METHOD AND DEVICE FOR WELL SHAFT CLEANING FROM PLUGS Russian patent published in 2020 - IPC E21B37/00 

FIELD: oil and gas industry.

SUBSTANCE: group of inventions relates to oil and gas industry, namely to methods and devices for cleaning of the well shaft, including horizontal ones. Proposed method comprises lowering of case with destructing head with downhole motor to the well on the non-rotating string, which provides, during pumping of flushing liquid through drilling pipes with creation of definite pressure drop rotation of destructing head at breakage of plug. Crushing head is equipped with a central water jet channel. Pressure drop for engine pulse rotation is due to reciprocal movement of downhole motor in the form of striker, which is created at thrust of destructing head on destructed rock and partial overlapping of jetting channel. Housing from above is equipped with annular chamber interconnected with external space. Crushing head is inserted inside the housing with possibility of rotation and from above on end along perimeter is equipped with inclined on one side sampling. Thrust is pressed from above by the spring inserted into the annular chamber to the end face of the cutting head of the hollow striker. Stop upper part is tightly inserted into the annular chamber. At the lower end of the hammer there are ledges for cutting head slots inclined on one side along the perimeter. To move up the striker between the inner annular narrowing of the body and the above annular shoulder of the striker, there is an annular hydraulic chamber communicated with the inner cavity of the striker. Housing above the chamber is equipped with radial holes made with possibility to communicate with the chamber when the striker is moving upwards. On external surface of annular ledge of hammer there is an annular shaped groove made of symmetric upper and lower alternating grooves connected in series by inclined grooves through its side wall. In opposite upper grooves are inserted paired symmetrical supports of housing with possibility of successive movement.

EFFECT: enabling passage of loose plugs due to jetting action, and dense sections of plugs by means of mechanical action, without wasting energy during erosion of plug on rotation of destructing head, and in case of mechanical destruction for waterjet exposure, and in automatic mode.

1 cl, 2 dwg