TY - JOUR A1 - Lazik, D. A1 - Ebert, S. A1 - Neumann, Patrick P. A1 - Bartholmai, Matthias T1 - Characteristic length measurement of a subsurface gas anomaly - A monitoring approach for heterogeneous flow path distributions T2 - International Journal of Greenhouse Gas Control N2 - Geogenic gases from natural sources, carbon dioxide (CO2) from a geological repository (carbon capture and storage - CCS) or a leaking gas pipeline can present serious risks in industrial and urban areas. To extend the lead time for risk treatment in such critical regions, reliable detection of gases within the shallow subsurface is required to observe critical gas accumulations before degassing into the atmosphere. A near real-time monitoring approach is introduced to determine the volumetric expansion of a leakinggas in the subsurface. Considering the pressure relaxation with the ambient air pressure, the approach enables the forecasting of the final size of a pressurized gas body in terms of characteristic lengths. According to theoretical basics, such a characteristic length, which enables us to perform a gas (safety) measurement based on a purely geometrical measure, behaves independently of subsurface properties,i.e., it enables a reliable quantification of the escaping gas irrespective of its heterogeneous or changingflow path distribution. A field test for a 10 l/min pinhole leakage injected into a 10 m long, 0.4 m wide, 0.95 m deep soil-filled trench that was equipped with linear sensors shows the lateral-vertical volumetric gas expansion along these sensors, and demonstrates the applicability of the characteristic length approach. PB - Elsevier B.V. KW - Monitoring KW - Carbon capture and storage KW - Leakage KW - Quantification KW - Subsurface KW - CO2 PY - 2016 UR - https://opus4.kobv.de/opus4-bam/frontdoor/index/index/docId/35425 AN - OPUS4-35425 SN - 1750-5836 VL - 2016 IS - 47 SP - 330 EP - 341 AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany