Abstract: A method for determining permeability of a porous medium is described which comprises the steps: a) obtaining a three-dimensional picture of the porous medium by an imaging system, b) dividing the three-dimensional picture into a number n of two-dimensional parallel slices, wherein n is an integer of 2 or more, c) identifying one or more pores in a first outermost slice (n1) using a grid which defines image pixels, d) identifying one or more pores in a second slice (n2) directly neighboring the first outermost slice (n1) using the same grid which defines image pixels as for the first outermost slice (n1), and e) labelling the one or more pores in the second slice (n2) as connected if at least one of its neighbours in the first outermost slice (n1) is a pore to give a number of connected pores as a connectivity result. Also described is a system comprising means for carrying out such a method.

Abstract: Monitoring scattered gamma rays is used to identify substances disposed between coaxial tubulars disposed in a subterranean wellbore. Gamma rays are strategically directed from within an inner most tubular and into the annulus, some of the gamma rays scatter from the substance between the tubulars and are detected with detectors set a designated axial distance from the gamma ray source. Gamma rays also scatter from fluid within the tubular, a ratio of the gamma rays detected that scatter from the fluid in the tubular and from the substance can be used to determine the substance.

Abstract: This device comprises a single radioactive source (44), capable of creating an incident beam (120), and a target (48) placed opposite the source (44). The target (48) is capable of creating the second beam (130) by interacting with a first part of the incident beam (120), a second part of the incident beam (120) passing through the target (48) to form the first beam (124).

Abstract: The present disclosure relates to apparatus and methods for evaluating an earth formation though a drillstring during tripping of the drillstring, particularly locating an area of circulation loss in a wellbore. The apparatus may include a neutron source and at least one radiation detector, which may be disposed on a logging instrument, configured to be dropped or pumped into a drillstring at the end of drilling. The logging instrument may be configured to make measurements through a homogenous portion of the drillstring while the drillstring is being tripped. The apparatus may include a memory and processor for logging data for later retrieval. The method may include adding a radiation absorbing substance to drilling fluid in the wellbore; exposing the earth formation to neutron radiation; and making a plurality of measurement indicative of radiation measurements of sigma or distinct energy peaks along the wellbore.

Abstract: Devices, methods and systems for making optical measurements of a fluid at elevated pressures and temperatures are disclosed. A cell is designed for the optical spectroscopic measurements of fluids or gas using light from ultra violet (UV) to far infrared wavelengths, among other wavelengths. A cell is described that is well suited for applications using very small fluid volumes, on the order of micro liters, such as microfluidic systems. Some described embodiments are suited for very high pressure and temperature environments (for example, 20 kpsi or greater at 175 degree C. or greater). Such conditions, for example, may be found in oilfield downhole environments. Some embodiments provide are inexpensive, and make use of replaceable lenses that are used as a pressure barrier and for collimation of the optical beam path for spectroscopic measurements.

Abstract: A method for estimating a parameter of interest of an earth formation having a fluid contained in pores of the earth formation, the method includes: conveying a carrier through a borehole penetrating the earth formation; irradiating the earth formation with neutrons from a neutron source disposed at the carrier; measuring radiation emitted from the earth formation resulting from the irradiating using at least one detector; calculating or determining a mathematical parameter from radiation measured by the at least one detector; predicting values of the mathematical parameter over a range of values of an earth formation property; and comparing the mathematical parameter to the predicted values to estimate the parameter of interest.

Abstract: The method for obtaining a fluid migration profile for a wellbore, including the steps of obtaining a static profile for a logged region of the wellbore, obtaining a dynamic profile for the logged region of the wellbore, digitally filtering the dynamic profile to remove frequency elements represented in the static profile, to provide a fluid migration profile, and storing the fluid migration profile on a computer-readable memory.

