On commission from the Norwegian Ocean Industry Authority (Havtil), THREE360 Energy has prepared a report assessing the properties and effectiveness of foam cement as a barrier element on the Norwegian continental shelf (NCS)
Foam cement is being increasingly used on the NCS, especially in depleted reservoirs. However, the use of foam cement presents challenges for the interpretation of log data. This is primarily due to the reduction in acoustic impedance that occurs when nitrogen is mixed into the cement composition.
Cement Bond Logging (CBL) is an acoustic measurement method for assessing the quality of the cementation between the casing and the formation. The main purpose of the technology is to ensure that the cement forms an effective barrier that prevents unwanted fluid and gas migration between different subsurface zones.
The THREE360 Energy report comprises two main sections:
Part 1: Technical evaluation and literature review
The first section examines methods of interpretation of foam cement logs and evaluates the reliability of foam cement as a barrier element. The study maps:
- Various methods for logging foam cement
- Simulation tools available
- Alternative approaches to verifying barrier function
In addition, the report contains a thorough review of relevant SPE publications and other literature to establish a solid foundation for best practice in the field.
Part 2: Experience-based knowledge
The second part of the report is based on a workshop in which representatives from four operators and three suppliers on the Norwegian shelf contributed their experiences and views. This section summarises the different contributors’ views and experiences of the logging and use of foam cement.