Horizontal fracture-stimulated completions remain the de facto method of producing hydrocarbons from shale formations. The vast majority of wells are completed using the "Plug and Perf"method, which requires either a jointed pipe or coiled tubing (CT) with a positive displacement motor (PDM) to mill out the composite plugs (CP) after the fracturing operations are finished. It is estimated that between 100,000 to 140,000 composite plugs are installed and milled each year in the US alone. Efficient removal of these composite plugs is critical in achieving operational efficiencies forboth the operator and service suppliers.
Currently many milling operations are planned at the well-site with engineering or operational risk assessments performed only after problems arise. This paper will provide data to assist operators in improving those risk assessments.
This paper will describe best practices and recommendations for pre-job planning, mill design, motor selection, fluid selection, weight on bit, wiper trip frequency and speed, whether to produce the well during milling, surface flowback equipment, operational contingencies and data analysis. These best practices have been developed from reviewing operational practices on many operations across the US.