Abstract: Method and apparatus for providing real-time data indicative of the isotopic composition of formation fluids during drilling. The method includes the steps of: (a) providing a reference fluid having a known isotopic composition in a reference cell; (b) capturing a sample of formation; (c) providing at least one laser beam; (e) passing a beam through the reference fluid, measuring the reference-measurement beam before and after it passes through the reference fluid; (f) and passing a beam through the sample, measuring the beam before and after it passes through the sample, and calculating a first isotope concentration from those measurements. The measurements can provide information relating to the carbon isotopic composition of individual compounds in hydrocarbon gas mixtures, with the individual compounds including methane, ethane, propane, iso- or normal butane, or iso- or normal pentane.

Abstract: The present invention provides systems utilizing fiber optics for monitoring downhole parameters and the operation and conditions of downhole tools. In one system fiber optics sensors are placed in the wellbore to make distributed measurements for determining the fluid parameters including temperature, pressure, fluid flow, fluid constituents and chemical properties. Optical spectrometric sensors are employed for monitoring chemical properties in the wellbore and at the surface for chemical injection systems. Fiber optic sensors are utilized to determine formation properties including resistivity and acoustic properties compensated for temperature effects. Fiber optic sensors are used to monitor the operation and condition of downhole devices including electrical submersible pumps and flow control devices. In one embodiment, a common fluid line is used to monitor downhole parameters and to operate hydraulically-operated devices.

Abstract: A system and method for rapidly analyzing elemental abundances in rock or soil samples (14) under field conditions. The system uses a portable neutron source (12) to allow neutron activation analysis of elements having identifiable radioactive decay characteristics. A radiation detector (18) detects radiation released by the sample (14) and provides radiation testing results to an amplifier (26) for computing the concentration of trace elements in the sample with a high degree of accuracy.

Abstract: The optical density of an oil sample at a plurality of wavelengths over a plurality of different (typically decreasing) pressures is monitored and used to find the size of agglomerated asphaltene particles which are precipitating from the oil sample. The optical density information used in finding the particle size is preferably optical density information relating to the scattering of light due to the asphaltene particles only. Thus, baseline optical density information of the oil sample at a high pressure is subtracted from optical density information obtained at test pressures at each wavelength of interest. Asphaltene particles of a radius of one micron and smaller were found to be powdery, while asphaltene particles of a radius of three microns and larger were found to include paving resins. The precipitation of asphaltenes is reversible by increasing the pressure under certain circumstances.

Abstract: The invention describes a method and apparatuses for characterizing groundwater measuring sites by differentiating between groundwater and static water and serves, for example, for determining the pumping-out times of groundwater measuring sites, optimum for investigations of the representative nature, as well as for identifying and localizing defects at groundwater measuring sites. The invention is based on measuring the radon activity concentration or the total activity concentration of the groundwater samples. The measurement of the concentrations by offline or online methods permits the ratio of groundwater to static water in a groundwater measuring site to be determined reliably. A novel flow-through measurement cell, as well as a borehole probe are described The invention can be employed wherever investigations of the nature of groundwater are carried out.

Abstract: A nuclear density gauge and test method is provided for measuring bulk density, especially of a cylindrically shaped sample such as asphalt paving material. The gauge comprises a base; a sample holder carried by the base and having a surface configured for receiving and holding a first generally planar end of the cylindrically shaped sample; a plate mounted in proximity to said sample holder; and at least three sources of gamma radiation located in said plate adjacent the sample holder. The sources are positioned in spaced-apart relation from one another for emitting gamma radiation from at least three spaced-apart locations into said one end of the sample. Each of the sources comprises an isotope having a characteristic primary energy. A detector is mounted to the base and is positioned adjacent the opposite end of the cylindrically shaped sample for receiving gamma radiation which has penetrated the sample.

