TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractThe continuous monitoring of the main reservoir parameters is usually very important in capturing data, which are then used for reservoir characterization and recovery process evaluation in reservoir studies. This characterization is used to define the production strategy and oil recovery efficiency of the fields. In the case of High Pressure and High Temperature reservoirs, the reservoir monitoring becomes a challenge. The Furrial field, located in Northeastern Venezuela, is an example of a very deep, HP and HT reservoir. During the design and application of a WAG pilot project in this field, several monitoring techniques were considered. Of these, some monitoring techniques were selected and subsequently some of them were implemented in the pilot. This paper presents some field results related to several monitoring techniques that have been applied during the different phases of the WAG pilot test in the Furrial field. The study considers conventional techniques such as chemical and radioactive tracers, and saturation, temperature, pressure and production logs. Also this study examines unconventional techniques such as natural tracers, pressure and temperature downhole gauges. Finally, the study investigates, new approaches for monitoring such as saturation downhole permanent gauges, post-mortem cores and crosswell seismic. All the techniques were analyzed and compared, considering the reservoir characteristics, application feasibility, market availability, time of response and costs, to select the most suitable techniques for this type of reservoir. The results from the Furrial field case show that even though permanently mounted downhole gauges seem to be the most appropriate way to capture reservoir data for a mechanistic pilot, they are not totally reliable, so far, for HP and HT reservoirs.