of the sample construction material. Further, a radiation detector is positioned apart from the radiation source. The radiation detector is operable to produce a signal representing an energy level of detected radiation. A material property calculation function is configured to calculate a value associated with the density of the sample construction material based upon the signal produced by the radiation detector. Further, the radiation source may be positioned on a surface of the sample construction material and adapted to emit radiation towards the surface of the sample construction material.

Abstract: An apparatus and a method for determining characteristics of earth formations traversed by a borehole that compensates the mudcake and standoff effects with fewer than usual detectors. The apparatus includes an radiation source effective to generate first and, spatially as well as temporally separate, second X-rays for irradiating earth formations from first and second entrance angles, one or more X-ray detectors capable of generating a first and a second signal indicative of the intensity of the first and second X-rays returned from earth formations to the detectors and a housing accommodating the radiation source and the detectors.

Abstract: Method and system for analyzing electrical pulses contained in a pulse train signal representative of the interaction of x-ray bursts with a nuclear detector configured for subsurface disposal. The pulse train signal is sampled to form a digitized signal. The total energy deposited at the detector during an x-ray burst is determined from the digitized signal, and a count rate of x-ray pulses from the burst is determined. A subsurface parameter is determined using the total energy deposit.

Abstract: A probe for inspecting an anchor borehole has a video head provided with a color CCD sensor, a lens, a conical viewing window, and light-emitting diode for illuminating and optically scanning a borehole surface. The probe also has a travel sensor, an electronics module including two position sensors, a memory module, and a battery section carrying an infrared interface. The probe is cableless and autarchic. The battery section is secured to a leading end of a push rod.

Abstract: A method for determining a chemical composition of a material in a borehole, the method including placing an analysis apparatus into the borehole; placing a sample of the material onto a metal surface of the apparatus; illuminating the sample at an interface between the sample and the metal surface with a first light beam and a second light beam; measuring sum frequency light generated from the illuminating; and analyzing the sum frequency light to determine the chemical composition of the material.

Abstract: Spectral analysis system for downhole applications is provided utilizing an inorganic replica-type grating that is configured to operate as a diffractive element that provides broad spectral coverage in high temperature downhole environments.

Abstract: A method is disclosed for measuring optical properties of a fluid downhole, the method comprising measuring intensity of light interacting with the fluid downhole for each of one or more wavelengths; integrating each intensity of light for each wavelength for an integration time; and estimating the optical property from a difference between a starting value and an ending value for the integral of the intensity of light over time divided by the integration time for the wavelength. An apparatus is disclosed for measuring an optical property of a fluid downhole, the apparatus comprising one or more photodiodes that measure an intensity of light interacting with the fluid downhole for each of one or more wavelengths; and one or more integration circuits that each integrates an intensity of light for one wavelength for an integration time.

Abstract: A fluid density determination apparatus and method comprising an X-ray generator emitting a high energy radiation signal and a low energy radiation signal; a sample cell housing a sample of interest and at least one of the high energy and low energy radiation signals being directed through the sample cell; and a radiation detector measuring the output radiation from the sample cell. Data gathered at the radiation detector using the high and low energy signals are used to calculate the density of the fluid sample of interest.

Abstract: An analysis system, tool, and method for performing downhole fluid analysis, such as within a wellbore. The analysis system, tool, and method provide for a tool including a spectroscope for use in downhole fluid analysis which utilizes an adaptive optical element such as a Micro Mirror Array (MMA) and two distinct light channels and detectors to provide real-time scaling or normalization.

Abstract: The invention relates lo a device for examining rotor drilled holes, which comprises a probe which comprises an optical detection device and which can be displaced in the drilled hole by means of a push rod. The rotor drilled hole probe (1) comprises a video head (10), which comprises a colour CCD-sensor (11) with a lens (12) which is provided with a cone-shaped mirror (13) and an observation window, in addition to light-emitting diodes (15), a path sensor (20), an electronic part (21), a storage module (22) and battery part (23) whereon an infrared interface is arranged.

