Rotary Steerable Tool Damage Prevention by Utilization of an Asymmetric Vibration Damping Tool

Abstract

Slick-slip (SS) and lateral shocks are harmful to many expensive downhole tools such as rotary steerable systems, and downhole measurement and logging tools. Due to this concern, an asymmetric vibration damping device has been engineered to reduce these specified vibrational modes. This tool is uniquely specialized that, when placed and ran with the recommended drilling parameters, reduces stick-slip tendencies as well as dampen lateral shocks by placing the drill string near the tool in Forward Synchronous Whirl (FSW). As a result of placing the BHA (bottom hole assembly) into FSW, other harmful vibrational modes such as chaotic whirl and backward whirl are prevented from occurring. Stemming from the exclusive geometry of the tool, the tool will interrupt harmonic modes during rotation that can lead to harmful shocks and SS. Extensive research has been performed in laboratory and field testing using the vibration damping tool, and its success has been proven in multiple deep water applications (primarily with hole opening BHA's), but also on land with bi-center bits. Recently, a new approach was undertaken, utilizing two vibration damping tools in a single BHA. This was intended to control vibrations and reduce shocks that were causing extensive damage to Rotary Steerable System (RSS) horizontal applications in North America. The initial trial wells used the dual placement within the vertical and horizontal sections, drilling into the Cotton Valley formation in North Louisiana. These applications have historically seen very high vibration levels due to both the trajectory and challenging formations.