The understanding of deep saline groundwater, and potential deep disposal zones (>250 m below surface) is essential for responsible development of the unconventional natural gas resource in the Montney Play. Deep groundwater provides a source of water for drilling and completion activities, and the identification of potential zones suitable for deep disposal of fluids is required for operational planning of natural gas facilities and activities.
The Montney Play in British Columbia’s Northeast Region is a world-class unconventional natural gas resource. Water is an essential component of shale gas development and is used for drilling and hydraulic fracturing. Hydraulic fracturing, also known as fraccing or fracking, is a process where a mixture of water and sand is injected into the deep shale at a high pressure to create small cracks in the rock which allows gas to flow.
In 2010, the Montney Water Project began to complete an inventory and digital compilation of publicly available information on water in the Montney Play. This component of the work focused on deep groundwater aquifer mapping and identification of potential deep zones for fluid disposal.
The goal for this project were to:
This project provides a better ability for operators and regulators to identify and utilize deep groundwater resources and disposal zones.
This project took place in the Montney Play in BC’s Northeast Region.
In the Plains study area, potential aquifers ranging from Middle Triassic Halfway to Upper Cretaceous Cardium were assessed. The best aquifer characteristics – thick net porous sandstones, high storativity, good to excellent potential deliverability, moderate to low salinities, and little or no H2S – were found in the Cadomin and Nikanassin aquifers. The Baldonnel, Bluesky, and Peace River formations offer more modest aquifer characteristics, but may still have local importance.
In the Foothills study area, potential aquifers range from the Mississippian Debolt to the Lower Cretaceous Bluesky; younger Cretaceous strata have shaled out in this area. In general, more extensive diagenetic degradation has reduced aquifer quality in the sandstone reservoirs, compared to those in the Plains study area. Test data indicate variable aquifer quality in Debolt and Baldonnel carbonates, with waters of moderate salinity and some H2S present. Drilling in foothills oil and gas production is limited to the crests of regional northwest-southeast structural trends, so there are insufficient data at this time to adequately characterize aquifer quality off-trend.
Key observations of the subsurface aquifer study include: