Screening Variables for Multilateral Technology

Abstract The multilateral well was one of the leading technologies of 1999, and it will continue to be one of the leading technologies for the next 5-10 years. It is likely that because of the cost reduction driver, management will ask, "Why isn't this a multilateral well?" much like the current justification for horizontal wells. The two challenges in 2000-01, unmet in 1999, will be consistent success of the technology and the low cost multilateral. When evaluating multilateral technology, it is important to understand three things. First, in its simplistic scenario, the only difference between a multilateral well and a sidetrack or redrill is that the original wellbore will remain open when placed on production. The second thing to note is that multilateral technology is a reservoir development technology rather than a drilling technology. The drilling department is simply the vehicle by which this reservoir technology is brought to fruition. And third, all major operating companies will utilize multilateral technology; the question of consequence is ‘when?’. The purpose of this paper is to present the first steps in applying multilateral technology to the operator in a practical way. This paper will cover only one aspect of multilateral technology – screening variables. These screening variables should be viewed as fundamental criteria from which, to begin a multilateral feasibility study. One of the screening variables is the driver for multilateral technology. Since the business driver must be evaluated before any other screening variable, it will be covered first. The remaining variables will be covered according to the order in which they appear in the planning, design, and implementation of a multilateral project. The completion variables will be specified first, followed by reservoir and geological screening variables. Finally, drilling and other general screening variables will be covered. Discussion of the different classifications or levels of multilaterals is taken from the TAML (Technical Advancement of Multilaterals) Classification system (Chambers1, Mackenzie and Hogg2).