Successful Sidetrack in Challenging Formation Resulted in CAPEX Reduction

Abstract

Abstract This paper discusses the added value of a new approach to exiting an existing wellbore, where the normal practice forces the plug and abandonment (P&A) of the existing lateral before cutting the window into a new lateral, particularly when an off-bottom cemented (OBC) liner is required. The new approach includes the construction of a Technology Advancement of Multilaterals Level 4 (TAML 4) junction to maintain well integrity and the successful development of a re-entry window that allows access to both the existing and the new slim wells. Not only has this technique unlocked massive potential, but it has also led to an enhancement in the utility and reduction in capital expenditure (CAPEX). The successful Level 4 sidetrack and re-entry window deployment is directly related to the robust system design. The application developed includes an anchor with a guide and high-torque capability, a TAML Level 4 junction created in a shape that will lead to smooth, repeatable access in the future, and a customized re-entry window system to further maximize the well potential. The true value is in allowing access to both the existing and the newly drilled lateral without using a rig or decompleting the well. Such operations use tubing exit whipstock (TEW) and pressure isolation sleeves, both of which can be run and retrieved in a rigless manner. The rigless access has allowed the existing lateral to be used as an observation well. Using permanent downhole gauges (PDHGs) enables real-time monitoring of the pressure and temperature and periodic logging to evaluate the reservoir. The newly drilled lateral can be the primary producing lateral; rigless access equally helps recover the well in case of any production challenges. The newly designed multilateral is a game changer for both mature and new developments because it maximizes reservoir production and helps reduce CAPEX by requiring fewer wells to be drilled. The improved well integrity minimizes well workover operations, which creates cost savings. This paper discusses the following aspects:A successful Level 4 junction construction from a slim re-entry existing/mature well.Repeatable accessibility to the lateral and motherbore.Meeting the motherbore objective as required.Delivering an OBC lateral liner and maintaining the well integrity.