Foam Cementing in Australian Coal Seam Gas Operations

Abstract

The Australian coal seam gas (CSG)/coal bed methane (CBM) fields present multiple challenges (i.e., losses, naturally fractured formations, and highly depleted zones) typically addressed using various well design and cementing techniques (i.e., additional casing strings, stage cementers/tools, lost-circulation materials, lightweight designs, and additional cement volume) to manage the potential risk of losses. Foamed cement is a viable option to address these challenges; however, despite the documented benefits, its application within Australia has been minimal at best. The lack of application can be primarily attributed to misconceptions concerning cost, potential risk, excessive equipment footprint, and a limited proven track record, which increases the potential risk of execution. A recent 10-well campaign conducted within the Bowen Basin, Queensland, Australia, demonstrated that foamed cement can be used as an alternative to traditional lightweight and/or elastomeric cement slurries. Further, the benefits of foamed cement make it an economically and technically advantageous solution compared to conventional cementing techniques used to overcome CSG challenges. This case study details the campaign challenges, cement design, and detailed results of the 10 wells with the intention of providing other engineers a road map to better understand foamed cementing with a specific Australian context and how it could be applied to their projects.