Drilling for the Next Generation of Multilateral Completion Systems

Abstract

The objective of drilling a well is to accommodate the completion string designed to optimize reservoir production. Streamlining a completion design for a mature field maximizes the chances of achieving the well objective with minimal drilling challenges. Therefore, introducing a new completion technology requires reevaluating the drilling procedures and practices to accommodate for the modified completion, and this is more true when running new completion designs into the open hole as opposed to cased hole completions. The Saudi Aramco drilling team were faced with the challenge of executing a multi-lateral well plan that will allow for running three open hole completions that will segment the open hole laterals and provide active control and monitoring capabilities for each segment. Such a completion requires a complex power and telemetry system that can energize all the segmented lateral completions including the ones that are deployed through the windows. The open hole laterals must be conditioned properly to successfully run the completion components in the open hole without restriction, and land the completions at the pre-planned target depths. The main power supply and telemetry conduit between the upper completion and the open hole completions is a cable cemented behind the 7 in. liner. This presented several challenges such as running and cementing the liner and milling the windows without intersecting the cable, which would jeopardize the success of the entire completion. The team addressed the challenges by developing procedures to properly execute the mentioned operations while maintaining the integrity of the power system and land the completions at depth. This was confirmed by conducting tests at various stages throughout the implementation process. An integrated project such as this requires focused collaboration between the drilling and completion teams because the traditional practice is to drill to total depth then complete the well, although this unique completion design requires a drill-complete-drill-complete sequence as the well progresses. In addition to highlighting the key factors in managing and implementing such a well construction project where various disciplines are interdependent and require continuous coordination, the paper will summarize the modifications applied to the drilling procedures to achieve the objective of the subject well. The emphasis will mainly be on three operations: Under-reaming while drilling the 8-1/2 x 9 in. hole section, hole preparation prior to running the open hole completion, and the implementation of a unique cable avoidance procedure during conventional window milling operations.