Methods and apparatus for monitoring steam injection in a steam assisted well are disclosed. The method involves obtaining a first temperature profile of a well by performing distributed temperature sensing on a first fibre optic. The method also obtains a second temperature profile of the well by interrogating a second fibre optic to provide distributed sensing of temperature variations. Interrogating the second fibre optic comprises repeatedly launching interrogations of one or more pulses of coherent radiation into said second fibre optic, detecting any radiation which is Rayleigh backscattered from each interrogation and analysing the detected backscattered radiation to detect any variation between interrogations due to temperature variation. The method combines said first and second temperature profiles to provide a steam injection profile. The method may also involve determining an acoustic profile of the well through distributed acoustic sensing. Measurements from a small number of downwell point temperature and pressure sensors may also be used to determine the steam injection profile.