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Browsing by Subject "wellbore stability"

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  • thumbnail.journal.alt
    Item type:Article, Access status: Open Access ,
    Influence of drilling direction on wellbore stresses
    (2011) Knez, Dariusz; Megao, Eddie; Knez, Janusz; Śliwa, Tomasz
    The transposed in-situ stress state relative to the borehole coordinate system (Cartesian borehole coordinate system) and the total stress component at the borehole wall (cylindrical coordinate system) exhibits cyclic behaviour with respect to drilling direction of borehole with respect to delta/H, Beta. On the other hand, with varying borehole inclination, a, the stress either increases or decreases with increasing a angles. Consequently the effective maximum, delta1 and average, delta2 principal stresses exhibits the same behaviour. It can be concluded generally that the effective principal stress state of a wellbore would vary in a cyclic behaviour and would have a maximum and minimum stress points. From these observations, it is obvious that in any situation, optimal combinations of alpha and Beta will have to be established before drilling is commenced in order to optimise stability of the borehole.