The occurrence of lithium in the world's oilfield waters is poorly understood and only limited literature exists. Therefore, the objectives of this report are to illustrate where lithium-rich formation waters occur in Alberta and to make inferences on the source environment, mobilization and transport of lithium and related minerals to form these unique brines.
The idea of a green mining operation - one that extracts minerals from waste well water for eco-friendly products - is appealing. Devonian formation waters associated with producing oil and gas wells in the Swan Hills area of west-central Alberta contain up to 140 mg/l lithium. This value is significant considering the average and median values of lithium in Alberta formation waters is 10 mg/l and 0.2 mg/l, respectively (based on 1511 analyses). The high-lithium brines also contain elevated potassium (up to 8000 mg/l), boron (up to 270 mg/l) and bromine (up to 410 mg/l), such that industry is considering building a multi-commodity extraction plant.
Major ion and strontium, lead and lithium isotopic geochemistry shows Alberta's lithium-rich brines form prior to halite precipitation, lack a freshwater source and involve alteration of silicates (particularly lithium- and potassium-bearing minerals). Viable lithium source models should involve direct contact between Devonian formation water and the crystalline basement or with immature siliciclastics deposited above the basement (basal Cambrian sandstone, Granite Wash or the Gilwood Member), and mobilization of silicate-bearing fluids to the aquifer. A number of thermal, potential-field and tectonic features in west-central Alberta are reviewed in this introductory investigation of lithium-rich oilfield waters, which may one day become an economically viable resource for Alberta.