Abstract: A technique facilitates geophysical exploration and comprises deploying an optical fiber in a borehole formed in a formation. A seismic signal, e.g. seismic waves, is excited into the formation, and an optical interrogation system is used to obtain data at a plurality of fixed, sampling locations along the optical fiber. The data is processed to determine features in the formation. Based on the processed data, updated sampling locations are selected along the optical fiber to enable further analysis of the features of interest.

Abstract: A technique facilitates geophysical exploration and comprises deploying an optical fiber in a borehole formed in a formation. A seismic signal, e.g. seismic waves, is excited into the formation, and an optical interrogation system is used to obtain data at a plurality of fixed, sampling locations along the optical fiber. The data is processed to determine features in the formation. Based on the processed data, updated sampling locations are selected along the optical fiber to enable further analysis of the features of interest.

Abstract: The invention relates to the area of borehole acoustics, in particular, to monitoring a logging tool position in a borehole, namely detection and estimation of a borehole logging tool eccentricity based on the measurement and analysis of mixed surface waves waveforms. The method is characterized by the steps of registering acoustic signals generated by passage of acoustic waves in the borehole while logging and detecting the misalignment of the logging tool to the axis of the borehole by the presence of mixed surface waves. A system for monitoring a looging tool position in a borehole comprising means for registering acoustic signals generated by passage of acoustic waves while logging and data processing means for detecting mixed surface waves propagating along the borehole wall.

Abstract: A system receives data corresponding to light signals in the plurality of cores, the plurality of cores including a first pair of cores spaced apart laterally along a first direction in the optical fiber, and a second pair of cores spaced apart laterally along a second direction in the optical fiber. The system determines a directional measurement of a dynamic parameter based on the data corresponding to light signals in the plurality of cores, wherein directionality of the directional measurement is indicated by a difference between a response of the first pair of cores to a stimulus and a response of the second pair of cores to the stimulus.

Abstract: A method for processing acoustic waveforms comprises acquiring acoustic waveforms in a borehole traversing a subterranean formation and transforming at least a portion of the acoustic waveforms to produce frequency domain signals. Then model dispersion curves are generated based on an anisotropic borehole-formation model having a set of anisotropic borehole-formation parameters. The frequency-domain signals are back-propagating using the model dispersion curves to correct dispersiveness of the signals and coherence of the back-propagated signals is calculated. Alternatively the difference between the measured and the model dispersion curves is determined. Model parameters are iteratively adjusted until the coherence reaches a maximum or exceeds a selected value, or alternatively until the difference between the measured and the model dispersion curves becomes minimal or is reduced to below a selected value. Then at least a portion of the set of anisotropic borehole-formation parameters is obtained.

Abstract: The method of a mud cake thickness determination provides sending short high-frequency signals into a formation from at least two positions located at different distances from the mud cake and recording arrival times of reflected echo signals. The mud cake thickness is determined based on the time measured.

Abstract: A system and method are provided for determining wall thickness of a structure such as a metallic pressurized pipe. The system includes an optical fiber having a plurality of Fiber Bragg Gratings (FBGs), and a mounting for securing the FBGs over discrete portions of the exterior surface of the pipe such that strain in the pressurized pipe wall is transmitted to the FBGs. The system further includes a light source and a light sensor coupled to an end of the optical fiber. The light sensor converts light reflected back from the FBGs into electrical signals that a digital processor converts into strain measurements. The FBGs are mounted around portions of the pipe expected to have significant metal loss as well as portions of the pipe expected to have negligible metal loss.

Abstract: A pressure response to low frequency harmonic pressure oscillations generated in a borehole by at least one oscillation source is registered by at least one acoustic sensor. A phase shift of stationary pressure oscillations registered by the acoustic sensor relatively to the low frequency harmonic pressure oscillations of the oscillation source and a ratio between an amplitude of the stationary pressure oscillations registered by the acoustic sensor and an amplitude of the low frequency harmonic pressure oscillations of the oscillation source are determined. A thickness of a mudcake is determined and based on the results a cake piezoconductivity or a fluid mobility or both are determined.

Abstract: At least one acoustic sensor registers a pressure response to a low-frequency non-oscillating pressure signal generated in a borehole by at least one source. At least one characteristic of a transient process of pressure change is determined from the registered signal. A thickness of a mudcake is determined. Then, based on the values received, a mudcake piezoconductivity or a fluid mobility or both are determined.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.

Abstract: The method of a mud cake thickness determination provides sending short high-frequency signals into a formation from at least two positions located at different distances from the mud cake and recording arrival times of reflected echo signals. The mud cake thickness is determined based on the time measured.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.

Abstract: A system and method are provided for determining wall thickness of a structure such as a metallic pressurized pipe. The system includes an optical fiber having a plurality of Fiber Bragg Gratings (FBGs), and a mounting for securing the FBGs over discrete portions of the exterior surface of the pipe such that strain in the pressurized pipe wall is transmitted to the FBGs. The system further includes a light source and a light sensor coupled to an end of the optical fiber. The light sensor converts light reflected back from the FBGs into electrical signals that a digital processor converts into strain measurements. The FBGs are mounted around portions of the pipe expected to have significant metal loss as well as portions of the pipe expected to have negligible metal loss.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.

Abstract: Methods and systems of measuring in-situ time variant temperature for subsurface formations utilizing an active heating and/or cooling device and temperature sensors for purposes of characterizing hydrocarbon-bearing formations by deriving formation thermal properties.

Abstract: Deploying systems and methods for deploying a plurality of seismic devices into a borehole comprising a cable including a plurality of inter-connected cable segments and ellipsoid seismic units with at least two rows of offset seismic protrusions to establish at least three points of contact between the seismic units and adjacent cylindrical surface of a borehole casing.

Abstract: This invention relates to well logging instrumentation, specifically, to measuring devices which use an advanced slip-free borehole contact interaction mechanism. A measuring probe for an oil and gas wells and/or casings includes a main body and at least one robotic arm, fixed to the main body and provided with a polygonal rotating contact tip at the arm's free end. The measuring probe is used as a measuring device and provides a successive slip-free continuous contact between the rotating surface of the tip and the inner wall of the oil & gas wells and/or casings. The tip is furnished with at least one sensor that picks up the geological formations response to a signal emitted directly to the geological formation via the points of contact.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.

Abstract: A method and system for monitoring any incursion of particulate matter from a gas hydrate formation into a well casing used for the production of the gas hydrate and determining the degree of incursion of particulate material within the distal end of the well casing.