Environmental Considerations in Decommissioning of Offshore Facilities
J S Sharma
Ph.D., STA Fellow (Environment), Japan
Former Group General Manager (Chem) - Head
Environment
Oil and Natural Gas Corporation Limited

In our country, there is no clarity on applicable regulations on decommissioning of offshore facilities except Site Restoration and Abandonment Guidelines for Petroleum Operations by the DGH. This is our experience that whenever issue of decommissioning comes, companies in India are not sure from where to start, what are the applicable regulations required to meet , what documents are to be prepared to move forward and how many regulating agencies are required to be contacted? Through this review on decommissioning of offshore facilities, an effort has been made to bring clarity to the readers or the concerned petroleum companies. Further it is also made very clear that this particular article solely focuses on the Environmental Consideration of decommissioning of offshore facilities.

Let us first understand what the term decommissioning means. Decommissioning usually is the part of an initial agreement when a company signs a lease for the offshore Oil and Gas exploration or Production, Right-of-way or Right-of -useand-Easement, the well, that is for safely plugging the hole in the earth's crust and disposing off the equipment which is used to support the production. This process is critical for environmental protection after a well is drilled, utilized for the production, is plugged and sealed when it is exhausted in the outer continental shelf.

Whereas guidelines on Site Restoration and Abandonment for Petroleum Operations on the subject clearly states i.e.

(a) Decommissioning means
  • Ending oil or gas operations; and
  • Returning the lease to a condition that meets the requirements of the regulations and other agencies that have jurisdiction over decommissioning activities.
(b) Obstructions means
  • Struc tures, equipment, or objec ts that were used in oil and gas operations or marine growth on such structures that, if left in place, would substantially hinder other existing users of the seafloor, may be considered as an obstruction. Such obstructions may be included, but are not limited to, shell mounds, wellheads, casing stubs, mud line suspensions, well protec tion devices, subsea trees, jumper assemblies, umbilicals, manifolds, termination skids, production and pipeline risers , platforms, templates, pilings, pipelines, pipeline valves, and power cables.
What should be the Decommissioning approach?
Ideally decommissioning must be conducted in accordance with prior approval of concerned regulatory agencies especially an approval on Environmental Management Plan (EMP) or which must include risk-based analysis to ensure activity risk levels are reduced to the extent practicable, to acceptable levels and must ensure affected stakeholders have been adequately consulted to ensure risks are appropriately assessed and impacts are understood. However, as per the prevailing regulation in Indian law it is applicable upto territorial waters. Offshore facilities located beyond territorial water i.e. in international water be dealt as per agreed international conventions or provisions of April 2017 Directorate General Hydrocarbon guidelines on the subject be followed.

Environmental Considerations at International Conventions
India being signatory to a number of international conventions relevant to offshore oil and gas dec ommissioning by which the issue c an be addressed;
  • The 1958 Geneva Convention on the Continental Shelf (Geneva Convention). The Geneva Convention determines the sovereign rights of coastal States to explore the continental shelf and produce its natural resources. Under Article 5(5) of the Geneva Convention, any installations on the continental shelf which are abandoned or disused must be entirely removed.
  • The 1982 United Nations Convention on the Law of the Sea (UNCLOS) (which modified the Geneva Convention). Article 60 of UNCLOS states that removal of installations or structures in the exclusive economic zone of a coastal State should take into account generally accepted international standards established by the competent international organization. In addition, Article 210 of UNCLOS requires States to adopt laws and regulations to prevent pollution from dumping at sea and requires national laws to be no less effective than global rules and standards in this regard.
  • The 1972 United Nations Convention on the Prevention of Marine Pollution by Dumping of Wastes and Other Matter (London Dumping Convention). The 1996 protocol to the London Dumping Convention broadened the definition of "dumping" to include requirements for abandonment or toppling at site of platforms or other man-made structures at sea. The International Maritime Organization (IMO) is responsible for administering the London Protocol.
IMO Guidelines
The International Maritime Organization (IMO) is the competent organization for the purposes of Article 60 of UNCLOS. In 1989 the IMO adopted Resolution A.672(16) "1989 Guidelines and Standards for the Removal of Offshore Installations and Structures on the Continental Shelf and Exclusive Economic Zone" (IMO Guidelines). Although the IMO G uidelines should be tak en into account under UNCLOS.

