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Calculation of elastoviscoplastic displacement of well walls in transversal and isotropic rocks

Записки Горного института
Фото © Форпост Северо-Запад / Андрей Кучеренко

OIL AND GAS ENGINEERING

Azat G. Gubaidullin, Candidate of Engineering Sciences, Assistant Lecturer, Ufa State Oil Technical University, Ufa, Republic of Bashkortostan, Russia;

Alexander I. Moguchev, Candidate of Engineering Sciences, Associate Professor, Ufa State Oil Technical University, Ufa, Republic of Bashkortostan, Russia.

Abstract

The relevance of the work is justified by the need to improve the technical and economic indicators of well construction based on forecasting and preventing drilling tools sticking due to the narrowing of an open well bore in the intervals of transversely isotropic rocks.

A mathematical model of elastic-viscous-plastic displacement of the walls of inclined and horizontal wells has been developed during the narrowing of the open borehole due to rock creep in the intervals of transversely isotropic rocks. In the program developed based on this mathematical model, the calculation of the elastic-viscous-plastic displacement of the walls of an obliquely directed and horizontal well in the reservoir of argillite from the Western Siberia deposit was carried out. As a result of the calculation, it was established that after opening the rock with bits, the cross-section of the open borehole due to the rock creep eventually takes the form of an ellipse, the small axis of
which is in the plane of the upper wall of the well and decreases with time.

Key words: bit sticking; instability of the walls of the wells; open hole narrowing; transversely isotropic rock; elasticviscoplastic movement of the borehole walls.

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Scientifiс periodical «Zapiski Gornogo Instituta / Journal of Mining Institute» has been published since 1907 as a periodical scientific and scientific-educational edition in Saint-Petersburg Mining University. The periodicity of publishing is 6 volumes per year.