Little Things, Big Effect-Identifying Causes and Addressing Vibrations Issues in Challenging Deepwater Applications

Abstract

As performance dysfunctions 1 , Vibrations 2 have drastic consequences on drilling operations. The challenges presented by vibrations get amplified on deepwater drilling programs. Vibrations cause downhole tool failures, thereby forcing multiple bottomhole assembly (BHA) trips. In some instances, connections become over-torqued and cannot be broken out on rigs. This situation creates logistical problems for service partners and operators alike (due to the requirement to have multiple back-ups for various tools), and with huge implications on project costs. Vibrations also create drilling inefficiencies with regards to borehole verticality and directional performance. Considering the total measured depths (TD) on deepwater projects, borehole verticality is usually a critical operational requirement. In other instances, the need to achieve specific wellbore trajectory requirements directionally based on project specifics also becomes critical. As a result, rotary steerable systems (RSS) are commonly used on these projects. However, and as documented extensively, vibrations compromise achievement of these goals even when RSS tools are used. Additionally, vibrations have negative effects on rate of penetration (ROP). This is why vibrations control continues to preoccupy the industry, particularly on deepwater projects. Considering the complexities associated with these projects and their much higher rig and spread rates, vibrations control is critical for project success.