The general requirement of the IMO Guidelines is that all installations and structures on any continental shelf or any exclusive economic zone should be removed except where such non-removal or partial removal is consistent with the IMO Guidelines, as summarized below.

Under the IMO Guidelines, any non-removal or partial removal decision should take into account:

Potential effects on safet y of navigation or other uses of the sea;
  • rate of deterioration of materials and possible future effect on the marine environment;
  • effect on the mar ine environment;
  • potential for materials to move on the sea bed;
  • cost, technical feasibility, and safet y of personnel;
  • and any new uses for the installation or structure remaining on the sea-bed or other reasonable justification.
IMO Guidelines requires ;
  • ensuring that materials left on the sea-bed do not adversely affect navigation or the marine environment.
  • States should identify a responsible party to maintain aids to navigation and monitor the condition of materials under specific plans for these purposes.
  • States should also ensure that the ownership of installations and structures that have not been entirely removed is unambiguous and that responsibility for maintenance and future damages is clearly established .
In 2000 the IMO adopted "Specific Guidelines for Assessment of Platforms or Other Man-Made Structures at Sea" for use by national authorities where disposal of a platform or other structure at sea is to be disposed off by dumping. Commonwealth Provisions
Commonwealth legislation relating to offshore oil and gas decommissioning also applies to petroleum facilities located in waters that extend beyond 3 nautical miles from the coastline and may, in some circumstances, be relevant to water under the jurisdiction of State or Territories. The purpose of the legislation is primarily to regulate resource management, safety and environmental impact.

Offshore Petroleum and Greenhouse Gas Storage Act (OPGGSA)
The principal Commonwealth legislation relating to offshore oil and gas decommissioning is the Offshore Petroleum and Greenhouse Gas Storage Act 2006 (OPGGSA).

The National Offshore Petroleum Safety and Environmental Management Authority(NOPSEMA) assesses Environment Plans required under the regulations for decommissioning, which may include full or partial removal of facilities .

Section 572(3) of the OPGGSA contains a general requirement for a titleholder to remove "all structures that are, and all equipment and other property that is, neither used nor to be used in connection with the operations".

Section 572(3) of the OPGGSA is subject to directions by NOPSEMA or the responsible Commonwealth Minister under subsections 574, 574A and 574B of the OPGGSA. These directions could permit the partial removal or leaving equipment or other property in-situ if it is not being used or to be used by a titleholder. Section 572(3) of the OPGGSA is also subject to any other provision of the OPGGSA or regulations made under the OPGGSA.

Importantly, section 270 of the OPGGSA addresses the requirements for the surrender of a title, which is typically the final step taken at the end of a title's useful life. Under section 270, the Joint Authority must not unreasonably withhold consent to the surrender of a title if (among other things) a titleholder has removed all property brought onto the area to be surrendered or made arrangements regarding that property that are satisfactory to NOPSEMA.

The Explanatory Memorandum to the Offshore Petroleum Bill in 2005 expressly contemplates the IMO Guidelines where "arrangements satisfactory to the Designated Authority" [now NOPSEMA] are permitted, stating these allow "an operator to leave or partially remove certain items if the complete removal involves significant cost or safety implications".

Decommissioning an offshore facility is a "petroleum activity" for the purposes of the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations 2009 made under the OPGGSA (Regulations). Under the Regulations, NOPSEMA determines the acceptability of a decommissioning proposal through its acceptance of an environment plan prepared by the titleholder.

The Environment Plan must demonstrate to NOPSEMA that the environmental impacts and risks of the activity will be reduced to "as low as reasonably practicable"(ALARP). Issues to be considered in an ALARP assessment are broad and are discussed in more detail in S ection 5 of these guidelines.

