Abstract: Methods of using capture gamma-ray spectroscopy for analyzing gravel-packs, frac-packs, and cement are disclosed herein. The methods can include distinguishing particles placed in a borehole region from particles placed in a subterranean formation outside of the borehole region, by utilizing a slurry comprising a liquid, particles, and a thermal neutron absorbing material to place the particles into the borehole region. The methods can also include obtaining first and second data sets by lowering into a borehole traversing the borehole region a pulsed neutron logging tool comprising a pulsed neutron source and a detector, emitting pulses of neutrons from the pulsed neutron source into the borehole region at intervals of one pulse per about 1,000 ?sec for the first data set and about one pulse per about 100 ?sec for the second data set, and detecting capture gamma rays resulting from nuclear reactions in the borehole and the subterranean formation.

Abstract: Methods for logging a well utilizing natural radioactivity originating from clay based particulates are disclosed. The methods can include utilizing a gravel pack slurry containing a liquid and gravel pack particles to hydraulically place the particles into a gravel pack zone of a borehole penetrating a subterranean formation and obtaining a post gravel pack data set by lowering into the borehole traversing the subterranean formation a gamma ray detector and detecting gamma rays resulting from a native radioactivity of the gravel pack particles. The methods can further include using the post gravel pack data set to determine a location of the gravel pack particles and correlating the location of the gravel-pack particles to a depth measurement of the borehole to determine the location, height, and/or percent fill of gravel-pack particles placed in the gravel pack zone of the borehole.

Abstract: A full bore spectral gas holdup tool that measures gas holdup that is corrected for effects of the flowstream lamination and the salinity of the liquid in the flowstream. The basic methodology utilizes spectral data from two gamma ray detectors at different spacings from a nuclear source that emits gamma radiation. 57Co is the preferred source and the gamma ray detectors are scintillation spectrometers. In addition to a full bore gas holdup measurement, the spectral gas holdup tool also provides indications of the degree of flowstream lamination and the salinity of the liquid in the flowstream. An iterative data processing method optimizes the accuracy of the measured flowstream parameters.

Abstract: Methods are provided for determining the location and height of a fracture in a subterranean formation using pulsed neutron capture (PNC) logging tools. The methods include obtaining a pre-fracture data set, hydraulically fracturing the formation with a slurry that includes a liquid and a proppant in which at least a portion of the proppant is tagged with a thermal neutron absorbing material, obtaining a post-fracture data set, comparing the pre-fracture data set and the post-fracture data set to determine the location of the proppant, and correlating the location of the proppant to a depth measurement of the borehole to determine the location and height of the propped fracture.

Abstract: Methods are provided for identifying the location and height of induced subterranean formation fractures and the presence of any associated frac-pack or gravel pack material in the vicinity of the borehole using pulsed neutron capture (PNC) logging tools. The proppant/sand used in the fracturing and packing processes is tagged with a thermal neutron absorbing material. When proppant is present, increases in detected PNC formation and/or borehole component cross-sections, combined with decreases in measured count rates, are used to determine the location of the formation fractures and the presence and percent fill of pack material in the borehole region. Changes in measured formation cross-sections relative to changes in other PNC parameters provide a relative indication of the proppant in fractures compared to that in the borehole region.

Abstract: Subterranean formation locations/heights of tagged proppant doped with a high thermal neutron capture cross-section material are determined using data obtained from before and after frac logging passes through a well of a logging tool having near and far neutron detectors. Proppant location inaccuracies arising from changes in lithology between a zone of no interest and a proppant-containing formation zone are made, after any required normalization for a between-log change in borehole fluid, using an observed difference between the near/far detector count rate ratios in the two passes to determine a count rate differential correction to be applied to the before frac detector count rate. The corrected before frac count rate log is then overlaid with the after frac count rate log such that suppression in the after frac count rate log relative to the corrected before frac count rate log indicates the presence of proppant.

Abstract: An orbital downhole separator for separating well fluids into constituents of different specific gravities. Specifically, it is designed to separate water from oil or gas. The apparatus comprises a housing with a rotating member therein driven by a motor in the housing. Well fluid flows through the rotating member and is subjected to centrifugal force to separate the components. A flow conditioner is used to facilitate separation. The invention includes several different versions of the flow conditioner including an impeller, a stator and controllers for controlling the speed of the motor in response to signals related to the amount of petroleum in the water.

