Beneath the surface of the United Kingdom lies a sprawling natural gas infrastructure. Based on recent (2014/15) ‘follow the thing’ fieldwork conducted in the UK onshore gas industry, this paper explores the ways that dangers related to the subterranean circulation of natural gas come to be visualised, and how these visualisations make possible different security interventions. These practices are shown to be limited by the ground, which despite its enrolment as a security device conceals from view the shifting landscapes of risk that surround these gaseous movements. Drawing on Manuel DeLanda's concept of the possibility space, I provide a conceptual framework for attending to security’s visualisation practices, describing how attempts are made to overcome the subsurface obfuscation of natural gas. I argue that, rather than being understood as a process of circulatory ‘filtration’ or ‘maintenance’, security must instead be regarded as a series of transformative practices of ecological (re)organisation that are predicated upon the visualisation of entities’ spaces of possibility. In the process, I provide an account of how the three-dimensional geographies and materialities of gas circulations and their milieus are intimately tied up in their governance and politics.