US 6,473,696 B1 · Method and process for prediction of subsurface fluid and rock pressures in the earth

Abstract

A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or front inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Claims51

Dependent claims

A method for determining a parameter of interest of a subsurface region of earth formations comprising:

(a) obtaining seismic survey information about the subsurface region;
(b) identifying a plurality of interpreted seismic horizons of interest from the obtained survey information;
(c) obtaining estimated seismic velocities corresponding to at least one interval between at least one pair of said plurality of seismic horizons;
(d) calibrating the estimated seismic velocities to the parameter of interest
(e) using the results of said calibration and the obtained seismic velocities to obtain the parameter of interest at any location within the seismic survey.

2 more elements

A method for determining a parameter of interest of a subsurface region of earth formations comprising:

(a) obtaining seismic survey information about the subsurface region;
(b) obtaining estimated seismic velocities corresponding to at least one interval of the subsurface from:
(i) coherency inversion analysis of P-wave or S-wave seismic data;
(ii) pre-stack inversion of P-wave seismic data;
(iii) post-stack inversion of P-wave seismic data;
(iv) pre-stack inversion of S-wave seismic data;
(v) post-stack inversion of S-wave seismic data;
(vi) normal moveout (NMO) velocity analysis of S-wave seismic data;
(vii) tomographic analysis of P-wave seismic data;
(viii) tomographic analysis of S-wave seismic data;
(ix) analysis of P-wave data from vertical seismic profiling (VSP) data;
(x) analysis of P-wave data from inversion of VSP look-ahead data;
(xi) analysis of S-wave data from vertical seismic profiling (VSP) data
(xii) analysis of S-wave data from inversion of VSP look-ahead data;
(c) calibrating the estimated seismic velocities to the parameter of interest
(d) using the results of said calibration and the obtained seismic velocities to obtain the parameter of interest at any location within the seismic survey.

13 more elements

Dependencies are inferred from the claim text.

Method and process for prediction of subsurface fluid and rock pressures in the earth

Life of this patent

Method and process for prediction of subsurface fluid and rock pressures in the earth

Life of this patent

Abstract

Claims51