Environmental Protection and Biodiversity Conservation Act (EPBC Act )
The EPBC Act provides for the environmental impact assessment and approval of the proposals that may involve significant impact to a matter of National Environmental Significance. Projects assessed and approved under the EPBC Act will be subject to committments made by the proponent and conditions that may have been imposed by the relevant Environment Minister.

Since 2014, all petroleum activities undertaken in Commonwealth waters in accordance with the OPGGSA have been approved as "approved classes of actions" that do not require referral, assessment and approval under the EPBC Act. Decommissioning offshore facilities is an approved class of action and is therefore subject to NOPSEMA's regulation.

Regional conventions : Oslo Paris Commission (OSPAR
In addition to the international legislative framework, there are a number of regional conventions which govern marine disposal in specific areas. However India is not signatory to this convention. But when the issue of offshore monitoring comes, the best practicing organizations in India do follow the provisions of OSPAR. The North East Atlantic is governed by OSPAR (the area reaches from the east coast of Greenland to the west coast of continental Europe and stretches from the Arctic down to the southern most tip of Europe at Gibraltar).

Similar conventions govern other seas such as Barcelona Convention (BARCOM) for the Mediterranean and Helsinki Convention (HELCOM) for the B altic Sea .

OSPAR is an international convention drawn up in 1992 and which came into force in March 1998. It replaced the 1972 Oslo Convention (on dumping from ships) and the 1974 Paris Convention (on discharges from land) to protect the marine environment of the Northeast Atlantic from pollution. The Convention's main roles are to control the disposal of all waste at sea and discharges from land. There are 16 contracting parties including the UK, and the EU in its own right.

The OSPAR Convention framework works alongside international legislation governing the removal of structures. Therefore, prior to the change to OSPAR regulations in February 1999, the OSPAR guidelines were only called upon for structures over the IMO's required size for total removal (i.e. structures in waters deeper than 100 metres and weighing more than 4,000 tons). This accounted for some 80% of the structures in the North Sea.

In July 1998, at the OSPAR Ministerial meeting in Portugal (Sintra), the section of the Convention governing the disposal of offshore installations was reviewed and a new regulatory framework - Decision 98/3 - now exists which no longer permits any disposal at sea of offshore structures.

OSPAR Decision 98/3 now requires the following:
  • All topsides of all structures must be removed to shore.
  • All sub-structures or jackets weighing less than 10,000 tons must be totally removed and brought to the shore for reuse, recycling or disposal
  • For sub-structures weighing over 10,000 tons, an assessment will be made on a case to case basis as to whether they should be totally removed or whether the footings might be left in place
  • Derogation may be considered for the heavy concrete gravity based structures listed in Annex 1 of the Decision as well as for floating concrete installations and any concrete anchor-base which results, or is likely to result, in interference with other legitimate users of the sea .
  • Exceptions can be considered for other structures when exceptional and unforeseen circumstances resulting from structural damage or deterioration or other reasons which would prevent the removal of a structure.
National and Local Legislation
Following relevant legislation and directives of the concerned organization be considered on the subject matter ;
i. Merchant Shipping Act.
ii. National Oil Spill Disaster Contingency Plan.
iii. EIA notification.
iv. CRZ notification, Wild Life Act, Eco Sensitive Area, Ministry of Environment, Forest and Climate Change.
v. Concerned navigation authorities.
vi. Department of Animal Husbandry, Dairying and Fisheries (DoF) within the Ministry of Agriculture and Farmers Welfare (MoA & FW) .
vii. State Pollution Control Boards (SPCB) & Disaster Management Authority .
viii. Directives of Oil Industry Safety Directorate, Directorate General Hydrocarbon and Ministry of Petroleum and Natural Gas.

