5 Well abandonment regulations

5.1 Introduction

Many CCS projects are likely to encounter existing abandoned oil and gas wells. In order to safely store CO2 in geological formations, it is of high importance to know the condition of these wells. However, often information on the current status of the abandoned wells is difficult to obtain. The condition of abandoned wells is primarily determined by the practiced abandonment measures. Therefore, the requirements governing the decommissioning of oil and gas wells principally determine their suitability for use in second life applications.

Worldwide, countries and/or states employ specific policies and procedures for well abandonment. This chapter presents an overview of official regulations concerning well abandonment for a selected number of countries and states (Table 5.1). The selection of countries included is based on two main criterions and therefore not exhaustive. First of all, the countries and regions considered in the current assessment are either significantly engaged in oil and gas production or involved in CO2 storage applications. Secondly, accessibility of regulatory data was taken into account. The fact that in many cases the official regulations concerning well abandonment are only available in the official language of the country further hampered incorporation of these regulations.

Table 5.1 Regulations of countries/international regulations reviewed.

Country State Regulation
Denmark A Guide to Hydrocarbon Licences in Denmark
France Article 49 (part of Decree no. 2000-278 (RGIE, 2000))
Germany
Norway NORSOK Standard D-010
The Netherlands the Mining Legislation and of the Working Conditions Regulation
United Kingdom Guidelines for the Suspension and Abandonment of Wells by UKOOA
Australia Western Schedule of Onshore Petroleum Exploration and Production
Australia Requirements - 1991
Queensland Petroleum and Gas (Production and Safety) Regulations 2004
Canada Alberta The Well Abandonment Guide described in Directive 20 of the Energy Resources Conservation Board
China Control Rules on offshore Oil Well Abandonment Operations of the People’s Republic of China
Japan Well abandonment regulations by the Japanese Ministry of Economy, Trade and Industry
United States of America US EPA Regulations on Plugging and Abandoning Injection Wells for Class II wells.
API guidance
Alaska The Alaska Administrative Code
California Section 1723 from the California Code of Regulations
Texas Rule 3.14 from the Texas Administrative Code
International Conventions London Convention 1972 and 1996 Protocol OSPAR Convention

The evaluation of assets for potential application in CO2 storage projects requires a detailed, site-specific approach. The information presented in this chapter gives a general overview and will not suffice drawing conclusions on the status of specific wells. In addition, it must be noted that only standard well abandonment regulations were studied, instead of specific CCS well abandonment regulations. Although an effort was made to describe historical developments in abandonment regulations, the majority of information in this chapter comprises current or recent regulatory descriptions. Furthermore, the evaluation of regulations in this chapter focuses on prescriptive requirements. If in force, complementary regulations on e.g. labour conditions and environmental impact can significantly influence the effective management of well abandonment. However, regulations concerning these subjects as well as regarding administrative tasks, such as abandonment reporting, are beyond the scope of this study.

No legal rights can be derived from the regulatory descriptions in this chapter, as they often involve unofficial representations and/or translations of the original documents. The meaning of terms used in the different documents may differ and it is advised to consult the original documents in case clarity is required. Authentic regulations are published by the legal authorities. Several involved authorities responded to our request to approve the information in this chapter.

5.2 Denmark

5.2.1 Introduction

Oil and gas exploration started in Denmark in 1935. In 1966, hydrocarbons were discovered in the Danish part of the North Sea. After that, the exploration continued and a series of oil and gas fields were found. The first oil was produced from the Dan field in 1972.

The Danish Energy Authority (DEA) [1] is an institution under the Ministry of Transport and Energy and was established by law in 1976. It is the responsibility of the DEA to follow and evaluate the Danish and international progress in the fields of energy production, supply and research. The DEA administrates and supervises energy legislation for power and heating supply, renewable energy, and exploration for and production of oil and natural gas according to the Danish Subsoil Act. The Subsoil Act lays down the basic framework for petroleum exploration and recovery. The Act is formulated as a ‘general terms act’ allowing for adaptations and more detailed regulations. It regulates exploitation and recovery activities in the Danish subsoil and the Danish Continental Shelf concerning minerals, and specifically hydrocarbons.

Apart from the DEA functions in the oil and gas sector, the activities of the licensees are subject to approval from other Danish authorities. Especially the environmental regulations and the approval procedures for oil spill contingency plans should be considered.

In 2007, the DEA published “A Guide to Hydrocarbon Licences in Denmark” (DEA, 2007). This guide7 contains the section “Guidelines for Drilling - Exploration” which was published in 1988 and revised in 2005. These guidelines apply to approval and supervision, which in consequence of the Danish Subsoil Act have been delegated to the DEA. The guidelines relate to exploration and appraisal wells for hydrocarbons and other minerals, offshore and on land as specified in Section I of the Subsoil Act. In addition, the section “Guidelines for Drilling – Exploration” provides guidelines for well abandonment. These guidelines are available in Appendix A.

5.2.2 Well abandonment regulations

An exploration well shall be abandoned permanently when drilling operations as well as relevant logging and test production have been carried out. However, under special circumstances the DEA may permit a well to be abandoned temporarily without permanent plugging. A well shall be plugged such that it is ensured that no fluid of flow through the hole and no communication from down hole formation to the seabed/surface via any casing annulus is possible. To this end, multiple plugs shall be placed. The total weight of the cement plugs in the well and the weight of the fluid between the plugs shall ensure that as a minimum the system is in balance with any pressure which may develop in the borehole.

