Alberta’s liquids business dates to the development of the Pembina field, when Dallas-based Goliad Oil and Gas received rights to recover solution gas from the field. Also known as "casing head gas" or "associated gas," solution gas is dissolved in reservoir oil at underground pressures. Released under the relatively low pressures at Earth’s surface, it usually includes natural gas liquids. Often, as at Pembina, these can be profitably extracted. While Goliad received the gas from Pembina, the separated liquids were returned to the producers.