Abstract: The compressibility of a formation hydrocarbon sample is determined downhole by using a borehole tool to obtain the sample downhole, and, at two different pressures, subjecting the sample to near infrared illumination and conducting spectral absorption measurement of peaks at and/or around about 6,000 cm−1 and/or at and/or about 5,800 cm−1 (the absorption peaks of methane and crude oil respectively). The compressibility of the sample is determined from the change in the peak areas, the change in pressure, and the measured peak area itself. According to a preferred embodiment of the invention, the pressure is changed at least 2000 pounds per square inch (psi), and preferably 4000 or more psi between measurements.

Abstract: The invention describes a method and a device for the continual and, in particular, for a fast detection of changes of the concentration of radon gas dissolved in water by means of a transfer into a measuring gas (Rn-222), which can be adopted for a variety of monitoring, control and regulation assignments. The invention is based on the fact that a membrane, which is permeable for the radioactive noble gas radon but extensively non-permeable for water, is circum-flushed on the one side of radon-containing water and on the other side of the carrier gas with, in each case, optimised flow velocities either in parallel or in counter-flow When stable peripheral conditions are ensured, the concentration of radon in the measuring gas is directly proportional to the concentration of radon in the water.

Abstract: The optical density of an oil sample at a plurality of wavelengths over a plurality of different (typically decreasing) pressures is monitored and used to find the size of agglomerated asphaltene particles which are precipitating from the oil sample. The optical density information used in finding the particle size is preferably optical density information relating to the scattering of light due to the asphaltene particles only. Thus, baseline optical density information of the oil sample at a high pressure is subtracted from optical density information obtained at test pressures at each wavelength of interest. Asphaltene particles of a radius of one micron and smaller were found to be powdery, while asphaltene particles of a radius of three microns and larger were found to include paving resins. The precipitation of asphaltenes is reversible by increasing the pressure under certain circumstances.

Abstract: The present invention provides a method for improving the quality of a formation fluid sample by taking the sample at a time when the formation fluid composition contains the most favorable portion of hydrocarbons. This task is accomplished by determining in real-time, the composition of the fluid flowing into a downhole tool from the formation. This method determines the optical density of the fluid as the fluid flows through the tool. An optical density spectrum is generated from the optical density measurement. The optical density spectrum is compared to a composite optical density spectrum generated from a database of known fluid samples. As a result of the comparisons, there is a determination of the derivations between corresponding features of the two spectra. Adjustments are made to the components of the composite spectrum until the deviations between the two spectra are at an acceptable minimum.

Abstract: The radometer is a portable instrument for the measurement of the concentration of atmospheric radon/thoron in a test area. A constant velocity pump pulls the air from the outside at a constant flow rate. If the air is too moist, some or all of the sample is passed through a desiccant filter prior to encountering an electrostatic filter. The electrostatic filter prevents any charged particles from entering the sampling chamber. Once the sample has entered the chamber, the progeny of the decay of radon/thoron are collected on a detector and measured. The measured data is compiled by a computer and displayed.

Abstract: The invention describes a method and apparatuses for characterizing groundwater measuring sites by differentiating between groundwater and static water and serves, for example, for determining the pumping-out times of groundwater measuring sites, optimum for investigations of the representative nature, as well as for identifying and localizing defects at groundwater measuring sites. The invention is based on measuring the radon activity concentration or the total activity concentration of the groundwater samples.

Abstract: A method and apparatus is provided for determining OBM filtrate fraction in a downhole fluid sample. One embodiment of the method is used when there is significant difference between the coloration of formation fluid and the coloration of OBM filtrate. Another is used when there is little or no difference between the coloration of formation fluid and the coloration of OBM filtrate. Another determines GOR of formation fluid corrected for OBM filtrate contamination. Another determines OD of formation fluid corrected for OBM filtrate contamination. Another determines conditions that would render optical density measurements invalid and sample capture premature. Another predicts the reduction of filtrate fraction for a specific extended pumping time. Another initiates sample capture when computed contamination fraction exhibits stable asymptotic convergence.

Abstract: A method and probe for subterranean determination of the concentration of a substance has a light-conducting optical fiber running from above the ground to a measurement cell below the ground. The system can be used effectively for fluorescent markers to track the ground water flow.

