Extended reach drilling
Extended Reach Drilling (ERD) is directional drilling of very long horizontal wells. The aims of ERD are: a) to reach a larger area from one surface drilling location, and b) to keep a well in a reservoir for a longer distance in order to maximize its productivity and drainage capability.
Early ERD-well definitions related wells to those that exceeded some step-out/vertical-depth ratio (often 2:1). However, for most highly deviated wells in deepwater environments, this definition clearly does not fit. Some methods have evolved to categorize wells according to their stepout within different vertical-depth ranges. ERD wells then can be described conveniently as shallow, intermediate, deep, and ultradeep. Other variants are associated with operating in deep water and high-pressure/high-temperature environments. Currently, there is no generally accepted ERD-well definition.
What exactly determines a well to be "extended reach" varies over time and location with the development of technologies and of experiences.
- On 24 April 2015 the world’s longest borehole was drilled and completed from the Orlan Platform in the Chayvo Field, Sakhalin-1 Project with a total measured depth of 13,500m (44,294ft) and a horizontal displacement of 12,030m (39,469ft)
- The previous world record was drilled and completed 30 March 2014 by the Yastreb land drilling rig in the Chayvo Field, Sakhalin-1 Project to a total measured depth of 13,000m (42,653ft) and a horizontal displacement of 12,130m (39,797ft)
New developments and innovations
New technologies emerge that claims to be pushing the existing boundaries of ERD. One of these is the Reelwell Drilling Method, a drilling method solving problems for challenging wells, particularly suited for long reach wells. This innovation aims at multiplying the distance drilled by conventional ERD methods.
- Kaiser, Mark J (2007-09-13) Indices Describe Complexity of Drilling Directional, Extended-Reach Wells Red Orbit, retrieved October 6, 2008
- Negrao, Alvaro (May 2009) Multilateral or Extended Reach SPE Website, retrieved October 6, 2008, link updated May 1, 2013
- Sakhalin-1 sets new extended reach drilling record, Rosneft says, 2015