Abstract: An apparatus for evaluating downhole fluids is disclosed. The apparatus includes: an optical block having an adjustable opening that receives electromagnetic energy emitted by an electromagnetic energy source; a controller operatively associated with the optical block for adjusting the opening size, wherein the opening size is adjusted at least in part based on one or more estimated downhole parameters; and a sensor that receives the electromagnetic energy emitted by the electromagnetic energy source after the emitted electromagnetic energy interacts with a downhole fluid. A method for evaluating downhole fluids is also disclosed.

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: A thermosetting resin composition include a liquid epoxy resin, a solid epoxy resin, a semisolid epoxy resin, an epoxy curing agent, and a filler. The liquid epoxy resin is liquid at 20° C. and has at least two epoxy groups in a molecule. A solid epoxy resin is solid at 40° C. and has at least three epoxy groups in a molecule. A semisolid epoxy resin is solid at 20° C. and liquid at 40° C. and has at least two epoxy groups in a molecule. A ratio of mass of the liquid epoxy resin to a sum of mass of the solid epoxy resin and mass of the semisolid epoxy resin is about 1:1 to about 1:10, and a ratio of the mass of the solid epoxy resin to the mass of the semisolid epoxy resin is about 1:0.5 to about 1:2.

Abstract: A C/O ratio is determined using measurements of inelastically scattered gamma rays with a pulsed neutron source. Combined with look-up tables, the C/O measurement is used as an indicator of formation fluid influx into wellbore such as gas kick.

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: 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 invention provides a method for determining phase transition pressure of downhole retrograde condensate. An OBM-contamination value is produced from a time-series of fluorescence values produced by measuring fluorescence emitted from a single-phase flow of OBM-contaminated formation fluid in a downhole cell during a cycle of time. The pressure of fluid in the cell is set at a transition boundary by incrementing drawdown pressure and monitoring the presence or absence of a phase transition. An apparent phase transition pressure value associated with the cycle of time is produced by setting apparent phase transition pressure value equal to cell pressure. This process is repeated for several cycles of time to produce a number of pairs of OBM-contamination value and apparent phase transition pressure value as OBM-contamination decreases over time.

Abstract: The invention relates to a device for determining and/or monitoring the density and/or the level (L) of a filling material in a container. A transmitting unit which emits radioactive radiation and a receiving unit which is arranged in such a way that it receives the radioactive radiation or the secondary radiation that is produced by the interaction of the radioactive radiation with the filling material are provided. A regulating/evaluating unit which determines the density and/or the level of the filling material in the container using the measuring data that is supplied by the receiving unit is also provided. The aim of the invention is to provide a device which enables the level or the density of a filling material in a container to be measured reliably. To this end, the receiving unit consists of individual detector units.

Abstract: A method and apparatus for analyzing a semiconductor surface obtains a sample from a localized section of a wafer. The sample is obtained by isolating a section of a wafer with a sampling apparatus, dispensing liquid onto the isolated section of the wafer, dissolving compounds of interest in the liquid, removing a portion of the liquid, and analyzing the liquid and dissolved compounds of interest. The liquid can be an etching solution, an organic solvent, or other suitable solvent. Samples and analyses can, thus, be obtained as a function of position on the wafer. Analyses as a function of depth can also be determined by sampling and analyzing an isolated portion of the wafer as a function of time.

Abstract: A method for determining which of a plurality of detectors transmitted a signal, such as a signal related to neutron or gamma emissions, includes connecting each of the detectors to a single cable, such as an environmentally rugged cable. Signals are transmitted from each of the detectors over the single cable. The two ends of the cable are connected to two receivers. A different unique delay is introduced between receipt by the two receivers of a signal over the cable for each of the detectors. The receivers, which have a preamplifier, an amplifier and a discriminator, receive the signals from the two ends of the cable. A timing analyzer, such as a time-to-amplitude converter, measures a delay between one signal from one end and the other signal from the other end of the cable. A processor employs the amplitude of the signal output by the timing analyzer.

