DEVICE FOR ISOLATING PROBLEMATIC ZONES BY PROFILE SHUTTER WITH CYLINDRICAL SECTIONS AT WELL DRILLING Russian patent published in 2017 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: device includes a profile shutter, at its end a shoe with a check valve seat and a catcher at the top, an expansion head consisting of several sections mounted one above the other with working surfaces diminishing towards the shutter and comprising on top a connection unit with the string of pipes, and at the bottom - a locking mechanism connected to the upper shutter end, with the lower mandrel and the catching head below for the shoe catcher. The upper shutter end is made in the form of a longitudinally corrugated pipe. The locking mechanism above the shutter is connected to a special mandrel of a guide rail, on which the inner mandrel is placed in the cylindrical shutter part. The special mandrel is made in the form of a cone widening from the bottom to the top, and the guide is made in the form of a cylinder on which the inner mandrel is tightly seated, with the possibility of moving upwards under the pressure inside the shutter during the installation prior to interaction with the special mandrel. Inside the locking mechanism there is a transverse partition with two longitudinal channels, one of which is made with a diameter that allows to pass the selected flow rate of a liquid for direct washing of the shutter, and the second one is provided with a tightly seated ball of the shoe check valve. The ball is made with the possibility to be squeezed out of the second channel, when the selected pressure difference is exceeded, above and below the partition and sealed into the shoe seat, on which the latch is mounted by means of shear elements for emergency disconnection of the shoe from the shutter using the catching head and the catcher.

EFFECT: increasing reliability, ensuring the possibility to flush the well.

5 dwg