In cases where the well is uncased opposite permeable zones, plugs are normally placed at least 50 m below and above the individual zones. Where there is an open hole below the deepest casing, a cement plug shall be placed in such a manner that it extends at least 50 m above and below the casing shoe. Alternatively, a mechanical plug may be positioned in the casing, within 50 m from the shoe. In addition, a cement plug, at least 50 m long shall be placed on top of this plug. Perforated intervals shall be isolated with cement plugs through the individual perforated zones and with 50 m long cement plugs below the lowermost perforation and above the uppermost perforation. Alternatively the perforated zones can be isolated by a combination of a mechanical plug and squeeze cementing of the perforations and cement plugging above the mechanical plug. In the innermost casing a cement plug must be placed from the shoe depth of the previous casing and 100 m up. A cement plug, at least 100 m long, shall be placed near the surface.

In general, plugs shall be pressure tested for sufficient time and with enough differential pressure to detect a possible leak or mechanical failure of the plug. In addition, the top of cement plugs shall be located by load testing.

5.2.3 Additional note

The “Guidelines for Drilling” (DEA, 2007) were defined in 1988, whereas the first oil was produced in 1972. This raises the question what happened to the wells that were abandoned before 1988. According to DEA8, the policy has always been the same and all individual well abandonments are approved by them. Secondly, it was noted that only two closed wells in Denmark have been leaking since 1980. Small leaks in abandoned offshore wells will, however, never be found, since these wells are generally not in the vicinity of existing platforms and are not monitored.

5.3 France

5.3.1 Introduction

Well abandonment regulations in France are defined by the Ministry of Economics, Industry and Employment (formerly the Ministry of Economics, Financial Affairs and Industry) in the ‘Règlement Général des Industries extractives’ (RGIE, i.e. General Regulations for the Extractive Industry). Within this regulation multiple decrees have been defined. In 1986, Decree no. 86-287 (RGIE, 1986) was defined for offshore drilling activities. In 2000, this decree was revised into Decree no. 2000-278 (RGIE, 2000). Within this decree, Article 49 ‘Fermeture définitive du puits’ (translated: “Definitive closure of wells”) was defined, focusing on both onshore and offshore well abandonment.

This section presents an overview of the regulations from Article 499. Detailed information can be found in Appendix B.

5.3.2 Well abandonment regulations

The required closure program in France depends on the age and the state of the wells. In addition, the knowledge of the operator on the status of primary cementing and casing is taken into account. If the state of the cementing is not adequately recorded, the closure shall be preceded by an investigation of the cement and casing. In case no cementing is present, or if the cementing is not sufficiently long or has reduced efficiency, it is necessary to place, extend or improve the cementing. The latter can be accomplished by for example, circulation of cement or resin after perforation. In addition, the current pressure in the annuli needs to be determined.

In general, in Article 49 it is stated that all necessary precautions must be taken to isolate reservoirs from each other. The abandonment operations must be performed such that the permeable layers will remain permeable and that no mixing of fluid between different permeable layers shall occur. To separate permeable layers, only materials are allowed to be used that do not degrade over time. The plugs shall be placed such that either two subsequent permeable layers are isolated, or other levels are isolated, if incontrollable flows between intermediate layers are acceptable. Plug lengths shall be at least 50 or 100 m, depending on the characteristics of the well bore.

5.3.3 General comments

In general, the plugs consist of cement, but sediments or resin are also allowed. The material that is used depends on the location of the plug. Only materials with known characteristics, such as resistance and plasticity, shall be used. The quality of isolation must be checked by means of a load test and a pressure test. The height and quality of the cement can be monitored by a Cement Bond Log (CBL).

5.4 Germany

5.4.1 Introduction

Germany has a long history for mining regulation, in particular concerning the right to explore and produce minerals. The first known legal basis dates back to the year 1158. In 1865 a new mining law was approved which concerned a central regulation. After the Second World War the existing jurisdiction concerning mineral resources was decentralised to the eleven states in the Western part of Germany. The Eastern part of Germany was directed to the government in Berlin and until 1947 only state companies received the right to explore and produce [4].

5.4.2 Well abandonment regulation

The first abandonment policies were established as ‘Bergpolizeiliche Vorschriften’ (Mining police orders) in the 19th century for each German state separate; Prussia, Saxony, Oldenburg, Schaumburg-Lippe etc. Until recently a complex regional history of regulations was in place. Currently the German exploration and production of hydrocarbons is regulated under the ‘Bundesberggesetz BBergG’ (Federal mining law) dated 13 August 1980, and the ‘UVP-VBergbau’(ordinance on the environmental impact assessment of mining projects) dated 13 July 1990, as well as the respective mining regulations of the various states. In addition, the ‘Verein Deutscher Ingenieure’ (Association of German Engineers) has issued a number of guidelines dealing primarily with the relevant mechanical equipment [5].

The Federal Institute for Geosciences and Natural Resources (BGR) in Hannover is currently documenting the well abandonment regulation per state in Germany. This report will be publicly available in the second half of 200910.

5.5 Norway

5.5.1 Introduction

As a result of the enforcement of the Continental Shelf Act in 1963 the first production license in Norway was granted by State in 1965, followed by the first production well drilled in 1966. The Norwegian petroleum production started after the discovery of the Ekofisk reservoir in 1969 which was the first commercially viable discovery. After the start of production on 15 June 1971 more discoveries were made in the Norwegian continental shelf. At the beginning of 2008, 57 new oil and gas fields were in production in Norway (Ministry of Petroleum and Energy, 2008), (Bull, 1981). The total number of non-active and active development, exploration, production and injection wells on the Norwegian Continental Shelf per 1 January 2006 can be found in Vignes et al. (2006), as well as ages of the wells.

