Abstract
This paper presents lessons learned and best practices using a scalable hydraulically actuated reamer shoe system for casing deployment. The technology was used in a few wells to successfully run 7 inch casing through problematic geological horizons where it had been impossible to do so with conventional float shoes.
A scalable and customizable high speed reamer shoe technology was deployed in three wells right after a well in which the 7 inch long-string could not be deployed to objective depth and had to be set prematurely, leaving a lengthy rathole below the casing shoe. Consequently, the production zone had to be drilled and completed in 4 ½ inch. This ultra-high speed scalabe reamer shoe technology was then deployed in subsequent wells in an attempt to address this concern. Three 7 inch reamer shoes with two different configurations were deployed. Two were configured for LCM tolerance, whilst the third tool was tuned towards more optimal performance at lower circulating rates. The 7 inch casing strings were successfully deployed and cemented in all three wells.
Tools with two variants of a new scalable, dual-chamber drive mechanism from the manufacturer were used. The major difference being in the flow pattern between the chambers. The LCM tolerant tools were the latest variant of the drive mechanism with a minimum restriction of 15mm, while the tool with the earlier variant of the scalable drive chamber, had a minimum restriction of 8 mm and a by-pass valve arrangement made up of 4 x 20mm ports. Activation flow rates were low though significantly different. The earlier tool activated at +/- 60 gpm whereas the more recent drive mechanism in the latest variant, activated at 26 gpm, indicative of a significant improvement in tool performance though configured for higher flow rates. Operating pressures were significantly higher in the earlier variant compared to the more recent drive mechanism. The differences in activation flow rates and operating pressures are due to how flow is altered and channeled through the drive mechanism as configured in each tool. All three tools were used to run 7 inch casing at low circulation (< 180 gpm) and successfully reamed through any obstructions encountered and cemented at target depth.
The use of this technology was instrumental in successfully deploying all three 7 inch casing strings to objective depth. Due to its low flow capbilities (<180 gpm), PTTEP was able to successfully manage the tight pressure margin required to land casing and displace cement. Furthermore, the tool was evidently effective at circulating rates as low as 100 gpm and low operating pressures, making it ideal for most tubular deployment applications.