Abstract: Measurements made with a nuclear logging tool are partitioned into bins to provide an energy spectrum. The energy spectrum is calibrated by maximizing a measure of similarity with a reference spectrum.

Abstract: A nuclear imaging probe 1 for measuring the density of a subsurface formation GF in a limited zone surrounding a well-bore hole WBH. The probe comprises: a pad 2 having a face arranged so as to be positioned in contact with a well-bore wall WBW, at least one radioactive source 4 arranged within the pad for transmitting incident photons PI towards the well-bore wall, and at least one sensor 5 spaced away from the radioactive source and isolated from the radioactive source by a shield 6 arranged into the pad for receiving photons scattered PS by the limited zone.

Abstract: Data acquired using a pulsed nuclear source are susceptible to two sources of error. One error is due to large statistical noise towards the end of an acquisition window. Another source of error is the contamination of the early portion of the data by borehole and other effects. The beginning of the processing window is adjusted based on the signal level at the end of the processing window for the preceding pulsing of the source. The end of the processing window is derived from statistical considerations.

Abstract: A laser spectroscopy system can determine the identity and/or quantity of a component of a fluid at a remote location such as downhole in a wellbore or inside a pipeline, particularly at high temperature, e.g. from about 75 to 175° C. The system includes a fiber laser doped with a rare earth element (e.g. Nd3+, Tm3+, Er3+, Th3+, Ho3+, Yb3+, Pr3+) and generates light in a wavelength between about 900 to about 3000 nm. The system may analyze a drilling mud such as an oil based mud or crude oil, and may detect components such as methane, ethane, carbon dioxide, hydrogen sulfide and the like.

Abstract: The present invention provides a method and apparatus for estimating a property of a fluid downhole by exposing the fluid to modulated light downhole and sensing changes in intensity of infrared radiation from the downhole fluid to estimate the property of the downhole fluid. The present invention senses changes in intensity of light by converting the changes to transient changes in temperature of a detector, such as a pyroelectric detector. The present invention performs spectroscopic analysis of fluids by optically filtering the light allowed to impinge on a pyroelectric detector, converting the changes in temperature of the pyroelectric detector to a signal and converting the signal to estimate the property of the downhole fluid. The light source is modulated by mechanically chopping the beam or by electrically pulsing the light source or by steering the beam between different path lengths of sample or between a reference cell (filled with a reference fluid or empty) and a sample-filled cell.

Abstract: Some principles described herein comtemplate implementation of downhole imaging for the characterization of formation fluid samples in situ, as well as during flow through production tubing, including subsea flow lines, for short term investigation, permanent, and/or long term installations. Various methods and apparatus described herein may facilitate downhole testing. For example, some embodiments facilitate multi-dimensional fluorescence spectrum measurement testing downhole and correlating the fluorescence with other oil properties.

Abstract: Some principles described herein contemplate implementation of downhole imaging for the characterization of formation fluid samples in situ, as well as during flow through production tubing, including subsea flow lines, for short term investigation, permanent, and/or long term installations. Various methods and apparatus described herein may facilitate downhole testing. For example, some embodiments facilitate multi-dimensional fluorescence spectrum measurement testing downhole.

Abstract: Data acquired using a pulsed nuclear source are susceptible to two sources of error. One error is due to large statistical noise towards the end of an acquisition window. Another source of error is the contamination of the early portion of the data by borehole and other effects. The beginning of the processing window is adjusted based on the signal level at the end of the processing window for the preceding pulsing of the source. The end of the processing window is derived from statistical considerations.

Abstract: A fluid analysis system for use downhole comprises an input light signal that is directed through a fluid sample housed in a sample cell. The input light signal may originate from a plurality of light sources. An output light signal from the sample cell is then routed to one or more spectrometers for measurement of the represented wavelengths in the output light signal. The output of the spectrometers is then compared to known values for hydrocarbons typically encountered downhole. This provides insight into the composition of the sample fluid. Additionally, the light from the light sources can be routed directly to the one or more spectrometers to be used in calibration of the system in the high temperature and noise environment downhole.

