Monte Carlo Method for Probabilistic Hazard Assessment of Induced Seismicity due to Conventional Natural Gas Production
Monte Carlo Method for Probabilistic Hazard Assessment of Induced Seismicity due to Conventional Natural Gas Production
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DOI：
10.1785/0120140302
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发表时间：
2015-06-01
影响因子：
3
通讯作者：
Doornhof, D.
中科院分区：
文献类型：
--
作者：
Bourne, S. J.;Oates, S. J.;Doornhof, D.
提出了一种基于蒙特卡罗方法的概率地震危险性分析方法，该方法适用于与压实气藏相关的诱发地震活动。该方法的地质力学基础是Kostrov（1974）和McGarr（1976）将地震目录中的总应变与地震力矩总和联系起来的工作。我们的蒙特卡罗方法通过对总地震矩、事件位置和震级以及由此产生的地面运动的抽样概率分布，模拟与历史地震和压实数据集一致的未来地震危险。地面运动被聚合在一组模拟目录上，以给出地面运动危害的概率表示。这种方法特别适合于考虑的时变诱发地震活动的特定性质。我们将该方法应用于格罗宁根气田产气后由储层压实引起的地震活动。通过用当地强震数据校准现有的地震动预测方程，推导出了一种适合格罗宁根油田的新的地震动预测方程（GMPE）。对于2013-2023年，我们发现有2%的机会超过0.57g的峰值地面加速度，有2%的机会超过最大压实面积以上22 cm/s的峰值地面速度。分解表明，震源距离最短为3公里的m - 4-5级地震和中位数以上两个标准差的地面运动对这种危险的贡献最大。危险的不确定性主要是由于不确定未来诱发地震的应变部分，以及地面运动及其变化将如何扩大到更大的震级。
A Monte Carlo approach to probabilistic seismic-hazard analysis is developed for a case of induced seismicity associated with a compacting gas reservoir. The geomechanical foundation for the method is the work of Kostrov (1974) and McGarr (1976) linking total strain to summed seismic moment in an earthquake catalog. Our Monte Carlo method simulates future seismic hazard consistent with historical seismic and compaction datasets by sampling probability distributions for total seismic moment, event locations and magnitudes, and resulting ground motions. Ground motions are aggregated over an ensemble of simulated catalogs to give a probabilistic representation of the ground-motion hazard. This approach is particularly well suited to the specific nature of the time-dependent induced seismicity considered.We demonstrate the method by applying it to seismicity induced by reservoir compaction following gas production from the Groningen gas field. A new ground-motion prediction equation (GMPE) tailored to the Groningen field has been derived by calibrating an existing GMPE with local strong-motion data. For 2013-2023, we find a 2% chance of exceeding a peak ground acceleration of 0.57g and a 2% chance of exceeding a peak ground velocity of 22 cm/s above the area of maximum compaction. Disaggregation shows that earthquakes of M-w 4-5, at the shortest hypocentral distances of 3 km, and ground motions two standard deviations above the median make the largest contributions to this hazard. Uncertainty in the hazard is primarily due to uncertainty about the future fraction of induced strains that will be seismogenic and how ground motion and its variability will scale to larger magnitudes.