Abstract: The present invention relates to an imaging sensor, particularly for use in oil-filled passages such as wells or pipelines, or for passages containing other similar viscous fluids. There is provided a downhole imaging system which operates in a wavelength region outside the visible band, preferably in the infrared region, to permit penetration of the surrounding fluid medium, e.g., oil. Positioning the optical part of the imaging sensor in a chamber whose walls are transparent to the radiation reduces the path length of the radiation in the oil. The chamber is filled with a material highly transmissive of the radiation.

Abstract: A process and apparatus for determining the levels in a vessel of two or more immiscible or partially-miscible components has been developed. The process begins with transmitting gamma rays, x-rays, microwaves, ultrasound waves, or sonar waves through the vessel by sequentially activating at least three stationary energy sources positioned adjacent to and in the vertical plane of the vessel. A set of intensities of the energy exiting the vessel corresponding to each energy source is measured using an array of stationary sensors where each set contains the intensity sensed by each sensor in the array of sensors. The sensors of the array are positioned in the vertical plane of the vessel and in alignment with the energy penetrating the vessel. The array of sensors contains a number of sensors that is at least one greater than the number of energy sources.

Abstract: A method is disclosed for determining the thickness of cement that has been placed in an annulus between a casing string and a wellbore penetrating a formation, wherein the method includes the steps of: logging the amount of radioactivity emitted by a radioactive material in the formation prior to emplacement of the casing and cement, including in the cement an amount of the radioactive material, placing the casing and cement in the wellbore, logging the amount of radioactivity emitted by the radioactive material and transmitted through the casing and calculating the amount of cement in the annulus by determining the amount of the radioactive material in the annulus.

Abstract: A method and apparatus determines three phase holdup fractions and flow rates for the individual phases of a fluid flowing in a well. A logging tool comprising a temperature compensated gradiomanometer having a differential pressure detector comprised of two pressure sensors and a nuclear densitometer having a beam source is lowered into a wellbore. The differential pressure between the pressure sensors is measured and an average fluid density is determined. The attenuation of a beam propagating from the beam source through the fluid and to the beam detector is measured, and holdup fractions of the fluid are calculated. Flow rates for the individual phases are determined by adding a flowmeter, and multiplying each holdup fraction by the total flow rate.

Abstract: A method for porosity determination in porous media such as earth and rock core samples by x-ray computed tomography in which a sample of the porous medium is scanned after saturation with a first reference fluid and then after saturation with a second reference fluid to determine the linear attenuation coefficients of the sample saturated with the respective fluids. The method includes determining the linear attenuation coefficients of the respective fluids and comparing the difference in the attenuation coefficient of the respective fluids and the attenuation coefficient of the samples as saturated with the fluids to determine the porosity of the porous medium. The respective fluids may be a gas and a liquid wherein the x-ray absorption of the two fluids is significantly different. The fluids may be different liquids or a single gas at different pressure conditions to obtain the different absorption characteristics.

Abstract: This invention relates to a system for monitoring, in a cavity in the earth, the position of, or changes in the position of, an interface between two immiscible liquids of different densities. In accordance with the invention, two pipes, one positioned within the other to form a space between them, extends into the cavity in the earth. A probe is mounted on the outer wall of the inner pipe and is vertically positioned near the interface to be monitored. The probe includes an emitting source and a detector-receiver and readings are taken of signals received by the detector after emission by the source and at least partially reflected by at least one of the liquids. From the readings the position of or change in interface may be computed since the signal reading will vary as a function of the relative position of the probe and the interface. The invention may be applied to the monitoring of excavations of underground salt cavities.

Abstract: A method is disclosed for monitoring the flood front movement during enhanced recovery operations wherein flooding fluids are pumped into a number of injection wells forcing residual oil movement toward a production well. A plurality of monitoring wells located between the injection wells and the producing well are logged to establish base logs functionally related to oil saturation and water salinity. Periodically during the water flood operation, the monitoring wells are relogged to detect changes in oil saturation and water salinity. By comparison of the base logs with the series of later derived logs it is possible to accurately monitor the flood front movement including detecting high-permeability zones and monitoring of the flood front profile.