Abstract: A method for determining a property of earth formations surrounding a borehole, including the following steps: isolating a region of the borehole, and obtaining a sample of borehole fluid from the isolated region; and implementing measurements, dowhole, of the Raman scattering of electromagnetic energy directed at the fluid sample; the property of the earth formations being determinable from the measurements. In a disclosed embodiment, the steps of isolating a region of the borehole and obtaining a sample of borehole fluid from the isolated region include: providing a logging device in the borehole in sealing engagement with the isolated region, causing formation fluid from the isolated region to flow in a flow line of the logging device, and providing a measurement cell in the logging device which receives the sample of formation fluid via the flow line.

Abstract: A pulsed neutron tool with three or more detectors is used for making measurements inside casing. The measurements may be used to determine gas saturation at a constant gas pressure, pressure at constant gas saturation, or to determine both gas saturation and gas pressure.

Abstract: System and method for formation logging using a gamma-ray detector. The techniques including acquiring gamma-ray signals using the gamma-ray detector, the acquired gamma-ray signals having energies that span at least a first-energy region and a second-energy region, wherein the first-energy region includes energies higher than a selected threshold and the second-energy region includes energies lower than the selected threshold; determining interference signals based on the acquired gamma-ray signals in the first-energy region; and correcting the acquired gamma-ray signals in the second-energy region based on the interference signals to provide corrected gamma-ray signals.

Abstract: A pulsed neutron tool with three or more detectors is used for making measurements inside casing. The measurements may be used to determine gas saturation at a constant gas pressure, pressure at constant gas saturation, or to determine both gas saturation and gas pressure.

Abstract: The invention concerns an apparatus for analysing water chemistry. According to the invention, the apparatus is adapted to operate downhole and comprises a colouring agent supply device for supplying a colouring agent to a water sample, the colour of the water sample thus supplied being indicative of the water sample chemistry, and a colorimetric analyser arranged to determine the colour of the water sample.

Abstract: A downhole fluid analysis system comprises an input light signal that is directed through a fluid sample housed in a sample cell. The input light signal may originate from a plurality of light sources. A light signal output from the sample cell is then routed to two or more spectrometers for measurement of the represented wavelengths in the output light signal. The output of the spectrometers is then compared to known values for hydrocarbons typically encountered downhole. This provides insight into the composition of the sample fluid. Additionally, the input light can be routed directly to the two or more spectrometers to be used in calibration of the system in the high temperature and noise environment downhole.

Abstract: It is described a logging tool 20 for underground formations surrounding a borehole 14, comprising an elongated body 21 along a major axis; a collar 22 disposed peripherally around said body 21 having a collar wall defined by an inner and an outer surface; a radiation emitting source 201 arranged to illuminate the earth formation 16 surrounding the borehole; at least one radiation detector 211 arranged to detect radiation reflected by the earth formation resulting from illumination by the source 201; at least one source collimation—window 202 and one detector collimation window 212 through which the earth formation is illuminated and radiation is detected; and characterized in that it further comprises at least one radiation shield 30 located between said inner collar surface and the outer surface of the tool, said radiation shield positioned so as to eliminate parasitic radiation that has not traversed the outer collar.

Abstract: Measurements made with porosity and density logging tools in a gas reservoir may differ due to invasion effects. The effects are particularly large on measurement-while-drilling applications where invasion is minimal. Using a Monte-Carlo method, a relationship is established between true formation porosity and porosity estimates from density and porosity tools. This relationship is used on real data to get an improved estimate of formation porosity and of gas saturation.

Abstract: Methods and apparatus for analyzing a hydrocarbon mixture are disclosed, comprising at least one light-emitting diode (LED) and at least one photodetector positioned to detect energy transmitted by the LED through a sample of the hydrocarbon mixture. In at least one embodiment an optical filter is coupled to the output of the LED to mitigate the adverse effects of the LED's sensitivity to temperature.