Abstract: The present invention relates to the exploration for and exploitation of formation hydrocarbons. According to the invention, a sample of material, representative of the impregnation with hydrocarbons of the rocks passed through, is taken during a drilling operation, with which sample a value of an emission flux, representative of the concentration of the fluorescent elements in the sample, and a value of a fluorescence quotient, which reflects the nature of the hydrocarbons present in the sample, are determined by spectrofluorimetry. The invention finds its application in analytical laboratories and on the drilling sites of petroleum production fields.

Abstract: The invention describes a method and apparatuses for characterizing groundwater measuring sites by differentiating between groundwater and static water and serves, for example, for determining the pumping-out times of groundwater measuring sites, optimum for investigations of the representative nature, as well as for identifying and localizing defects at groundwater measuring sites. The invention is based on measuring the radon activity concentration or the total activity concentration of the groundwater samples. The measurement of the concentrations by offline or online methods permits the ratio of groundwater to static water in a groundwater measuring site to be determined reliably. A novel flow-through measurement cell, as well as a borehole probe are described. The invention can be employed wherever investigations of the nature of groundwater are carried out.

Abstract: Method and device for measuring the resistivity index curve (Ir) of a solid sample such as a geologic sample independently of the capillary pressure curve (Pc). Multi-frequency complex impedance measurements are carried out for a sample subjected to a radial confining pressure, during operations of drainage or imbibition of a first, initially saturating fluid, through a semipermeable membrane permeable to this first fluid, placed at a first end of a containment cell, by injection of a second fluid under pressure at the opposite end thereof. One or more injection pressure stages are applied and the continuous variations of the resistivity index (Ir) as a function of the average saturation (Sw) variation are measured without waiting for the capillary equilibria to be reached. Electrodes pressed against the sample on the periphery thereof are used, these electrodes having a given longitudinal extension in relation to the length of the sample and being connected to an impedance meter.

Abstract: A logging tool system for analyzing the carbon dioxide concentration in a fluid sample downhole in a borehole. A chamber is filled with the fluid sample and is closed to isolate the fluid sample from the borehole. The interior chamber volume is expanded to decompress the fluid sample, and a transmitter discharges light in the mid-infrared range. A sensor measures the absorbance of mid-infrared light by the decompressed fluid sample and generates a signal representing the carbon dioxide concentration. Mid-infrared light absorbance in the range between 4.1 and 4.4 microns can be analyzed by the processor to identify the carbon dioxide concentration in the fluid sample, and infrared absorbance in the mid-infrared range between 3.2 and 3.6 microns can be analyzed to identify methyl and metheylene components. A wiper cleans the transmitter and sensor between readings to reduce measurement errors caused by fluid sample contamination.

Abstract: The invention concerns a method for determining the presence and quantity of an amine-based additive in fluids, particularly aqueous fluids used in hydrocarbon recovery such as drilling fluids, drill-in fluids, completion fluids, and the like. It was discovered that, after isolating the amine-based additive, the amount of clay stabilizer is linearly dependent upon the spectrometric count of its peak fluorescent spectrum. The method is reproducible and is not bothered by the presence of lignosulfonate and/or lignite which interferes with conventional methods.

Abstract: A method of using natural oil inclusions in rock that is capable of oil entrapment to determine whether that rock has had, or presently contains, oil, comprising the steps of: selecting two or more regions on a sample of the rock; determining a ratio of the number of regions that contain oil inclusions, or the number of regions that do not contain oil inclusions, as against the total number of regions selected; and comparing that ratio against standard rock samples to thereby enable the determination to be made as to whether or not the rock has had or presently contains oil. The method can also be used to locate boundaries of different fluid phases in geological sites capable of retaining oil.

Abstract: A method and apparatus are provided to concentrate and detect very low levels of radioactive noble gases from the atmosphere. More specifically the invention provides a method and apparatus to concentrate xenon, krypton and radon in an organic fluid and to detect these gases by the radioactive emissions.

