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Abstract: In June 2009, the EU Directive on the Geological Storage of Carbon Dioxide entered into force. The European Member states are obliged to transpose the directive in their national legislations no later than 25 June 2011. The EU legislator has applied a regime of minimum harmonisation when drafting the CCS Directive, amongst others to achieve that an agreement could be reached on the CCS Directive by a majority of Member States. In other words; Member States have considerable discretionary powers while implementing the Directive. The CO2 Storage Directive is mainly transposed into Dutch legislation by means of adaptation of the Dutch Mining Act. There are, however, still some issues in the implementation of this directive that need further clarification. The way these issues are addressed may impact the deployment of large-scale CO2 capture and storage (CCS) in the Netherlands and Europe. [Copyright &y& Elsevier]

In this paper we present a review of controlling geological, tectonic and engineering factors for induced seismicity associated to gas depletion in the Netherlands and we place experiences from extensive Dutch geomechanical studies in the past decade in the context of generic models for induced seismicity. Netherlands is in a mature gas production phase, marked by excellent subsurface structural and stratigraphic characterization. Over 190 gas fields of varying size have been exploited. No more than 15% of these fields show seismicity. Geomechanical studies show that, similar to the EGS stimulation phase, largest seismicity is localized on pre-existing fault structures. However, the prime cause for seismicity in gas depletion is differential compaction, whereas in EGS stimulation related pressure build-up and fluid pressure diffusion along the faults form the prime mechanism. On the other hand, our study has a close theoretical analogy to reservoirs where the fluid volumes extracted are significantly larger than the re-injected volumes, and which can result in (differential) reservoir compaction.The observed onset of induced seismicity in the Netherlands occurs after a considerable pressure drop in the gas fields. Geomechanical models show that both the delay in the onset of induced seismicity as well as the non-linear increase in seismic moment observed in the induced seismicity, can be explained using a model of differential compaction, if the faults involved in induced seismicity are not critically stressed at the onset of depletion. The presented model serves to highlight key aspects of the interaction of initial stress and differential compaction in the framework of induced seismicity in Dutch gas fields. It is not intended as predictive model for induced seismicity in a particular field. To this end, a much more detailed field specific study, taking into account the full complexity of reservoir geometry, depletion history, mechanical properties and initial stress field conditions is required. [ABSTRACT FROM AUTHOR]

Abstract: Tectonic modeling is often neglected in the basin modeling workflow and heat flow is most times considered a user input. Such heat flows can, therefore, result in erroneous basin modeling outcomes, resulting in false overoptimistic identification of prospective areas or failure to identify prospects. This is particularly true for areas with limited data control such as frontier basin areas, or deep unexplored plays in mature basins. Three major factors obstruct routinely use. Firstly, because of the focus of most tectonic models on lithosphere scale processes a large range of models, including the McKenzie rift model, fail to take into account effects which are of paramount importance for basement heat flow such as transient effects of sediment infill and erosion, and changes in crustal heat production over time. Secondly, lithosphere tectonic models often fail to allow inversion of basin data, making forward tectonic modeling a cumbersome exercise. Non-vertical sediment movements and 2D and 3D loading effects can play an important role, hampering a unique inversion. Thirdly, lithosphere tectonic models generally fail to aid the user to understand the sensitivity of the model results in terms of basin maturation for permissible ranges of tectonic model parameters and for uncertainties in tectonic scenarios such as absence or presence of underplating or two-layered stretching vs a McKenzie model For this reason, we have developed a multi-1D probabilistic tectonic heat flow model, which is capable of calculating tectonic heat flows, incorporating a variety of tectonic scenarios. The model is capable of inversion of burial histories, calibrated to temperature and maturity data. Calibration and sensitivity analysis is done through Monte Carlo sampling analysis using an experimental design technique for computational efficiency. The tectonic heat flows can easily be used as input for basin modeling in commercially available 3rd party software. [Copyright &y& Elsevier]