Abstract: A method of extracting hydrocarbons from a subterranean formation includes injecting a surfactant composition into the subterranean formation and collecting hydrocarbons displaced by the injected surfactant composition. The surfactant composition can have at least one polyamine surfactant compound of formula R1R2NA(RNA)xNR3R4, where x is an integer from 0 to 3, R1, R2, R3, R4 and each R are independently a hydrogen atom or an alkyl group, each A is an alkylene group, and the total number of carbon atoms in the surfactant compound is from 10 to 21. The surfactant composition can include liquid or supercritical carbon dioxide.

Abstract: The invention relates to a method of extracting hydrocarbons from a subterranean formation, comprising: —injecting a surfactant composition into the subterranean formation, and —collecting hydrocarbons displaced by the injected surfactant composition; wherein the surfactant composition comprises at least one surfactant compound of formula (I): wherein x is an integer from 0 to 3, R1, R2, R3, R4 and each R are independently a hydrogen atom or an alkyl group, each A is an alkylene group, and the total number of carbon atoms in the surfactant compound of formula (I) is from 10 to 21. The invention also relates to a composition comprising liquid or supercritical carbon dioxide and at least one surfactant compound of formula (I).

Abstract: Methods and systems for detecting an anomaly in a passenger flow towards a transport device. Historical data relating to the passenger flow is aggregated and a forecast passenger flow value for a target time frame is determined based upon the historical data. A first forecast is computed based upon the passenger flow in a first set of the time frames directly preceding the target time frame. A second forecast is computed based upon the passenger flow in a second set of the time frames, the second set of time frames having occurred on a same weekday and at a same time as the target time frame, in weeks preceding the target time frame. The first and second forecasts are combined to produce the forecast passenger flow value for the target time frame.