The Utah FORGE research team has achieved yet another major milestone in advancing enhanced geothermal system technologies with the successful completion of the first large scale 10-day stimulation trial (April 14-24, 2022) in the deep deviated well 16A(78)-32. Three intervals were tested in sequence at greater than 10,000 ft depth, including the open hole at the toe of the well (Stage I), followed by two shallower 20 ft intervals that were lined with solid casing (Stages 2 and 3). In each stage, between 3000 and 4000 barrels of water were injected under pressure, causing pre-existing fractures in the reservoir to dilate and transfer heat to the injected cold water. After a 4-hour shut in, the hot injected water was produced back to the surface under controlled flow conditions. The stimulation trial ran according to schedule and plan, including the seamless deployment and retrieval of the bridge plugs at high pressures and temperature.
The ability to initiate, propagate and ideally control hydraulic fracture growth is essential for realistically evaluating the potential for commercial EGS applications. Success here is important for promoting technical and hybrid EGS methods that use hydraulic injection to provide a heat exchange network or to achieve more effective connections with potentially productive natural fractures.
In late 2022 or early 2023, a second deep deviated well, the production well, will be drilled to intersect the hydraulic fractures. The connectivity of the fractures between the two wells will be established or improved, and short-term circulation testing will begin to assess the thermal viability geothermal reservoir.