Advanced Stress & Failure

The Advanced Stress & Failure strip contains functionality for assessing stress and wellbore stability. Specifically, it was designed to aid you in your analysis of the relationship between in-situ stress and compressive, tensile, and shear failures in vertical and inclined boreholes.

The Advanced Stress & failure strip comprises three sub-strips for constraining in-situ stress and predicting wellbore stability: Constrain Stress, Get Stress and Borehole Stress. These modules let you constrain the complete stress tensor using observation of failure in oriented wellbores.

The Constrain Stress and Get Stress sub-strips are used for stress determination using borehole failures such as wellbore breakouts or drilling-induced tensile fractures or drilling enhanced tensile region. Drilling-induced tensile fractures as well as tensile regions may be detected on acoustic, electrical, or other image logs. Oriented 4-arm (dipmeter) or 6-arm calipers as well as image logs may detect wellbore breakouts. Data from MWD tools that produce lower-resolution oriented images of resistivity, porosity, or density may also be analyzed to provide input information.

The Constrain Stress sub-strip constrains the range of magnitudes of the horizontal stresses from the occurrence of borehole breakouts and/or drilling-induced tensile fractures, using the depth at which the borehole failed and the orientation of the principal horizontal stress, with extensions to model thermal effects.

The Get Stress sub-strip determines the magnitude of the horizontal stresses as well as the azimuth of the maximum horizontal stresses, using information about the orientations of breakouts in deviated wells. You select which sub-strip to use based on the specific data available.

With the Borehole Stress stub-strip you evaluate stress and failure either in the rock surrounding the borehole or at the borehole wall.

All three sub-strips are available in log and depth mode.

Existing data such as principal stresses and mud weight logs, calculated as part of the 1D Model workflow, can be leveraged in this workflow to aid in your assessment. Otherwise, the data necessary for the calculation can be imported via the Data strip. The options available to you depend on the choices you make on the Advanced Mode form in the Setup sub-strip.