Hydrocarbon Detection With Passive Seismic Data

A method for hydrocarbon detection in a subsurface region using passive-source seismic data, comprising:

• (a) obtaining passive-source seismic survey data for the subsurface region, wherein the survey's receivers were seismometers located generally over said subsurface region and spaced for hydrocarbon prospecting, said seismometers being suitable for global seismology earthquake detection;
• (b) determining one or more earthquakes from tabulations or other sources of earthquake information that can be identified in the seismometer data, and taking source location information for such earthquakes from the tabulations or other sources, and wherein said one or more earthquakes include at least one event identified in an earthquake table to be of a magnitude sufficient to contain a dominant frequency in a range of 0 to 8 Hz;
• (c) retrieving time segments from the seismometer data corresponding to records of each of said identified earthquakes;
• (d) inverting the segments of seismometer data and earthquake source location information to infer a physical properties model giving values of at least one physical property at different locations in the subsurface region;
• and
• (e) using the physical properties model to predict hydrocarbon potential for the subsurface region.

A method for producing hydrocarbons from a subsurface region, comprising:

• (a) obtaining passive-source seismic survey data for the subsurface region, wherein the survey's receivers were seismometers located generally over said subsurface region and spaced for hydrocarbon prospecting, said seismometers being suitable for global seismology earthquake detection;
• (b) determining one or more earthquakes from tabulations or other sources of earthquake information that can be identified in the seismometer data, and taking source location information for such earthquakes from the tabulations or other sources, and wherein said one or more earthquakes include at least one event identified in an earthquake table to be of a magnitude sufficient to contain a dominant frequency in a range of 0 to 8 Hz;
• (c) retrieving time segments from the seismometer data corresponding to records of each of said identified earthquakes;
• (d) obtaining at least one other type of geophysical data for the subsurface region, selected from a group consisting of active source seismic, controlled source electromagnetic, magnetotelluric, magnetic, and gravity;
• (e) deriving a physical properties model giving values of at least one physical property at different locations in the subsurface region by simultaneously using the segments of seismometer data and earthquake source location information and the at least one other type of geophysical data;
• (f) using the physical properties model to predict hydrocarbon potential for the subsurface region;
• and
• (g) in response to a positive prediction, drilling a well into the subsurface region and producing hydrocarbons.

A method for hydrocarbon detection in a subsurface region using earthquake-source seismic data in conjunction with active-source seismic data, comprising:

• (a) obtaining earthquake-source seismic survey data for the subsurface region, wherein the survey's receivers were seismometers located generally over said subsurface region and spaced for hydrocarbon prospecting, said seismometers being suitable for global seismology earthquake detection, and wherein said earthquake-source seismic data include at least one event identified in an earthquake table to be of a magnitude sufficient to contain a dominant frequency in a range of 0 to 8 Hz;
• (b) obtaining active-source seismic survey data for the subsurface region;
• (c) jointly inverting the earthquake-source seismic survey data with the active-source seismic survey data to derive a velocity model of the subsurface region;
• and
• (d) using the velocity model to predict hydrocarbon potential for the subsurface region.