METHOD FOR ISOLATION OF WELL DRILLING PROBLEM AREAS AND DEVICE FOR ITS REALISATION Russian patent published in 2009 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: group of inventions is related to drilling and overhaul of wells, in particular, to methods for isolation of drilling problem zones by profile shutters. Method comprises lowering of shutter in problem zone, expansion of profile sections by pulling of hydraulic pressure, expanding of cylindrical sections with threaded joints and calibration of profile sections by mandrelling. All subsequent cylindrical sections prior to expanding are isolated from already expanded by means of their mechanical blockade from effect of force produced by expanding of the next ones, in particular, by means of anchor devices rigidly fixed to each other and mounting equipment inside shutter on both sides from expanded threaded joint. Device comprises mandrelling head of several sections installed stepwise with mandrelling elements that reduce in diameter in direction of expanding, shoe with check valve installed in bottom end of shutter, rigidly fixed to each other gripping element, anchor unit and unit of connection to drill pipes, additional anchor unit and hydraulic jack that contains hollow hydraulic cylinders and hollow stem that is coaxially movable relative to them with annular pistons, being rigidly fixed by its upper end to anchor unit, and by its lower end - to griping element, cavities of which are hydraulically communicated to each other and to shutter cavity. Gripping element is provided with support for shutter suspension and is equipped by relief valve that covers stem cavity in case of its displacement downwards relative to shutter. Additional unit is installed at the lower end of stem. Mandrelling head is rigidly fixed to hydraulic cylinders and is arranged from single hydraulic section and at least one mechanical one.

EFFECT: improvement of isolation reliability.

2 cl, 5 dwg