Anisotropic NMO correction and its application to attenuate noises in VSP data

A method for performing a physical formation-related operation based on corrected vertical seismic profile (VSP) data of an earth formation, the method comprising:

• performing a VSP survey using a seismic data acquisition system to provide VSP data that includes reflection wave data;
• applying, with a processor, a normal moveout (NMO) correction equation to the VSP data inclusive of the reflection wave data;
• reducing noise in the VSP data by solving, with the processor, the NMO correction equation by using a simulated annealing (SA) algorithm to provide VSP NMO corrected data, the SA algorithm comprising a coherence coefficient of semblance analysis of an NMO corrected reflection event within a time window as a cost function in the SA algorithm;
• applying, with the processor, a median filter to the VSP NMO corrected data to provide median-filtered VSP NMO corrected data that attenuates unaligned noises;
• and
• performing the physical formation-related operation at at least one of a location, a first selected depth or a depth interval based on the median-filtered VSP NMO corrected data, the physical formation-related operation comprising at least one of (i) drilling a borehole using a drilling system based on the median-filtered VSP NMO corrected data, (ii) perforating a casing in the borehole at a second selected depth or depth interval based on the median-filtered VSP NMO corrected data, or (iii) stimulating the earth formation to at least one of open up existing fractures or create new fractures at a third selected depth or depth interval based on the median-filtered VSP NMO corrected data.

A method for performing a physical formation-related operation based on corrected vertical seismic profile (VSP) data of an earth formation, the method comprising:

• performing a VSP survey using a seismic data acquisition system to provide VSP data that includes reflection wave data;
• applying, with a processor, a normal moveout (NMO) correction equation to the VSP;
• reducing noise in the VSP data that includes the reflection wave data by solving, with the processor, the NMO correction equation by using a simulated annealing (SA) algorithm to provide VSP NMO corrected data, the SA algorithm comprising a coherence coefficient of semblance analysis of an NMO corrected reflection event within a time window as a cost function in the SA algorithm;
• applying, with the processor, a median filter to the VSP NMO corrected data to provide median-filtered VSP NMO corrected data that attenuates unaligned noises;
• applying, with the processor, a reverse NMO algorithm to the median-filtered VSP NMO corrected data to provide reverse median-filtered VSP NMO corrected data;
• and
• performing the physical formation-related operation at at least one of a location, a first depth or a depth interval based on the reverse median-filtered VSP NMO corrected data, the physical formation-related operation comprising at least one of (i) drilling a borehole using a drilling system based on the reverse median-filtered VSP NMO corrected data, (ii) perforating a casing in the borehole at a second selected depth or depth interval based on the reverse median-filtered VSP NMO corrected data, or (iii) stimulating the earth formation to at least one of open up existing fractures or create new fractures at a third selected depth or depth interval based on the reverse median-filtered VSP NMO corrected data.