Overview: Well Stimulation (July 2007)

Abstract

For this month's issue of featured well-stimulation papers, the ongoing work in acidizing earns my recognition as the most enlightening and yet overdue progress. Although the papers spotlighted in this issue are strong presentations on diverse subjects, I was most surprised by the volume of engaging papers focusing on acids and fracture acidizing. There are great papers in my list with information on horizontal wells, gravel packing, and viscoelastic fluids; however, each of these technologies is young compared to acidizing reservoir rock. In one of the additional-reading selections, "Fracture Acidizing: History, Present State, and Future," we learn that acidizing carbonates dates back to 1895. Therefore, the use of acids to increase production is more than a century old. With many of the modern acidizing theories developed around 1972 by Neirode and others, it is still a 35-year-old technology that needs a fresh look with modern methods. Whether we are studying etching behavior to forecast conductivity or predicting long-term reductions in performance caused by creep, we still have a lot to learn about this venerable practice. Therefore, the question becomes: "How can acidizing oil wells be more than 100 years old, yet we just now are beginning to unravel these fundamental concepts?" The world produces approximately 85 million BOPD, and assuming just USD 50/B, we generate more than USD 1.5 trillion/yr in world oil revenue. Whatever the historical disconnect has been between oil revenues and funding oil science, I am pleased to recommend these compelling technical papers on subjects vital to our industry, including the common practice of pumping acid into a formation to increase production. Well Stimulation additional reading available at the SPE eLibrary: www.spe.org SPE 108075 "Horizontal-Well Completion and Stimulation Techniques—A Review With Emphasis on Low-Permeability Carbonates" by Valdo Ferreira Rodrigues, SPE, Petroleo Brasileiro, et al. SPE 107772 "The Effects of Acid Contact Time and the Resulting Weakening of the Rock Surfaces on Acid-Fracture Conductivity" by M.G. Melendez, Texas A&M University, et al. SPE 107760 "Acid Stimulation of Extended-Reach Wells: Lessons Learnt From N'Kossa Field" by J.M. Mazel, Total, et al. SPE 106371 "Fracture Acidizing: History, Present State, and Future" by Leonard J. Kalfayan, SPE, BJ Services