5.5.2 Exploration and operation phase

On 1 July 1985 the 1963 Continental Shelf Act was replaced by the Norwegian Petroleum Act containing requirements for preparing a field specific environmental impact assessment (EIA) for the exploration and operation phase of petroleum activities in the Norwegian shelf. However, the first Norwegian EIAs were criticised for focussing too little on field development concepts and the technical design of the installations (Kinn, 1981). The 1985 Petroleum Act was revised in 1997 in which a legal basis was established for requiring Regional EIAs (REIA). With REIAs the total planned and expected activity and its effects within an area are evaluated.

Norway participates in the establishment of international standards, ISO and EN, which form the basis of petroleum activity. To ensure continuance in the Norwegian safety framework and climate conditions amendments are required. Therefore, in 1993 NORSOK standards were established by the Norwegian petroleum industry to ensure adequate safety, value adding and cost effectiveness for petroleum industry developments and operations [5].

5.5.3 Well abandonment regulation

Decommissioning activities in Norway are regulated under the 1996 Petroleum Act as well as under the obligations of the OSPAR Convention (Convention for the Protection of the Marine Environment of the North-East Atlantic). The Petroleum Act requires licensees to submit a decommissioning plan to the Ministry of Petroleum and Energy two to five years prior the expiring or surrender of a license or the termination of a facility. The decommissioning plan must consist of two main parts; a disposal plan and an impact assessment. OSPAR Decision 98/3, which came into force on 9 February 1999, concerns rules on the disposal of offshore installations at sea (NPD, 2008), (Ministry of Petroleum and Energy, 2008). See for more information on these regulations the OSPAR Convention description in Section 5.13.2.

Specific abandonment regulations are developed in NORSOK Standard D-010 (Standards Norway, 2004) which focuses on well integrity. The standard was amended in 2004 in order to account for technological development including CO2 storage. The standard defines the minimum functional and performance oriented requirements and guidelines for well design, planning and execution of safe well operations in Norway. A detailed description of relevant guidelines concerning well abandonment is available in Appendix C. In the remainder of this section a brief description of the standard is presented. In addition, a number of discussion points concerning the NORSOK Standard D-010 in relation to CO2 applications is presented.

5.5.4 General well abandonment regulations

In general, permanently plugged wells shall be abandoned with an eternal perspective. There shall be at least one well barrier between surface and a potential source of inflow, unless it is a reservoir that contains hydrocarbons and/or has a flow potential where two well barriers are required.

Plug lengths of 100 m are required. It must extend, at a minimum, 50 m above a source of outflow or leakage point. A plug in transition from open hole to casing should extend at least 50 m below the casing shoe. If the plug is set inside the casing and with a mechanical plug as a foundation, the minimum length must be 50 m.

The plug installation shall be verified through documentation of job performances. In addition, the position of the plugs shall be verified by either tagging or pressure tests. If a mechanical plug is placed, only this plug shall be tested. The cement plug on top of the mechanical plug does not have to be verified.

5.5.5 Discussion points

In a report prepared by SINTEF (Randhol et al., 2007), some topics in the NORSOK D-010 standard are criticised in relation to CO2 applications. In addition, more stringent requirements are needed in some areas for the application on CO2 wells:

  • material selection of barriers for abandoned wells: the requirements for material are too general and specific details are not provided, e.g. type of steel, cement.
  • well barrier in several stages: no cement plug is placed in the caprock which is insufficient for wells exposed to CO2.
  • completion string: according to NORSOK the tubing can be left in place in case of permanently abandonment which is inadequate for CO2 applications.
  • temporary well abandonment: is not regulated to a certain time frame.
  • monitoring permanently abandoned wells: guidelines are missing

5.6 The Netherlands

5.6.1 Introduction

In the Netherlands the regulations and guidelines for mining activities date back to the Napoleonic times of 1810 (‘Loi des Mines’). These regulations were mainly aimed at natural resources mined in quarries and coal mines. Only in the 20th century wells were drilled to explore for hydrocarbons. The first commercial oil was found in 1943 (Schoonebeek) and first gas was struck in 1948 (Coevorden). In 1959 the giant Groningen gas field was discovered (ca. 2800 billion cubic meters) which led to a sharp increase of drilling activity, both onshore and offshore. Eventually this led to new regulations in 1964 to cope with the new situation. These regulations consisted of the Mining regulations (‘Mijnregelement 1964’) and the Mining Regulations Continental Shelf (‘Mijnregelement Continentaal Plat’) which came into force in 1967 (no offshore wells were drilled prior to this date). In 2003 these regulations were updated and united by a new updated Mining act. The regulations and guidelines concerning well abandonment there were not changed since 1964. Before that time well abandonment was not explicitly dealt with.

In the Netherlands there are some 1140 wells drilled before the Mining act was updated in 1964 and 1967. For these wells no general regulations on well abandonment were in place. Therefore, more specific investigations will have to be executed to determine their appropriateness for future applications such as geological storage of CO2.

