Seismic monitoring and control method

Abstract

A seismic communication system suitable to communicate information to an underground device is disclosed. A seismic source (preferably on or near the surface of the earth) generates a timed series of seismic shots. These shots are then detected by one or more seismic receivers underground. Depending on the timing of these seismic shots, and the communication protocol selected, various information may be communicated to the underground target. Such a system is particularly desirable when the underground device includes a perforating gun because the perforating gun may not only be remotely detonated without the drawbacks of previous methods, but the detonation of the perforating gun charges may also be detected, giving an indication whether substantially fewer than all of the explosive charges detonated. The seismic communication system may also be used, as a component within a multi-functional well seismic system, for seismic reservoir monitoring or seismic monitoring of well operations.

1 . A method of utilizing a seismic system suitable for communication of information to an underground location, said method comprising the steps of: 
 transmitting coded information as seismic energy initiated from a seismic source in a series of seismic shots, said seismic shots being initiated at selected pre-determined times;    receiving said seismic energy from said series of seismic shots at an underground location by a seismic receiver; and,    determining the presence or absence of said seismic shots initiated at pre-determined times by the presence of seismic shot energy caused by each of said seismic shots at a selected pre-determined time or by the absence of said seismic shot energy at a non-selected pre-determined time, said determination being facilitated by an underground processor in communication with an underground clock and said seismic receiver whereby said underground processor decodes information from said presence or absence of seismic shots.    
   
   
       2 . The method of  claim 1  that utilizes a communication protocol in which the number of consecutive shots initiated at consecutive pre-determined times signifies at least a portion of said information.  
   
   
       3 . The method of  claim 1  in which potentially selectable pre-determined times are separated by equal time intervals.  
   
   
       4 . The method of  claim 1  in which an initial seismic shot of said series of seismic shots may occur at any one of potentially selectable pre-determined times.  
   
   
       5 . The method of  claim 1  in which said seismic source initiates each of said seismic shots from the same site.  
   
   
       6 . The method of  claim 1  in which said seismic source initiates said seismic shots from a surface site.  
   
   
       7 . The method of  claim 1  in which said seismic source initiates said seismic shots from a subsurface site.  
   
   
       8 . The method of  claim 1  in which said seismic source initiates said seismic shots from more than one site.  
   
   
       9 . The method of  claim 1  that utilizes multiple seismic sources.  
   
   
       10 . The method of  claim 1  in which at least a portion of said information causes an alteration in the operation or the configuration of an underground tool associated with said underground processor.  
   
   
       11 . The method of  claim 1  in which at least a portion of said information taken together with other measured conditions or received signals causes an alteration in the operation or configuration of an underground tool associated with said underground processor.  
   
   
       12 . The method of  claim 1  in which at least a portion of said information causes an alteration in the operation or configuration of said seismic receiver.  
   
   
       13 . The method of  claim 1  in which at least a portion of said information taken together with other measured conditions or received signals causes an alteration in the operation or configuration of said seismic receiver.  
   
   
       14 . The method of  claim 1  in which said seismic receiver and said underground processor periodically monitor ambient seismic noise, commence listening for said series of seismic shots when ambient seismic noise levels fall below a pre-programmed or dynamically computed threshold level for a pre-programmed period of time, and discontinue said listening if ambient seismic noise rises above said threshold level for another pre-programmed period of time.  
   
   
       15 . The method of  claim 14  in which said underground processor periodically monitors local temperature and only commences said periodical monitoring of said ambient seismic noise and said listening for said series of seismic shots if said local temperature is within pre-programmed ranges.  
   
   
       16 . The method of  claim 14  in which said underground processor periodically monitors borehole pressure and only commences said periodical monitoring of said ambient seismic noise and said listening for said series of seismic shots if said borehole pressure is within pre-programmed ranges.  
   
   
       17 . The method of  claim 1  in which said underground processor has a communication link to a downhole tool, said tool altering its operation or configuration in response to at least a portion of said information.  
   
   
       18 . The method of  claim 17  in which said downhole tool is a controllable device  
   
   
       19 . The method of  claim 17  in which said downhole tool comprises a selectively actuated device.  
   
   
       20 . The method of  claim 1  in which said underground processor has a communication link to a downhole tool, said tool altering its operation or configuration in response to at least a portion of said information taken together with other measured conditions or received signals.  
   
   
       21 . The method of  claim 20  in which said downhole tool is a controllable device  
   
   
       22 . The method of  claim 20  in which said downhole tool comprises a selectively actuated device.  
   
   
       23 . The method of  claim 1  in which said underground processor determines said presence or said absence of said seismic shot energy by mathematical comparison of at least two seismic wave profiles, each representing potential seismic shot energy received.  
   
