Abstract: A method of attenuating multiples in signals recorded during a marine seismic survey is described using a multi-component data set of the survey and summing selected components of the data set after filtering components with a filter that combines recorded data from more that one receiver location and operates indiscriminately on P- and S-wave data.

Abstract: A technique is disclosed for determining the gas-filled porosity and oil-filled porosity in a region of investigation of earth formations surrounding a borehole including the following steps: (a) providing a logging device that is moveable through the borehole; (b) generating, from the logging device, a static magnetic field in the region of investigation of the formations, the static field having a magnetic field gradient that is not constant in the region of investigation; (c) determining the gradient distribution of the static magnetic field in the region of investigation, and determining a first function of the gradient distribution and the diffusion coefficient of oil, and a second function of the gradient distribution and the diffusion coefficient of gas; (d) generating a first sequence of magnetic field pulses in the region of investigation of the formations using a first wait time, and detecting a first sequence of nuclear magnetic resonance spin echoes from the formations; (e) generating a second seq

Abstract: A method and apparatus for characterizing a multiphase mixture by irradiating the mixture with X-rays, collecting the photons that emanate from the mixture in response to the irradiation, generating a signal responsive to the aggregate energy of the collected photons, and analyzing the signal to characterize the mixture. Preferably, the mixture is irradiated by repetitively pulsing an X-ray tube and the photons are collected using a multi-layer detector. The method and apparatus may be used to determine the flow rate, flow velocities, and/or composition of the multiphase mixture. In other embodiments, a plurality of X-ray sources and/or detectors may be used.

Abstract: A method for determining a representation of an anisotropic earth formation is described, wherein the inversion step for generating the representation from recorded seismic data is performed using several values of a pre-defined anisotropy parameter addition to components of the moveout velocity. The anisotropy parameter is preferably introduced into the moveout equation or dispersion relation, which in turn is used in the inversion process.

Abstract: An integrated interpretation methodology is described that evaluates carbonate reservoirs. The methodology consists of first classifying the rock facies. A geometrical model specific to the classification is then used to predict the response of the rock to a variety of stimuli. A reconstruction of the geometrical model is made by comparing the measurements with the model predictions. The model is then used to predict the resistivity and the hydraulic transport properties of the rock, thereby enabling computation of both the reserves and their production behavior.

Abstract: Single point optical probes for measuring three-phase characteristics of fluid flow in a hydrocarbon well and methods of processing signals generated by the probe are disclosed. A single fiber optic probe is coupled to a light source and apparatus for detecting reflectance and fluorescence. Light is delivered to the tip of the probe where it exits the probe and illuminates the liquid ambient the probe tip or is internally reflected in the probe when gas is located at the probe tip. If the fluid at the probe tip is oil, the light exits the probe, illuminates the oil, and causes the oil to fluoresce. According to one signal processing method of the invention, the reflectance signal is binarized at a threshold to provide a gas/liquid quasi-binary signal which changes over time. A time fraction of the signal values is used to calculate the gas holdup.

Abstract: A method and apparatus for analyzing drill core rock samples is described, utilizing a collimated beam of polychromatic X-ray photons of a brightness of at least 10.sup.15 photons/sec/mrad.sup.2 /0.1% bandwidth and energies of at least 20 keV. A suitable source of such X-rays is a synchrotron.

Abstract: A computer-based apparatus for creating subsurface models having a graphical display device, a user input device, means for selecting a region of the world to be modeled; means for providing geophysical and geographical data corresponding to the selected region of the world; means for providing an archive of known geological structures; and means for providing an interface which permits a user to create a subsurface model of the identified region. The invention further involves related computer-based apparatuses for interactive creation of geological subsurface models, for managing geological hypotheses, and for providing information for creation of a geological model.

Abstract: A method for using S-waves recorded at sea floor to determine anellipticity relating to at least one rock substrate is provided. In particular the method comprises identifying an S-wave event in recorded pre-stack seismic data and then determining at least one anisotropy parameter by adjusting moveout of a corresponding modeled S-wave event to agree with moveout of the identified S-wave event. The method is particularly applicable to mode converted S-waves in seismic signals.

Abstract: Methods and apparatus for estimating values for formation parameters such as permeability, relative permeability, and skin factors for a plurality of locations in the formation are provided. Fluid is forced into a capped borehole at a measured rate, and a borehole logging tool is run in the borehole to measure indications of pressure and conductivity. Estimates of the parameters and the measured fluid flow rate(s) into the formation are used in conjunction with a jointly inverted pressure transient model and saturation-conductivity model in order to compute indications of expected pressure and indications of expected conductivity-related profiles as a function of depth and time. The expected pressures and expected conductivity related profile indications are then compared to the pressures and conductivity indications measured by the borehole logging tool, and an iterated comparison between the computed values and the measured values is used to provide determinations of the formation parameters.

