| Popis: |
We present a new perforating technology based on new wireline conveyance equipment and advanced downhole modeling to maximize operational efficiency in long pay-zones under all pressure conditions. Results of perforating jobs of long pay-zones carried out on wireline in very short times compete with traditional Tubing Conveyed Perforation (TCP) operations which take much more time. Also, perforating jobs with large gun sizes that until recently were not possible in a single run with traditional wireline conveyance, are now efficiently executed in a single run. The new technology that allows conveying long lengths of perforating guns on wireline in a single run is based on four main elements: wireline systems with safe working loads up to 30,000 lbf, cutting-edge shock resistant mechanical weak points and disconnect systems, conveyance modeling, and an advanced transient dynamic modeling for perforating shock prediction. The perforating job design modeling is based on the reservoir zones and completion information, both a conveyance and a wellbore dynamics and shock simulation are carried out to determine the highest payload that can be more safely deployed per wireline run, and with the number of runs required, costs and risks are compared between wireline and TCP shoot and pull operations. For a well with a 750 ft thick pay zone, a North Sea operator requested a comparison between this new wireline perforating technology and conventional electric wireline deployment in terms of reservoir productivity, risks, and operational performance. For this well TCP was not considered due to reservoir and operational risks and challenges. Compared to the conventional electric wireline conveyance this new perforating technology offers better efficiency with only two wireline runs using a cable with 18,000 lbf of safe working load and a 10 Kpsi surface pressure control equipment compared to 6 to 8 conventional runs. The longest run consisted of 388 ft of 3 3/8″ guns, which was a new world record on wireline, with energetic liner charges and dynamic underbalance to ensure maximum perforation tunnel cleanup and well productivity. The total operational time for the perforating job was significantly less than conventional electric wireline, which translated into significant rig time savings. This paper demonstrates how the application of innovative technologies have minimized the risks of wireline conveyance with long and heavy perforating gun strings. We utilized well and reservoir information to design a more safe and reliable job execution, including prediction of perforating shock, tension profiles and wellbore dynamics. The new perforating technologies described in this paper have extended considerably the range of perforating jobs where wireline conveyance can be more efficient than traditional coiled tubing and tubing conveyed perforating. |