Abstract: Methods according to the invention include providing an OFA tool which subjects formation fluids to NIR illumination and which provides a spectral measurement of peaks at about 6,000 cm.sup.-1 and about 5,800 cm.sup.-1. The methods according to the invention also include calculating a ratio of the amplitudes of the absorption peaks to determine GOR. According to an alternate embodiment, the methods of calculating the ratio include referring to a database of spectra of hydrocarbons found in formation fluid and adjusting the amplitudes of the methane and oil peaks to account for the influences of other hydrocarbons on the spectrum of the formation fluid. A borehole apparatus for measuring the spectral peaks of oil and methane includes a testing region, a conduit for directing formation fluid into the testing region, a light source emitting at least near infrared rays into the testing region, a spectral detector optically coupled to the testing region, and a processor coupled to the spectral detector.

Abstract: A galvanic cell is formed when ground water within a sump reservoir, tub or other pool, rises to contact electrodes constructed of dissimilar metals, the electrodes mounted in a bridge, with recessing, expansion brackets, to facilitate covering the sump hole and including an alarm device adapted to provide a warning signal should the water level exceed a predetermined level to contact the electrodes. Because an unsealed sump well is the major point of entry of radon gas, an scintillator with associated circuitry monitors the sump well to protect against the undesirable intrusion of radon gas. When the presence of radon is detected, an audible alarm is sounded when the level exceeds 4 picocuries per liter (4 pCi/L.).

Abstract: A borehole tool analyzes the composition of gases flowing from a formation. The tool includes an optical fluid analyzer (OFA) and a gas analysis module (GAM). The OFA determines when fluid flowing into the tool has become substantially only gas. The gas is then diverted to the GAM, thereby avoiding the possibility of oil depositing itself on a optical window and interfering with a proper analysis. The GAM includes a near infrared ray light source, at least one photo-detector, a gas sample cell (or cells) having portions with different path lengths, each portion having an optical window, and fiber optics which direct light in first paths from the source to the sample cell, and from the sample cell to the photo-detectors. By providing cells with different path lengths, issues of dynamic range are obviated.

Abstract: A system for measuring the size distribution of particles on which radioactive atoms are attached including: an air flow channel for receiving an influx of the radioactive atoms, a fan for controlling the air flow rate in the channel, one or more wire mesh screens in the channel, and alpha particle detectors located in the channel so as to detect the radioactive atoms. The outputs of the detectors may be connected to a computer for analysis of the outputs.

Abstract: A method for reducing the concentration of radioactive material in a contaminated area by removing contaminated soil from the contaminated area; determining a field survey specific activity concentration representative of the remaining soil in the contaminated area; comparing the field survey specific activity concentration with a field validation data set to determine the total concentration of contaminating radioactive material in the contaminated area and removing additional quantities of contaminated soil from the contaminated area as required. The soil area may alternatively be blended with clean soil to reduce the concentration of radioactive material in the soil or a combination of blending and removal may be used. A method for estimating the total concentration of radioactive material in a soil sample is provided.

Abstract: A method for evaluating the API gravity of a sample of underground formation includes steps of:Solvating a known volume of an underground formation sample in a known volume of a solvent which will solvate hydrocarbons;Quantitatively measuring with a changeable filter portable fluorometer the emission fluorescence of the solvated sample at a fixed excitation wavelength with measurements of emission intensities at two points;characterizing the oil by the ratio of two emission intensities obtained at a fixed excitation wavelength;determining the yield;applying regression analysis to a data base of oils to obtain an equation which results in an algorithm value; andinterpreting the value of the algorithm to give a value for API gravity and estimate in-situ oil concentration.

Abstract: A production logging device, insertable into a cased or uncased wellbore for determining concentration of specified components in flowing production fluid, is provided having a tool body sized smaller in diameter than the wellbore so that flowing fluid production is not blocked. A line is connected to the tool body by which movement of the tool body within the wellbore casing can be selectably controlled from a remote location, and by which information signals can be communication from the tool body to the remote location. An infrared radiation source operatively connected to the tool body. A plurality of infrared transmission sites are circumferentially spaced around the tool body directed so that infrared radiation from the infrared radiation source is transmitted through flowing production fluid in the wellbore.