Abstract: There is provided a method of accurately estimating the permeability of sedimentary rock formations from well logging data. The method involves a short relaxation time strategy with the identification of the key k-Lambda parameter S/V.sub.p, which is the surface-to-pore ratio. The inverse of T.sub.2 is related to this ratio by the surface relaxivity, .rho.2. The k-Lambda estimator is given by: ##EQU1## where: .DELTA.V.sub.1 represents the volume elements of the T.sub.2 distribution and the sum over i=1 to n represents some set of early to later volume elements; and V.sub.p is the total pore volume.

Abstract: The invention relates to a method of measuring the resistivity of a drilling mud by means of a sonde provided with an annular current electrode (A.sub.0) and with annular guard electrodes (A, A'), current I.sub.0 being emitted into the surrounding formation together with focusing currents I and I'. A signal representative of R.sub.m is produced in response to I.sub.0. Various apparatuses for implementing the method are described. Another method implements a technique of computed focusing. Corresponding apparatuses are also described.

Abstract: A computer implemented-method of creating subsurface models, including, for example, the steps of: selecting a region of the world to be modeled; providing geophysical and geographical data corresponding to the selected region; providing an archive of known geological structures; and providing an interface which permits a user to create a subsurface model of the identified region. The invention further involves related computer-implemented methods for interactive creation of geological subsurface models, for managing geological hypotheses, and for providing information for creation of geological models.

Abstract: In this invention a new interpretation methodology has been developed. A pore structure model is used to compute the relaxation behavior. This model is then used as the kernel of a best-fit inversion scheme against the measured data, in contrast to inverting for a T.sub.2 distribution that relies on regularization. Parameters of the model are obtained by "best fitting" the model with the data. The method considers a geometrical or physical model comprising both intergranular and intragranular porosity (microporosity). The NMR relaxation is computed by one of the several methods. The model is compactly represented by a set of physical parameters that are iterated upon until a match with relaxation data is obtained in the best fit sense. The result is obtained in terms of these physical parameters, and then integrated with other types of measurements.

Abstract: An article of manufacture for use in connection with a computer, said article of manufacture comprising a computer-readable storage medium having a program recorded thereon that enables a user of a computer executing said program to interactively: display data obtained from a subsurface area; select an object from a plurality of different three-dimensional objects; place the selected three-dimensional object within a model of the subsurface area; and transform the selected three-dimensional object to better fit the data obtained from the subsurface area. The invention further involves related methods for interactive creation of a subsurface model.

Abstract: Methods and apparatus are described for seismic signal acquisition utilizing an odd number of vibratory sources arranged in line and positioning the sources for one sweep cycle at positions occupied by other sources during the previous sweep cycle. The method has advantages in particular for marine seismic acquisitions.

Abstract: Single point optical probes for measuring three-phase characteristics of fluid flow in a hydrocarbon well and methods of processing signals generated by the probe are disclosed. A probe having a single fiber optic is coupled to a light source and apparatus for detecting reflectance and fluorescence. Light is delivered to the tip of the probe where it either is internally reflected in the probe or exits the probe and illuminates the fluid (liquid) ambient the probe tip. If the fluid at the probe tip is oil, the light exits the probe, illuminates the oil, and causes the oil to fluoresce. If the fluid is water, no fluorescence occurs. If the fluid is gas, at least some light is internally reflected in the probe. A detection system including at least one beam splitter and fluorescence and reflectance detectors is provided in conjunction with the probe. Preferably, the fluorescence detector is coupled to the fiber optic by a wavelength division multiplexer.

Abstract: A method for measuring formation resistivity uses a tool including a central current electrode and a series of voltage electrodes arranged in pairs on either side of the current electrode. A series of measurements is made using the current electrode with different numbers of pairs of voltage electrodes maintained at a predetermined voltage so as to allow resistivity in the formation to be determined with different depths of investigation. In this manner these measurements are focused and are relatively unaffected by the borehole or by adjacent layers in the formation. The central current electrode is segmented azimuthally into a series of electrodes, and the current flowing out of each azimuthal segment is measured separately. This can yield resistivity images of the formation surrounding the borehole. The azimuthal imaging capability can be used for stratigraphic or lithologic analysis of the formation and to detect fractures in the rock.

Abstract: A method and apparatus for determining the hydraulic isolation of layers in an earth formation. The characteristics of various interfaces between the materials in the borehole are evaluated. An acoustic investigation is performed by directing an acoustic signal at a radial segment of the borehole. The signal passes through the casing and the fill material and produces a resulting signal which has travelled along a path encountering various interfaces in the borehole. This signal is processed to make hydraulic isolation determinations.

Abstract: A marine seismic survey is described which uses measurements made in a mid-field region of the source signature to correct an estimate of the far-field source signature as derived from individual contributions of the seismic source elements. The technique reduces the effects of perturbations which else have a considerable impact on the estimation of the far-field.