Connecting assembly of SK type is applied in tool assemblies when performing works using coil tubing (CT) in tubing strings with a diameter of 73÷89 mm.
CA connecting assembly consists of the four units:
I – circulation diaphragm valve is designed to provide fluid circulation when pulling the downhole equipment as well as for emergency depressurization in CT, if necessary.
II – emergency disconnector is designed to release CT from the downhole equipment or object being pulled if the force generated by the injector is insufficient for releasing of stuck pipes.
III – back-pressure clappet valve is designed to prevent reverse fluid flowing in CT.
IV – connecting crossover is designed to connect CT with connecting assembly. Connecting assembly set may also include a matrix of MGT 38 type designed to prepare CT for connection with SK–54 case.
The connecting assemblies manufactured have 45 and 54 mm nominal diameters.
Basic parameters and dimensions:
|Rated string size, tubing string, mm||60; 73; 89||73; 89|
|Coil tubing nominal diameter, mm||38.1|
|Working pressure, MPa||10|
|Shear pressure of pins after positioning the ball in the seat of the disconnected section or circulation valve seat, MPa, not greater than||15|
|Diaphragm fracture pressure (unit I), MPa, not greater than:
– inner choke No. 1 (with one screwdriver slot) o11 mm
– inner choke No. 2 (with two screwdriver slots) o10.5 mm
|Bore minimum diameter, mm, not less than||12||15|
|Connecting assembly length, mm, not greater than||1,015||1,210|
|Outer diameter, mm||45||54|
|Weight, kg, not greater than||10||13.8|
|Working fluid||Drilling fluid, oil, water|
|Fluid temperature, °С, not greater than||100|
|Connecting thread dimensions as per GOST 24705-81, 8724-81, 9150-81||М х 42||М х 42|