Smart Snake Wells in Champion West—Expected and Unexpected Benefits From Smart Completions

Abstract

Abstract Snake wells are laterally weaving ("snaking") extended reach horizontal wells that drain a number of vertically stacked, structurally dipping reservoirs. This creates multiple drainage points in each sand and effectively achieves a similar drainage pattern to a multilateral well at a fraction of the cost and technical complexity. The wells are completed with multiple hydraulically controlled interval control valves (ICV) and external casing packers or swellable packers. In addition, the completion includes permanent downhole gauges (PDHG) and distributed temperature sensing (DTS). Seven of these smart snake wells have been successfully drilled in Champion West as of April 2006 and three more are planned during the remainder of 2006. The well design not only facilitates initial clean-up, but is used for reservoir management purposes and to manage gas and water breakthrough. Throughout the well life, variable ICVs are used to achieve equal drawdown along the well bore, leading to a significant increase in reserves by delaying gas breakthrough. In addition, some unexpected benefits materialized from the use of smart completions: In one case, the smart completion enabled the clean-up of the initially uncompleted toe, significantly increasing total recovery from the well. In another case, the smart completion mitigated the risk from a potentially bad cement job, saving a cement repair job or, more likely, a sidetrack. In another well the flexibility of the design enabled the effective shutoff of water bearing zones that were drilled because of slight departures from the planned well trajectory. Through modification of the planned segmentation an expensive re-drill was avoided. The smart snake wells have thus been a key enabler for the economic development of the Champion West field and we expect they will continue to add further value over the lifetime of the wells.