METHOD FOR CONNECTION AND DISCONNECTION OF PIPES FOR BITUMINOUS OIL EXTRACTION AND DEVICE FOR LASER WELDING AND CUTTING WHEN IMPLEMENTING METHOD Russian patent published in 2017 - IPC E21B43/24 E21B19/00 B23K26/24 

FIELD: oil and gas industry.

SUBSTANCE: method for connecting and disconnecting pipes for bituminous oil extraction involves lowering pipes into well with laser welding junction and lifting pipes with laser cutting per one turn around the junction. At that, the utilised pipes are made of low-carbon steel. The upper edge of pipes is equipped with annular limiters which enable such laser welding and cutting that laser welding and cutting beam is at the pipes joint when rotating around welded or cut pipes when applying to wellhead equipment. When lowering the first pipe to be connected into the well, the pipe is secured by wellhead equipment to prevent axial displacement and turning and the annular limiter prevents it against leaving well. The second pipe is joined end to end to the first pipe. After that, the joint area is covered with laser welding device focusing on the limiter of the first pipe, with the possibility of rotation at a rate that allows high quality and air-tight welding of pipes to be joined. When the laser welding device is rotated for the first time, the joint location is checked. When it is rotated for the second time, the pipes joint is welded by laser followed by welded seam quality control. The pipes are lowered and the second pipe is fixed due to its annular limiter in the wellhead equipment. The pipes welding process is repeated until all welded pipes are lowered in the well. When pipes are removed from the well, the pipe closest to the edge is removed, and the second one is fixed by wellhead equipment to prevent axial displacement and turning and the annular limiter prevents it against leaving well. After that, the joint area is covered with laser cutting device focusing on the limiter of the second pipe, with the possibility of rotation at a rate that enables high quality cutting of the pipes to be joined. The laser cuts the pipes, when the laser cutting device is rotating. The first pipe is sent to the pipe racks, and the second pipe is removed from the well. The next pipe is secured in the wellhead equipment. The pipe cutting process repeats until the required number of pipes is extracted from the well.

EFFECT: increased reliability of the pipe string when injecting heat carrier.

3 cl, 2 dwg