   
       24 . The method of  claim 1  in which said underground processor determines said presence or said absence of said seismic shot energy by the variation of energy level with time following a said pre-determined time.  
   
   
       25 . The method of  claim 23  in which said comparison includes computation of a cross-correlation of at least two seismic wave profiles.  
   
   
       26 . The method of  claim 25  in which said cross-correlation is analyzed for time of maximum amplitude, value of maximum amplitude or value of normalized cross-correlation maximum amplitude.  
   
   
       27 . The method of  claim 23  in which at least one of said seismic wave profiles is formed by mathematical combination of two or more seismic wave profiles, each of which was derived from the received seismic shot energy from one seismic shot.  
   
   
       28 . The method of  claim 1  in which an improved representation of said seismic shot energy is computed by mathematical combination of received seismic shot energy from two or more seismic shots of said series of seismic shots.  
   
   
       29 . The method of  claim 1  wherein said seismic receiver is operative for vertical seismic profiling operations.  
   
   
       30 . The method of  claim 29  wherein said seismic source is operative for vertical seismic profiling operations.  
   
   
       31 . The method of  claim 1  in which said seismic source is monitored by one or more surface or subsurface seismic receivers in addition to said seismic receiver at said underground location.  
   
   
       32 . The method of  claim 1  in which said seismic shots are initiated at times measured by a system master clock.  
   
   
       33 . A seismic system for communicating information to an underground location, said system comprising: 
 a seismic source for transmitting coded information to an underground location by a series of seismic shots initiated at selected pre-determined times;    a seismic receiver positioned at said underground location for receiving seismic energy from said series of seismic shots;    an underground processor in communication with said seismic receiver and an underground clock for determining the presence of seismic shot energy initiated at selected pre-determined time and for determining the absence of seismic shot energy at a non-selected pre-determined time,    said underground processor further de-coding information from a sequence of present or absent seismic shots at respective predetermined times.    
   
   
       34 . The seismic system of  claim 33  in which said seismic source initiates said seismic shots from a surface site.  
   
   
       35 . The seismic system of  claim 33  in which said seismic source initiates said seismic shots from a subsurface site.  
   
   
       36 . The seismic system of  claim 33  in which said seismic source initiates said seismic shots from more than one site.  
   
   
       37 . The seismic system of  claim 33  that utilizes multiple seismic sources.  
   
   
       38 . The seismic system of  claim 33  in which at least a portion of said information causes an alteration in the operation or the configuration of said underground processor.  
   
   
       39 . The seismic system of  claim 33  in which said seismic receiver and said underground processor periodically monitor ambient seismic noise, commence listening for said series of seismic shots when ambient seismic noise levels fall below a pre-programmed or dynamically computed threshold level for a pre-programmed period of time, and discontinue said listening if ambient seismic noise rises above said threshold level for another pre-programmed period of time.  
   
   
       40 . The seismic system of  claim 39  in which said underground processor periodically monitors local temperature and only commences said periodical monitoring of said ambient seismic noise and said listening for said series of seismic shots if said local temperature is within pre-programmed ranges.  
   
   
       41 . The seismic system of  claim 39  in which said underground processor periodically monitors borehole pressure and only commences said periodical monitoring of said ambient seismic noise and said listening for said series of seismic shots if said borehole pressure is within pre-programmed ranges.  
   
   
       42 . The seismic system of  claim 33  in which said underground processor has a communication link to a downhole tool, said tool altering its operation or configuration in response to at least a portion of said information.  
   
   
       43 . The seismic system of  claim 42  in which said downhole tool is a controllable device.  
   
   
       44 . The system of  claim 42  in which said downhole tool comprises a selectively actuated device.  
   
   
       45 . The seismic system of  claim 33  in which said underground processor has a communication link to a downhole tool, said tool altering its operation or configuration in response to at least a portion of said information taken together with other measured conditions or received signals.  
   
   
       46 . The seismic system of  claim 45  in which said downhole tool is a controllable device.  
   
   
       47 . The seismic system of  claim 45  in which said downhole tool comprises a selectively actuated device.  
   
   
       48 . The seismic system of  claim 33  in which an improved representation of said seismic shot energy is computed by mathematical combination of received seismic shot energy from two or more seismic shots of said series of seismic shots.  
   
   
       49 . The seismic system of  claim 33  in which said seismic source is monitored by one or more surface or subsurface seismic receivers in addition to said underground seismic receiver.  
   
   
       50 . The seismic system of  claim 33  in which said seismic shots are initiated at times measured by a system master clock.