This review is intended as a starting point for discussion between industry, government and community in the development of a recommended approach for decision-making on decommissioning the oil and gas facilities in territorial or International waters from following point of views;
  • Prevailing position on r egulatory requirements.
  • Environmental Considerations
The legal framework around decommissioning is evolving. It initially focused on full the removal of all offshore installations, but has more recently recognized other options, such as in-situ decommissioning, may provide better overall benefits. The key components may include:
  • A robust and uniform policy, legal and regulatory framework that specifically addresses decommissioning.
  • methodology for assessing decommissioning options and comparing their relative/Environmental Impact and also impacts to identify the option that reduces the risks to as low as reasonably practicable (ALARP ) and
  • Stakeholder consultation and engagement .
Lastly, due to the significant diversity of facilities installed to access hydrocarbon resources, determining the appropriate decommissioning option for a specific installation or facility needs to be considered on a case to case basis. In addition before decommissioning Environment Impact assessment be done considering all the aspects of marine environment contamination point of view including Oil Spill, toxicity, temperature, fisheries, flora fauna etc. including applicable prior regulatory permission.

Guidelines to both offshore Oil & Gas Production Site Abandonment
The following sections refer to both offshore oil and gas production site abandonment. These guidelines are not prescriptive but allow flexibility within the existing regulatory framework.

Government authorities and their respective roles on the Abandonment Plan
The responsibilities of various authorities listed below are categorized into the following.
i. Approval role: These authorities will need to approve the Abandonment Plan.
ii. Consulting role: These authorities will play an advisory role, providing their inputs on the Abandonment Plan, if any, in a time bound manner.
iii. Information only: These authorities will be informed of the Abandonment Plan. The Abandonment Plan will be submitted to the Oil Industry Safety Directorate(OISD) (for offshore production sites only)/ Directorate General of Mines Safety(DGMS) (for onshore production sites only) with a copy to the authorities with 'consulting role' for comments, if any, within 45 days of submission of Abandonment Plan in line with the guidelines.

Approval Role
► Ministry of Petroleum & Natural Gas (MoPNG) - Approval role [through Management Committee (MC)]
► Directorate General of Hydrocarbons (DGH) - A pproval role (through MC)
► Oil Industry Safety Directorate (OISD) - Approval role (for offshore production sites only)

Consulting Role
► Ministry of Environment, Forest and Climate Change (MoEF & CC) - Consulting role for Abandonment Plan (However, the Environmental Impact Assessment (EIA), where applicable, would need to be approved by the MoEF & CC)
► Ministry of Defence (MoD) - Consulting role (for offshore production sites only)
► Ministry of Shipping (MoS) - Consulting role (for offshore production sites only)
► Department of Animal Husbandry, Dairying and Fisheries (DoF) within the Ministry of Agriculture and Farmers Welfare (MoA & FW) - Consulting role (for offshore production sites only)
► State Pollution Control Boards (SPCB) - Consulting role (for onshore production sites and offshore production sites up to 12 nautical miles/ jurisdiction of EP Act )

Information Only
► State maritime board/ wild life and forest department – Consulting role for onshore production sites only
► Ministry of Water Resources - Information only (for onshore production sites only)
► State Governments (concerned departments) - Information only (for onshore production sites only)
► Coastal State Government nearest to the offshore production site – Information only (for offshore production site only)
► State, District and Local Authorities - Information only (for onshore production sites only) During project execution, necessary permits and consents would have to be taken by the Contractors from relevant authorities in line with existing rules and regulations.

Regulatory Requirements
It is essential that the Contractor carrying out a decommissioning project has a clear understanding of relevant regulations.

Administration of a decommissioning project should not be strictly limited to regulations. In addition to the regulations, an attempt should be made to provide relevant background information and asset history. Additionally, consideration should be given to issues which impact decommissioning activities. These include, but are not limited to, certain provisions regarding impact on land, protected areas, water and endangered species and artificial reef programs.

The regulations with respect to decommissioning of offshore production sites shall be administered by the Oil Industry Safety Directorate (OISD) while the Directorate General of Mines Safety (DGMS) shall administer decommissioning of onshore production sites. In addition, it is envisaged that establishment of artificial reefs for offshore platforms shall be administered by the OISD.

Note 1: These Site Restoration Guidelines for Petroleum Operations are applicable only for field abandonment upon cessation of production from producing fields only. However, the Contractor shall have the flexibility to carry out well Plugging and Abandonment (P & A) and flushing/cleaning activities on a stand-alone basis with the approvals from the Management Committee.

