The terms “cement” and “isolation” are used interchangeably in the oil field. Stating the obvious, cement is a material that is mixed as a slurry, pumped into place, and then predictably turns into an impermeable (very low permeability) solid. Despite cement’s remarkable properties, the search continues for enhancements in the areas of cost and isolation performance. Several themes are evident throughout the sessions and papers that were presented at SPE events this year. Efficiencies and enhancements have been explored even to the point of replacing cement with other materials. Along with each improvement, verification of zonal isolation has been investigated.
Replacements for cement systems, such as geopolymers and resins, are investigated in a number of papers. Geopolymers have promising long-term strength and bonding properties. Resins also have desirable performance characteristics, especially related to strength and flexibility. However, we have yet to find a system that exceeds both the economic and the technical performance of cement in today’s wells for zonal isolation. As we continue to search for new isolation systems, we also continue to enhance our existing processes and materials.
Enhancing performance in cementing is a necessary component of challenging, and improving, the costs of drilling a well. New components, updates to additives, and specifically designed cement systems are enablers to providing zonal isolation in increasingly challenging environments, including deeper water, long-reach wells, and wells subjected to large temperature and pressure cycles throughout the life of the well. Every geographic location presents unique challenges.
As engineers in the drilling industry, we also continue to look for verification that isolation has been achieved. Programs, laboratory tests, real-time monitoring, and post-job documentation all contribute to a holistic approach to cementing and barrier verification. The featured papers, along with the additional reading, explore new materials, improved techniques, and optimized performance for zonal isolation.
SPE/IADC 184672 High Assurance on Barrier Placement and Evaluation for Deepwater Wells in Brazil by V. Reveth, Schlumberger, et al.
SPE 180344 Relating Cement-Additive Performance to Mix-Water Composition for Deepwater and Salt-Zone Applications by B.R. Reddy, Aramco, et al.
SPE/IADC 184675 True Self-Healing Geopolymer Cements for Improved Zonal Isolation and Well Abandonment by Xiangyu Liu, The University of Texas at Austin, et al.
Gunnar DeBruijn, SPE, Principal Instructor, Schlumberger
01 May 2017