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.

Waves from cement bond logging with a sonic logging-while-drilling tool (LWD-CBL) are often contaminated with tool waves and may yield biased CBL amplitudes. The disclosed LWD-CBL wave processing corrects the first echo amplitudes of LWD-CBL before calculating the BI. The LWD-CBL wave processing calculates a tool wave amplitude and a phase angle difference as the difference of the phases between the tool waves and casing waves. The tool waves are then used to correct the LWD-CBL casing wave amplitude and remove errors introduced from tool waves. In conjunction with the sets of operations described, the LWD-CBL wave processing also include array preprocessing operations. Array preprocessing may employ variation of bandpass filtering and frequency-wavenumber (F-K) filtering operations to suppress tool wave.

A lift based acoustic source is towable in an undersea environment by a towing vessel. A controller provides a combined lift control signal and an acoustic source signal. A control cable is joined between the towing vessel and a towed depressor having an active lift control system. The combined signal is used to control the towed depressor active lift control system. The towed depressor lift fluctuates in response to the source signal to generate the undersea acoustic signal. A hydrophone or hydrophone array can be provided for measuring the generated acoustic signal for feedback and monitoring.

A lift based acoustic source is towable in an undersea environment by a towing vessel. A controller provides a combined lift control signal and an acoustic source signal. A control cable is joined between the towing vessel and a towed depressor having an active lift control system. The combined signal is used to control the towed depressor active lift control system. The towed depressor lift fluctuates in response to the source signal to generate the undersea acoustic signal. A hydrophone or hydrophone array can be provided for measuring the generated acoustic signal for feedback and monitoring.

Methods of mapping a subterranean formation using imploding particles are described. In some cases, the particles contain a material that generated a gas which passes through a water-insoluble coating to create a void within the particle. In some aspects, the implosive particles have a coating that dissolves in the subterranean formation.

Methods of mapping a subterranean formation using imploding particles are described. In some cases, the particles contain a material that generated a gas which passes through a water-insoluble coating to create a void within the particle. In some aspects, the implosive particles have a coating that dissolves in the subterranean formation.

A method and systems for performing a borehole operation with a borehole fluid that includes applying an amplitude oscillation deformation force to a sample of the borehole fluid over a period of time, measuring the deformation force from the sample, determining a storage modulus of the borehole fluid over the period of time based on the measured deformation force, determining a gel strength of the borehole fluid by correlation with the storage modulus, comparing the gel strength with a desired gel strength and if the gel strength is outside of an acceptable range of the desired gel strength, adjusting a drilling parameter, a composition of the borehole fluid, or a combination thereof, and using the borehole fluid in the borehole operation. Determining the storage modulus and the gel strength may be done using a processor and the force may be applied using a piezoelectric device.

A seismic source system uses at least one seismic source, a screw in piling ground anchor installed into the earth/ground and means of coupling the energy from the seismic source to the screw in piling ground anchor.

An outer tubular is imaged by a pad assembly disposed within an inner tubular inserted within the outer tubular. The pad assembly is in contact with the inner tubular, and includes an acoustic pressure source, a backing mounted to a side of the acoustic pressure source, and an intervening layer between the acoustic pressure source and inner tubular. Signals generated by the pad assembly propagate radially outward from the inner tubular and reflect from the outer tubular. The generated and reflected signals travel through a medium between the inner and outer tubulars. An estimate of the distance between the inner and outer tubulars is based on the time from generation of the signal to when the reflected signal is sensed.

A method may include obtaining seismic data regarding a geological region of interest. The seismic data may include various pre-processed gathers. The method may further include obtaining a machine-learning model that is pre-trained to predict migrated seismic data. The method may further include selecting various training gathers based on a portion of the pre-processed gathers, a migration function, and a velocity model. The method may further include generating a trained model using the training gathers, the machine-learning model, and a machine-learning algorithm. The method may further include generating a seismic image of the geological region of interest using the trained model and a remaining portion of the seismic data.