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In recent years public concern about earthquakes induced by gas production has increased in the Netherlands. This has mainly been caused by numerous seismic events related to gas depletion in the Groningen gas field, the largest gas field in Western Europe. Induced seismicity has also been observed in 31 smaller gas fields located on land (onshore) or in the area close to the Dutch coast. Earthquakes with magnitudes as high as M L  = 3.5 have occurred in Roswinkel and Bergermeer causing damage to buildings. In 2016 State Supervision of Mines (SSM), with input from the geological survey of the Netherlands (TNO) and the onshore operators, proposed a guideline for a qualitative seismic risk analysis for depletion induced seismicity arising from gas production in the small fields in the Netherlands. The guideline follows international practices for risk assessment using a risk matrix approach. This paper elaborates the seismic risk guideline and reports on the application of the guideline to the gas fields in the Netherlands. Risk is a combination of hazard and consequences. The result of the seismic risk analysis is qualitative and gives a relative scoring of the producing gas fields in the Netherlands in terms of risk. In order to obtain more information on the quantitative assessment of the risk, more detailed studies are needed. The Groningen gas field clearly poses a much larger seismic risk than that obtained for the other, smaller gas fields, most of which fall into the lowest risk category. Because of the large difference in risk between the Groningen field and the other smaller gas fields, the guideline of SodM deems it sufficient to carry out a qualitative risk analysis for the other gas fields in the Netherlands, as performed in this paper. Based on the combination of the hazards and consequences, the risk can be further interpreted and, if necessary, appropriate measures can be implemented. [ABSTRACT FROM AUTHOR]

Abstract: Shell CO2 Storage B.V. (SCS) is planning to inject up to 10 million tonnes of CO2 in two depleted gas fields: Barendrecht (BRT) and Barendrecht-Ziedewij (BRTZ). This paper describes the process of selecting an optimised commercial value chain design for capture, transportation, injection and marketing of the CO2, requiring a helicopter view of the full system from source to sink over the 30 year injection life cycle of the project. The commercial concepts considered, selection criteria used and the selected concept will be discussed. Second, the economic modelling criteria for the main value drivers of the project will be discussed and the main differences with traditional petroleum economics will be indicated. Although the project is not pursued for financial profit, the use of the evaluation methodology described below has resulted in an optimal value proposition and value chain for Government, project, sub-contractors and society. The analysis showed that the project differed significantly from other CCS projects due to the relative weight of the transportation value component. The risk and uncertainty approach for the economic modelling of the key value drivers of the projects has resulted in a robust economic model to assist decision making for any changes to the project in a rapidly changing political environment. [Copyright &y& Elsevier]

Abstract: The onshore Barendrecht CO2 storage project in the densely populated West of the Netherlands is designed to prevent CO2 to migrate out of the deep underground through geological formations and outside of wells. Achieving maximum safe containment is facilitated by selecting depleted gas fields as CO2 storages having stored natural gas over millions of years. This also allows choosing a final storage pressure that is lower than the ambient natural pressure in the surrounding rock formations. The inverse pressure gradient prohibits potential outflow from the storage reservoir. Additional proven safety barriers are the existence of sealing caprocks and large saline aquifers that overlie the storage reservoir. These saline aquifers alone have the capacity to sequester multitudes of the CO2 volumes that are planned to be stored in the depleted gas reservoirs. It is widely accepted that wells hold the main potential of forming a migration path. In the case of Barendrecht this would mainly mean potential migration of reservoir fluids of overlying formations into the CO2 storage reservoir as pressure equalization–returning to a natural equilibrium as existed prior to start of gas production without any overpressures–is not expected to occur before hundreds to thousands of years. Nevertheless assessing the evolution of current and future well integrity with CO2 injection is crucial for ensuring containment of the injected CO2 during injection and in the long term. The Barendrecht fields have respectively two and three drilled and completed wells penetrating the CO2 storage reservoir. This paper describes the most relevant subsurface related highlights from various studies that were carried out in connection with the Barendrecht CO2 storage project. [Copyright &y& Elsevier]

Abstract: This paper describes the development and application of an methodology to screen and rank Dutch reservoirs suitable for longterm large scale CO2 storage. The screening is focused on off- and on-shore individual aquifers, gas and oil fields. In total 177 storage reservoirs have been taken into consideration (139 gas fields, 4 oil fields and 34 aquifers, with a total storage potential of about 3200 Mt CO2). These reservoirs have been selected from over five hundred potentially suitable CO2 storage reservoirs. The total number of storage reservoirs has been reduced by applying preconditions with associated threshold values. Nevertheless, the number of reservoirs is still significant and limits the possibility to use any pair-wise comparison method (e.g. Multi-Criteria programs such as Bosda or Naiade). Therefore, a excel tool has been developed based on linear aggregation. The tool screens the reservoirs based on three criteria: storage potentials, costs and effort needed to manage risk. [Copyright &y& Elsevier]