1. Introduction

The lost circulation sub is a brand  product designed and manufactured by Orient Energy & Technologies Co., Ltd. through controlling loss circulation of mud flow during drilling. By utilizing the elastic deformation of rubber, the sub can allow valve core to make reciprocating motion via different pressure so as to achieve loss circulation mud injection without pulling out of hole. It is an excluded tool for loss circulation control so as to simplify the process of loss circulation control and then to reduce drilling cost substantially.

2. Function of Loss Circulation Sub

In the process of drilling, the side holes of loss circulation sub are used to realize loss circulation control without drilling down again when the loss circulation occurs. Thus, it will reduce the time of round trip of drilling to enhance the economic benefit.

3. Operation Principle of Loss Circulation Sub

By utilizing the elastic deformation of rubber, the loss circulation sub will force valve core to make downward motion through pressure change when rubber ball is thrown in to the sub. Then the loss circulation mud hole opens and releases loss circulation mud.

4. Parameter Table