Development of the artificial seabed technology and implementation pretrial well in the South China Sea

Abstract

This paper introduces the recent highly significant activity of China Oilfield Services Ltd. (COSL) in the South China Sea, where COSL conducted pretrial drilling in June of 2008. The paper discusses some key research and new practices which led to the fabrication of related equipment which was evaluated in the trial. The market for deepwater drilling in the world has grown over the past 10 years but there are few drilling vessels or platforms suitable for drilling in deepwater or super deepwater. China needs equipment capable of deepwater drilling operations. COSL has some semisubmersible platforms, but they are only considered suitable for operations in water depths less than 475 m. An enabling technology, referred to as an artificial seabed, has been under development by COSL since 2004, and it applies the research results and experiences of many experts in deepwater drilling. COSL hopes this technology will allow drilling to depths of approximately 1 000~1 500 m with its current platforms. The paper presents research progress and improvements in fabrication and necessary upgrades to equipment for extending deepwater drilling. The pretrial well was executed at a water depth of nearly 500 m. COSL will drill the trial well around 2009 at the same location in the South China Sea.

Risk Assessment and Reduction for an Innovative Subsurface Well Completion System

“…As it would take a long time to construct a totally new deep-water semi-submersible, COSL finally decided to utilize proper facilities for improving existing semi-submersibles' drilling capacity at various water depths. Be aware of the attractive technical features of subsurface wells in deep water, COSL has, since June 2004, carried out a series of laboratory tests and sea trials to prove the technical feasibility of the subsurface well for deep-water drilling activities based on the Artificial Seabed Deep-water Drilling system (ASDD system) [7][8][9][10]. Large trial subsurface well operations had been performed in the South China Sea (SCS) in the period of 2008 to 2009 with successful results.…”