# US 11,906,694 B2 · Method to estimate the depth of the weathering layer using gravity response

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,906,694 B2
- Document ID: US11906694B2
- Status: Granted
- Kind: B2
- Application number: 17/703,555
- Filed: 2022-03-24
- Published: 2023-10-05
- Granted: 2024-02-20
- Earliest claimed: 2022-03-24
- Assignees: Saudi Arabian Oil Company
- Applicants: Saudi Arabian Oil Company
- Inventors: Hassan Ali AlJanobi
- Web page: https://patentgrep.com/patent/US11906694B2

## CPC

- G01V 7/06: Analysis or interpretation of gravimetric records
- G01V 1/42: using generators in one well and receivers elsewhere or vice versa (G01V1/52 takes precedence)
- G01V 11/00: Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
- G01V 2210/1299: Subsurface, e.g. in borehole or below weathering layer or mud line
- G01V 2210/1425: Land surface
- G01V 2210/622: Velocity, density or impedance
- G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02)

## Abstract

A method to estimate a depth profile of a weathering layer in a subterranean formation of a field is disclosed. The method includes obtaining gravity survey data of the field, generating an equivalent source density profile based on the gravity survey data, wherein the equivalent source density profile describes a set of equivalent gravitational sources to substitute rock layers of the subterranean formation, generating an equivalent source gravity response based on the equivalent source density profile, wherein the equivalent source gravity response excludes a gravity contribution from the weathering layer, calculating a separated weathering layer gravity response based on a difference between the gravity survey data and the equivalent source gravity response, wherein the separated weathering layer gravity response corresponds to the gravity contribution from the weathering layer, and generating a modeled weathering layer depth profile based on the separated weathering layer gravity response.

## Claims

### Claim 1

A method to estimate a depth profile of a weathering layer in a subterranean formation of a field, comprising:
obtaining seismic uphole survey data;
obtaining gravity survey data of the field;
generating an equivalent source density profile based on the gravity survey data, wherein the equivalent source density profile describes a set of equivalent gravitational sources to substitute rock layers of the subterranean formation;
generating an equivalent source gravity response based on the equivalent source density profile, wherein the equivalent source gravity response excludes a gravity contribution from the weathering layer;
calculating a separated weathering layer gravity response based on a difference between the gravity survey data and the equivalent source gravity response, wherein the separated weathering layer gravity response corresponds to the gravity contribution from the weathering layer;
generating a modeled weathering layer depth profile based on the separated weathering layer gravity response; and
facilitating a field development operation based on the modeled weathering layer depth profile,
wherein the modeled weathering layer depth profile is generated by applying a linear inversion process to the separated weathering layer gravity response,
wherein the linear inversion process is constrained based on the seismic uphole survey data.

### Claim 2 (depends on 1)

The method of claim 1,
wherein the equivalent source density profile is generated by applying a linear inversion process to the gravity survey data.

### Claim 3 (depends on 1)

The method of claim 1,
wherein the linear inversion process minimizes a Tikhonov parametric function using a least-square approach.

### Claim 4 (depends on 3)

The method of claim 3,
wherein the Tikhonov parametric function is based on a regularization parameter that is selected using an L-curve method.

### Claim 5

An analysis and modeling system for estimating a depth profile of a weathering layer in a subterranean formation of a field, comprising:
a computer processor; and
memory storing instructions, when executed causing the computer processor to:
obtain seismic uphole survey data;
obtain gravity survey data of the field;
generate an equivalent source density profile based on the gravity survey data, wherein the equivalent source density profile describes a set of equivalent gravitational sources to substitute rock layers of the subterranean formation;
generate an equivalent source gravity response based on the equivalent source density profile, wherein the equivalent source gravity response excludes gravity contribution from the weathering layer;
calculate a separated weathering layer gravity response based on a difference between the gravity survey data and the equivalent source gravity response, wherein the separated weathering layer gravity response corresponds to the gravity contribution from the weathering layer;
generate a modeled weathering layer depth profile based on the separated weathering layer gravity response; and
facilitate a field development operation based on the modeled weathering layer depth profile,
wherein the modeled weathering layer depth profile is generated by applying a linear inversion process to the separated weathering layer gravity response,
wherein the linear inversion process is constrained based on the seismic uphole survey data.

### Claim 6 (depends on 5)

The analysis and modeling system of claim 5,
wherein the equivalent source density profile is generated by applying a linear inversion process to the gravity survey data.

### Claim 7 (depends on 5)

The analysis and modeling system of claim 5,
wherein the linear inversion process minimizes a Tikhonov parametric function using a least-square approach.

### Claim 8 (depends on 7)

The analysis and modeling system of claim 7,
wherein the Tikhonov parametric function is based on a regularization parameter that is selected using an L-curve method.

### Claim 9

A system for estimating a depth profile of a weathering layer in a subterranean formation of a field, comprising:
a seismic survey system configured to obtain seismic uphole survey data,
a gravity survey system configured to obtain gravity survey data of the field;
an analysis and modeling system configured to:
generate an equivalent source density profile based on the gravity survey data, wherein the equivalent source density profile describes a set of equivalent gravitational sources to substitute rock layers of the subterranean formation;
generate an equivalent source gravity response based on the equivalent source density profile, wherein the equivalent source gravity response excludes gravity contribution from the weathering layer;
calculate a separated weathering layer gravity response based on a difference between the gravity survey data and the equivalent source gravity response, wherein the separated weathering layer gravity response corresponds to the gravity contribution from the weathering layer; and
generate a modeled weathering layer depth profile based on the separated weathering layer gravity response; and
a drilling system configured to perform a drilling operation based on the modeled weathering layer depth profile,
wherein the modeled weathering layer depth profile is generated by applying a linear inversion process to the separated weathering layer gravity response,
wherein the linear inversion process is constrained based on the seismic uphole survey data.

### Claim 10 (depends on 9)

The system of claim 9,
wherein the linear inversion process minimizes a Tikhonov parametric function using a least-square approach.

### Claim 11 (depends on 10)

The system of claim 10,
wherein the Tikhonov parametric function is based on a regularization parameter that is selected using an L-curve method.