Surface detection and location of microseismic events and earthquakes without the use of a velocity model
AssigneeReal Time Geomechanics, LLC
InventorsJie Zhang, Wei Zhang, Xiong Zhang
Life of this patent
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Abstract
A system and method for hydraulic fracturing and monitoring microseismic events related to hydraulic fracturing are described. One method describes a method of hydraulic fracturing gas production comprising drilling and casing a gas production well with a horizontal section within a formation layer, perforating the horizontal section of the well at a known location, and monitoring the resulting seismic waves using an array of geophones. Using the seismic waves resulting from the perforation shot, subsequent microseismic events may be located using a root mean square velocity and average velocity and without the use of a depth velocity model.
Claims14
A method of hydraulic fracturing gas production comprising:
- drilling and casing a gas production well, wherein the well comprises a horizontal section within a formation layer;
- perforating the horizontal section of the well at a known location using a perforation shot;
- monitoring seismic waves produced by the perforation shot using an array of geophones;
- determining a root mean square velocity value and an average velocity value using the seismic wave data from the perforation shot and the known location of the perforation shot;
- pumping fracturing fluid into the formation layer;
- monitoring subsequent seismic wave data using the array of geophones;
- identifying microseismic events;
- determining the horizontal location of an identified microseismic events and vertical travel time of seismic waves resulting from the microseismic event.
A system for locating microseismic events related to hydraulic fracturing, the system comprising:
- a plurality of geophones arranged in an array wherein the array is operably connected to a processor, and wherein the processor is configured to record and maintain a record of seismic data;
- wherein the processor is configured to determine the location of microseismic events based on the maintained record, and wherein the record does not require a depth velocity model or information regarding multiple geological layers.
A method of locating a microseismic event in the absence of a depth velocity model, the method comprising:
- initiating an intentional seismic event at a known location;
- monitoring seismic waves related to the intentional seismic event using a surface monitoring array, wherein the monitoring array comprises a plurality of geophones;
- determining a root mean square velocity and average velocity of the seismic waves traveling from the intentional seismic event to the plurality of geophones;
- monitoring subsequent seismic waves to identify a subsequent microseismic event;
- identifying the location of the subsequent microseismic event based on the subsequent seismic waves, root mean square velocity, and average velocity without the use of a depth velocity model.
Dependencies are inferred from the claim text.