System and program for locating seismic events during earth fracture propagation

A computer program for determining the location of a seismic event in an earth formation zone using seismic traces corresponding to the event collected from one or more sensors in the zone, the program being stored on a computer-readable media for operation by a user on a computer having a graphical user interface, the program comprising:

• instructions for displaying a graphical data window of the seismic traces corresponding to the event, the traces representing observed arrival time signals from the sensors plotted with respect to time;
• instructions for displaying a window of a base map of the one or more sensors within the zone;
• instructions for displaying in the graphical data window a curve plotting calculated arrival time signals for the traces, the curve being developed from a user-selected one of the observed arrival time signals displayed in the graphical data window and from a user-selected trial location of the event selected in the base map window;
• and
• instructions for user-repositioning of the trial location in the base map window such that the displayed curve moves in correspondence with the repositioning of the trial location, the trial location being repositioned by the user until an acceptable visual coincidence of the curve is reached with the observed arrival time signals of the traces to thereby yield the location of the event.

A computer program for determining the location of a seismic event in an earth formation zone using seismic traces corresponding to the event collected from one or more sensors in the zone, the program being stored on a computer-readable media for operation by a user on a computer having a graphical user interface, the program comprising:

• instructions for displaying a graphical data window of the seismic traces corresponding to the event, the traces representing observed arrival time signals from the sensors plotted with respect to time;
• instructions for displaying a window of a base map of the positions of the one or more sensors within the zone;
• instructions for generating a map-locating the event by displaying in the graphical data window a curve plotting calculated arrival time signals for the traces, the curve being developed from a user-selected one of the observed arrival time signals displayed in the graphical data window and from a user-selected trial location of the event selected in the base map window, followed by user-repositioning of the trial location in the base map window such that the displayed curve moves in correspondence with the repositioning of the trial location, the trial location being repositioned by the user until an acceptable visual coincidence of the curve is reached with the observed arrival time signals of the traces to thereby yield the location of the event;
• and
• instructions for pick-locating the event to further refine its location after the map-locating, including displaying timing marks at positions of the curve on the traces, repositioning picked ones of the timing marks to more accurately visually coincide with the observed arrival time signals, and performing a functional analysis on the calculated arrival time signals following repositioning of the timimg marks to yield a refined location of the event based on the changes in the calculated arrival time signals caused by the repositioning of the timing marks.

A method for determining the location of a seismic event in an earth formation zone using seismic traces corresponding to the event collected from one or more sensors in the zone, the method for performance by a user on a computer having a graphical user interface, the method comprising:

• displaying a graphical data window of the seismic traces corresponding to the event, the traces representing observed arrival time signals from the sensors plotted with respect to time;
• displaying a window of a base map of the positions of the one or more sensors within the zone;
• and
• map-locating the event by displaying in the graphical data window a curve plotting calculated arrival time signals for the traces, the curve being developed from a user-selected trial location of the event selected in the base map window, the curve then being repositioned to visually coincide with the observed arrival time signals of the traces and thereby indicate the location of the event based on the changes in the calculated arrival time signals caused by the repositioning of the curve.

A system for determining the location of an extension of a hydraulic fracture within an earth formation zone of interest comprising:

• seismic signal sensors placed in an array with respect to the formation zone;
• means for transmitting signals relating to an event caused by extension of the fracture from the sensors at a predetermined sampling rate to a memory device;
• means for selectively retrieving the signals from the memory device and determining the location of the event by displaying a graphical data window of the seismic traces corresponding to the event, the traces representing observed arrival time signals from the sensors plotted with respect to time;
• displaying a window of a base map of the positions of the sensors within the zone;
• and displaying in a graphical data window a curve plotting calculated arrival time signals for the traces, the curve being developed from a user-selected trial location of the event selected in the base map window, the curve then being repositioned to visually coincide with the observed arrival time signals of the traces and thereby indicate the location of the event based on the changes in the calculated arrival time signals caused by the repositioning of the curve.