5.6.2 Regulatory instruments of well abandonment

Regulatory instruments involved in the evaluation of abandonment programmes are laid down in the prescriptive legislation of the Dutch Mining Regulations, as well as in the goal-setting legislation of the Dutch Mining Decree and the Working Conditions legislation. The wells and boreholes section in the Mining Regulations dictates prescriptive rules on abandonment measures. The Mining Decree includes general and fit for purpose requirements to the construction, intervention and abandonment of boreholes and wells to prevent damage to health, safety and environment (HSE) interests. Compliance to these goal-setting elements of the Mining Decree is generally demonstrated by using best practices and state-of-the-art techniques in order to reach an acceptable risk level. In addition, the Mining Decree is coupled to the Working Conditions Act, including a Safety Case regime that requires a justification of risks to workers on a mining location or installation, in each step of its lifetime, to be acceptable. This also accounts for activities like construction, intervention and abandonment of wells that are carried out on these mining works. The coupling of the Mining Decree to the Working Conditions legislation provides an extra requirement to prevent adverse effects on HSE. As a result the Safety Case extends beyond the Mining Regulations by including the external risks that are projected from the mining location or installation to surrounding HSE interests. The integral legislation framework associated with Mining is enforced by the State Supervision of Mines under the Dutch Ministry of Economic Affairs.

5.6.3 Dutch Mining Act

Dutch Mining Act consists in fact of three levels: the ‘Mijnbouwwet’ (Mining Act itself), the ‘Mijnbouwbesluit’ (Mining Decree) and the ‘Mijnbouwregeling’ (Mining Regulations). The current Mining Act, accepted at October 12, 2002 and installed at January 1, 2003, contains rules in relation to the exploration and development of mineral resources and in relation to mining activities. It aims to give a clear framework for responsible and effective mining. The Mining Decree specifies the main elements of the Mining Act. More technical details of the whole Mining Act system are set forth in the Mining Regulations.

5.6.3.1 Mining Regulations

Chapter 8 of the Mining Regulation deals with boreholes and wells. Sections 8.18.4 deal respectively with general issues, working program and reporting, construction of boreholes and reparation of wells, and equipment of wells. Section 8.5 deals with abandonment of boreholes and wells.

Besides well plugs, the presence of a primary cement sheath outside of the casing is an important issue, since gases can migrate relatively easily when a well is uncemented at the level of a gas-bearing zone. Dutch Mining Regulation Chapter 8 gives extensive regulations for the placement of cement plugs when abandoning wells and for uphold safety requirements and installations, but pays little technical attention to down hole primary well cementing. This is regulated on the goal setting Mining Decree level. Without any further description Section 8.2.1 demands a working programme describing the cementing per casing interval (8.2.1.1.e). A good primary well cementing job is in fact secured by the required monitoring of casing pressures in Section 8.4.4. This system leaves in fact the freedom to the operator to adjust the primary cementing to the specific prevailing field conditions. Operators have extensive internal regulations and guidelines for primary well cementing.

Concerning the regulations on cement jobs when setting the casings intervals or and setting cement plugs while abandoning the well as stated in the current Mining Regulations have not been amended in the latest version. This implies that they are equal to those in the previous Mining Regulations Continental Shelf and the Mining Regulations 1964. Detailed information can be found in Appendix D.1.

5.6.4 Working Conditions Act

The purpose of the Working Conditions Act is to have equivalent and safe working conditions in all companies in the Netherlands, regardless of the number of employees. Employers are primarily responsible for the working conditions in their company. And employers and employees cooperate on improving the working conditions. The health and safety service can advise in this. The Health and Safety Inspectorate supervises employers’ compliance with the Working Conditions Act.

The Working Conditions Act describes the main features for health and safety policy. The general rules of the Working Conditions Act are elaborated upon in the Working Conditions Decree and the Working Conditions Regulation. The Working Conditions Decree contains concrete provisions which employers must follow, classified by subject. A number of subjects in the Working Conditions Decree have been elaborated upon in the Working Conditions Regulation. Detailed information can be found in Appendix D.2.

5.6.4.1 Safety cases

The requirement for the mining industry to produce and submit a safety and health document (safety case) emanated from the Piper Alpha disaster. Following publication of Lord Cullen’s report of the Public Inquiry into the Piper Alpha disaster, Government stated its commitment to implement those recommendations of relevance to mining activities in The Netherlands.

The safety case regime is laid down in the Working Conditions legislation and requires companies to follow a logical structured approach, when undertaking an objective critical review of their installations, locations, facilities or units and the operations and activities performed therein, including in wells. It identifies four key elements considered essential in the work performed by companies in compiling a safety and health document. This work provides the degree of assurance necessary to satisfy Company management, their workforce and finally, to demonstrate to Government, that operational activities can be performed safely, with due regard to the protection of human life. These elements are:

  • risk identification;
  • risk evaluation;
  • risk elimination and reduction;
  • risk control and management.

The primary objective of the safety case process is, to ensure that the safety and health protection of all personnel involved in mining operations and associated activities, is safeguarded. This requires the implementation of measures necessary to ensure:

  • that the design, use and maintenance of mining installations, locations, facilities, units and of the equipment and systems therein, whether fixed, mobile, portable or for individual use, are safe and remain in good condition;
  • that the risks incurred by personnel at their place of work, both operational and occupational, have been identified and evaluated;
  • that adequate measures exist or will be taken to ensure that workplaces are and will be maintained safe and that risks to personnel have been eliminated, or reduced to a level that is “As Low As is Reasonably Practicable” (ALARP);
  • that improvements to the existing situation, resulting from advances in technology and technical knowledge will be adopted.

5.7 United Kingdom

5.7.1 Introduction

The first oil and gas legislation was established in 1918 when the Petroleum (Production) Act was enacted. The Crown now had the right to control exploration and production in the UK and to grant licences. The 1918 act was revoked by the introduction of the Petroleum (Production) Act in 1934. The Petroleum (Production) Act 1934 and elements from the Continental Shelf Act 1964 was consolidated into the Petroleum Act 1998. This act contains, among others, rules relating to decommissioning of offshore installations [7].

5.7.2 Abandonment of wells

5.7.2.1 Onshore well abandonment

Decommissioning of onshore wells and associated hydrocarbon installations will be addressed through IPPC legislation. Permission to decommission onshore wells is also required from the Department of Trade & Industry under The Petroleum (Production) (Landward Areas) Regulations 1995.

5.7.2.2 Offshore well abandonment

Abandonment of offshore wells has to be carried out in accordance with the Oil & Gas UK Guidelines for the Suspension and Abandonment of Wells developed by the UK Offshore Operations Association (UKOOA). The full text of this guideline (UKOOA, 1995) can be found in Appendix E.

5.7.2.3 Description of the UKOOA (1995) guideline

The required standards for well abandonment involve an acceptable permanent barrier (the main characteristics of abandonment materials (plugging material)), the location of the permanent barrier for isolation from the surface, minimum requirements for permanent barriers and a verification procedure.

The barrier requirements involve the main characteristics of abandonment material, e.g. low permeability, long term integrity, no shrinking. The cement plug must be a column of at least 100 ft depth made out of good cement. Where possible 500 ftAHD plugs must be used. The guidelines distinguish between a cased hole plug and a open hole plug, as well as cemented casing and alternative plugging material. Two permanent barriers from surface/seabed are required by these guidelines to achieve effective isolation of hydrocarbon bearing permeable zones. The first barrier should extent at least 100 ft above the highest point of potential inflow, the second barrier acts as a backup of the first barrier.

The minimum requirements for permanent barriers are set per specific circumstances; open hole, casing shoe, perforated casing, behind casing and casing cuts and liner caps.

According to the guidelines it is important that the position and effectiveness of barriers can be confirmed. The guidelines do not outline specific requirements for verification. They do, however, recommend minimum requirements in case of open hole (weight tested), cased hole (first barrier: tagged and pressure tested, second barrier: tagged), annulus, casing cuts and liner laps (log).

When the isolations are achieved the removal of downhole equipment is not required. Typically, well conductor and casing strings are cut 3-5m below the mudline, and conductors, casings and wellhead are withdrawn (O’Connor et al., 2004).

5.8 Australia

5.8.1 Introduction

By the end of the 19th century and the beginning of the 20th the first wells were drilled in Australia. These wells were mostly for the purpose of water extraction, however also oil substances and gas were found. Australia’s first oil field was discovered in 1924, as a result of an attempt to drill for water [8]. In 1923 the Petroleum Act was implemented which covered petroleum (oil and gas) exploration and transmission (Petroleum and Gas Inspectorate, 2005).

Western Australia has been producing crude oil since 1967 and condensate since 1972. The first discovery of oil in the State was at Rough Range in 1953, but this field was too small for commercial development. The State’s first commercial field, on Barrow Island, began operations in 1967. The first commercial quantities of natural gas in the onshore Perth Basin were produced from Dongara in 1971 and Mondarra in 1972. Offshore exploration began on the North West Shelf in 1967. Although the search was initially for oil, there were shows of gas as early as 1968. Major discoveries of gas were made at North Rankin, Goodwyn and Scott Reef in 1971 and have continued up to the present day.

5.8.2 Well abandonment regulations

In the second half of 1950 abandonment of wells was first taken up in the Petroleum Act of 1923 which was updated in 1955 and 1958. A new subdivision of the Petroleum Act of 1923 was made in 1962, including the amendments until then. The last amendment was in the year 2000 (The Office of the Queensland Parliamentary Counsel, 2008).

In Western Australia, onshore well abandonment has since 1991 been provided for in the Schedule of Onshore petroleum Exploration and Production Requirements - 1991. This Schedule is served on petroleum titleholders in lieu of regulations.

5.8.2.1 Offshore wells

The main operations concerning petroleum exploration and production in Australia is situated offshore. About 96 per cent of oil and 83 per cent of gas is produced from offshore sources (Australian Government, 2008).

Since 2005 NOPSA (National Offshore Petroleum Safety Authority, a Statutory Agency regulating Commonwealth, State and Territory coastal waters with accountability to the relevant Ministers) administers offshore petroleum safety regulations in order to regulate the Australian offshore petroleum industry and assist it to reduce the health and safety risks to an acceptable level. For offshore petroleum operations currently the Offshore Petroleum Act 2006 (Offshore Petroleum and Greenhouse Gas Storage Act 2006) provides the legislative background as well as the Environment Protection (Sea Dumping) Act 1981 [10]. Approval of decommissioning is based on international protocols and treaties as set out in the Guidelines for the Decommissioning of Offshore Petroleum Facilities. In practice, extensive experience of such upstream petroleum decommissioning is probably not yet available in Australia (Australian Government, 2008).

Each State and Northern Territory has made or will make corresponding amendments to existing legislation, so as to create an equivalent occupational health and safety regime for petroleum activities in State and Northern Territory coastal waters.

5.8.2.2 Onshore wells

Onshore oil and gas projects involving more than one jurisdiction, due to individual state based legislation. Especially, Western Australia and Queensland established a comprehensive basis of legislation for onshore well abandonment. These two examples of state legislation in Australia are presented in the following sections.

5.8.3 Western Australia

Western Australia has a petroleum legislation that is common to both its onshore and offshore areas. The legislation is similar to the national Offshore Petroleum Act 2006. Requirements for onshore petroleum exploration and production were established in 1991, in which decommissioning of onshore wells in the state is regulated. The requirements which are set for well abandonment and plugging can be found in Appendix F.1.

