Introduction

Safety joint is divided into H type and AJ type

        H type safety joint, which is installed on the position required for subsurface drill stem and can bear in fishing operation all kinds of loads for pulling or pressing and used to transmit torque, is a subsurface safety equipment. In down hole operation, in case of being needed, the safety joint is easy to be discharged off so as to take out the drill stem above it. It is easy to butt the safety joint to go on fishing operation when running in hole again.

        AJ type safety joint is a specialized joint consisting of two parts. The specialized joint takes protective effect for drilling stem in drilling , repairing and test oil (gas) engineering, etc. It is used to treat well bottom accident and used to be on -the -way test in drilling and coring operation. It is connected to the required position of drilling stem to protect drilling stem without any influence on the normal working of drilling tool.