Lance Ruffel, Lance Ruffel OG Joseph Strasburg and Jeff Clark, BJ Services Co.

Options for improving productivity in older wells are re-stimulating the well or adding laterals extending past the original wellbore. A new technique achieves both in limestone formations. This technique creates pre-stimulated "tunnels" that bypass near-wellbore damage to make contact with newly exposed reservoir rock. This technology relies on hydrochloric acid's ability to dissolve limestone along with a coiled tubing bottomhole assembly made to kick over toward the formation. A nozzle then jets acid at the formation creating tunnels extending from the wellbore. The technique works in all open-hole wells drilled in limestone and can be used to make multiple laterals in new or old wells. This procedure was recently used in the United States for the first time. Three tunnels were created in an Oklahoma stripper well. This paper describes the tool and design including an operational timeline; lessons learned during the Oklahoma operation, pre- and post-job production information, and a cost/benefit analysis for the treatment.