Development of remotely operated adjustable stabilizer to improve drilling efficiency

In the application of conventional stabilizers, changes in the bottom-hole assemblies (BHA) are realized by tripping the drillstring out of the wellbore to add or remove stabilizers to or from the drillstring on the ground surface. However, an adjustable stabilizer can be controlled to generate different types of BHA without needing to trip out the wellbore. In this paper, an adjustable stabilizer considering two different diameters is developed, wherein each situation is controlled by opening and stopping the drilling mud pump. A new remotely operated adjustable stabilizer to improve the drilling efficiency is presented. Firstly, a mechanism for the adjustable stabilizer to control the borehole trajectory is provided based on a theoretical derivation. Secondly, the structure of the adjustable stabilizer is presented followed by its operating principle. Thirdly, key components of the adjustable stabilizer are verified through numerical simulations. The results of the simulations show the stresses of the key components and pressure conditions of the fluid channel. For the extreme condition, the maximum stress of all the components is 184.9 MPa and the maximum pressure loss is about 1.0 MPa. Finally, the results of laboratory experiments are shown to verify the structure design and numerical simulations. The results of the laboratory experiments show that the adjustable stabilizer works well with a pressure difference in the drilling fluid in and out of the stabilizer above 3.21 MPa and that different operational conditions can be realized.