METHOD OF SEALING HEAD OF ROTATING LINER IN WELL Russian patent published in 2024 - IPC E21B33/14 E21B23/06 E21B43/10 

FIELD: mining.

SUBSTANCE: invention relates to a method for sealing the head of a rotating liner in a well. Method involves connection of the lower part of the housing of the device with a detachable device through the upper part of the housing of the device to the lower end of the transportation string of drill pipes. Method also includes lowering into the well to a given depth of a liner equipped with a detachable device with an upper part equipped with through slots, and a lower part equipped with external projections, with possibility of their combination with through slots of the upper part. Method also involves pumping of the estimated volume of the grouting mortar into the transportation string of drill pipes. Also, the method includes starting from the wellhead after the last portion of the grouting mortar of a displacement plug and its squeezing with a displacement fluid until it is fixed in the mounting seat of the block of conical cuffs. Method also involves creating excess pressure with further shear of screws and movement of the suspended cementing plug in the assembly with the unit of conical cuffs under the action of increased pressure down to the stop ring and receiving a signal on completion of the cementing process, disconnection of the transportation string of drilling pipes and flushing of excess grouting mortar with flushing fluid. After washing out excess grouting mortar, well fluid is replaced with water-swellable packer – WSP – activation fluid, upper part of uncoupling device is removed at wellhead, WSP is lowered into well, having slots in its lower part with possibility of their combination with external protrusions of lower part of uncoupling device. Length of packer part WSP is selected depending on pressure drop in well. With increasing pressure, the length of the packer part increases. WSP is connected to the drilling pipe transportation string through a coupling having a left-hand thread in its lower part, after alignment of WSP slots and external protrusions of lower part of housing of uncoupling device, transportation string of drilling pipes together with coupling is turned to the right until complete uncoupling from WSP with subsequent extraction of the transportation string of drilling pipes to the surface of the earth. Well is left to wait for cement hardening and reaction of the activation fluid with WSP until complete swelling of the WSP packer part and tight shutoff of the annular space on the liner head.

EFFECT: creation of effective method of sealing of annular space on head of rotating liner after cementing, which allows its use in wide range of pressure drop.

1 cl, 7 dwg