1D Geomechanical Earth Model

Purpose

The 1D Geomechanical Eath Model allows users to evaluate the minimum and maximum horizontal stresses and evaluate the mudweight window to better understand intervals where shear failure or borehole breakout may occur. The calculations consider the wellbore inclination and azimuth relative to the stress field orientation.

Primary Outputs

The following curves are the primary interpretations made in this module:

Screenshot showing the 1D Geomechcanical Earth Model module in a cpi file.

Discussion

This module is used to investigate wellbore stability and to help identify potential problem intervals. In order to effectively use this module the user should have already utilized the Geomechanics, Synthetic Shear (if a measured shear sonic is not available), and Pore Pressure modules.

In conducting the interpretation it is important to pay attention to the lithology as many of the correlations are specific to certain rock types. For methods that utilize a conversion to a static Youngs modulus it is also important to select methods applicable for the stress regime.

Minimum horizontal stress can be calculated via four methods and maximum horizontal stress by three methods.

In order to take full advantage of the visualizations it is importan to import your mudweight data as this will allow a visual inspection of where the pore-pressure exceeds the mudweight (blowout hazard) and where mudweight exceeds the horizontal stress, which can cause compressive or tensile failures.