Real-Time Downhole Data Transforms the Efficiency and Safety of Tubing Conveyed Deepwater Multizone Perforation Operations

Tubing conveyed perforating (TCP) is an essential part of the completion in many fields in the Gulf of Mexico and elsewhere. However, there are many risks associated with the operation which can cause significant non-productive time (NPT). These are generally to do with not having visibility of what is actually happening downhole below closed multistage valves. Until recently there has been no real-time data available to understand this. In particular, the pressure reading below the closed valve has not been known. Different operators perforate in different ways as regards the pressure balance in the well, some prefer to perforate over balanced and some under balanced. Before the valve is opened the well is "balanced" to what is assumed to be the pressure regime below the valve after perforation. If this assumption of the pressure is incorrect then the well can either go on losses or can induce an influx into the well depending on whether you are overbalanced or underbalanced to the now perforated zones. This is further exacerbated if you are attempting to perforate several zones in the same run with different zones being at differing pressures in relations to each other. This can cause crossflow and backflow between the various zones making an understanding of what the pressure regime is likely to be more complicated. To counteract this then often in multi-zone wells each zone may be perforated separately with a follow up deburring run in between each perforation run. This method particularly on deepwater vessels can be time consuming and therefore costly, whilst still not knowing exactly what the pressure is under the closed valve after perforation. This paper will demonstrate how an acoustic telemetry and measurement system can communicate data in real-time below the closed valve and then back along the drill pipe to allow for safely managing the well if there is an influx. This allowed multiple zones to be safely perforated in the same run. Additionally, the system can be used for improving the torque and drag models for the subsequent lower completions runs which are difficult to manage in multi zone completions. We will show with data from a sequence of wells how this was introduced and implemented into the tubing conveyed perforating operations eliminating multiple runs and derisking the operations through the use of real-time downhole data. In particular how the processes were changed to deal with influxes over the campaign of wells.