METHOD OF SECONDARY DRILLING OF PRODUCTIVE FORMATIONS Russian patent published in 2015 - IPC E21B43/11 

FIELD: oil and gas industry.

SUBSTANCE: method includes transportation of the rock-drilling machine into a well bottomhole, its fixing, perforation of walls of a casing string, unfixing of the rock-drilling machine and its lifting to the surface. The rock-drilling machine transported into the perforation zone with tubing, before fixing it is aligned by rotation of the tubing string so that at the initial stage of formation oil production the working bodies of the rock-drilling machine to arrange in the vertical plane towards the top of productive formation. Then, as the inactive hydrocarbons the near top zone of productive formation are being exhausted, the perforated zones in bottomhole part of the casing string are blocked by means of the permanent packer, the rock-drilling machine is transported into the bottomhole zone interfaced to the packed section, the rock-drilling machine is oriented by rotation of the tubing string so that at the subsequent stage of the formation oil production the working bodies of the rock-drilling machine to be in the horizontal plane of the productive formation, providing an arrangement of the perforated channels in the area characterised by presence of more mobile hydrocarbons. When performing operations of aligning of working bodies of the rock-drilling machine the angle of position of working bodies of the rock-drilling machine is monitored in the plane, perpendicular to longitudinal axis of the well.

EFFECT: increase of coefficient of oil recovery by orienting of working bodies of the rock-drilling machine in the vertical and horizontal planes.

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