Method to estimate the depth of the weathering layer using gravity response

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.

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.