5mm well as example to study the design approach of inverted pendulum drill assembly and provide the basis for Inverted pendulum drill assembly optimized design.

This paper makes a calculation of bit side force to the flexible pendulum stem and pendulum stem on the basis of vertial and horizontal bending theory, which, theoretically, shows that flexible pendulum stem has a better inclination correction effect than pendulum stem.

Experimental study on longitudinal vibration characteristics of pendulum assembly in straight hole;

According to hole straightening technique in drilling straight wells and sidetracking technique in drilling directional well,this paper proposes 3 lateral drilling methods in open holes,which are sidetracking by pendulum assembly,sidetracking by milling fish and sidetracking by downhole assembly.

Pendulum assembly is a kind of BHA for hole straightening, which is applied widely in drilling practice.

This paper makes a calculation of bit side force to the flexible pendulum stem and pendulum stem on the basis of vertial and horizontal bending theory, which, theoretically, shows that flexible pendulum stem has a better inclination correction effect than pendulum stem.

It was hard to control well path while drilling by using conventional pendulum assembly with single stabilizer.