Development of an adjustable stabilizer for controlling the borehole trajectory

Abstract

During the drilling process, many types of bottom-hole assembly are used to adjust the well inclination and azimuth. For the drilling of inclined wells or horizontal wells, it has to face problems of repeated round trips so as to control the borehole trajectory. Such problems lead to the increase in non-productive time and the drilling cost. In order to address this issue, the idea of generating different types of bottom-hole assembly without round trips of drill-string was formed. In this paper, an adjustable stabilizer has been developed to avoid repeated round trips of the drill-string. Firstly, the mechanism of adjustable stabilizer controlling the borehole trajectory is presented. Secondly, the structure and operating principle of the adjustable stabilizer are described. Thirdly, numerical verifications of the key components of the adjustable stabilizer are conducted. Finally, laboratory tests and field tests are carried out to examine the design. Results of the numerical simulations and the laboratory and field tests show that the adjustable stabilizer operates normally and three phases of the radial pistons can be reached through regulating the flow of the drilling fluid. In addition, the pressure differences for starting the phases are measured.