New and innovative technology has a way of significantly influencing peripheral products and processes. A case-in-point is the relationship between solid expandable tubulars and cementing practices. The early years of cementing expandable casing were filled with researchers working to develop novel chemistries and resourceful techniques for annular sealants that varied from modified conventional cements to highly-specialized non-Portland systems such as resins. Experience and time relegated many of these chemistries and systems to specific situations.
Instead of needing atypical techniques and unique products, the more effective and applicable approach with solid expandables consisted of modified placement practices, training, logistics, and refined engineering of conventional cementing methods. But, as solid expandable tubulars are installed in deeper and higher-angled wells, annular sealant methods and products will be required to function in more extreme conditions.
This paper will examine the evolution of cementing processes and products for solid expandable tubulars. Emphasis is placed on best practices and lessons learned, with the intent of giving the reader a practical field guide. Checklists for key slurry design issues and how they correlate with the job logistics of the expansion operation will be included. This paper will also discuss foreseeable application trends in expandable use and logical modifications and enhancements in cementing procedures, technology and chemistries.
Introduction
Solid expandable tubulars have built a reputation as a practical and enabling technology with well over 600 installations in seven years. Initially used as a last resort to preserve hole size, the systems now are frequently planned into the original wellbore design to optimize hole size. The systems are being installed at greater depths and in more extreme conditions. Although the operating parameters are dynamic and continue to be redefined (Figure 1), the technology's provenance remains rooted in proven principles. Predecessor technology, such as expandable casing patches, has been used for decades, but significant differences include the following:
Since the technology's inception, miles of solid expandable tubulars have been installed in diversely varied applications (Figure 2 & 3). An early concern in the development of these systems was that their use would require development of new and novel cementing products.1, 2 This issue is analogous to the concerns for extended reach drilling, slimhole drilling, casing drilling, and other specialized well construction methods. Cementing service suppliers acted accordingly, developing specialized extended-set cements, non-Portland cements, and even revisited mud-to-cement chemistry, also known as settable spotting fluids.3 This reaction was a natural response to ancillary processes required for new technology introduction. However, while these new systems are relevant and have all been successfully used, much of the early concern about the requirement for novel and unique cement systems or additives for solid expandable applications has abated. Common sense recognized that due diligence in planning and training, informational and logistical coordination between multiple service providers and modification of laboratory testing and pumping procedures allows adaptation of most existing cementing systems and engineering practices for solid expandable tubular installations. 4–6
