Excessive thermal water volumes have been extracted from porous sedimentary rocks in the Hungarian part of the Pannonian Basin. Thermal water production in Hungary increased significantly from the early 1970s. Regional-scale exploitation of geothermal reservoirs without re-injection resulted in basin-scale pressure drop in the Upper Pannonian (Upper Miocene) sediments, leading to compaction. This compaction resulted in ground subsidence primarily through poro-elastic coupling. We investigated surface deformation at the Szentes geothermal filed, SE Hungary, where the largest pressure decline occurred. Subsequently, hydraulic head recovery in the western part of the geothermal reservoir was initiated in the mid-1990s. We obtained data from the European Space Agency’s Envisat satellites to estimate the ground motions for the period of November 2002–December 2006. We applied inverse geomechanical modeling to estimate reservoir properties and processes. We constrained the model parameters using the Ensemble Smoother with Multiple Data Assimilation, which allowed us to incorporate large amounts of surface movement observations in a computationally efficient way. Ground movements together with the modeling results show that uplift of the Szentes geothermal field occurred during the observation period. Since no injection wells were operated at Szentes before 2018, and production temperatures remained relatively constant through the entire production period, we explain ground uplift with pore pressure increase due to natural recharge. The estimated decompaction coefficients of the reservoir system characterizing the elastic behavior of the Szentes geothermal reservoir varies between ~ 0.2 × 10–9 and 2 × 10–9 Pa−1. Compaction coefficients of the reservoir system corresponding to the earlier depressurization period, from ~ 1970 to the mid-1990s, may be significantly larger due to the potential inelastic behavior and permanent compaction of clay-rich aquitards. The improved parametrization enables better forecasting of the reservoir behavior and facilitates the assessment of future subsidence scenarios that are helpful for the establishment of a sustainable production scheme.

中文翻译：

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匈牙利东南部 Szentes 地热区孔隙压力变化引起的地面运动

从潘诺尼亚盆地匈牙利部分的多孔沉积岩中提取了过多的热水量。自 1970 年代初以来，匈牙利的热水产量显着增加。在没有回注的情况下对地热储层进行区域规模的开采导致上潘诺阶（上中新世）沉积物的盆地尺度压力下降，从而导致压实。这种压实主要通过孔隙弹性耦合导致地面沉降。我们调查了匈牙利东南部 Szentes 地热田的地表变形，那里发生了最大的压力下降。随后，在 1990 年代中期开始了地热储层西部的水头恢复。我们从欧洲航天局的 Envisat 卫星获得数据，以估计 2002 年 11 月至 2006 年 12 月期间的地面运动。我们应用逆地质力学模型来估计储层特性和过程。我们使用具有多数据同化的集成平滑器来约束模型参数，这使我们能够以计算有效的方式合并大量的表面运动观测。地面运动和模拟结果表明，Szentes 地热场的隆升发生在观测期间。由于在 2018 年之前在 Szentes 没有运行注入井，并且生产温度在整个生产期间保持相对恒定，我们解释了由于自然补给导致的孔隙压力增加的地面隆起。表征 Szentes 地热储层弹性行为的储层系统的估计解压系数在 ~ 0.2 × 10-9 和 2 × 10-9 Pa-1 之间变化。由于富含粘土的隔水层的潜在非弹性行为和永久压实，对应于早期减压期（从~ 1970 年到 1990 年代中期）的储层系统压实系数可能显着更大。改进的参数化能够更好地预测储层行为，并有助于评估有助于建立可持续生产计划的未来沉降情景。由于富含粘土的隔水层的潜在非弹性行为和永久压实，对应于早期减压期（从~ 1970 年到 1990 年代中期）的储层系统压实系数可能显着更大。改进的参数化能够更好地预测储层行为，并有助于评估有助于建立可持续生产计划的未来沉降情景。由于富含粘土的隔水层的潜在非弹性行为和永久压实，对应于早期减压期（从~ 1970 年到 1990 年代中期）的储层系统压实系数可能显着更大。改进的参数化能够更好地预测储层行为，并有助于评估有助于建立可持续生产计划的未来沉降情景。