Extreme-line casing pipe N-S.*BM flush-joint high-hermetic

Purpose

Casing pipes are used for borehole wall lining after drilling, overlapping and isolating oil-, gas- and water-bearing formations and interlayers from each other.

Field of application

The N-D.*BM threaded connection has flush-joint of inside and outside pipe diameters, which allows reducing the string diameter and therefore its weight due to the reduction of the final borehole diameter, a rational combination of casing string and bore bit diameters.

To improve performance characteristics, the threaded joint uses additional tapered surfaces that on interference fit create a metalto-metal seal, which provides a high tightness.

When making up the connection, the thrust ends of the pin and flared pipe ends come into contact with each other, creating high contac pressures on the thrust surfaces, which further contributes to the tightness of the connection.

Advantages of a streamlined threaded joint

• High tightness of the joint and higher tensile strength compared to the triangular profile thread.
• Low cost of the pipe string due to the absence of couplings.
• Flush joint.
• Additional sealing barrier.