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In the formation of the well under the influence of an axial load and speed core drilling shell is curved, with its lower bottomhole part consists of elements of different stiffness: a set of core and drill pipe. The researches allowed to formulate a number of conclusions. To determine the length of the half-wave in this part of the technological tools used energy method, according to which the whole work of external forces on the length of said potential energy goes into twisted drill. The half-wave length decrea...

A mechanism of core blocking that is drilled out during the coring from deep wells in the direct and indirect flushing with drilling mud is examined. Using methods of technical mechanics and hydromechanics, a formula for flow rate excluding a core blocking is obtained during the backwashing. The value of necessary flow rate depends on not only a direction and intensity of fracturing of rocks, geometrical and density parameters of core pieces, but also on structural strength of drilling mud. A mechanism of core sel...