| Abstract |
Field pressure signal testing is widely used to support reservoir diagnostics, model calibration, and operational decision-making in geothermal systems. However, conducting such tests in operating low-temperature geothermal reservoirs (typically with wellhead temperatures below ~70 °C) still presents substantial operational and data-quality challenges under real field conditions. This study does not focus on the pressure signal test itself, but instead uses it as an example to highlight the data-processing difficulties that arise even before interpretation begins. A key issue examined here is wellbore pressure loss, which can obscure the true reservoir response and complicate signal analysis if not properly corrected. By focusing on this step, the aim is to raise awareness of the practical complexities involved in acquiring and processing field pressure data. For this work, a quadruplet of active wells—two production wells (FHQY#1 and FHQY#4) and two reinjection wells (FHQY#2 and FHQY#3)—at a district-heating station in a low-temperature sandstone reservoir in northern China was selected. Measurements revealed clear differences between near-surface and bottomhole pressure variations, typically 0.4 to 1 bar under flowrates of 25–60 m³/h. Maximum pressure drops in the production wells reached ~30% and could up to ~60%, while reinjection wells showed wellbore-loss contributions of ~13–17% of the maximum reinjection pressure increase. These wells therefore provided a representative setting to investigate real-world data acquisition constraints and the need for careful pressure-loss correction before reservoir interpretation. |