Flow Isolation Tube for Milling and Sand Jet Perforating

Abstract

Sand jet perforating (SJP) is currently gaining acceptance in unconventional resource plays where horizontal development has shown the need for methods to perforate these formations. This paper examines a new design for a tool assembly that allows fluid to flow through the sand jet perforator while operating a PDM (Positive Displacement Motor) with a mill or cutting tool. In multi-stage fracturing operations where through tubing mills are often used for cleanout runs prior to perforating, the flow isolation tube assembly can be added to the tool string to achieve cleanout in conjunction with perforating in one trip. The design allows an operator to isolate the SJP tool, which is resident in the work string and perforate casing and formation, then restore flow to the PDM to continue operations such as milling or further well cleanoutall in a single trip.Discussion of the assembly design process and laboratory testing results are included as a part of the paper and will analyze the effectiveness of the technology and tools as well as the economic impact of this type of program. Economics includes process costs as well as cost savings from support equipment that is gained by the combination of operations. The program's translation to other shale plays like the Marcellus, Bakken, and Haynesville are also discussed.Shale plays dominate domestic drilling as well as production today and being able to combine completion operations to save both time and money is of interest to all producers. Using the flow isolation tube assembly will save cost and wear for coil tubing units as well as costs for other surface support equipment. Finally, safety is increased and the quality of the perforations is improved with SJP; giving a better perforating job for a lower cost.