A method of estimating a position of a well path within a subsurface formation of the Earth includes determining a well path estimate using navigation measurements from a downhole tool and a position estimate derived from seismic data. A method of geosteering includes estimating a position of the well path and controlling a drill bit in response to the estimated position of the well path to follow a desired well trajectory.

A method of estimating a position of a well path within a subsurface formation of the Earth includes determining a well path estimate using navigation measurements from a downhole tool and a position estimate derived from seismic data. A method of geosteering includes estimating a position of the well path and controlling a drill bit in response to the estimated position of the well path to follow a desired well trajectory.

Systems, devices and methods for evaluating an earth formation intersected by a borehole. Method include detecting a reflective boundary in the earth formation by: generating a multipole acoustic signal with a logging tool in the borehole; identifying a shear wave signal resulting from shear body waves reflected in the formation in a near-field region of the formation around the borehole responsive to the generated multipole acoustic signal; and estimating at least a depth along the borehole of the boundary based on the shear wave signal. The boundary may have an angle of incidence with respect to the borehole of greater than 70 degrees. The boundary may be at least one of i) a fracture; and ii) a fault. The method may include evaluating the boundary using at least one attribute of the shear wave signal and the estimated depth.

A method for estimating in real time the geomechanical properties using drilling data and an accurate drilling model. An initial structural framework and initial distribution of the geomechanical and other rock properties is adjusted in real time by estimating accurately the corrected mechanical specific energy (CMSE), which is then used to estimate the geomechanical and other rock properties. For example, the updated geomechanical model can be used to geosteer the well toward the brittle zones that will achieve the best stimulation when using hydraulic fracturing in unconventional wells.

A method of monitoring hydraulic fracturing using DAS sensors in a treatment well and/or observation well is described. The raw data is transformed using a low pass filter (?0.05 Hz) and down-sampled to show the signal as the stimulation progresses. The resulting data can be used to optimize the hydraulic fracturing or improve reservoir models for other reservoirs.

The present invention is essentially a portable seismic survey device and method using reflection seismology for mapping subterranean formations. The device includes an upper assembly, a firing pin operably associated with a firing pin actuator, a lower assembly including a cartridge holder capable of retaining a blasting cartridge, and a detonation sensor capable of detecting detonation of the blasting cartridge. The detonation sensor transmits a signal to an event marking device to trigger a recordation of detonation time and geographic location of the seismic survey device. A seismic wave is generated upon detonation which is then reflected back toward seismometers. Data from the event marking device and seismometers can then be processed to provide geological formation information.

An acoustic ranging system utilizes gradiometric data to determine the distance between a first and second well without any knowledge or involvement of the borehole or formation characteristics. An acoustic signal is generated from a downhole or surface source, propagated along a first well, and then received by receivers positioned along the second well. Processing circuitry coupled to the receivers takes a ratio of the absolute signal to the gradient signal in a certain direction to thereby determine the relative position and distance between the two wells.

A method for determining position of a wellbore in the Earth's subsurface can include: actuating a seismic energy source at a selected location along the wellbore; detecting seismic energy with sensors located at known geodetic positions along the wellbore, the detected seismic energy being at least partially reflected by a casing of an adjacent wellbore; and determining the geodetic position of the wellbore at the selected location from the detected seismic energy.

A method is provided for constraining a seismic inversion using real-time measurements. The method comprises: receiving a seismic signal/seismic data; obtaining logging-while-drilling (LWD) measurements made during a drilling procedure; using the LWD measurements to constrain an inversion of the seismic signal/data; and using the inverted seismic signal/data to: obtain an image of a subterranean section of the Earth, determine properties of the subterranean section of the Earth and/or update a model of the subterranean section of the Earth.

A method for automatically selecting a frequency band for transmission of a telemetry signal includes transforming acquired measurements from a time domain to a frequency domain to obtain a spectrum of measurements. The spectrum of measurements is processed to compute a total energy in band and a standard deviation of the power spectral density in band for a plurality of frequency bands. A ratio of the total energy in band to the standard deviation acquiring a plurality of measurements of transmitted telemetry signals and of the power spectral density in band is computed for at least two of the plurality of frequency bands. The frequency band having the highest computed ratio is selected and automatically downlinked to a downhole transmitter.