Abstract: Proppant placed in a subterranean fracture zone is detected with a spectral identification method in which capture gamma ray spectra are obtained during a logging run carried out with a logging tool having a neutron emitting source and at least one detector sensitive to thermal neutron capture gamma rays. Capture gamma rays from one or more high thermal neutron cross-section materials in the proppant are distinguished from capture gamma rays produced by thermal neutron capture reactions with other downhole formation and borehole constituents utilizing a spectral processing/deconvolution technique. The capture gammas rays from the high thermal neutron capture cross section material in the proppant are used to identify propped fracture zones either alone or in combination with other proppant identification methods which rely on measuring thermal neutron related count rates and/or thermal neutron capture cross-sections from neutron, compensated neutron, and/or pulsed neutron capture logging tools.

Abstract: Methods are provided for identifying the location and height of induced subterranean formation fractures and the presence of any associated frac-pack or gravel pack material in the vicinity of the borehole using pulsed neutron capture (PNC) logging tools. The proppant/sand used in the fracturing and packing processes is tagged with a thermal neutron absorbing material. When proppant is present, increases in detected PNC formation and/or borehole component cross-sections, combined with decreases in measured count rates, are used to determine the location of the formation fractures and the presence and percent fill of pack material in the borehole region. Changes in measured formation cross-sections relative to changes in other PNC parameters provide a relative indication of the proppant in fractures compared to that in the borehole region.

Abstract: A full bore spectral gas holdup tool that measures gas holdup that is corrected for effects of the flowstream lamination and the salinity of the liquid in the a flowstream. The basic methodology utilizes spectral data from two gamma ray detectors at different spacings from a nuclear source that emits gamma radiation. 57Co is the preferred source and the gamma ray detectors are scintillation spectrometers. In addition to a full bore gas holdup measurement, the spectral gas holdup tool also provides indications of the degree of flowstream lamination and the salinity of the liquid in the flowstream. An iterative data processing method optimizes the accuracy of the measured flowstream parameters.

Abstract: A separating system for separating a fluid mixture incorporates a smart surface having reversibly switchable properties. A voltage is selectively applied to the smart surface to attract or repel constituents of a fluid mixture, such as oil and water produced from a hydrocarbon well. The smart surface can be used in a conditioner to increase droplet size prior to entering a conventional separator, or the smart surface and other elements of the invention can be incorporated into an otherwise conventional separator to enhance separation. In a related aspect, a concentration sensor incorporating smart surfaces senses concentration of the fluid mixture's constituents.

Abstract: Subterranean formation locations/heights of tagged proppant doped with a high thermal neutron capture cross-section material are determined using data obtained from before and after frac logging passes through a well of a logging tool having near and far neutron dectors. Proppant location inaccuracies arising from changes in lithology between a zone of no interest and a proppant-containing formation zone are made, after any required normalization for a between-log change in borehole fluid, using an observed difference between the near/far detector count rate ratios in the two passes to determine a count rate differential correction to be applied to the before frac detector count rate. The corrected before frac count rate log is then overlaid with the after frac count rate log such that suppression in the after frac count rate log relative to the corrected before frac count rate log indicates the presence of proppant.

Abstract: A system and method for selecting a training data set from a set of multidimensional geophysical input data samples for training a model to predict target data. The input data may be data sets produced by a pulsed neutron logging tool at multiple depth points in a cases well. Target data may be responses of an open hole logging tool. The input data is divided into clusters. Actual target data from the training well is linked to the clusters. The linked clusters are analyzed for variance, etc. and fuzzy inference is used to select a portion of each cluster to include in a training set. The reduced set is used to train a model, such as an artificial neural network. The trained model may then be used to produce synthetic open hole logs in response to inputs of cased hole log data.