Abstract: Methods are disclosed for evaluating wet cutting from a well borehole to determine the hydrocarbon content of the earth formations penetrated by the well borehole. The wet cuttings to be measured are mixed with a polar hydrocarbon solvent which has both hydrophilic and hydrophilic properties. The solution of the solvent and cutting is filtered and then its emission (fluorescence) spectrum is measured by irradiating it with ultraviolet radiation excitation at wavelengths at which most petroleum compounds fluoresce. The hydrocarbon content of the sample wet cuttings is then determined by comparing its fluorescence emission to the emission fluorescence of known samples.

Abstract: A method and apparatus for evaluating the composition of an oil sample. The method and apparatus are premised on the discovery that spectral differences can be observed in the luminescence, excitation, light scattering and absorption spectra in the near UV, visible and near IR regions for various crude oil components, such as asphaltenes, deasphalted crude oil and organic solid residues. Accordingly, in one preferred embodiment the method comprises illuminating an oil sample with light of a suitable excitation wavelength, measuring the resultant fluorescence therefrom and comparing the resultant fluorescence to appropriate standards derived from known components of crude oil.

Abstract: A radon test package of simplified and low cost construction. A generally flat outer packet is formed from a single sheet of radon barrier material folded to define two panels with facing inner surfaces sealed along side edge portions, leaving a closeable open edge portion. The outer packet is expandable so as to define a chamber, having an access opening corresponding to the open edge portion. The facing inner surfaces have a surface layer of fusible low density polyethylene, and a sheet of gas-permeable kraft paper is adhered by heat sealing directly to the inner surface of one of the panels in an adhesion pattern which defines a closed triangular pocket containing activated charcoal. When the packet is expanded, the access opening is square, and a block of open cell foam material is inserted to maintain the opening in a standardized configuration, as well as to eliminate the effect of air currents.

Abstract: A method and apparatus for identifying cuttings from a wellbore is disclosed. The cuttings can be identified by measuring emissions such as alpha, beta, or gamma particles which emanate from the cuttings. A continuous wellbore profile of the alpha or beta emissions can be constructed by measuring the emissions from cuttings taken from different locations in the wellbore, and by documenting such emissions. The effects of cuttings dispersion caused by differing particle sizes can be reduced by collecting cuttings of an intermediate size for analysis. The profile of the intermediate size cuttings can be compared with a well log to identify the original elevation of the cuttings within the wellbore.

Abstract: A casing-less down hole sampling system for acquiring a subsurface sample for analysis using an inductively coupled plasma system is disclosed. The system includes a probe which is pushed into the formation to be analyzed using a hydraulic ram system. The probe includes a detachable tip member which has a soil point mad a barb, with the soil point aiding the penetration of the earth, and the barb causing the tip member to disengage from the probe and remain in the formation when the probe is pulled up. The probe is forced into the formation to be tested, and then pulled up slightly, to disengage the tip member and expose a column of the subsurface formation to be tested. An instrumentation tube mounted in the probe is then extended outward from the probe to longitudinally extend into the exposed column. A balloon seal mounted on the end of the instrumentation tube allows the bottom of the column to be sealed.

Abstract: A method of quantitative analysis of free organic components in a drilling fluid comprising separating solid and liquid components of the drilling fluid using a non-filtering technique such as centrifuging, mixing a sample of the liquid components with a solution of an inorganic carrier such as 2M KBr and analyzing the mixture using infrared spectroscopy so as to determine the amount of organic components in the mixture and deriving the amount of free organic components in the drilling fluid from this analysis. In one embodiment, the mixture is dried to leave a solid mixture of the organic components and the carrier. In this case, the sample is preferably analyzed using a reflectance technique such as diffuse reflectance infrared spectroscopy. In another embodiment, the mixture is analyzed as a liquid, preferably using a direct transmission technique. In both the liquid and solid cases, Fourier transform infrared spectroscopy is preferred.

