A Novel Drillstring Dynamics Experimental Setup to Be Integrated Into Hardware in the Loop Capable Drilling Simulators

One of the limiting factors for maximizing drilling performance is drillstring vibration/dynamics. With the development of in-bit, at bit or near bit vibration monitoring sensors, it has been reported that while drilling with PDC bits in hard formations, stick-slip is mostly observed before other types of vibration. Commonly, stick slip is a mathematical problem that can be resolved using various technics (like analytical, numerical, etc.). To compliment this theoretical effort, experimental measurements are required to verify mathematical models under controlled conditions and assess their range of applicability. This is why a large number of laboratory setups around the world exist. A comprehensive literature research has shown that most of the known experimental setups are smaller than 10 m length and focused mainly on vertical wells. Building a setup that reproduces real hydrocarbon wells, including the drill string inertia and the delayed response between bit and surface, as well as the complex friction transfer process taking place between the wellbore and the drillstring, is not feasible. Thus, downscaling the typical drillstring parameters is necessary for the study of vibrations and vibration suppression at laboratory conditions. Vibration suppression modeling and validation require a particular, dedicated laboratory setup. The design of such an installation will be presented in the following paper. The newly proposed experimental setup will exceed all existing stick-slip or lateral vibration experimental setups on the market by size, while adding new features like axial movement (mimicking ROP or heave compensation) and curved sections. This new facility will be the first to integrate the hardware in the loop capabilities and can be connected with any drilling simulator that supports such an option. This design will account not only for torsional vibrations, but will also allow the string to move axially while RPM, WOB and flow rates may be directly linked to a drilling simulator. Because of its design, to resemble medium to small radius of curvature, the stick slip process can be captured and highlighted for a wide range of directional well situations. Once the range in operating conditions was defined, the equipment and mechanical components for the facility were selected and designed. The new facility will significantly improve our ability to reproduce the physics of drill string vibrations and will lead to better optimization of downhole vibration suppression. The incorporated link to drilling simulators can improve the development of the next generation of vibration suppressing models and hardware.