Note 2: The Contractor shall submit the third party audit report on the contractor's work completion dossier to OISD/DGMS and DGH which shall be considered as certification of completion of the site restoration /decommissioning/ abandonment work.

Environmental Impact Assessment (EIA)
Currently, there are no specific guidelines in India for Environmental Impact Assessments for decommissioning of Oil & Gas assets. Minimum requirements should therefore be determined and it is recommended that offshore and onshore Oil & Gas producing assets. EIAs for offshore and onshore areas in India should be formulated.

The EIA for the selected decommissioning methodology should take into account environment protection measures in consultation with the MoEF & CC on a case to case basis and may not be mandatory in all cases. Approved EIA report for the selected concept will be submitted by the Contractor to OISD along with site restoration plan.

Handling of Naturally Occurring Radioactive Material (NORM)
Identifying, labeling, maintaining, storing and disposing of equipment contaminated with Naturally Occurring Radioactive Material (NORM) shall follow the guidelines of the Department of Atomic Energy (DAE).

Site Restoration Fund
The Site Restoration Fund ("SRF"), where applicable, is governed by the relevant provisions of the respective Production Sharing Contracts (PSCs) and the Site Restoration Fund Scheme (SRFS) of 1999. Regarding Site Restoration Fund, following guidelines are made:
  • Contractor will open SRF account immediately after first commercial oil/gas production.
  • In the case of new fields, Contractor can alternatively submit Bank Guarantee(BG) for the initial period up to 3 years after first commercial oil/gas production. The Contractor shall create SRF account for the subsequent years of PSC period.
  • In the case of existing fields with commercial production, where SRF is not yet established, the Contractor can alternatively submit Bank Guarantee within 6 months after policy guidelines notification for a period up to 3 years. The Contractor shall create SRF account for the subsequent years of PSC.
  • The Amount of SRF or BG will be in accordance with decommissioning estimates as proposed by the Contractor and approved by Management Committee.
  • The funding in SRF account or BG amount will be calculated using Unit of Production method i.e. Reserve of the field to Production ratio .
  • Due to the varying operating lives of individual assets and changes in resource costs, decommissioning and site restoration costs may be evaluated and updated every 3 years. The decommissioning cost estimate, duly assessed by a qualified independent third party, will be submitted by the Contractor to the DGH. The revised estimates will become the basis for amount in SRF or BG.
The withdrawal of funds from SRF account is governed by para 8 of the SRFS of 1999. To provide further guidance in accordance with para 8, it is recommended that the following additional steps need to be followed:
  • The Contractor shall propose estimates of the site restoration activities in the Annual Work Programme & Budget (WP & B) to the Management Committee including provisional work schedule and corresponding estimated payment on a Financial Year Basis
  • Based on such approved Work Progress and Budget (WP & B), the Contractors would be allowed to withdraw funds in four or more phases from SRF account towards expenditure. The Contractors shall submit to the DGH, a phase-wise utilization Certifi cate validated by independent third party who is acceptable to Management Committee, showing utilization of funds during or at the end of each phase. For release of advance for subsequent phase, Contractor to ensure that utilization Certificate is submitted for 75% of the funds drawn for the current phase and 100% of the funds drawn for all previous phases. As an alternative, the contractor shall have an option of withdrawing an advance of up to 100% of the fund required for Site restoration and abandonment as per the plan approved by the Management Committee by submitting Bank Guarantee of an equivalent amount.
  • Within 60 days after end of a financial year, the Contractors should submit final expenditure and utilization statement for previous year
  • In case of BG amount, the BG amount can be adjusted/reduced (on pro -rata basis) by the Contractor on an annual basis at the end of the financial year in accordance with the value of balance site restoration work to be completed as per the approved Abandonment Plan.
  • The Contractor would undertake site abandonment activities as per the approved Abandonment Plan and submit the completion certificate.
  • The contributions to the SRF account should be used only for the purpose of Field Abandonment & Site Restoration by all parties. The balance amount in SRF after Site restoration and abandonment shall be dealt with in accordance with provisions of PSC and SRF Scheme, 1999 .
Commencement of Site Abandonment
Regarding notice to the Government for commencement of site abandonment and approval of the Site Restoration Plan,
  • An estimated high level schedule for the abandonment should be submitted to the DGH for review one year prior to the expected cessation of production. Shorter time frames may be allowed by DGH if necessary .
  • The Site Abandonment and Restoration Plan should be submitted to the OISD/DGMS for approval not later than 1 year after cessation of production.
  • Abandonment Plan shall be approved by the OISD/DGMS within 60 days of submission of the Abandonment Plan by the Contractor in line with these guidelines. In case OISD/DGMS has any query regarding any deficiencies in the documentation, the approval shall be granted by OISD /DGMS within 15 days of receipt of the satisfactory reply and correct relevant document from the Contractor.
  • Initiation of abandonment should begin as per timelines approved in the abandonment Plan, subject to all regulatory approvals, permits, clearances etc being granted in a timely manner.
Guidelines for Decommissioning Offshore Production Sites in India

