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Date submitted2018-01-15
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Date accepted2018-03-24
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Date published2018-06-22
Designing of well trajectory for efficient drilling by rotary controlled systems
- Authors:
- M. V. Dvoinikov
The main directions of increasing the efficiency of drilling wells by improving methods for designing profiles of directional and horizontal wells are identified. The feasibility and necessity of using at drilling with rotary controlled systems the trajectories of directed wells' profiles with continuous curving, that do not contain conjugated sections, on the basis of plane transcendental curves are theoretically substantiated and experimentally confirmed. An algorithm and software are developed that allow optimal selection of a profile or a trajectory section, taking into account minimization of twisting, bending, compressive and tensile stresses that ensure the efficiency of technical and technological parameters of well drilling.
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Date submitted2016-09-01
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Date accepted2016-11-05
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Date published2017-02-22
Research on technical and technological parameters of inclined drilling
- Authors:
- M. V. Dvoinikov
An analysis of operational capabilities of inclined drilling equipment and technology is presented. Two options of rotary drilling are reviewed as technical and technological solutions, facilitating construction of wells with difficult profiles. The first option implies that the driver unit of the drill bit is represented by downhole drilling motor, the second one utilizes sophisticated rotary steerable systems. Practical results of drilling wells with difficult profiles are presented. A quality assessment of drilling is provided through the example of comparing designed and actual trajectories, using different driver units for the drill bit, as well as properties of surrounding rocks, rheology of the drill fluid and other characteristics of dynamically active systems. A range of rotation speed has been determined that allows rotary steerable systems to have minimal oscillation amplitude of the bottom-hole assembly. Analysis of investigation results showed that the main source of oscillations is linked to bending and compressing stresses, caused by well deviations as well as rigidity of the drilling tool. In effect, in the bottom-hole assembly occur auto-oscillations, making it impossible to correct azimuth and zenith angles. Alteration of rigidity in the bottom part of the tool and drilling parameters, implying reduced rotation speed of the drill string and regulation of drill bit pressure, can partially solve this problem, though increase in rotation speed is limited by technical characteristics of existing top drive systems.