Abstract: A method for measuring the linear flow velocity, radial position, direction, and the flow rate of water flowing within and behind a well borehole casing. A logging tool containing a source of essentially monoenergetic 14 MeV neutrons and at least one gamma ray detector is positioned within the well borehole opposite the zone in which water flow measurements are desired. The neutron source is turned on thereby irradiating any flowing water and other areas in the vicinity of the well borehole with high energy neutrons. After a predetermined irradiation time, the neutron source is turned off. Following a quiescent period of several milliseconds to allow thermal capture gamma radiation to decay to a negligible level, the gamma ray detector is turned on and the count rate from the N-16 induced within the flowing water is recorded as a function of time. The linear flow velocity, the Full Width Half Maximum time period, and the total count are determined directly from the resulting count rate curve.

Abstract: A method for determining the widths of fractures in reservoir earthen cores utilizes a series of CT X-ray scans which are translated into an estimated porosity image. A region of interest within the image is selected and a frequency histogram of the porosity distribution is created. The contribution of the fracture widths to the pore volume is determined from the histogram.

Abstract: A elecret substrate (10), which is exposed to the environment so as to collect molecular contamination, lies at the bottom of a holder (20). Above the substrate a sensor head (100) is supported. Signals from the sensor head are relayed to an electrostatic voltmeter (130). The voltage reading at electrostatic voltmeter (130) is a function of the amount of polar molecule contamination on substrate (10).

Abstract: A method of quantitative analysis of products, such as barite, bentonite or polymers, in a drilling fluid circulating in a wellbore being drilled is described. The method includes the steps of sampling the drilling fluid, and analysing the sample to determine the density of the fluid and the weight fraction of solids in the fluid. In addition, a known weight of the sample is dried to constant weight so as to obtain the products under the form of solids, which solids are analysed by an infrared spectroscopy technique. The concentration of the products in the drilling fluid is then determined. The method can be applied to the control of the drilling operation by monitoring the quantity of products added to the drilling fluid, such as barite and polymers, or a product coming from the borehole wall or the underground formation being drilled. The invention also applies to the control of the working condition of the mud solids equipment.

Abstract: A method for determining the secondary (Vugular) porosity of a reservoir core sample uses X-ray (CT) computed tomography to quantify the porosity. This is then compared with log derived secondary porosity and used to quantify secondary porosity heterogeneity in wells where no core samples are available.

Abstract: A system for determining the relative permeabilities of gas, water and oil in a core sample has a microwave emitter/detector subsystem and an X-ray emitter/detector subsystem. A core holder positions the core sample between microwave absorbers which prevent diffracted microwaves from reaching a microwave detector where they would reduce the signal-to-noise ratio of the microwave measurements. The microwave emitter/detector subsystem and the X-ray emitter/detector subsystem each have linear calibration characteristics, allowing one subsystem to be calibrated with respect to the other subsystem. The dynamic range of microwave measurements is extended through the use of adjustable attenuators. This also facilitates the use of core samples with wide diameters. The stratification characteristics of the fluids may be observed with a windowed cell separator at the outlet of the core sample.

Abstract: Methods of determining stimulation related characteristics of a subterranean zone penetrated by a well bore prior to stimulating the zone are provided. The methods basically comprise injecting a small amount of a stimulation fluid having an X-ray contrasting agent admixed therewith into the zone and then obtaining one or more preserved core samples from the zone. The core samples are scanned with X-rays and computed tomographic images are produced for determining the characteristics of the zone.

Abstract: A radon gas detector comprises a housing having an air inlet port leading to an interior, a radiation detection (e.g. alpha particle measurement) chamber and an air exhaust port leading from the interior chamber to the exterior of the housing. The chamber is closed to the entry of ambient light by a pair of light-obstructing baffles that respectively couple the air inlet and air exhaust ports to the interior chamber. Coupled with the air inlet port is a first removable, electrically conductive mesh filter. Coupled with the air exhaust port is a second, fixed electrically conductive mesh filter. Since each mesh filter is electrically conductive, it readily traps radon daughter products before they can enter into the interior chamber. Also, because of its mesh configuration, each filter readily permits substantial air flow. To measure radon concentration in the air being circulated through detector, a radiation (e.g.

