VH Reservoir Mapping with Borehole Sensors

Abstract

A method and system of detecting and mapping a subsurface hydrocarbon reservoir includes determining ratio data for a plurality of orthogonal spectral components of naturally occurring low frequency background seismic data. The ratio data may be compared, plotted, contoured and displayed as a subsurface hydrocarbon reservoir map or a hydrocarbon potential map. The ratio data may represent a vertical spectral component of the seismic data over a horizontal spectral component of the seismic data. The subsurface hydrocarbon reservoir map may include contouring the ratio data over a geographical area associated with the seismic data.

1 - 30 . (canceled) 
     
     
         31 . A set of application program interfaces embodied on a machine readable medium for execution by a processor in conjunction with an application program for detecting a subsurface hydrocarbon reservoir, the set of application program interfaces comprising: a first interface that receives ratio data acquired with sensors positioned below ground in a borehole, representative of a vertical spectral component relative to a horizontal spectral component, the spectral components derived from ambient seismic data; and a second interface that receives the ratio data to compare with a predetermined threshold value, wherein ratio data exceeding the threshold value indicates the location of a subsurface hydrocarbon reservoir. 
     
     
         32 . The set of application interface programs according to claim  1  further comprising: a third interface that receives vertical motion component data from ambient seismic data for a data transform to obtain a vertical spectral component; and a fourth interface that receives horizontal motion component data from naturally occurring low frequency background seismic data for the data transform to obtain a horizontal spectral component. 
     
     
         33 . The set of application interface programs according to claim  1  wherein the data transform for the third and fourth interface is selected from the group consisting of: a discrete Fourier transform, a continuous Fourier transform, a continuous wavelet transform, and a discrete wavelet transform. 
     
     
         34 . The set of application interface programs according to claim  1  further comprising a fifth interface to receive data to merge two horizontal spectral components to obtain a merged horizontal spectral component. 
     
     
         35 . The set of application interface programs according to claim  1  further comprising a sixth interface to receive the ratio data in a form for display. 
     
     
         36 . The set of application interface programs according to claim  1  further comprising a seventh interface to receive the ratio data for contouring in a form for display as a map. 
     
     
         37 . A computerized method of mapping a subsurface hydrocarbon reservoir comprising: deriving a ratio data from a plurality of orthogonal spectral components of ambient seismic data acquired with sensors positioned below ground in a borehole; using a processing unit for determining ratio data which exceed a predetermined threshold value indicative of a subsurface hydrocarbon reservoir to determine subsurface hydrocarbon reservoir map location positions; and storing the map location positions in a form for display. 
     
     
         38 . The method of claim  7  further comprising determining ratio data representing a vertical spectral component of the seismic data over a horizontal spectral component of the seismic data. 
     
     
         39 . The method of claim  7  further comprising creating a subsurface hydrocarbon reservoir map by contouring the ratio data over a geographical area associated with the seismic data. 
     
     
         40 . The method of claim  7  wherein the orthogonal spectral components are determined by: applying a data transform to a plurality of orthogonal components of motion for the naturally occurring low frequency background seismic data. 
     
     
         41 . The method of claim  10  wherein the data transform is selected from the group consisting of: discrete Fourier transform, continuous Fourier transform, continuous wavelet transform, and discrete wavelet transform. 
     
     
         42 . The method of claim  7  further comprising: processing the plurality of orthogonal spectral components by at least one selected from the group of: smoothing with a low pass filter, smoothing with a fixed bandwidth moving window, smoothing with a variable bandwidth moving window, averaging with an arithmetic mean, and averaging with a geometrical mean. 
     
     
         43 . An information handling system for determining the presence of subsurface hydrocarbons associated with an area of seismic data acquisition comprising: a memory coupled to a processor, the memory for storing ambient seismic data acquired with sensors positioned below ground in a borehole; a processor configured to determine a ratio calculated from a plurality of orthogonal spectral components of ambient seismic data; an application program configured to determine when the ratio exceeds a predetermined threshold value associated with subsurface hydrocarbons; and a computer readable medium for storing the determined ratio. 
     
     
         44 . The information handling system of claim  13  wherein the processor is configured to apply a data transform to the naturally occurring low frequency background seismic data to obtain a vertical spectral component and to obtain at least one horizontal spectral component. 
     
     
         45 . The information handling system of claim  13  wherein the predetermined threshold value for the ratio is equal to or greater than 1.5. 
     
     
         46 . The information handling system of claim  13  wherein the ratio is determined for vertical spectral component frequencies and horizontal spectral component frequencies between 1 Hz and 5 Hz. 
     
     
         47 . The information handling system of claim  13  further comprising: a graphical display coupled to the processor and configured to present a view of the ratio as a function of position, wherein the processor is configured to generate the view by contouring the ratio over an area associated with the seismic data.