A system for continuous determination of annulus pressure in subsurface wells comprises one or more electro acoustic technology sensor assemblies permanently installed in each annulus surrounding a subsurface well; and a fiber optic cable in close proximity to the electro acoustic technology sensor assemblies and in communication with a surface distributed acoustic fiber optic interrogator.

A method of characterizing an inflow into a wellbore includes obtaining an acoustic signal from a sensor within the wellbore. In addition, the method includes determining a plurality of frequency domain features from the acoustic signal. Further, the method includes identifying at least one of a gas phase flow, an aqueous phase flow, or a hydrocarbon liquid phase flow using the plurality of the frequency domain features. The method also includes classifying a flow rate of the at least one of the gas phase flow, the aqueous phase flow, or the hydrocarbon liquid phase flow using the plurality of frequency domain features. The acoustic signal comprises acoustic samples across a portion of a depth of the wellbore.

Systems and methods include a number of optical pulses are transmitted by transmitting, by a distributed acoustic sensor (DAS), where the optical pulses are transmitted at an input port associated with a multimode fibers (MMF) used by the DAS, and where the fundamental mode of the MMF is excited. A number of backscattered Rayleigh signals are collected by the DAS. The Rayleigh signals are recorded as an output intensity profile. A position along the MMF that is subject to vibrations and corresponding vibration parameters are determined by analyzing the recorded output intensity profile.

The present disclosure relates to systems and methods for treating subterranean formations through adjacent well communications. A method to determine well communication, comprises generating one or more pressure excitation signals via an electrical pump in a first well, wherein the one or more pressure excitation signals produce one or more response signals based on the one or more pressure excitations signals interacting with a subterranean formation; measuring the one or more response signals through transmission of the one or more response signals to a second well with a fiber optic cable, wherein the one or more response signals are measured as time-series data; determining a formation response by processing the one or more response signals with an information handling system; determining a well parameter via one or more sensors; and performing a treatment operation to mitigate well interference between the first well and the second well.

Various embodiments include methods and apparatus structured to investigate a structure of multiple strings of pipe in a wellbore and material around the pipes in the wellbore. An array of acoustic receivers can be used to monitor sound energy from the structure and material within and around the structure. The received sound energy can be segregated and coherent signal processing of the received sound energy can be conducted with respect to location. A bond map of the structure and regions around the multiple strings of pipe can be derived from the coherent signal processing. Additional apparatus, systems, and methods can be implemented in a variety of applications.

Provided in some embodiments is a well torpedo system that includes a torpedo adapted to be advanced in a wellbore of a subterranean well. The torpedo including an integrated spool adapted to hold a fiber-optic (FO) umbilical including a FO line adapted to couple to a surface component, and an engine adapted to combust solid propellant to generate thrust to propel advancement of the torpedo in the wellbore.

A distributed acoustic system (DAS) with an interrogator, an umbilical line attached at one end to the interrogator, and a downhole fiber attached to the umbilical line at the end opposite the interrogator. A method for optimizing a sampling frequency may begin with identifying a length of a fiber optic cable connected to an interrogator, identifying one or more regions on the fiber optic cable in which a backscatter is received, and optimizing a sampling frequency of a distributed acoustic system (DAS) by identifying a minimum time interval that is between an emission of a light pulse such that at no point in time the backscatter arrives back at the interrogator that corresponds to more than one spatial location along a sensing portion of the fiber optic cable.

Provided in some embodiments is a well torpedo system that includes a torpedo adapted to be advanced in a wellbore of a subterranean well. The torpedo including an integrated spool adapted to hold a fiber-optic (FO) umbilical including a FO line adapted to couple to a surface component, and an engine adapted to combust solid propellant to generate thrust to propel advancement of the torpedo in the wellbore.

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 to generate a vertical seismic profile includes acquiring a set of distributed acoustic sensing measurements from a set of overlapping measurement channels on an optical fiber, wherein each of the set of distributed acoustic sensing measurements are measured at a gauge length. The method also includes generating a set of virtual seismic measurements corresponding with subdivisions in the set of overlapping measurement channels based on the set of distributed acoustic sensing measurements and generating the vertical seismic profile based on the set of virtual seismic measurements.