To effectively produce oil and gas from a reservoir we need to locate faults. A geostatistical method is developed to correlate wells mathematically to determine their relative stratigraphie alignment. With more than two wells the change in dip angle is used to identify a fault. Uncertainty can be reduced when more wells on both sides of the fault are included in the analysis. The major advantages of this new method are: (1) more data can be correlated at the same time to detect otherwise unidentifiable faults, (2) the analysis can be done quickly on a computer, and (3) the correctable range of well spacing can be determined from geostatistical theory with the variogram.