It certainly is. The technique has even been used for more than 20 years, and a common service in Norwegian Oil and Gas activities for at least 15.

Allowing it to be near real-time is, of course, dependent on the number of satellites you have access to, as the imaging satellites are in low earth or polar orbits and thus not fixated over the same point, meaning you will have to wait for a revisit to get an update. This has become more accessible in the last 3-5 years with the European Copernicus satellites as well as TerraSAR and other commercial satellites.

Literally all images captured by these satellites that are obtained are scanned for signs of spills. However, if there is a big crisis like in the Mexico Gulf, you would rather execute an order to have satellites point directly to the spot and not have to wait for a new revisit of another satellite.