Abstract
Thousands of liner hangers are deployed on a global basis per year. They are deployed to reduce the time and risk, with the inherent associated cost, of running longer single casing strings. Originally these liner hanger systems required a mechanical actuation, such as rotating and or reciprocating the drill pipe in order to deploy the liner system. In the last several decades there has been an ever-increasing trend in the complexity of wells, particularly in relation to the complexity of the well profile, with thousands of highly deviated or horizontal wells. This increase in deviation and complex trajectories or increased tortuosity limits the ability to activate the liner system through rotation and reciprocation. To combat this the industry then also developed hydraulically actuated systems, and these are now found in both conventional and expandable liner hanger systems. The traditional method for setting a hydraulic liner hanger is through dropping an activation ball. This is either a single activation or a multiple activation device. Hydraulic activation allows for reciprocation and rotation, within the limits of the well deviation. Dropping a ball and landing it on a ball seat creates a pressure increase to the work string which then activates the liner hanger and running tool.
There are, however, still multiple failures of liner hanger deployments and setting. These can include, in these highly complex wells, the inability to get the liner to the correct setting depth. In complex well trajectories, in high pressure high temperature wells and in wells with very narrow mud weight windows, or being operated under managed pressure conditions, failure to set the liner hanger systems correctly or in the correct place can lead to significant Non-Productive Time (NPT). It could also lead to the well being unable to make the desired depth or be unable to run an appropriate completion. The main failure points in deploying these systems have been hindered by not having downhole measurements to verify what is happening downhole, for example what is the actual downhole torque and weight at the running tool? What is the pressure at the critical points of the well. Has the ball correctly set on the seat?
We will demonstrate a fully integrated system that allows both real-time data to be sent both from just above the liner hanger, but also along the string whilst running the system. This acoustic telemetry system, which transmits data through the wall of steel drill pipe without the need for surface or downhole modification of existing systems, includes measurements of downhole weights, downhole torques and internal and external pressures and temperatures. In addition, the system transmits all the time and can be run independent of flow or fluid and operates whilst tripping. The system is also fully through bore allowing the passage of balls, bars or even wireline tools through the bore. This acoustic telemetry system is also intrinsically bidirectional, meaning that not only can data be sent up from downhole and along the string, but also acoustic commands can be sent down to activate downhole devices, in this case the liner hanger and running tool.
The development of such a system providing both real-time downhole measurements that neither relies on mechanical manipulation or dropping an activation ball from surface has the potential to dramatically decrease high impact NPT and increase the overall operational capabilities of liner hanger systems.