(a) Decommissioning means:
(1) Ending oil or gas oper ations; and
(2) Returning the lease to a condition that meets the requirements of the regulations and other agencies that have jurisdiction over decommissioning activities.

(b) Obstructions means:
(1) Structures, equipment, or objects that were used in oil and gas operations or marine growth on such structures that, if left in place, would substantially hinder other existing users of the seafloor, may be considered as an obstruction. Such obstructions may include, but are not limited to, shell mounds, wellheads, casing stubs, mud line suspensions, well protection devices, subsea trees, jumper assemblies, umbilicals, manifolds, termination skids, production and pipeline risers, platforms, templates, pilings, pipelines, pipeline valves, and power cables.
Note: Various terms such as Site Restoration Plan, Abandonment Plan, Decommissioning Plan, Site Restoration and Abandonment Plan, are used interchangeably. However, they all mean the same document.

Cessation of Production
Within 180 days upon cessation of production, Contractor shall notify the MoP & NG/ DGH/ OISD, that all production of the facility has ceased and submit the Abandonment plan to the OISD within one year of cessation of production.

General Decommissioning Requirements
The guidelines on decommissioning requirements are as follows.
  • Decommission wells by permanently plugging the wells. Sub-sea well head structures, Christmas trees, casings and tubings can be left in -situ provided they are stable in place and they do not have significant risk of interference with potential users of the site. The decommissioning methodology for Subsea well head structures, Christmas trees, casings and tubings shall be decided by a transparent and objective comparative assessment process which will take into account factors including geotechnical aspects, erosion processes, environmental considerations and safety etc.
  • Platforms may be removed as per IMO resolutions / guidelines. Reefing may be permitted if considered environmentally beneficial.
  • Subsea hardware and pipelines are to be decommissioned and left in -situ, provided the geotechnical, engineering analysis and other information demonstrate that hardware and pipelines are stable. The pipeline decommissioning methodology shall be decided by a transparent and objective comparative assessment process which will take into account factors including geotechnical aspects, erosion processes, environmental considerations and safety etc.
  • Where piling or conductors are severed, these should be removed to a level at or below the mud line.
  • Conduct all decommissioning activities in a manner that is safe, does not unreasonably interfere with other uses of the seafloor, and does not cause undue or serious harm or damage to the human, marine, or coastal environment.
Application Process for Decommissioning of Offshore production sites
  • Submit preliminary schedule to mc, seek work program and budget approval for studies
  • Carry out appropriate studies towards development of abandonment plan
  • Submit proposal for abandonment plan to OISD to consult other relevant stakeholders
  • (mos, mod, moef & cc, dof, spcb) oisd grants approval
  • Seek mc approval of abandonment plan and work program and budget for abandonment
  • Carry out abandonment activities as per approved abandonment plan
  • Cessation of production
  • Mc concurrence
  • Inform other relevant stakeholders
Note: The Contractor shall have the fl exibility to carry out well P & A and fl ushing/ cleaning activities on a stand-alone basis with the approvals of the Management Committee.

