A method for monitoring hydraulic fracturing range of a surface vertical shaft is provided by the present disclosure, belonging to the technical field of ultrahigh-pressure hydraulic fracturing monitoring of the coal mine vertical shafts. The method comprises the following steps: connecting, by an eight-thread communication cable, a high-precision portable micro-seismic monitoring acquisition instrument to a high-sensitivity deep hole sensor, and performing uphole-crosshole-downhole monitoring simultaneously, specifically as follows: providing uphole-crosshole-downhole monitoring holes respectively, and installing deep hole geophones in the monitoring holes; then laying communication cables uphole-crosshole-downhole to connect the geophones to the portable high-precision micro-seismic acquisition instrument respectively; then performing high-precision positioning on the fissure development range by monitoring recorded events and time, thus determining the directions and ranges of a main fracture and secondary induced fractures of hydraulic fractures.

A method of detecting an event by: obtaining a first sample data set; determining a frequency domain feature(s) of the first sample data set over a first time period; determining a first threshold for the a frequency domain feature(s) using the first sample data set; determining that the frequency domain feature(s) matches the first threshold; determining the presence of an event during the first time period based on determining that the frequency domain feature(s) matches the first threshold; obtaining a second sample data set; determining a frequency domain feature(s) of the second sample data set over a second time period; determining a second threshold for the frequency domain feature(s) using the second sample data set; determining that the frequency domain feature(s) matches the second threshold; and determining the presence of the event during the second time period based on determining that the frequency domain feature(s) matches the second threshold.

A seismic source (50) is buried in a multi-layered subsurface formation below a fast layer (30) and above a reflecting interface (10). The seismic source (50) excites a critically refracted (CR) wave that travels laterally along a fast layer bottom interface (35), and emanates downwardly into a slow layer (40) that is below and adjacent to the fast layer (30). One or more receivers (60), positioned below the fast layer (30) and above the reflecting interface (10) are used to detect seismic waves (84, 86). The one or more receivers (60) are positioned within a borehole (65). At least one reflected CR wave is isolated from the received signals, which is a CR wave that has reflected off of the reflecting layer (10) below the one or more receivers (60). A seismic profile of the multi-layered subsurface formation is created, using the at least one reflected CR wave. Time-lapse seismic monitoring of hydrocarbon extraction operations, such as steam injection, is also provided.

A seismic source (50) is buried in a multi-layered subsurface formation below a fast layer (30) and above a reflecting interface (10). The seismic source (50) excites a critically refracted (CR) wave that travels laterally along a fast layer bottom interface (35), and emanates downwardly into a slow layer (40) that is below and adjacent to the fast layer (30). One or more receivers (60), positioned below the fast layer (30) and above the reflecting interface (10) are used to detect seismic waves (84, 86). The one or more receivers (60) are positioned within a borehole (65). At least one reflected CR wave is isolated from the received signals, which is a CR wave that has reflected off of the reflecting layer (10) below the one or more receivers (60). A seismic profile of the multi-layered subsurface formation is created, using the at least one reflected CR wave. Time-lapse seismic monitoring of hydrocarbon extraction operations, such as steam injection, is also provided.

Methods and systems for assessing cross-well interference and/or optimizing hydrocarbon production from a reservoir by obtaining low frequency DAS and DTS data and pressure data from a monitor well, when both the monitor and production well are shut-in, and then variably opening the production well for production, and detecting the temperature and pressure fluctuations that indication cross-well interference, and localizing the interference along the well length based on the low frequency DAS data. This information can be used to optimize well placement, completion plans, fracturing plans, and ultimately optimize production from a given reservoir.

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.

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.

A method, downhole tool, and system, of which the method includes deploying a perforation charge into a wellbore, signaling the perforation charge to detonate, deploying a cable into the wellbore, determining a fluid flow rate at a predetermined location in the wellbore using the cable, and determining whether the perforation charge detonated at the predetermined location based on the fluid flow rate.

A distributed fiber optic acoustic detection device employs a novel distributed acoustic detection method using a phase noise cancelling distributed acoustic sensing (PNC-DAS) technique.

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.