Agenda

To accompany the field development mode using multi-well pads and pad complex development, what changes can be made to the cementing practices and processes to optimize well construction efficiency, drive continuous improvement, reduce nonproductive time (NPT), and eliminate unnecessary costs while ensuring high quality zonal isolation and well integrity?

Hydraulic fracture stimulation induces significant stresses that can damage wellbore integrity with consequences to effective fracture development and maintenance of zonal isolation. This session will discuss the initial stress state of the wellbore system and the magnitude of the induced stresses in relation to the mechanical properties of steel, cement, rock, and their interfaces. The Session will describe potential failure mechanisms and design criteria for controlling unwanted damage.

One of the main criteria of well construction is to deliver a well with the desired well integrity. The ultimate test of well integrity is obtained by analyzing the pressure information on the annulus. In the unconventional world we currently see sustained casing pressure (SCP) on more than one annulus. How is this being mitigated during cementing? What is the impact to fracturing operations? What is the ultimate cost of failure? How do we remediate?          

You would think having several thousand feet of lateral casing sections would be the most challenging aspect of cementing. However, we often find the vertical and intermediate casing sections to be most problematic, with zones of severe losses, depletion, water flows, and shallow gas. How do we overcome these cementing challenges in the vertical and intermediate casing sections?  

The most important operation performed on an unconventional well is the primary cementing job for the production string. It must achieve complete zonal isolation in the wellbore by obtaining a hydraulic seal of cement-to-casing and cement-to-formation while at the same time eliminating mud or gas channels within the cement sheath. An optimally engineered design of the cement slurry meets all wellbore production and regulatory requirements. Slurry design is affected by many factors including; well geometry and ever increasing lateral length, reservoir pressures and temperature, mud properties and types, pump time, quality of mix water, flow regime, type of cement, additives and resulting properties obtained, gels and strength development, and life of the well slurry mechanical properties to withstand fracturing intensity.

Effective placement is the foundation for zonal isolation. The placement process in horizontal wells is complex and sensitive to variations in wellbore tortuosity and variances in fluid properties during execution of the cementing operation. This session will explore the variables and interactions that govern effective placement. Through this exploration, we can identify concepts and robust methodologies for effective cement placement design for unconventional wells.

Although zonal isolation rationale may differ between conventional and unconventional wells, isolation is still a key requirement in unconventional wells for both well integrity and well performance purposes. Conventional methods of cement evaluation can be challenging in unconventional wells, however unconventional wells also bring opportunities for both additional data, and often more direct data that can in turn be used for a more effective cement evaluation.

Obtaining and maintaining an effective annular cement barrier for the life of the well is an essential component in ensuring the safe and economic harvesting of hydrocarbons. In terms of repairing a failed cement barrier, the industry has historically used a Portland cement-based system. However, depending on the mode of cement failure, the use of a Portland cement-based system may not be effective. In this interactive session, we will encourage and enable attendees to share their experiences with using non-Portland cement materials to repair a failed annular cement barrier.

The process of permanent abandonment should strive to replace the natural seals in the subsurface that were broken during the drilling process with the objectives to; prevent the migration of sub-surface fluids or gas to surface; prevent cross flow between subsurface zones; and to protect potable water sources. These objects can be at times challenging to meet, requiring the placement of well barriers that isolate the well across the entire cross-section and materials that will stand the test of time. Well design, and well construction techniques, that consider future well abandonment plans can significantly simplify future permanent abandonment operations. The application of good cementing practices in establishing annular cement can also simplify the challenges that operators may encounter during well abandonment. How are these challenges being managed in the unconventional world of well construction? What is working well? Are there opportunities to improve?