Abstract: A method of quantitative analysis of drilling fluids comprising subjecting an untreated wet sample of the fluid to a reflectance infrared spectroscopy technique, typically attenuated total reflectance spectroscopy, and comparing the spectrum obtained with spectra obtained from calibration samples of fluids of known composition. The sample can be obtained directly from the flowing mud with no preparation or alternatively the sample might comprise a prepared sample which is re-suspended in a liquid phase carrier. The sample can also be analysed for non-spectral properties which might also provide useful information in conjunction with spectral data. The method requires little or no sample preparation and can be used to quantitatively analyse both water-based and oil-based drilling fluids using a continuous in-line and/or on-line arrangement.

Abstract: A method for measuring the azimuthal strike orientation of induced fractures in subterranean formations from which the maximum and minimum in situ stress direction can be inferred. The method utilizes an oriented core of a formation and computed tomography imagery for measuring the azimuthal strike orientation of induced fractures.

Abstract: This invention relates to the application of on-line or inprocess elemental analysis by X-ray fluorescence spectroscopy and in particular to improvements in the field of continuously analyzing flowing dry powder samples from processes such as raw mix cement, iron ore, slag, mineral concentrates, concentrator feeds, phosphate, food products and similar materials.

Abstract: Methods for distinguishing among oil samples, and more particularly between a fluid containing oil base mud and formation oil samples are described. The methods all rely on the discovery that the optical absorption spectrum of all crude oils in the visible and near infrared spectra can be described according to the equation OD=ae.sup.Eb, where (OD) is a measured optical density, (b) is a value between 0.37 and 0.55 chosen according to the wavenumber (E) and can be chosen as a constant equal to 4.6.times.10.sup.-4 cm, and (a) is an unknown which classifies the crude oil. By making measurements and solving for (a), a crude oil can be classified. In a flow stream which has a changing oil content, such as may be obtained by a borehole tool which obtains fluid samples from the formation, by monitoring the unknown (a), a determination may be made as to when a formation oil is being obtained as opposed to a mud filtrate.

Abstract: This invention provides a method for diagnosing formation damage mechanisms through the use of radially oriented core samples cut from the wellbore wall. Core samples are taken from the wellbore and analyzed under a number of different analytical methods. From the analysis of the cores the operator should be able to determine the type, extent, and severity of the formation damage, as well as the distance that damage extends out into the formation.

Abstract: Disclosed herein is a radiation detector providing for the in situ automatic sampling of fluids containing substances emitting radiation, especially Cerenkov radiation. The detector permits sampling within well casings and is self-purging such that no additional provisions must be established for the storage and disposal of contaminated fluids.

Abstract: An apparatus for determining the time-integrated volume specific activities of radon and thoron daughters without the participation of an operator during the measurement includes an air pump connected to a perpendicularly disposed pipe with plugged ends provided with two longitudinal rectangular orifices which are in contact with two endless aerosol filter bands which are rotated by a clock mechanism at periods of 1 hour and 12 hours respectively. Radiation detectors are disposed in seats of a cylindrical support while the latter is disposed within a protective housing.

Abstract: This invention relates to the field of prospecting to locate mineral deposits particularly gravel and clay deposits. The method of prospecting to locate these mineral deposits includes the steps of traversing an area of the earth's surface and obtaining measurements of gamma radiation corresponding to the presence of uranium, potassium and thorium at spaced points along the traverse. The data collected are used to determine an area mean value for the gamma radiation measurements obtained. The mineral location is obtained by noting areas within the area traversed in which the variations of the measurements of gamma radiation corresponding to each of uranium, potassium and thorium relating to the respective area mean values are indicative of the particular mineral being located.