System and method for guiding a drill using a subsurface model generated by successive full waveform inversions (FWI) on surface data and seismic-while-drilling (SWD) data. A server receives surface data from at least one surface sensor that records elastic energy radiated from surface seismic source and SWD data from at least one surface or at least one subsurface crosswell sensor (i.e., deployed in a nearby well). The server also receives top-drive measurements. A drillbit source signature estimation is performed, on the SWD data, by the server by blind deconvolution or by using drill string modeling and top-drive measurements. The server then performs FWI on the surface data by using the background subsurface velocity obtained by kinematic analysis of surface seismic data, to obtain an updated approximation of the subsurface velocity. The new approximation along with the drillbit source signature is then used when performing FWI on the SWD data.

Provided in some embodiments is a method of distributed acoustic sensing in a subterranean well. The method including advancing a torpedo into a first portion of a wellbore of a subterranean well (the torpedo including a distributed acoustic sensing (DAS) fiber-optic (FO) umbilical that is physically coupled to a surface component and adapted to unspool from the torpedo as the torpedo advances in the wellbore, and an engine adapted to generate thrust to propel the torpedo), and activating the engine to generate thrust to propel advancement of the torpedo within a second portion of the wellbore such that at least some of the DAS FO umbilical is disposed in the second portion of the wellbore.

A method for imaging non-specular seismic events as well as correlating non-specular events with physically measurable quantites in a volume of Earth's subsurface. Includes entering as input to a computer signals detected by a plurality of seismic sensors disposed above and/or within the volume in response to actuation of at least one seismic energy source above and/or within the volume. Parameter analysis is performed to populate the initial model with point-wise, best-fit wavefront travel-time approximations. Imaging is performed to obtain undifferentiated specular and non-specular representations of the volume. Specular boundaries are mapped using the imaged volume and using the boundaries to form a model of specular components of the volume. Beamforming is used to characterize seismic attributes associated with specular and non-specular reflections as separate and differentiated data sets.

A method for characterizing a hydraulic fracture in a subsurface formation includes inducing a pressure change in a borehole drilled through the subsurface formation. At least one of pressure and a time derivative of pressure is measured in the borehole for a selected length of time. At least one physical parameter of at least one fracture is determined using the measured pressure and/or the time derivative of pressure. A method for characterizing hydraulic fracturing rate uses microseismic event count measured through the borehole and its real-time implementation.

The present invention provides a method and device for determining an excitation point of a seismic source. The method includes: determining, according to a selected medium type, a distribution region corresponding to the selected medium type in a three-dimensional surface model corresponding to a preset surface range, where a preset position of the excitation point of the seismic source is located in the preset surface range, and a first mapping position corresponding to the preset position of the excitation point of the seismic source is located in the three-dimensional surface model; determining a second mapping position in the three-dimensional surface model according to the first mapping position and the determined distribution region; and determining, according to the second mapping position, a target position of the excitation point of the seismic source corresponding to the second mapping position in the preset surface range.

A seismic survey system for prospecting for sub-sea minerals including a first vessel towing a first seismic source and a seismic detector and a second vessel towing a second seismic source. The seismic detector is arranged to receive acoustic signals resulting from the reflection and/or refraction by the sea bed of acoustic signals emitted from both the first and second seismic sources.

Marine surveys carried out with multiple source arrays comprising three or more sources are discussed. Each source of a multiple source array is an array of source elements, such as air guns. The sources of a multiple source array may be arranged in particular type of configuration that is effectively maintained while the survey vessel travels a sail line. The sources of the multiple source array are activated to acoustically illuminate a subterranean formation with acoustic signals. Two or more sources of a multiple source array may be activated to create blended seismic data. Methods to deblend, source deghost, and attenuate noise in the blended seismic data obtained by using a multiple source array are also discussed.

A method and apparatus for determining a pressure in an annulus between an inner casing and an outer casing. An acoustic transducer is disposed within the casing at a selected depth within the inner casing and is configured to generate an acoustic pulse and receive a reflection of the acoustic pulse from the inner casing. A time of flight is measured of the acoustic pulse to the inner surface of the inner casing. An inner diameter of the inner casing is determined from the time of flight. The pressure in the annulus is determined from the inner diameter. A processor can be used to measure time and determine inner diameter and annulus pressure.

A system for estimating a property of a region of interest includes an acoustic measurement device including a transmitter configured to emit an acoustic signal having at least one selected frequency configured to penetrate a surface of a borehole in an earth formation and produce internal diffuse backscatter from earth formation material behind the surface and within the region of interest, and a receiver configured to detect return signals from the region of interest and generate return signal data. The system also includes a processing device configured to receive the return signal data, process the return signal data to identify internal diffuse backscatter data indicative of the internal diffuse backscatter, calculate one or more characteristics of the internal diffuse backscatter, and estimate a property of the region of interest based on the one or more characteristics of the internal diffuse backscatter.

A downhole tool having an acoustic transducer for downhole measurements. A backing is in contact with an inner surface of the transducer. A first structure is coupled to a first housing. A second structure is coupled to a second housing. A member includes first, second, and third portions. The first portion is coupled to the first structure. The second portion is coupled to the second structure. At least one of the first and second structures is coupled to the member and has a degree of freedom relative to the member. The third portion extends longitudinally through the backing between the first and second portions such that compressional forces on the first and second housings are transferred through the first and second structures and the backing. A canister contacts an outer surface of the transducer and exerts radial forces on the transducer when exposed to pressures higher than atmospheric pressure.