Well Plug and Abandonment
Wells P & A shall be carried out in ac cordance with OISD Standard 175. Deviations from OISD standard 175, if any, shall be submitted to the OISD for approval on a case to case basis.

Rigless well abandonment is a viable option. The Contractors should have the option to abandon a well in the most economical, safe manner of their choice . Project specific procedures for Rigless P & A shall be submitted to OISD for approval.

Each Reservoir isolation plug(s) must pass one or both of the following tests to verify plug integrity:
  • A pipe weight of at least 15,000 pounds on the plug; or
  • A pump pressure of at least 1,000 pounds per square inch. Ensure that the pressure does not dr op more than 10 per cent in 15 minut es .
Decommissioning platforms and other facilities
All platforms and other facilities must be decommissioned as per the approved Abandonment Plan.
All production risers must be flushed with seawater before they are removed.

Information to be included in Abandonment Plan for a Platform or other facility
Submit the following information (as relevant) as part of the Abandonment Plan for approval to the OISD:

(a) Identification of the applicant including:
  • Contractor;
  • Address;
  • Contact person and telephone number, email, fax and
  • Shore base.
(b) Identification of the structure that will be decommissioned including:
  • Platform Name
  • Location (lease, area, block, and block coordinates);
  • Date installed (year);
  • Proposed date of decommissioning (Month/Year); and
  • Water depth.
(c) Description of the structure to be decommissioned including:
  • Configuration (attach a photograph or a diag ram);
  • Size;
  • Number of legs/casings/pilings;
  • Diameter and wall thickness of legs/casings/pilings;
  • Whether piles are grouted;
  • Brief description of soil composition and condition;
  • The sizes and weights of the jacket, topsides (by module), conductors, and pilings; and
(d) Identification of the purpose, including:
  • Lease expiration date; and
  • Reason for removing the structure.
(e) An overview of the removal method,
(f) Plans for transportation and disposal (including as an artificial reef ) or salvage of the removed platform.
(g) The results of any recent biological surveys conducted in the vicinity of the structure and recent observations of turtles or marine mammals at the structure site.
(h) Plans to protect archaeological and sensitive biological ecosystem during removal operations, including a brief assessment of the environmental impacts of the removal operations and procedures and mitigation measures to take to minimize such impacts.
(i) A statement whether or not divers will be used to survey the area after removal to determine any effects on marine life.

Information to be submitted once a platform or other facility has been decommissioned.
Within 90 days after the decommissioning of a platform or other facility, submit a written report to the OISD that includes the following:
(a) A summary of the decommissioning operation including the date it was completed;
(b) A description of any mitigation measures taken; and
(c) A statement signed by an authorized representative that certifies that the types and amount of explosives used in removing the platform or other facility were consistent with those set forth in the approved Abandonment Plan.

Decommissioning Pipelines
Pipelines are to be decommissioned and left in-situ
To decommission a pipeline in-place:
(a) Submit the following information as part of the Abandonment Plan for approval to the OISD:
  • Reason for the oper ation;
  • Proposed decommissioning procedures;
  • Length (meters) of segment to be decommissioned.
  • Plans for disposal and sal vage
  • Stretch of pipeline passing through eco-sensitive areas like national parks, wildlife sanctuaries and protected areas etc at land fall point and plan of their protection.
(b) Pig the pipeline, unless pigging is not pr actical;
(c) Flush the pipeline;
(d) Fill the pipeline with sea water;
(e) Cut and plug each end of the pipeline;
(f) Where required, bury each end of the pipeline at least 1 meter below the seafloor or cover each end with sand/ c oncrete mattress;
(g) Remove those pipeline valves and other fittings that could unduly interfere with other uses of the seafloor.

Post Pipeline Decommissioning
Within 90 days after the completion of pipeline decommissioning, submit a written report to the OISD that includes the following:

(a) A summary of the decommissioning operation including the date it was completed;
(b) A description of any mitigation measures taken; and
(c) A statement signed by an authorized representative that certifies that the pipeline was decommissioned according to the approved Abandonment Plan .

