In Alberta and Saskatchewan, proposed legislation aims to reduce venting from Cold Heavy Oil Production with Sand (CHOPS) sites. The volumes venting to atmosphere are small. In some cases, there is incentive to reduce the emissions with Carbon Tax Credits for sites producing less than 500 m3/d. The greatest challenge in reducing emissions is designing systems to capture and utilize the low flow volumes and intermittent flow from the surface casing and tank venting and the ability to measure these volumes. Additional difficulties encountered are designing for the low pressures experienced from the venting and the fact the gas is water wet and will freeze without heat tracing. Typically, there is no power on site to provide electric tracing which compounds the problem. Numerous technologies were investigated, but none can be implemented easily with the exception of the Hexa-Cover solution. The solution reduces the tank vapours, but these vapours account for no more than 5% of the methane emissions from a typical site. Therefore, capture of excess casing gas is required to provide effective emission reduction at CHOPS sites. Since the design considerations tend to become complex, the solutions will involve proper engineering to solve the site-specific problem to ensure the sites can be safely operated. Additional challenges will be present at sites where pipeline and power infrastructure does not exist. In this case the Producer will find that combustion solutions are currently the best alternative.
Conceptual Engineering Study of Technologies for Reducing Methane Venting