Correlation Techniques for Passive Electroseismic and Seismoelectric Surveying

Abstract

A method for surveying, may include receiving, by a processor, first survey data from a first source, the first source comprising a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal. The method may also include receiving, by the processor, second survey data from a second source and processing the first survey data and the second survey data to determine one or more properties of a subsurface earth formation.

What is claimed is: 
     
         1 . A method for surveying, comprising:
 receiving, by a processor, first survey data from a first source, the first source comprising a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal;   receiving, by the processor, second survey data from a second source; and   processing the first survey data and the second survey data to determine one or more properties of a subsurface earth formation.   
     
     
         2 . The method of  claim 1 , wherein the first signal comprises a vertical component of an electromagnetic signal or a seismic signal. 
     
     
         3 . The method of  claim 1 , wherein processing the first survey data comprises:
 applying at least one time-domain filter or at least one frequency-domain filter to the first survey data to obtain filtered first survey data; and   identifying a signal of interest from the filtered first survey data, the signal of interest indicating the one or more properties of the subsurface earth formation.   
     
     
         4 . The method of  claim 1 , wherein the second source comprises a second signal generated by a subsurface earth formation in response to a controlled source electromagnetic signal, the controlled source electromagnetic signal generated by a power source configured to drive an electric current into the earth. 
     
     
         5 . The method of  claim 1 , wherein the second source comprises a second signal generated by a subsurface earth formation in response to an active source of seismic energy. 
     
     
         6 . The method of  claim 5 , further comprising:
 receiving, by the processor, the first signal during one or more time periods in which the second signal is attenuated.   
     
     
         7 . The method of  claim 1 , wherein the second source comprises a measurement of a horizontal electromagnetic field at the surface of the earth, the horizontal electromagnetic field responsive to the subsurface earth formation. 
     
     
         8 . The method of  claim 1 , wherein the first survey data is obtained by a first plurality of sensors configured to detect the first signal while moving in a body of water. 
     
     
         9 . The method of  claim 1 , wherein the second survey data is obtained by a second plurality of sensors configured to be arranged in a pattern and operable to detect a horizontal electromagnetic field at the surface of the earth, the horizontal electromagnetic field responsive to the subsurface earth formation. 
     
     
         10 . The method of  claim 1 , wherein the second available source comprises a passive measurement of spontaneous potential generated between a ground sensor and a wellbore at least one depth. 
     
     
         11 . The method of  claim 1 , further comprising:
 generating, based, at least in part, on the first survey data and the second survey data, a model of the subsurface earth formation.   
     
     
         12 . A system comprising:
 a plurality of sensors operable to detect first survey data by detecting a first signal generated by a subsurface earth formation in response to a passive-source electromagnetic signal, wherein the electromagnetic signal is generated by an electroseismic or seismoelectric conversion of the passive-source electromagnetic signal;   a processor operable to:
 receive first survey data from at least one of the plurality of sensors; 
 receive second survey data from a second source; and 
 process the first survey data and the second survey data to determine one or more properties of a subsurface earth formation. 
   
     
     
         13 . The system of  claim 12 , wherein the first signal comprises a vertical component of an electromagnetic signal or a seismic signal. 
     
     
         14 . The system of  claim 12 , wherein processing the first survey data comprises:
 applying at least one time-domain filter or at least one frequency-domain filter to the first survey data to obtain filtered first survey data; and   identifying a signal of interest from the filtered first survey data, the signal of interest indicating the one or more properties of the subsurface earth formation.   
     
     
         15 . The system of  claim 12 , wherein the second source comprises a second signal generated by a subsurface earth formation in response to a controlled source electromagnetic signal, the controlled source electromagnetic signal generated by a power source configured to drive an electric current into the earth. 
     
     
         16 . The system of  claim 12 , wherein the second source comprises a second signal generated by a subsurface earth formation in response to an active source of seismic energy. 
     
     
         17 . The system of  claim 16 , wherein the processor is further operable to:
 receive the first signal during one or more time periods in which the second signal is attenuated.   
     
     
         18 . The system of  claim 12 , wherein the second source comprises a measurement of a horizontal electromagnetic field at the surface of the earth, the horizontal electromagnetic field responsive to the subsurface earth formation. 
     
     
         19 . The system of  claim 12 , wherein the first survey data is obtained by a first plurality of sensors configured to detect the first signal while moving in a body of water. 
     
     
         20 . The system of  claim 12 , wherein the second survey data is obtained by a second plurality of sensors configured to be arranged in a pattern and operable to detect a horizontal electromagnetic field at the surface of the earth, the horizontal electromagnetic field responsive to the subsurface earth formation.