THERMAL RESERVOIR CHARACTERISTICS OF HIGH-QUALITY SANDSTONE IN THE WEST SLOPE BELT OF DONGPU SAG

There are serious sand production and recharge difficulty in the sandstone reservoir geothermal wells of Neogene Minghuazhen Formation in the west slope belt of Dongpu Sag. To find out the geothermal geological characteristics of high-quality sandstone reservoir in the area, the paper studies the regional structure, distribution rule of geothermal field and detail of thermal reservoir, and optimizes the design of exploration wells combined with the structure, reservoir and geotemperature conditions. The results indicate that the Neogene structure in the west slope belt is stable with the floor depth of 2 000-2 200 m for Guantao Formation where the high-quality sandbodies are developed in its lower part (1 800-2 200 m) with the temperature above 65℃, showing good thermal storage property and development potential for geothermal resources. The hydraulic testing results of sandstone reservoir geothermal wells of Guantao Formation in Changyuan area are consistent with the prediction, which further confirms the geothermal exploration and development potential in the area.