The BC Oil and Gas Commission recently completed an aerial survey of 98 decommissioned gas wells between Hudson’s Hope and the Alberta border.
Three wellsites had shown initial indications of methane, though subsequent site inspections found no evidence the wells were leaking.
As part of the commission’s mandate to ensure the integrity of decommissioned wells, it has conducted aerial surveys for the past four years using a laser-based methane detector mounted on the underside of a helicopter. This survey method allows easy access to sites in difficult and inaccessible terrain, is fast, cost effective, and can detect very low concentrations of methane. The long-term goal of this program is to obtain a representative sampling of decommissioned wells throughout all areas of northeast B.C.
Multiple passes over the decommissioned wellsites were made over two days in September 2020. The wells were randomly selected and included wells with a variety of abandonment plug types and wells with previous history of surface casing vent flows.
Three wells were identified through the aerial survey as potentially having emissions and commission inspection staff have completed on-the-ground inspections of those sites. No evidence of leaking wells was discovered. An additional round of inspections will be conducted in 2021 to confirm those findings.
The aerial surveys in 2017 and 2018 were focused in the vicinity of Fort St. John and found about one per cent of decommissioned wells were emitting methane. The 2019 survey, completed east of Fort Nelson, found a higher frequency of emissions, at about three per cent. Results from this year’s investigation will inform inspection programs and help drive improvements to well decommissioning practices. The commission intends to continue the aerial inspection program annually, focusing on different areas throughout northeastern British Columbia.
As a result of an agreement with the federal government on equivalency, amendments were made to the Drilling and Production Regulation (DPR) under the Oil and Gas Activities Act. These amendments specify leak detection and repair (LDAR) and other requirements which came into force on Jan. 1, 2020.
In addition to aerial surveys of decommissioned wells, the commission performs field-based inspections for leaks, and under the DPR amendments, permit holders are required to inspect for and repair any leaks found.