Patent Document ID: 20030004648
Application ID: 10224793
Patent Flag: 0

Claim One:
1. In a method for determining a fracture pressure gradient 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 said fracture pressure gradient at any location within the seismic survey; an improvement comprising: (i) deleting erroneous leak-off test values for at least one well; (ii) displaying depth-correlated leak-off test and overburden data for the at least one well, and (iii) applying one of the three following methods I. curve fitting of the leak off test data from one or more offset control wells to determine a fracture gradient, II. determining a percentage of the overburden stress that honors the available regional data, and III. applying an appropriate stress ratio (Ko) to fit the leak-off test data