Abstract: The instrument and method locate anomalies and the interface between two materials having little difference in their density in a mining or storage well. More particularly, the method comprehends the generation of gamma rays and the detection of scattered rays at a point spaced from the point of generation of the gamma rays. By moving the points of generation and detection through the well, there will be observed a pronounced change in the detection rate of the scattered gamma rays when various interfaces and anomalies are traversed.The focus interface instrument includes a decentralizer, collar locator, electronics assembly, detector, and radiation generator, all enclosed in a nonmagnetic stainless steel housing except for the electronics assembly whose housing is made of tubular steel. The radiation generator has a radioactive source which emits gamma rays, and the detector detects those rays reflected back to the detector.

Abstract: A method is disclosed for determining oil saturation in a petroleum reservoir using logging signals indirectly related to the abundance of carbon nuclei in the reservoir rock. The first step of the invention is to record a log sensitive to the abundance of carbon nuclei after the region surrounding the well bore is caused to have oil saturations representative of the bulk of the reservoir. A purposeful change is then made in the fuel saturations in the region surrounding the well bore by injecting a liquid capable of displacing substantially all of the original fluids. The log is recorded a second time. The displacing fluid is then itself displaced by brine, and a third log is recorded. Oil saturation is then determined from differences between the logs and from known fractional volume carbon contents of the reservoir oil and the first injected liquid. It is not necessary that the log responses be independent of the material in the bore hole, the casing, the casing cement, or the reservoir rock.

Abstract: A method is disclosed for determining gas saturation in a petroleum reservoir using logging signals indirectly related to the abundances of oxygen and carbon nuclei in the reservoir rock. The first step of the invention is to record first and second logs sensitive to the abundance of oxygen and carbon nuclei, respectively, after the region surrounding the well bore is caused to have fluid saturations representative of the bulk of the reservoir. A purposeful change is then made in the fluid saturations in the region surrounding the well bore by injecting a liquid capable of displacing substantially all of the original fluids. The logs are recorded a second time. The displacing fluid is then itself displaced by brine, and a third suite of logs is recorded. The total fluid and oil saturations are then determined from the differences between respective corresponding logs and from known fractional volume oxygen and carbon contents of the reservoir brine and oil and the first injected liquid.

Abstract: A method is disclosed for determining water saturation in a petroleum reservoir using logging signals indirectly related to the abundance of oxygen nuclei in the reservoir rock. The first step of the invention is to record a log sensitive to the abundance of oxygen nuclei, after the region surrounding the well bore is caused to have fluid saturations representative of the bulk of the reservoir. A purposeful change is then made in the fluid saturations in the region surrounding the well bore by injecting a liquid capable of displacing substantially all of the original fluids. The log is recorded a second time. The displacing fluid is then itself displaced by brine, and a third log is recorded. Water saturation is then determined from differences between the logs and from known fractional volume oxygen contents of the reservoir brine and the first injected liquid. It is not necessary that the log responses be independent of the material in the borehole, the casing, the casing cement, or the reservoir rock.

Abstract: The interface between two fluids such as oil and water in an underground cavern may be detected by placing a gelled substance containing a source of gamma radiation at the interface and detecting the emissions from the gelled substance.

Abstract: A method for locating water-producing zones and/or water thief zones in a subterranean formation penetrated by a well bore comprising the sequential steps of:A. injecting into said formation an aqueous solution containing from about 0.01 to 7.5 weight percent of an irradiated water soluble compound, said compound having preferential silica adsorptive characteristics;B. passing radioactivity detection means through the well bore and recording the measurement of radioactivity;C. returning the reservoir or injection well to normal production or normal water injection;D. passing said radioactivity detection means through the well bore and recording the measurement of radioactivity of said formation; and,E. comparing the measurements of radioactivity to determine water producing zones and/or water thief zones.