5.8.4 Queensland

In Queensland the abandonment of offshore wells is regulated according to the NOPSA requirements. In case of onshore wells, Queensland established requirements for abandonment in the Petroleum and Gas (Production and Safety) Act 2004 and in the Petroleum and Gas (Production and Safety) Regulations 2004. An overview of relevant issues concerning onshore well abandonment in the regulations can be found in Appendix F.2. In this appendix, the requirements for plugging and abandoning petroleum wells and bores are described in ‘Schedule 3’. Specific requirements for plugging and abandonment are not set in the regulations.

5.9 Alberta, Canada

5.9.1 Introduction

Every province in Canada (Figure 5.1) has specific policies and procedures for well abandonment procedures. For this study, only the Alberta Basin is considered. From 1947 on, this field has been exploited.

Effective January 1, 2008, the Alberta Energy and Utilities Board (EUB) has been realigned into two separate regulatory bodies. Firstly, the Alberta Utilities Commission (AUC) has been installed, which regulates the utilities industry. Secondly, the Energy Resources Conservation Board (ERCB) has been installed, which regulates the energy industry. The ERCB is an independent, quasi-judicial agency of the Government of Alberta [14]. This board has formulated several directives concerning the oil exploration and exploitation activities in the Alberta Basin. The Well Abandonment Guide is described in Directive 20. This latest revised release of the directive was in December 2007 (ERCB, 2007). Amendments to this directive have been made in Directive 72 (ERCB, 2008) and will be incorporated in a future release of Directive 20.

Figure 5.1 Left: Canada, with Alberta [15]. Right: Four Program Areas in Alberta, adapted from ERCB (2007).

5.9.2 Well abandonment process

The information in the remaining part of this section has been summarized from ERCB (2007), unless stated otherwise.

The objective of a well abandonment is to cover all nonsaline groundwater and to isolate or cover all porous zones. A difference is made between open-hole abandonment requirements and cased-hole abandonment requirements. An overview of the requirements for both types is provided in the next sections. The last section deals with surface abandonment.

5.9.3 Open-hole abandonment requirements

The abandonment program for an open-hole well depends on the location of the well within the province and whether the well is in an oil sands area. For open-hole abandonments, the province Alberta is subdivided into four program areas (Figure 5.1): Western Alberta (Program Area 1), Northeastern Alberta (Program Area 2), East Central Alberta (Program Area 3) and Southeastern Alberta (Program Area 4). Designated oil sands areas exist in Program Areas 1 and 2.

The geology of Program Area 1 is too diverse to support a single plugging program. Therefore, licensees of wells in this region must develop their own plugging program that meets the requirements of Directive 20. For the remaining three Program Areas, prescribed plugging programs have been developed by the EUB (now ERCB).

In general, cement plugs must be placed that are of sufficient length and number to ensure that crossflow between porous zones does not occur. Secondly, plugging programs must cover all nonsaline groundwater by cement, and must isolate or cover all porous zones. The general and Program Area specific requirements are presented Appendix G.1.

5.9.4 Cased-hole abandonment requirements

The abandonment program for a cased-hole well depends on the location of the well, if the well was completed, and whether the well penetrated any oil sands zones. In a cased-hole abandonment, the licensee must abandon each completed pool separately and must cover all nonsaline groundwater with cement. If the casing strings in a cased-hole well were not cemented according to the requirements in Directive 009 (ERCB, 1990) the cement location and condition must be evaluated.

Different abandonment requirements have been defined for wells that do and do not penetrate oil sands zones. An overview is given in Appendix G.2.

5.9.5 Additional requirements

Appendix G.3 presents additional requirements concerning removing casings and setting cement plugs.

5.10 China

At the end of the 1950s China’s offshore oil industry started in the South China Sea. After 1965 the exploration focus was repositioned to the Bohai Bay in the North of China. Until the year 1972 simple technology was used for discovery wells for oil and gas. From 1966 to 1972 in total four fixed drilling platforms were built, 14 wells were drilled and three oil-bearing structures were discovered in Bohai Bay. In this period experience was built up for offshore oil exploration. After 1973 the development equipment began to be renewed, and a supply of jack-up vessels, three-purpose (towing, weighing anchor and casting anchor, supply) workboats, geophysical survey vessels were built at home and introduced from abroad for conducting exploration and development tests in Bohai Bay.

On 30 January 1982 the Chinese State Council promulgated Regulations of the People’s Republic of China concerning the Exploitation of Offshore Petroleum Resources in Cooperation with Overseas Partners and decided to establish China National Offshore Oil Corporation (CNOOC). CNOOC has the exclusive right of conducting oil exploration, development, production and selling and taking charge of the business on exploiting offshore oil resources in the country’s sea areas, possibly in cooperation with overseas partners [16].

5.10.1 Onshore well abandonment regulations

Information on onshore regulations in China appeared to be difficult to obtain.

5.10.2 Offshore well abandonment regulations

CNOOC established the Control Rules on offshore Oil Well Abandonment Operations. In Appendix H the English translation of the regulations can be found. The main focus of the text is on the technical requirements for well abandonment operations, in which among other topics conditions of well abandonment operations, permanent well abandonment and temporary well abandonment are addressed.

5.11 Japan

The Japanese Ministry of Economy, Trade and Industry (METI) [18] specifies the provision and the standards for the necessary measures of an abandoned oil well. The standard of abandoned oil wells is specified in 1986 and is based on the Mine Safety Act11. METI provided the Japanese regulations on well abandonment in Japanese (METI, 1986).

The Japanese authorities distinguish two different cases for abandonment. First of all, regulations are defined for abandonment of wells for oil or natural gas production from structural reservoirs. Secondly, regulations are defined for wells producing natural gas that is dissolved in water. Appendix I contains an unofficial translation of the regulations.

