Overview modelling gas production-induced seismicity mechanisms

Several studies have been carried out at Delft University of Technology in order to analyse seismicity that might be related to gas production. An overview will be given in this paper. Models show that the sensitivity for fault activation due to differential compaction evidently depends on the fault-reservoir geometry. This behaviour is supported by several subsequent case studies of fault behaviour in producing gas reservoirs. Examples of such reservoirs, presented in this paper, are Eleveld and Bergermeer in the Netherlands. A comprehensive study about an anticline-shaped reservoir concluded also in activation of a normal fault at reservoir level as dominant mechanism. In another study, the effects of gas storage on the relationship between pore pressure variations and fault slip are investigated. The results from this numerical modelling are that during the initial production phase, fault slip might occur locally, due to compaction of the reservoir, and that no significant amounts of additional slip occur when the reservoir is subjected to alternating injection/extraction periods.Old - CITG Section Engineering Geolog