Site Clearance Requirements of a Permanently Plugged Well, Removed Platform, or Other Removed facility
After completion of abandonment activities, verify that the site is clear of obstructions by using one of the following methods:

a) Sonar Cover 100 percent of the appropriate grid area.
Use a sonar signal with a frequency of at least 500 kHz.
(b) A diver Ensure that the diver visually inspects 100 percent of the appropriate grid area.
Ensure that the diver uses a search pattern of concentric circles or parallel lines spaced no more than 3 meters apart.
(c) An ROV (remotely operated vehicle).
Ensure that ROV camera records videotape over 100 per \cent of the appropriate grid area.
Ensure that the ROV uses a pattern of concentric circles or parallel lines spaced no more than 3 meters apart.

Post Site Clearance and Verification
(a) For a well site, submit a Completion Letter within 90 days after completion of the verification activities, to include:
  • A signed certification that the well site area is cleared of all obstructions;
  • The date the verification work was performed and the vessel used;
  • The extent of the area surveyed;
  • The survey method used.
(b) For a platform or other facility site, submit a Completion Letter within 90 days after the completion of the verification activities, to include:
  • A letter signed by an authorized company official certifying that the platform or other facility site area is cleared of all obstructions and that a company representative witnessed the verification activities ;
  • A letter signed by an authorized official of the third-party company that performed the verification work certifying that the platform or other facility site has been cleared of all obstructions;
  • The date the verification work was performed and the v essel used ;
  • The extent of the area surveyed;
  • The survey method used.
Note : Within 180 days of carrying out site clearance, the Contractor shall submit the third party audit report on the contractor's work completion dossier to OISD/DGH which shall be considered as certification of completion of work.

Monitoring and Survey Requirements of Abandoned Pipelines
(a) Perform an environmental and stability baseline survey.
(b) A pipeline location survey should also be carried out by the Contractor to establish stability of the abandoned pipelines, after at least one monsoon season has elapsed since the abandonment of such pipelines.
(c) Post abandonment monitoring is not necessary.

ANNEX 1: THE REGULATORY FRAMEWORK
Note: The following information about the current regulatory framework in respect of decommissioning has been lar gely taken from the UKOOA website12.
The process of decommissioning is regulated by international, regional and national legislation.

The distinction between the removal and disposal of disused offshore oil and gas installations is important as they come under very different types of legislative frameworks. Whilst interlinked, the legal requirements for removal are primarily concerned with safety of navigation and other users of the sea. The disposal of structures comes under the pollution prevention regulatory framework.

The 1989 IMO Guidelines require the complete removal of all structures in waters less than 100 metres (since January 1998 - previously it was 75 metres) and substructures weighing less than 4,000 tonnes. Those in deeper waters can be partially removed leaving 55 metres of clear water column for safety of navigation13. All new structures installed after 1 January 1998 must be designed so as to be feasible for complete removal.

12 http://www.ukooa.co.uk/issues/decommissioning/framework.htm. The DTI Guidelines themselves are available on http://www.og.dti.gov.uk/regulation/ guidance/guidenote.doc. 13 This requirement is partially linked to defence requirements. Submarines require a depth of 55m to be able to remain submerged. The requirement does not apply to structures that are not removed and are left protruding above the water line.

National and Local Legislation
The legislation governing the decommissioning of offshore structures on the UK continental shelf involves a number of different government departments and bodies. All Government departments concerned with decommissioning and with the issuing of any permits or consents co-operate to ensure that their procedures are compatible. The international laws described above are enshrined in the UK's national legislative framework.

The principal legislation for decommissioning comes under the Petroleum Act 1998 which is administered by the DTI and which provides a framework for the decommissioning of disused offshore installations and pipelines on the UKCS .

The DTI also provides operators with guidelines on how to undertake the process of decommissioning. These are described in the DTI's Oil & Gas Directorates draft 'Guidance Notes for Industry - Decommissioning of Offshore Installations and Pipelines under the Petroleum Act 1998'.