Step Change Improvement and High Rate Learning are Delivered by Targeting Technical Limits on Sub-Sea Wells

Abstract

Step Change Improvement and High Rate Learning are Delivered by Targeting Technical Limits on Sub-Sea Wells. SPE Members Abstract This paper presents an alternative approach to the drilling and sub-sea completion process, the Technical Limit, which has resulted in a "Step Change" in Woodside's performance. Using a simple philosophy characterised by the questions:–Where are we now?–What is possible?–How do we get there? and applying this tool, three new wells and six subsea completions were completed 20% under budget. Our target was to drill a directional well in 20 days when the previous best was 42 days. On subsea completions a target of 12 days was set when a conventional approach had previously set 20+ days. The approach was to ask what would be possible if everything went perfectly with every operation making up the well time. This isn't the usual trouble free time but a well time built up of individual components, with each component performing it's theoretical best performance. Presented is operational data which confirms that the Technical Limit can be approached. As a result the well construction performance when managed against the Technical Limit delivered step change performance improvement with high rate of learning. Introduction Woodside's drilling performance offshore on the North West Shelf of Australia from 1968 to 1992 was erratic. A simple plot of time versus total depth (Figure 1), showed unacceptable scatter and a high average drilling time, particularly when benchmarked against published data (Noerager et al). The authors believed the well construction process was not in control. When faced with an upcoming development project (Wanaea and Cossack developments) we undertook to remedy this. To get the desired performance an aggressive target setting and planning methodology was developed based on the question "What is possible?" rather than the question "How can we improve?" Our approach was greatly influenced by achievements in other parts of the world. During the late 70s/early 80s, as documented by Shute et al, Conoco UK Ltd set some drilling operations standards in the North Sea which in our opinion endure today as world class. A major factor claimed in the success of this work came from time analysis which rigorously pursued the identification and removal of drilling problems. The application of this approach was extremely successful. Work by Huber et al also in the North Sea, took a similar approach which, likewise produced excellent results. Latterly Unocal in Thailand have apparently been setting standards in the Far East few can match. Unfortunately, Unocal has published very little on how this high level performance has been achieved. We understand that necessity and aggression drove their improvements. The high level objective for the Wanaea and Cossack projects the requirement for highly productive wells and low construction cost. P. 299

Borehole-Quality Design and Practices To Maximize Drill-Rate Performance

“…This is seen in important early work such as the process used by the industry to optimize hydraulics (Lummus 1970) and later in the "technical limit" workflow in the late 1990s (Bond et al 1996) and the operator's "limiter redesign" workflow implemented in 2005 Dupriest 2006). Each reflects the intuitive process through which progress is made in any endeavor, which is to identify an issue, make changes to address it, and then repeat the process on the basis of the results.…”

“…The industry has traditionally used objective-based mechanisms such as target wells, well budgets, elimination of nonproductive time (NPT) (Kadaster et al 1992), or calculated technical-performance limits (Bond et al 1996) to move the organization toward a desired endpoint. In this continuous improvement, workflow limiters are identified and extended without a targeted endpoint, or regard of the actual performance achieved (Walton 1988).…”