Fugitive gas migration database development and statistical analysis toward enhancing the understanding of occurrence, attributes, and potential causes of gas migration at BC Oil and Gas Activities Act (OGAA) wells
Gas migration (GM) refers to the flow of gas outside the surface casing of a well. Well drilling and completion regulatory requirements are designed to ensure cementing procedures are conducted to seal the wellbore annulus around the surface casing and subsequent casing strings. In a small percentage of wells (estimated <1% of wells in BC), however, there is evidence of the vertical movement of gas outside the surface casing as GM. Gas migration has potential environmental and safety implications related to groundwater impacts, subsurface gas phase accumulation and greenhouse gas emissions. The BC Oil and Gas Commission (BC OGC) maintains an extensive database that contains numerous attributes for OGAA wells related to drilling and completion, subsurface fluids, geology, and spatial information. This project involves developing a custom “subset” database of selected relevant attributes for wells with GM and then conducting a comprehensive statistical analysis of the data. Common attributes of wells that exhibit GM in BC will be identified and analyzed against a control group to develop (a) a science-based framework for assessing the likelihood for GM in Northeast BC, and (b) an enhanced understanding of potential causes of GM. To ensure data context is considered as an integral part of the research, the project will be conducted as a collaborative effort between UBC EERI and BC OGC subject matter experts, with input from a technical advisory committee with industry participation.
Orphan gas well in Peace region of North East BC.