Cementing/Zonal Isolation

Topics: Offshore

In 2015, more papers were devoted to well construction in shale plays than in any prior year. Those shale topics also covered a diverse range of subjects within the sphere of optimizing construction efficiency and performance. Our industry’s demonstrated ability to innovate and continually improve well-construction technology will be all the more valuable to all plays if low oil prices persist, but especially so for shale and other high-cost-per-barrel plays. With rig counts decreasing, smart, effective workovers of existing wells will be even more important to maintaining production levels. Some examples of effective construction and workover techniques are provided within the papers provided here. I hope you find them of interest.

In paper SPE 170789, I was surprised to see the level of production improvements achieved with the use of wireline stackable straddle systems. This was accomplished in an openhole gravel-packed completion without external casing packers or consolidation of the gravel pack, a significant simplification.

Paper SPE 171015 is a good example of the widespread, innovative efforts to improve cost efficiency in shale wells. Case histories demonstrate the successful use of biodegradable, temporary diverting agents, rather than cement squeezes or mechanical tools, to simplify and reduce the cost of fracturing and refracturing operations. With fewer new wells being drilled, refracturing may offer a viable option to slow the decline of existing shale wells.

The industry has been working to relate cement mechanical properties to success/failure with annular isolation in the actual well for approximately 20 years; however, there are still no American Petroleum Institute standardized cement-testing and -evaluation protocols for cement mechanical properties, and there is much room for improvement. The investigative paper SPE 168650 relates how anelastic-strain and impact-resistance testing may enhance real-world predictive abilities.

Recommended Additional Reading

SPE 169514 Effect of Well Downspacing on Estimated Ultimate Recovery for Shale Oil Formations by Susrut Gautam Bharali, University of Houston, et al.

SPE/IADC 170480 Challenges of Casing Design in Geothermal Wells by Angelito Torres, Chevron

SPE 170712 Cement Evaluation—A Risky Business by Glen Benge, Baker Hughes

Bob Carpenter, SPE, is a research consultant with Chevron Energy Technology Company’s Cement Team. He has 37 years of experience in field operations, technical support, and research and development (R&D). Previously, Carpenter was with Arco Exploration and Production Technology and BJ Services’ Technology Center. He has served on the SPE Drilling and Completions Advisory Committee and the SPE International Symposium on Oilfield Chemistry Program Committee, along with other industry groups. Carpenter has authored or coauthored 15 SPE papers and severalJPT articles and has been issued 26 US patents. His areas of expertise include technical support and R&D of all areas of primary and remedial cementing. Carpenter also has extensive expertise in coiled-tubing cementing, spacer-fluid development, and remediation of sustained casing pressure. He serves on the JPT Editorial Committee.

Cementing/Zonal Isolation

Bob Carpenter, SPE, Research Consultant, Chevron Energy Technology Company

01 May 2015

Volume: 67 | Issue: 5

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