Ray Brister, SPE, Chevron Petroleum Technology Company
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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 thedifferent classifications or levels of multilaterals is taken from the TAML (Technical Advancement of Multilaterals) Classification system (Chambers1, Mackenzie and Hogg2). Business Drivers for Multilateral Technology While the following list of business drivers for multilateral technology is not complete, it represents the primary justification for considering the technology application. All multilateralprojects will have a combination of drivers specific to the field application. Cost Reduction This business driver is almost always considered in conjunction with one or more drivers. The purpose of the technology is to reduce CAPEX. The concept of multilateral technology is to incur only the additional cost of rig time, tools, services, and equipment needed to drill and complete an averagedeviated lateral of 300-1500 feet. The costs of mobilization/ demobilization, casing, and drilling to top of zone will essentially be borne by the main wellbore. A typical cost reduction model would have the multilateral well contributing up to twice the production, but only 1.5 times the cost of a monobore completion. Similarly, a trilateral may cost twice the monobore completion, but supply up tothree times the production. Increased Reserves Additional reserves may be isolated lenses of pay or compartmentalized reservoirs. The degree of the compartmentalization will dictate the number of laterals and the wellbore geometry needed to optimally exploit the reservoir. Multilateral technology may also allow access to smaller or marginal reservoirs that, if evaluated as separate drilling projects,would be uneconomic. Accelerated Reserves Drainage optimization is especially important when price per barrel or OPEX is high. Multilaterals implemented under this driver are typically drilled in the same horizontal plane to
Introduction 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 islikely 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...