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This paper describes the ongoing development of a new lateral reentry system that provides access to all levels of multilateral wells. The inability to selectively enter Level 1 and 2 lateral extensions (classifications of the Technical Advancement of Multilateral wells, TAML) has traditionally limited rig-based and rig less coiled tubing operations in these wells. Although coiled tubing as a means to work in live wells offers distinct advantages in the late stages of well construction, until recently no reliable coiled tubing reentry technique was available. The new system design includes a reentry bottomhole assembly (BHA), which consists of a surface-controlled orienting tool and a controllable bent sub. The system identifies the window of the selected lateral before attempting reentry, and confirmation of successful identification and entry is visible at surface through a software-displayed pressure log. The technique does not require a wired coiled tubing string; the corrosion-resistant reentry tool is operated solely on flow and is conveyed with standard coiled tubing equipment. Field examples are presented that demonstrate the success of this system in reentering a designated lateral on the first attempt for operations such as matrix stimulation and openhole formation wash treatments. Current developments that enlarge the scope of applications to wellbore logging are also described. With the introduction of a new reentry technique, operations such as openhole formation washes, selective matrix stimulation, production logs and nitrogen kickoff operations can be performed on coiled tubing in live, flowing multilateral wells. The ability to access all levels of multilateral wells with coiled tubing adds a new planning and contingency option to the operator's and driller's decision matrix for the drilling and completion phase. |
