Under-Rig-Floor Openhole Logging in the Gulf of Thailand: Operational Implementation of the Oil Industry's First Simultaneous Openhole Wireline Logging and Drilling Operation

Abstract

Summary Chevron Thailand, on average, drills 12,000-ft measured-depth/8,200-ft total vertical depth wells in approximately 4.5 days. The factor that contributes most to this level of performance is the "offlining" of as many drilling-rig activities as possible. In our drilling operation, almost all pipe-handling and cementing operations are performed offline (i.e., off the critical-operations path and therefore simultaneous to other activities on the rig). We have now taken the next logical step in performing offline operations. In May 2007, Chevron Thailand introduced the world's first simultaneous openhole wireline logging and drilling operation on Seadrill RT-7 (a tender-assist drilling rig) and currently is deploying the same system on additional tender-assist rigs (TARs) and jackup rigs. This paper is the second in a series of two that describe the engineering design and operational implementation of the tools and techniques necessary to make offline openhole wireline logging a reality. The first paper (Upchurch and Graves 2008) in this series details the engineering design aspects, and the resultant benefits, of this paradigm-changing logging system. This second paper describes the processes that were used to implement the system, along with the inherent risks and benefits of each phase of the implementation. Implementing radically new processes such as this into pre-existing drilling systems significantly increases the risk for technical failure, well control incidents, and personnel injury. This paper details the processes that were developed for avoiding all three. In the case of this new technology, our phased approach to implementation has resulted in smooth, incident-free introductions to the various rigsites. The benefits of this new system, and our method for implementing it without incident, are paying significant dividends to Chevron Thailand.