Abstract: Reservoir characterization based on observations of displacements at the earth's surface. One method of characterizing a reservoir includes the steps of: detecting a response of the reservoir to a stimulus, the stimulus causing a pressure change in the reservoir; and determining a characteristic of the reservoir from the response to the stimulus. The response may be the pressure change which varies periodically over time, or a set of displacements of a surface of the earth. In another example, a method includes the steps of: detecting a set of displacements of the earth's surface corresponding to a pressure change in the reservoir; and determining a characteristic of the reservoir from the surface displacements. In yet another example, a method includes the steps of: detecting a set of displacements of the earth's surface corresponding to a change in volume of the reservoir; and determining a characteristic of the reservoir from the surface displacements.

Abstract: Methods for determining the locations/heights of fractures in a subterranean formation use a post-fracture log obtained with a compensated neutron or pulsed neutron logging tool. Utilizing predetermined relationships between tool count rates and associated near/far count rate ratios, the methods detect the presence of proppant containing high thermal neutron capture cross-section material, substantially eliminating proppant determination uncertainty resulting from changes in formation hydrogen index. In an interval of a well with given borehole and formation conditions, and not containing proppant, a relationship is developed between detector count rate and near/far ratio. This relationship is used to compute count rate from the ratio in intervals of the well possibly containing proppant and which have similar formation and borehole conditions.

Abstract: A separating system for separating a fluid mixture incorporates a smart surface having reversibly switchable properties. A voltage is selectively applied to the smart surface to attract or repel constituents of a fluid mixture, such as oil and water produced from a hydrocarbon well. The smart surface can be used in a conditioner to increase droplet size prior to entering a conventional separator, or the smart surface and other elements of the invention can be incorporated into an otherwise conventional separator to enhance separation. In a related aspect, a concentration sensor incorporating smart surfaces senses concentration of the fluid mixture's constituents.

Abstract: A separating system for separating a fluid mixture incorporates a smart surface having reversibly switchable properties. A voltage is selectively applied to the smart surface to attract or repel constituents of a fluid mixture, such as oil and water produced from a hydrocarbon well. The smart surface can be used in a conditioner to increase droplet size prior to entering a conventional separator, or the smart surface and other elements of the invention can be incorporated into an otherwise conventional separator to enhance separation. In a related aspect, a concentration sensor incorporating smart surfaces senses concentration of the fluid mixture's constituents.

Abstract: Methods are provided for determining the locations and heights of fractures in a subterranean formation using a neutron-emitting logging tool. Utilizing predetermined relationships (1) between logging tool count rates and associated apparent formation hydrogen index values and (2) between logging tool count rate ratios and associated apparent formation hydrogen index values, the methods detect the presence and heights in the formation of proppant containing high thermal neutron capture cross section material in a manner substantially eliminating proppant determination uncertainty resulting from a prior change in formation hydrogen index values. A second, associated, method employing logging tool count rates and count rate ratios to determine the presence of proppant containing high thermal neutron capture cross section absorbers utilizes a crossplot of count rate versus ratio.

Abstract: Proppant placed in a subterranean fracture zone is detected with a spectral identification method in which capture gamma ray spectra are obtained during a logging run carried out with a logging tool having a neutron emitting source and at least one detector sensitive to thermal neutron capture gamma rays. Capture gamma rays from one or more high thermal neutron cross-section materials in the proppant are distinguished from capture gamma rays produced by thermal neutron capture reactions with other downhole formation and borehole constituents utilizing a spectral processing/deconvolution technique. The capture gammas rays from the high thermal neutron capture cross section material in the proppant are used to identify propped fracture zones either alone or in combination with other proppant identification methods which rely on measuring thermal neutron related count rates and/or thermal neutron capture cross-sections from neutron, compensated neutron, and/or pulsed neutron capture logging tools.

Abstract: A method for determining the location and height of a fracture in a subterranean formation using a neutron emitting logging tool. The method includes obtaining a pre-fracture data set, fracturing the formation with a slurry that includes a proppant doped with a high thermal neutron capture cross-section material, obtaining a post-fracture data set, comparing the pre-fracture data set and the post-fracture data set to determine the location of the proppant, and correlating the location of the proppant to a depth measurement of the borehole to determine the location and height of the fracture. Using a pulsed neutron capture tool, it is also possible to determine whether the proppant is located in the fracture, in the borehole adjacent to the fracture, or in both. The method may also include a plurality of post-fracture logging procedures used to determine various fracture and production characteristics in the formation.