6 DIRECTIVES AND REGULATIONS RELATED TO STORAGE SITE CLOSURE AND POST CLOSURE
This chapter provides an overview on the methods and the
regulatory requirements for CO2 injection sites over the
period of closure and post closure. It is structured
chronologically, starting with the process of abandoning the
injection wells and concludes with an overview of how the liability
for the project site can be transferred to the relevant
authorities.
The first part briefly discusses the different regulations
concerning CO2 site closure, which are still under
development (especially the national directives). The chapter also
provides information on already existing requirements for well
abandonment in the hydrocarbon industry, using international
conventions as well as accessible regulatory data from countries
engaged in oil and gas production. The regulations for
decommissioning of oil and gas production operations have already
served as a general basis for developing guidelines concerning the
handling of CO2 sites because of the similarity of the
subject.
Among the activities conducted during site abandonment, well
abandonment is considered the most important process, as it should
prevent all physical hazard induced by the well, prevent any
migration of contaminants and ensure that no communication between
originally separated hydrological systems is occurring. Therefore,
the chapter also provides a brief overview on the potentially
required technical details (plug placement) as well as overall
objectives of proper well abandonment (preserve hydrogeological
systems).
Following well abandonment, the post-closure phase is described,
starting with a brief discussion on how to prove the safety of
stored CO2. After summarising the iterative process of
characterisation of the reservoir, the general requirements for
long-term storage safety, certain modelling techniques, risk
management and suitable monitoring options are discussed. As all
monitoring plans must be chosen according to the particular risks
of the project, a variety of monitoring options also are
presented.
The last step in the post-closure phase is represented by the
transfer of liability. Exemplary regulations, like the EU Guidance
Documents are discussed briefly.
Generally the phase of closure and post-closure is the part of
the CCS life-cycle that has been practised the least, which leaves
room for developments and discussion, especially concerning the
final step of transferring the responsibility of the site.
The following sections provide an overview on the methods and the regulatory requirements for CO2Carbon dioxide injectionThe process of using pressure to force fluids down wells sites over the period of closure and post closure. Primarily based on the "Report on the international regulatory requirements on CO2Carbon dioxide geological storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere and site abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones" (Korre, 20112011 - A. KorreCO2CARE D1.1 International regulatory requirements on CO2 geological storage and site abandonmentsee more) and the "D1.2 Report on the current site abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones methodologies in relevant industries" (Wollenweber, 2012) by the project CO2Care - CO2Carbon dioxide Site Closure Assessment Research the objective is to summarise and provide updates on international, EUEuropean Union and national directives as wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids as guidelines for abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones methodologies.
Site abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones is generally defined as any actions taken by the operator to close down a previously operating field. The regulations concerning CO2Carbon dioxide site closure are, especially the national directives, still in a stage of development. That is why additionally the chapter gives information on the already existing requirements for wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones in the hydrocarbon industry, which due to the similarity of the subject already served as basis for guidelines concerning the handling of CO2Carbon dioxide sites. Also many CCSCarbon dioxide Capture and Storage projects will need to know the conditions of existing/abandoned oil and gas wells to decide if they are suitable for use in CO2Carbon dioxide storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere.
Concerning CO2Carbon dioxide site closure there are a few terms which are frequently used but have slightly varying meanings for the different regulations in use.
Generally in the UK and the EUEuropean Union, the term "closure" defines the moment of cessation of CO2Carbon dioxide injectionThe process of using pressure to force fluids down wells. Internationally the US UIC (Underground InjectionThe process of using pressure to force fluids down wells Control) and IEAInternational Energy Agency (International Energy Agency) speak of closure when the operator is released from site care. IEAInternational Energy Agency mentions additionally a "closure period" which defines the time between cessation of injectionThe process of using pressure to force fluids down wells and the point when the operator is no longer responsible for the site. Abandonment(wells) Actions taken to ensure permanent isolation of the fluids and pressures of exposed permeable zones within a well from the surface and from lower pressured zones defines the general process required when the wellManmade hole drilled into the earth to produce liquids or gases, or to allow the injection of fluids is no longer in use. "Post closure" is the period after the end of injectionThe process of using pressure to force fluids down wells. Different protocols provided by IEAInternational Energy Agency (International Energy Agency), IOGCC (Interstate Oil and Gas Compact Commission) and WRI (World Resources Institute) define "post closure" as the period after a certificationIn the context of carbon trading, certifying that a project achieves a quantified reduction in emissions over a given period of closure (by the appropriate authority). This certificationIn the context of carbon trading, certifying that a project achieves a quantified reduction in emissions over a given period may also contain the release of the operator and the "transfer of liability", which defines the moment when site care is transferred to the authorities or when the authority certifies that the site is safe.