INVERSION methods to determine the in-situ stresses

Abstract

The challenges pose by the uncertainty in the in-situ stress measurement in the petroleum and mining industries are enormous. A handy computer tool to estimate the magnitude and direction of the horizontal in-situ stresses is developed is this thesis. The tool is based on the mathematical model proposed by Bernt S. Aadnøy which makes use of data from hydraulic fracture test to back calculate to obtain the horizontal principal in-situ stresses. To demonstrate the reliability of the program it was applied to real fracture data from wells in the North Sea. Two field cases were considered. The first field case illustrated the ability of the programming tool to accurately estimate the state of stress of the formation and also verify the validity of the results by computing the estimated formation fracture pressure to be compared with the measured data form LOT. The second field case exhibited the tool’s ability to predict the fracture pressure of a future well to be drilled. The results obtained showed excellent correlations with tests data.