5.12 United States of America

5.12.1 Introduction

Regulations regarding the abandonment procedure and requirements were first installed in the USA after 1930 and in some states even after World War II (Calvert and Smith, 1994). The initial prescriptions were significantly improved in 1952, when the American Petroleum Institute (API) presented a list of standard cement compositions and additives which divided the cement in eight classes depending on the depth of application and additives. The API classification is still being used for specification of the composition of wellbore plugging cements used at specific downhole conditions. Since 1953 developments in plugging procedures were mostly restricted to changes in plug lengths and the number of plugs applied per well (Ide et al., 2006).

The US regulations show a distinct regional nature. While the objective of plugging is the same in all states (i.e. protection of potable water aquifers and isolation of hydrocarbon zones), abandonment regulations differ from one state to another on more detailed levels (e.g. plug lengths, additives).

5.12.2 Underground Injection Control (UIC)

The most significant improvement with respect to the original requirements was effected by the introduction of the Safe Drinking Water Act (SDWA) in 1974 that embraced the philosophy of zonal isolation or displacement. Under this Act the Underground Injection Control (UIC) Program was established in order to enable the safe injection of fluids in subsurface reservoirs by maintaining the current and future sources of drinking water. The UIC Program is responsible for regulation in the USA at regional level of the construction, operation, permitting, and closure of injection wells that inject fluids in underground reservoirs for storage. Adopting this approach required operators to isolate all fresh water drinking zones from hydrocarbon reservoirs by cement plugs (Ide et al., 2006) and to prevent movement of other fluids into the wellbore by applying adequate mud fluids (Englehardt and Wilson, 2001).

The UIC Program defines five classes of wells based on similarities in the fluids injected, construction, injection depth, design, and operating techniques:

Class I : inject industrial non-hazardous liquids, municipal wastewaters or hazardous wastes beneath the lowermost underground sources of drinking water (USDW). These wells are most often the deepest of the UIC wells and are managed under technically sophisticated construction and operation requirements.
Class II: inject fluids in connection with conventional oil or natural gas production, enhanced oil and gas production. Most of the injected fluid is brine.
Class III: inject fluids associated with the extraction of minerals or energy, including the mining of sulfur and solution mining of minerals.
Class IV: inject hazardous or radioactive wastes into or above USDWs. Few Class IV wells are in use today; these wells are banned unless authorized under an approved Federal or State ground water remediation project.
Class V: includes all injection wells that are not included in Classes I-IV. In general, Class V wells inject non-hazardous fluids into or above USDWs; however, there are some deep Class V wells that inject below USDWs. This well class includes Class V experimental technology wells including those permitted as geologic sequestration pilot projects [20].

5.12.3 Environmental Protection Agency (EPA)

Under the SDWA (see Section 5.12.2), the Environmental Protection Agency (EPA) sets standards for drinking water quality. In 2008 the EPA proposed a rule for the creation of a Class VI well category which would concern wells which only inject CO2 (EOR wells remain Class II wells).

According to the US EPA, the objectives of an abandonment procedure of injection wells are to [19];

  1. eliminate physical hazards;
  2. prevent groundwater contamination;
  3. conserve aquifer yield and hydrostatic head;
  4. prevent intermixing of subsurface water.

A selection of the appropriate methods of well abandonment should be made after considering;

  1. the casing material;
  2. casing condition;
  3. diameter of the casing;
  4. quality of the original seal;
  5. depth of the well;
  6. well plumbness;
  7. hydrogeologic setting;
  8. the level of contamination and the zone or zones where contamination occurs.

If no cross-contamination can occur between various zones and contamination cannot enter from the surface, grouting the well from bottom to top without removing the casing may be sufficient. However, since the primary purpose of monitoring well abandonment is to eliminate the vertical migration of fluids along the borehole, removal of the casing is the preferred method of well abandonment. When the casing is removed, the borehole can be sealed completely and there is less potential for channelling in the annular space or inadequate casing/grout seals [19].

Regulatory requirements for well abandonment vary depending on the class wells as well as the state. Each state can choose on the enforcement of EPA regulations. On state level seven states share authority with EPA [21]. In Figure 5.2 the implementation of regulation in the different U.S. states is shown.

Figure 5.2 The implementation of regulation in different states of the USA. Most states are responsible for the implementation of the UIC program (green). The red coloured states implement it jointly with the EPA and in case of the blue coloured states the EPA implements the program directly [23].

In Appendix J.1 the text available from the EPA website concerning the general requirements for plugging and abandoning wells as well as for class II wells is presented.

5.12.4 American Petroleum Institute (API)12

The American Petroleum Institute (API) provides in its API Bulletin E3 (API, 1993) guidance on environmentally-sound abandonment practices for wellbores drilled for oil and gas exploration and production operations, primarily focused on onshore wells. API states that several safeguards utilized during well construction and during plugging operations prevent fluid migration in plugged and abandoned (P&A) wells.

Figure 5.3 Schematic of properly plugged well (reproduced courtesy of the American Petroleum Institute)

Safeguards provided during the construction of a well include surface casing and production casing installed and adequately cemented. Cement and mechanical plugs placed at critical points in the wellbore during either prior remedial or plugging operations prevent fluid migration within the wellbore. Safeguards provided during plugging and abandonment operations include cement plugs set in open holes as well as cement or mechanical plugs set above perforated intervals in production or injection zones, at points where casing has been cut, at the base of the lowermost fresh water aquifer, across the surface casing shoe, and at the surface. Figure 5.3 shows a schematic of a typical properly plugged and abandoned well. Some US state agencies specify additional plug placements in some situations. An overview of the API guidance is presented in Appendix J.2.