Abstract: As a method for using a hard X-ray sensor that can detect weak hard X-rays or the like with a higher resolution, a method for accurately evaluating natural resources of crude oil, natural gas, etc. existing underground, for example, is provided. A buried object evaluating method includes a detecting step of arranging a radiation detector to be opposed to a hard X-ray source radiating first hard X-rays with a buried object buried in a first substance being interposed between the radiation detector and the radiation source and, by using the radiation detector, detecting second hard X-rays transmitted through the buried object out of the first hard X-rays and third hard X-rays not transmitted through the buried object, and an evaluating step of evaluating the buried object based on a strength of the first hard X-rays and a strength of the second hard X-rays detected by the radiation detector.

Abstract: Methods and apparatus for measuring a phase fraction of a flow stream are disclosed. An infrared phase fraction meter includes a light source for emitting into a flow stream infrared radiation that includes first and second wavelength bands. The first wavelength band substantially transmits through first and second phases of the flow stream and is substantially absorbed by a third phase. In contrast, the second wavelength band is substantially absorbed by the second phase relative to the first and third phases. One or more detectors simultaneously detect attenuation of the first and second wavelength bands upon the infrared radiation passing through at least a portion of the flow stream, and a phase fraction of the second phase is determined based on the attenuation. As an example, the first, second and third phases are gas, water and oil, respectively, produced from a well.

Abstract: The invention comprises an apparatus and method for simple fluorescence spectrometry in a down hole environment. The apparatus and method utilization of two UV light bulbs and an optically clear UV coupler and a fluid containment system. The optically clear UV coupler and fluid containment system are made of sapphire. The apparatus is attached in a manner that enables light transmitted from a light source on the far side of the fluid containment system to pass through a pathway in a plate holding the UV bulbs. UV light illuminates the fluid, which in turn fluoresces light. The fluoresced light is transmitted back towards the UV bulb mount and through the pathway towards an optical spectrum analyzer.

Abstract: The present invention relates to an in-vessel or down-hole optical imaging sensor or system for operating in structures which may contain media with different spectral transmission characteristics. The imaging sensor of the present invention selectively emits and/or detects two or more independently controllable wavelengths or wavebands. The imaging sensor comprises an illuminator for emitting radiation of a specified wavelength or waveband through a medium to a target, at least one detector for detecting the radiation deflected by said target and at least one amplifier for providing non-linear amplification of the detector output.

Abstract: The present invention provides an down hole apparatus and method for ultrahigh resolution spectroscopy using a tunable diode laser (TDL) for analyzing a formation fluid sample downhole or at the surface to determine formation fluid parameters. In addition to absorption spectroscopy, the present invention can perform Raman spectroscopy on the fluid, by sweeping the wavelength of the TDL and detecting the Raman-scattered light using a narrow-band detector at a fixed wavelength. The spectrometer analyzes a pressurized well bore fluid sample that is collected downhole. The analysis is performed either downhole or at the surface onsite. Near infrared, mid-infrared and visible light analysis is also performed on the sample to provide an onsite surface or downhole analysis of sample properties and contamination level.

Abstract: The present invention describes a unique method and apparatus for applying near-infrared spectroscopy to estimate weight percent of methane in crude oil from which one can then infer gas-oil ratio (GOR) of crude oils downhole in real time while collecting a fluid sample. The correlation equations provided by this invention use two wavelengths, one centered at 1670 and the other centered at 1682 nm. Both wavelengths are primarily sensitive to the methane peak absorption. To significantly improve the fit, non-spectroscopic parameters, such as temperature or pressure, can be included in the correlation equation. Also, this invention can be used to monitor sample cleanup by monitoring the increase in GOR associated with cleanup as a fluid being pumped from the formation transitions from mostly gas-free filtrate to mostly gas-containing crude oil.