DOI: https://dx.doi.org/10.24866/2227-6858/2019-3-9

Ignatovich V., Kuzmina A.

VLADILEN IGNATOVICH, Candidate of Engineering Science, Associate Professor, e-mail: v.s.ignatovich@mail.ru
ANNА KUZMINA, Senior Teacher, Graduate Chair, e-mail: a.61kuzmina@mail.ru
Department of Ocean Technology and Shipbuilding
Sevastopol State University
33 University St., Sevastopol, Russia, 299053

Analysis of factors affecting the strength and environmental
operational safety of floating drilling rigs

Abstract: In this paper the authors analyze possible factors of structural strength failure of the self-elevating floating drilling rigs, as well as ensuring the safety of their operation under conditions not provided for by the calculations. The methods of calculating the loads under the operating mode of a self-elevating floating drilling rig were considered, the calculated bearing capacity was determined, as well as the shear stability of the structure in the working position. The shear condition was verified by comparing the load and the ultimate bearing capacity. The obtained results allow choosing the method of calculation depending on the place and operation conditions of a self-elevating floating drilling rig. The support columns turned out to be the most critical and loaded structures in all modes of operation.
Analysis of the loads acting on the structure shows that lowering of the support columns leads to a proportional decrease in the bending moment in the supporting section of the column in the body of the self-elevating floating drilling rig. The strength analysis of the most loaded supports of drilling rigs in all modes of operation was performed. The most dangerous mode for support columns is the storm sludge under the influence of the maximum possible external loads. Lowering the columns into the water by 1/4–1/3 of the support length does not reduce the heave parameters of the structure. However, it allows reducing stresses in the structural elements of the supports. The maximum stresses when pulling out supports from the ground are about half of the stresses in case of storm sludge, which is completely acceptable and does not affect the safety of the structure.
Keywords: drilling rig, damage, strength, shear, support columns, leg pulling, storm holding anchorage, multifaceted approach.

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