5.12.5 Alaska

The first commercial oil well developed in Alaska was in the year 1902 in the Katalla Oil Field. The regulatory agency in Alaska overseeing the underground operation of the Alaska oil industry on private and public lands and water is the Alaska Oil and Gas Conservation Commission (AOGCC). It is responsible for regulating drilling and production of oil and gas. Its origin dates back to 1955 [24].

5.12.5.1 Well abandonment

In The Alaska Administrative Code, the abandonment and plugging of wells is addressed (The Alaska Administrative Code, 2009). In the Article the abandonment of wells, plugging of well branches, suspended wells, well plugging requirements, shut-in wells, well abandonment marker, water wells, onshore location clearance and offshore location clearance is addressed. The original text can be found in Appendix J.3.

5.12.5.2 Well information databases

The AOGCC also maintains an Oil and Gas Information System containing information on public well and production files and databases. The database can be found on its website [24]. Oil and gas data, well files, and digital log data can be found there.

5.12.6 California

In 1915, the first regulations for drilling of wells were published in California (McLaughlin, 1915). This was mainly due to the widespread demand among oil operators for regulations to prevent damaging the property of a neighbour by the infiltration of water. According to the State Mining Bureau it was not necessary to instruct the experienced operators. The regulations, therefore, were rather supporting than strictly prescribing. Section 16 of this law describes the well abandonment. It states that it is the duty of the owner of a well to prevent that water enters the oil-bearing strata.

In 1970, the California Environmental Quality Act was defined. The Division of Oil, Gas and Geothermal Resources (DOGGR) from the California Department of Conservation (DOC) implemented this act in the California Code of Regulations (DOGGR, 2006). These regulations define well abandonment regulations for both onshore and offshore wells. These regulations are presented in Appendix J.4.

5.12.7 Texas

The Texas Administrative Code (TAC) is a compilation of all state agency rules in Texas and was created by the Texas Legislature under the Administrative Code Act in 1977 [25]. In the Administrative Code Act, the Legislature directed the Office of the Secretary of State (SOS) to compile the TAC. Each title within the TAC represents a category. Each title is divided into multiple parts, to which related agencies are assigned. The Railroad Commission of Texas (RRC)13 is assigned to Part 1 of Title 16 (Economic Regulation). Chapter 3 within this part is dedicated to the Oil and Gas Division (SOS, 2007). The first version of this rule was adopted in January 1976 and the most recent amendments were adopted in January 2007.

5.12.7.1 Well abandonment

The rules for plugging and well abandonment are listed in Rule 3.14 (SOS, 2007). The information in this section has been compiled from this rule, unless stated otherwise.

Wells shall be plugged to insure that all formations bearing usable quality water, oil, gas or geothermal resources are protected. Plugs shall be set to isolate each productive horizon and usable quality water placing the required plug at each depth as determined by the Texas Commission on Environmental Quality or its successor agencies.

Appendix J.5 presents Rule 3.14 from the Texas Administrative Code. An important note is that cement plugs shall be placed by the circulation or squeeze method through tubing or drill pipe. Dump bailing is not permissible.

5.13 International Conventions

5.13.1 London Convention 1972 and 1996 Protocol

One of the oldest global conventions is the London Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter 1972 covering the North Sea and North-East Atlantic. In 1996 the convention was amended to allow captured CO2 to be stored into sub-seabed geological formations under certain restrictions. In 2006 the 1996 Protocol to the Convention entered into force. It is the first time that a maritime treaty governs storage of wastes in the seabed, as well as the abandonment of offshore installations. The amendment forms a basis in international law to regulate storage of CO2 in geological reservoirs under the seabed [27]. Under certain circumstances, the Convention governs the issue of permits for the disposal of installations at sea. Specific laws for governing decommissioning are prepared and implemented by national governments.

The following is stated on well integrity in relation to CO2 storage in the last amendment: “Particular attention should be paid to integrity of the wells. Over the longer term, the risk assessment should also address any change in the integrity of the seal and of the plugs in the abandoned wells and might include the effects of CO2 dissolution and mineralization.” and “Special care should be taken to use sealing plugs and cement that are resistant to degradation from carbonic acid.” (London Protocol, 2006b).

5.13.2 OSPAR Convention

The OSPAR Convention also applies to waste disposal and other activities in geological reservoirs under the seabed. In 2007 the OSPAR Commission amended the Convention to allow for environmentally safe storage of CO2 in the Northeast Atlantic and at the same time excluding the injection of CO2 in the water column and the disposal onto the seabed. The OSPAR convention concerns the Northeast Atlantic and is seen as one of the most comprehensive and strict legal frameworks in place for the protection of the marine environment. The Commission of the OSPAR Convention stresses that carbon capture and storage is one option as part of a package of possible measures reducing CO2 emissions [28]. Specific regulation for abandonment of wells is not included.

7 DISCLAIMER: The English version of this document is an unofficial translation. In case of discrepancy, the original Danish text shall prevail.

8 Communication with DEA in February 2009.

9 DISCLAIMER: The English version of this document is an unofficial translation. In case of discrepancy, the original French text shall prevail.

10 Personal communication with BGR.

11 Personal communication with METI, February 2009.

12 Reproduced courtesy of the American Petroleum Institute from API Bulletin E3

13 The RRC was established in 1891. Nowadays, the RRC has primary regulatory jurisdiction over oil and natural gas industry in Texas [26].