bp’s operations in the giant Azeri-Chirag-Gunashli (ACG) Field in the Caspian Sea were facing a challenge. All well slots on the operator’s platforms were in use and consequently, infill drilling necessitated sidetracks from existing wellbores. SLB had installed optical fibers for distributed temperature sensing (DTS) in the main bores of multiple wells, enabling continuous reservoir surveillance. As a result, bp was able to evaluate production, water injection profiles, fracture effectiveness, and flow-related events, even in high-rate producers and injectors. Permanently installed with the completion, the fibers provide continuous data without interventions. But while DTS had proved an effective monitoring tool in 9 5/8-in wells, the existing CLWM connector was incompatible with the 7 5/8-in casing required in the sidetracks.
This self-orienting device connects control lines across junctions in multitrip completions. A continuous optical fiber is subsequently pumped down the control line into position, enabling acquisition of distributed measurements while avoiding downhole splices. The size limitation hindered bp’s ability to monitor reservoir behavior and optimize production in the sidetracks.
Initial feasibility studies showed that scaling down the conventional 9 5/8-in connector design was technically possible but there was a high risk of plugging during gravel packing. bp wanted a safer, reliable, and cost-effective solution.
To address the challenge, SLB developed the 7 5/8-in CLWM connector. The new technology retains adequate turbulent flow around itself to avoid gravel deposition, which could inhibit fiber deployment. This innovation enabled the pumped deployment of optical fiber for continuous real-time profiling across the wellbore in the sidetracks, which had inclinations up to 80°. The solution was integrated with a gravel pack using a standard service tool, ensuring operational efficiency and minimizing the risk of plugging with sand.
Two installations have been completed to date, enabling bp to monitor reservoir conditions in sidetracks with the same reliability as in the main bore. As a result, this operator will be able to continue to detect water and gas breakthrough earlier, optimize production, and reduce production logging runs (from >0.5 to <0.1 per well per year, based on existing wells), hence lowering costs. bp now has a robust solution for smaller-diameter completions, ensuring that DFOS remains a key part of its reservoir surveillance strategy offshore Azerbaijan.
