Multilateral wells are a popular choice for fields where maximum fixed asset utilization is required. Although Drilling and Intervention (Stimulation) techniques for such wells are mature and reliable, reservoir surveillance required novel method for lateral access. Such technology was developed and used in more than 40 wells in Middle East. Summary of experience, description of tools and methods, lessons learned and vision for further development will be described in this work.
In order to be useful for lateral reentry and logging, intervention system should comply with following minimum requirements:
Be compatible with logging tools and systems provided by various Service companies and with various conveyance methods.
Operate with logging systems, not equipped with wired through capability.
Be of slim design so it can be used in variety of completions.
Be equipped with diagnostics systems to detect laterals and confirm successful entry.
All these requirements were implemented in new Multilateral reentry system. Once in field, system was proven reliable and useful for logging intervention in multilateral wells in various operating conditions.
Multilateral reentry system, consisting of motorized bend sub, wireless communication bridge and diagnostic section was designed, tested and further deployed in field. Within 40 jobs performed it was operating in variety of environments (onshore, offshore); open hole and cased hole completions; was run in oil, gas and water wells, in conjunction with most of commonly used logging systems. Although during most of jobs conveyance was performed using electric line Coiled Tubing, some of wells were accessed on wireline using Well Tractor technology. The system was proven reliable and practical experience was gathered for successful operation of this and any other multilateral reentry system to be designed in future. Application of this system allowed to receive important data needed for fields development and allowed optimization of completion systems in some cases. Although overall application of multilateral intervention system was a success, improvement areas were identified in order to increase operational portfolio; and will be presented in this paper. Recommendations of intervention friendly well design will be shared as well.
As unique experience of running Multilateral reentry system for logging purpose is described here, with practical recommendations on well construction, surveillance planning, execution and evaluation, this paper will be interesting to wide category of practicing engineers of various specialties.