Well completions in the United States are predominantly completed using the plug and perforate process. Following the fracture stimulation treatment, coiled tubing (CT) is utilized to convey a downhole milling assembly to remove these plugs and clean out the wellbore. As wells continue to extend in lateral length, an extended reach tool (ERT) is commonly used to aid in achieving these depths.
In order to truly understand the milling process using an ERT, a downhole memory tool was developed. The memory tool is run in-line with the milling assembly and obtains weight on bit (WOB), torque, pressure, temperature, and vibration at one second sampling rates. The tool has been run on multiple bottom hole assemblies (BHA) on both 2 3/8-in and 2 5/8-in CT on over 35 jobs accounting for 1,500 composite frac plugs.
The data collected is compared to surface data providing a detailed view of the overall plug milling operation. The ERTs used provide WOB while milling at a level that is unpredictable by commercial CT modeling software. Comparison of the surface weight gauge with the downhole WOB enables a clearer understanding of the forces delivered by the ERT. This data provides an avenue for better job planning and informed decisions on ERT selection.