Overview

Cost-effective access to remote offshore reserves from fixed platforms or to offshore reserves that exist close to onshore locations often requires the use of extended-reach drilling (ERD) and multilateral technology. The ability to apply this technology routinely in future oil provinces, such as those in remote Arctic locations, will be vital to ensure economic success.

A recent class of wells, termed ultra-ERD, has highlighted technical challenges that require both the nurturing and advancement of technology. Note that an ultra-ERD well can be loosely defined as one that has significantly higher step-out than other wells in the same reservoir horizon. The feasibility of drilling and completing such wells is primarily determined by stepout, vertical depth, and degree of difficulty imposed by the subsurface environment. Currently, the industry is looking to drill its first 12-km-stepout ultra-ERD well.

Current technology development is targeted at increasing reliability of downhole tools, evolving novel methods of reducing equivalent circulating density, and honing techniques that deliver effective and quantifiable torque and drag reduction. One key obstacle is that of reliably proving up prototype technology before its application in the field. In many cases, through necessity, only laboratory tests or limited field trials have been carried out.

Designs for ultra-ERD wells also pose an interesting challenge. One key to success is to identify the most critical operations correctly and build the well design around those operations. In this context, one particular mindset that must be overcome is that of being constrained by standard casing sizes; instead, design the well to be fit for its intended purpose. However, this requirement must be tested against the challenge of long lead times for nonstandard steel products and the likely constraint of having to work with a nonoptimal rig.

While incremental improvements in drilling hardware are undoubtedly occurring, there are clear opportunities for performance gains through real-time analysis, monitoring, diagnostics, and visualization of drilling and casing/completion-running operations. This initiative will require a joint effort by both operators and service providers to identify and meet industry needs.

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Colin Mason, SPE, is a senior drilling engineering specialist with BP’s E&P Technology Group. He has spent more than a decade working on the many facets of ERD operations. Previously, Mason was involved in the application of mathematics to solve engineering problems in the fields of gas transmission and pipeline design. He holds MS and PhD degrees in numerical analysis from Imperial College, London. Mason serves on the SPE Annual Technical Conference and Exhibition Drilling Design and Operations editorial committee and is an SPE Distinguished Lecturer for 2006–07. He also serves on the JPT Editorial Committee.

Overview

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