Method for predicting quantitative values of a rock or fluid property in a reservoir using seismic data
First Claim
1. A method for determining a value of a designated rock or fluid property in a subterranean geologic volume, the method comprising:
- assigning a first predicted value of a rock or fluid property to a cell within a multi-dimensional layered model that is correlated to a subterranean geologic volume;
calculating first predicted values of seismic response for said cell from a response model using said first predicted value of said rock or fluid property and based upon compressional velocity, shear velocity and bulk density, wherein said response model is responsive to changes in predicted values of said rock or fluid property;
comparing synthetic traces that are generated from said first predicted values of seismic response to the corresponding traces obtained from sets of actual seismic data corresponding to the subterranean geologic volume to ascertain a difference between said synthetic traces and said corresponding traces, said step of comparing involving maintaining consistency between the types, scales and dimensions of said first predicted value of a designated rock or fluid property and said sets of actual seismic data;
adjusting said first predicted value of said designated rock or fluid property in response to said difference to create a second predicted value of said designated rock or fluid property, wherein said second predicted value generally reduces said difference; and
storing said second predicted value for later use.
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Abstract
A method is provided for predicting a value of a designated rock or fluid property in a subterranean geologic volume. A first predicted value of the designated rock or fluid property is also assigned to a volume of a multi-dimensional, multi-scale model. A first predicted value of seismic response for the model volume is calculated from a response model using the first predicted value of the designated rock or fluid property, wherein the response model is responsive to changes in predicted values of the designated rock or fluid property. A synthetic trace is generated and iteratively compared to the corresponding trace obtained from one or more sets of actual seismic data to determine a difference while consistency is maintained between the types, scales and dimensions of values and data. The first predicted value of the designated rock or fluid property is adjusted in response to the difference to create a second predicted value of the designated rock or fluid property, wherein the second predicted value generally reduces the difference.
112 Citations
21 Claims
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1. A method for determining a value of a designated rock or fluid property in a subterranean geologic volume, the method comprising:
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assigning a first predicted value of a rock or fluid property to a cell within a multi-dimensional layered model that is correlated to a subterranean geologic volume; calculating first predicted values of seismic response for said cell from a response model using said first predicted value of said rock or fluid property and based upon compressional velocity, shear velocity and bulk density, wherein said response model is responsive to changes in predicted values of said rock or fluid property; comparing synthetic traces that are generated from said first predicted values of seismic response to the corresponding traces obtained from sets of actual seismic data corresponding to the subterranean geologic volume to ascertain a difference between said synthetic traces and said corresponding traces, said step of comparing involving maintaining consistency between the types, scales and dimensions of said first predicted value of a designated rock or fluid property and said sets of actual seismic data; adjusting said first predicted value of said designated rock or fluid property in response to said difference to create a second predicted value of said designated rock or fluid property, wherein said second predicted value generally reduces said difference; and storing said second predicted value for later use. - View Dependent Claims (2)
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3. A method for determining an error-minimized value of a designated rock or fluid property at a location in a subterranean geologic volume which is characterized by a multi-dimensional layered model volume having a plurality of model subvolumes, said method comprising:
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assigning a first predicted value of a designated rock or fluid property to each of said plurality of model subvolumes; calculating first predicted values of a seismic response for the interface between at least two groups of subvolumes based upon compressional velocity, shear velocity and bulk density; comparing synthetic traces that are generated from said first predicted values of seismic response to the corresponding traces obtained from a plurality of response volumes of actual seismic data corresponding to the subterranean geologic volume to determine a first difference between said synthetic traces and said corresponding traces, said step of comparing involves maintaining consistency between the types, scales and dimensions of said first predicted value of a designated rock or fluid property and said plurality of response volumes of actual seismic data; adjusting said first predicted value of said designated rock or fluid property in response to said difference to create a second predicted value of said designated rock or fluid property, wherein said second predicted value generally reduces said first difference; and storing said second predicted value for later use. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method of characterizing a subterranean geologic volume, the method comprising:
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assigning a first predicted value of a rock or fluid property to a cell within a multi-dimensional layered model that is correlated to a subterranean geologic volume; simultaneously calculating first predicted values of seismic response for multiple angles of incidence for said cell from a response model using said first predicted value of said rock or fluid property and based upon compressional velocity, shear velocity and bulk density; simultaneously comparing synthetic traces that are generated from said first predicted values of seismic response for multiple angles of incidence to corresponding traces obtained from corresponding multiple angles of incidence of actual seismic data for the subterranean geologic volume to ascertain a difference between said synthetic traces and said corresponding traces; adjusting said first predicted value of said designated rock or fluid property in response to said difference to create a second predicted value of said designated rock or fluid property, wherein said second predicted value generally reduces said difference; and storing said second predicted value for later use. - View Dependent Claims (21)
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Specification