Overview: Completions Today (September 2007)

Abstract

A key aspect to effective completion design is an accurate understanding of the reservoir and bounding formations. Nearly every well completed in a prolific sandstone formation requires sand control, either as a preventive measure or as remediation later in its production life. Formation damage is another problem associated with wells that produce sand unchecked. The possible creation of void spaces behind the casing can leave the casing and any shaly streaks in the reservoir unsupported. The much less permeable shaly streaks that remain can collapse around the slotted or perforated casing, causing severe and irreparable restrictions to production. Most authorities recommend that sand-control techniques be applied immediately upon indication that a formation will produce sand. This practice will allow the highest success rate and the lowest production loss possible after sand control is applied. Laboratory studies have shown that once unconsolidated sand is disturbed, the sand cannot be packed back to its original permeability. Therefore, sand control should be applied before the reservoir rock is seriously disturbed by sand production. Also, operators are opting for advanced sand-control completion technologies in demanding gravel-pack and frac-pack completions. In this environment, the next generation of sand-control completion technologies must be able to handle larger proppant volumes and higher pump rates and place proppant or gravel-pack sand effectively along the sandface completion void free. For most open holes drilled in unconsolidated formations, a gravel pack is the preferred completion option. By filling the annulus between the liner or screen and open hole with specially sized, high-permeability gravel-pack sand, the wellbore is stabilized to control production of formation sand and protect the screen from plugging or erosion. When performed with proper procedures and tools that use the next-generation sand-control completion technologies, gravel-pack and frac-pack completions can be highly productive and long-lasting completions. Finally, the ultimate objective is to create cost-effective technology that builds on proven sand-control technologies and best practices that help operators overcome these serious well-production sand-control challenges successfully. Completions Today additional reading available at the SPE eLibrary: www.spe.org SPE 101987 "Effects of Formation Damage and High-Velocity Flow on the Productivity of Slotted-Liner-Completed Horizontal Wells" by Yula Tang, SPE, Chevron Energy Technology Company, et al. SPE 106757 "Expandable Liner Hanger Resolves Sealing Problems and Improves Integrity in Liner-Completion Scenarios" by James Williford, SPE, Halliburton, et al. SPE 103668 "Case History of One-Trip Monobore Completion System—2 Years of Cement-Through-Monobore Completions in the Gulf of Thailand" by Walt Chapman, Baker Oil Tools SPE 103986 "Improving Performance of the Naturally Fractured Carbonate Reservoirs by Means of Various Stimulation and Completion Techniques" by H. Jahediesfanjani, SPE, University of Oklahoma, et al.