Patent Document ID: 7941307
Application ID: 11250804
Patent Flag: 1

Claim One:
1. A method for producing a substantially calibrated numerical model, which can be used for calculating a stress on any point in a formation, the method comprising: a. predetermining a number, n, of strata suitable for modeling the formation, wherein n=a whole integer≧1 and s n independently designates each stratum, respectively; b. predetermining for each s n a corresponding thickness, H n , and a corresponding present-day Poisson ratio, v n,Present ; c. obtaining stress calibration data L f , for at least one location in the formation, wherein for a first location in the formation, L f =L 1 stress calibration data; d. predetermining at least one set, i, of values comprising a burial Poisson ratio corresponding to each s n , v n,Burial-i , wherein each v n ,Burial-i ≦0.5 and each v, n,Burial-i >v n,Present , wherein for i=1 a first set of values for burial Poisson ratio, v n,Burial-1 , is predetermined; e. predetermining at least a 1 st gravitational load, GL 1 , associated with the formation; f. using at least each of the GL 1 , the H n and the v n,Burial-i values to perform stress calculations with a numerical modeling program on multiple points in the formation so that at least one modeled formation-stress analysis, FSA i , can be produced, wherein for i=1 a first modeled formation-stress analysis, FSA 1 , is produced with the numerical modeling program; g. producing from each FSA i a corresponding set, i, of modeled stress profiles for L f , SP i,Lf , having at least one principal stress, wherein for i=1 and L 1 , a first set of modeled stress profiles, SP 1,L1 , is produced; h. comparing each SP i,Lf to the L f stress calibration data, wherein for i=1 and L 1 , SP 1,L1 is compared to the L 1 stress calibration data; i. determining a degree of deviation, D i , from comparing, respectively, each of SP i,Lf and the L f stress calibration data, wherein for i=1 a first degree of deviation, D 1 , is determined from comparing at least the SP 1,L1 and the L 1 stress calibration data; j. obtaining a first substantially calibrated numerical model incorporating each modeled formation-stress analysis and modeled stress profile, the first model having degree of deviation D 1 , wherein D 1 is greater than a pre-determined maximum deviation and the model incorporates stress calculations and formation stress-analysis; k. predetermining, a second set of burial Poisson ratio values under element (d) wherein for i=2, v n,Burial-i is v n,Burial-2 ; l. performing the stress analysis of element (f) using at least each of the GL 1 , the H n values, and, instead of the v n,Burial-1 values, using the v n,Burial-2 values to perform stress calculations on multiple points in the formation so that a second modeled formation-stress analysis, FSA 2 , is produced; m. producing from the FSA 2 , a second set of modeled stress profiles, SP 2,Lf , wherein for L 1 , a second set of modeled stress profiles, SP 2,L1 , is produced; n. determining a second degree of deviation, D 2 , from comparing, respectively, each of SP 2,Lf and the L f stress calibration data according to elements h) through i), wherein D 2 is determined from comparing at least SP 2,L1 to the L 1 stress calibration data; and o. obtaining the second substantially calibrated numerical model incorporating each modeled formation-stress analysis and modeled stress profile, the second model having degree of deviation D 2 , wherein each set of v n,Burial-1 and v nBurial-2 values is correlated to v n,Present by a predetermined relationship, wherein each set of v n,Burial-1 and v n,Burial-2 values corresponds to a predetermined iteration constant, X i , wherein for i=1 a first iteration constant, X 1 , is predetermined and for i=2 a second iteration constant, X 2 , is predetermined.