Time-lapse seismic has shown many successful offshore applications, but has turned out to be much more cumbersome when applied onshore. Successful applications are mainly observed for shallow objectives and large acoustic impedance changes, such as thermal EOR and CO2 injection. The dominant problems for onshore time-lapse are caused by near-surface variations between base and monitor surveys [Pevzner 2011]. By taking appropriate measures in acquisition and processing it is possible to overcome these problems. We demonstrate that with a continuous seismic time-lapse field trial in Schoonebeek, The Netherlands, where thermal EOR is applied. The time-lapse measurements not only enable us to observe pressure and temperature variations in the reservoir, but also to quantify these variations. These measurements complement the measurements made in wells, enabling the reservoir engineer to construct more accurate dynamic models, which make it possible to make better reservoir management decisions. We will describe the steps taken in acquisition and processing of the data and show an interpretation of the measurements.