A technique facilitates monitoring of acoustic signals to measure a velocity vector of a borehole. Acoustic sensors are arranged in a desired acoustic sensor array and positioned along a body of a tool, e.g. a sonic logging tool. The acoustic sensor array is then positioned in fluid along a wall of a borehole formed in a subterranean formation. The acoustic sensors are used to collect acoustic signal data while the acoustic sensors are maintained in a non-contact position with respect to the wall of the borehole. The data may be processed to determine the desired velocity vector.

A method for treating a well includes hydraulically isolating an interval in a first well having a plurality of intervals along the first well, each interval having been fracture treated. A tube wave is induced in the first well in the isolated interval. Reflections are detected from the induced tube wave. Hydraulic boundary condition and hydraulic conductivity of a fracture connected to the first well in the isolated interval are determined using the detected reflections. A refracture treatment is performed in the isolated interval when the hydraulic boundary condition and the hydraulic conductivity are within a predetermine range.

A smart frac plug assembly including an instrument plug module with a sensor for collecting data during a hydraulic fracturing process. This assembly when used in conjunction with a wireless or tubing conveyed data logger and other related recording/processing systems, provides direct measurements of pressure, temperature, observed velocity field and/or observed acceleration field in a subsurface.

Uncertainty in microseismic monitoring sensor data can be reduced. A computing device can receive information about at least one sensor that is monitoring a subterranean formation, including a location, after a fracturing fluid is introduced into the formation. The computing device can also receive information about a microseismic event and determine a seismic ray bath between a location of the event and the at least one sensor, and an uncertainty value of the location based on information about the formation and the information about the event. The computing device can determine a total uncertainty value associated with the locations of a plurality of microseismic events, including the microseismic event. The computing device can determine a solution to an objective function based on the total uncertainty value and a number of sensors. The computing device can determine a new location of the at least one sensor based on the solution.

A method of analysing seismic data to detect possible hydrocarbons includes determining a set of data tiles from a seismic data cube of seismic data and testing each data tile in the set of data tiles to determine whether it corresponds to a possible fluid contact.

A method of performing measurements of an earth formation includes disposing at least a first receiver and a second receiver in one or more monitoring boreholes in a formation, and injecting fluid into the formation from an injection borehole, wherein injecting includes operating a fluid control device to generate seismic and/or acoustic noise having an identifiable characteristic. The method also includes detecting seismic and/or acoustic signals at the first receiver and detecting seismic and/or acoustic signals at a second receiver, the seismic and/or acoustic signals corresponding to the seismic and/or acoustic noise, calculating an estimate of a Green's function between the first receiver and the second receiver by processing seismic and/or acoustic waves detected by the first receiver and the second receiver to at least partially reconstruct the Green's function, and estimating variations in a velocity of a region of the formation by determining variations in the reconstructed Green's function.

A data acquisition program, which includes core, image log, microseismic, DAS, DTS, and pressure data, is described. This program can be used in conjunction with a variety of techniques to accurately monitor and conduct well stimulation.

An embodiment of a method of stimulating an earth formation includes: disposing a stimulation device at a borehole in an earth formation, the earth formation having been stimulated by an initial stimulation operation; subsequent to the stimulation operation, performing a probe operation configured to cause movement of existing fractures in the formation; and measuring microseismic events occurring in the formation by one or more seismic receivers. The method further includes: identifying one or more target zones in the formation based on the measuring, the one or more target zones exhibiting a reduced micro seismicity relative to another zone in the formation; and designing a re-stimulation operation configured to stimulate the one or more target zones to increase hydrocarbon production from the formation.

Techniques for determining a breakdown pressure of a subterranean formation include identifying in-situ stresses for a portion of a wellbore formed into a subterranean formation; transforming the in-situ stresses (and induced stresses) from a global coordinate system to a wellbore coordinate system of a deviated portion of the wellbore that includes at least one perforation tunnel for a hydraulic fracturing treatment; transforming the in-situ stresses from the wellbore coordinate system to a perforation coordinate system through at least one rotation matrix; determining one or more stresses at a wellbore-perforation interface of the perforation tunnel from the in-situ stresses in the perforation coordinate system; calculating one or more hoop stresses at a perforation tunnel wall of the perforation tunnel from the determined stresses on the wellbore-perforation interface; and determining a breakdown pressure for the subterranean formation based on the calculated one or more hoop stresses and an effect of casing-cement-formation interaction.

Method for characterizing subterranean formation is described. One method involves simulating a poroelastic pressure response of known fracture geometry utilizing a geomechanical model to generate a simulated poroelastic pressure response. Compiling a database of simulated poroelastic pressure responses. Measuring a poroelastic pressure response of the subterranean formation during a hydraulic fracturing operation to generate a measured poroelastic pressure response. Identifying a closest simulated poroelastic pressure response in the library of simulated poroelastic pressure response. Estimating a geometrical parameter of a fracture or fractures in the subterranean formation based on the closest simulated poroelastic pressure response.