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US 9,435,904 B2Granted
Method of correcting velocity for complex surface topography
AssigneeChevron U.S.A. Inc.
InventorsMaisha Lara Amaru, Cory James Hoelting
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Abstract
Embodiments of a method for correcting velocity models for complex topographies are disclosed herein. In general, embodiments of the method utilize velocity corrections based on geomechanical effects to correct a velocity model to take into account complex surface topographies. In particular, embodiments of the method use a nucleus strain theory to determine the velocity corrections. Further details and advantages of various embodiments of the method are described in more detail herein.
Claims18
A computer-implemented method of correcting a velocity model, the method comprising:
- (a) selecting a velocity model of a subsurface region of interest, the subsurface region of interest located proximate to a surface comprising one or more topographic anomalies;
- (b) determining an anomalous overburden stress caused by the one or more topographic anomalies;
- (c) determining an overburden strain caused by the one or more topographic anomalies;
- (d) using a nucleus of strain theory to determine an anomalous stress propagation in the subsurface region of interest by calculating
- S
- z
-
- (
- r
- a
- ,
- i
- )
- =
- -
- C
- m
- R
- 3
- Sz(ra,i)=−Cm/R3
- wherein Sz(ra,i)=anomalous stress at a particular subsurface location ri caused by cell “a” in the anomalous topography, R=distance between subsurface cell “i” and a cell “a” in the one or more topographic anomalies with
- C
- m
- =
- 2
-
- G
-
-
- V
- a
-
- E
- 0
-
- (
- r
- a
- )
- 4
-
- π
- Cm=2G VaE0 (ra)/4π
- where G=shear modulus, Va=volume of a cell in the one or more topographic anomalies, E0(ra)=anomalous overburden strain at location ra;
- (e) determining a velocity correction factor from the anomalous stress propagation;
- and
- (f) using the velocity correction factor to generate a corrected velocity model, wherein at least one of (a) through (f) is performed on a computer.
44 more elements
A computer system, comprising:
- an interface for receiving a seismic input volume, the seismic input volume comprising a plurality of seismic traces;
- a memory resource;
- input and output functions for presenting and receiving communication signals to and from a human user;
- one or more central processing units for executing program instructions;
- and program memory, coupled to the central processing unit, for storing a computer program including program instructions that, when executed by the one or more central processing units, cause the computer system to perform a plurality of operations for correcting a velocity model, the plurality of operations comprising:
- (a) selecting a velocity model of a subsurface region of interest, the subsurface region of interest located proximate to a surface comprising one or more topographic anomalies;
- (b) determining an anomalous overburden stress caused by the one or more topographic anomalies;
- (c) determining an overburden strain caused by the one or more topographic anomalies;
- (d) using a nucleus of strain theory to determine an anomalous stress propagation in the subsurface region of interest by calculating
- S
- z
-
- (
- r
- a
- ,
- i
- )
- =
- -
- C
- m
- R
- 3
- Sz(ra,i)=−Cm/R3
- wherein Sz(ra,i)=anomalous stress at a particular subsurface location ri caused by cell “a” in the anomalous topography, R=distance between subsurface cell “i” and a cell “a” in the one or more topographic anomalies with
- C
- m
- =
- 2
-
- G
-
-
- V
- a
-
- E
- 0
-
- (
- r
- a
- )
- 4
-
- π
- Cm=2GVaE0(ra)/4π
- where G=shear modulus, Va=volume of a cell in the one or more topographic anomalies, E0(ra)=anomalous overburden strain at location ra;
- (e) determining a velocity correction factor from the anomalous stress propagation;
- and
- (f) using the velocity correction factor to generate a corrected velocity model.
49 more elements
A computer-implemented method of correcting a velocity model, the method comprising:
- (a) selecting a velocity model of a subsurface region of interest, the subsurface region of interest located proximate a surface comprising one or more topographic anomalies;
- (b) using a nucleus of strain theory to determine a velocity correction factor for the one or more topographic anomalies by calculating
- S
- z
-
- (
- r
- a
- ,
- i
- )
- =
- -
- C
- m
- R
- 3
- Sz(ra,i)=−Cm/R3
- wherein Sz(ra,i)=anomalous stress at a particular subsurface location ri caused by cell “a” in the anomalous topography, R=distance between subsurface cell “i” and a cell “a” in the one or more topographic anomalies with
- C
- m
- =
- 2
-
- G
-
-
- V
- a
-
- E
- 0
-
- (
- r
- a
- )
- 4
-
- π
- Cm=2GVaE0(ra)/4π
- where G=shear modulus, Va=volume of a cell in the one or more topographic anomalies, E0(ra)=anomalous overburden strain at location ra;
- and
- (c) using the velocity correction factor to generate a corrected velocity model, wherein at least one of (a) through (c) is performed on a computer.
41 more elements
Dependencies are inferred from the claim text.