To advise duty holders and HSE inspectors of the matters to be considered and precautions to be taken when approaching to, setting-up and departing from a fixed installation using a jack-up rig.
1 As a result of a safety case in which the duty holder (DH) was planning to execute a jack-up approach and departure whilst maintaining production from the fixed platform, HSE has undertaken a review of current practice regarding the precautions taken on a variety of fixed installations when conducting such an operation. For the purposes of this SPC, "approach" means from the time the jack-up begins final movement into position at the fixed installation until the derrick has been skidded into position, with "departure" being the reverse operation.
2 Precautions on the UKCS have included combinations of the following
3 To date on the UKCS, no examples were found where production was maintained while a jack-up drilling rig approached, or departed from a fixed installation. However, there is currently a specialist well servicing jack-up rig operating in the UKCS which does approach and depart from producing installations.
4 In the UK the key reference document for the offshore industry is the Oil & Gas UK Guidelines 1 , which describe the matters to be considered for all stages of jack-up approach, jacking-up and departure, generally with respect to the marine operations control, structural integrity, stability, pre-load and safety management. The document does not recommend that fixed installations should be shut-in and/or depressurised during rig movement, but does offer some very broad guidance on risk control during this operation including:
1. Guidelines for Safe Movement of Self-Elevating Offshore Installations (Jack-Ups), April 1995, Issue No. 1, Oil & Gas UK
5 In the US, the key document describing risk controls during jack-up approach, set-up and departure is the US Code of Federal Regulations 2. The Mineral Management Services, District Guidelines to these regulations requires that all production wells are to be shut-in when the jack-up is within 500 yards of the installation - this applies for drilling, completion and work over operations. In addition, the guidelines require the wells to remain shut-in until the rig has stabilised on the sea floor, and during cantilevering out over the drilling platform.
2. Minerals Management Services (MMS) Interior, Code of Federal Regulations, 30 CFR Ch. II (7-1-02) Ed. Sub Chapter B - Offshore, Part 250.
6 The guidelines imply, but do not specify, that wells, for example, are to be shut-in during rig elevation (after pre-loading) and lowering. The guidelines also do not cover the issue of topsides and riser de-pressurisation, or venting, during rig approach and departure operations.
7 The Norwegian Petroleum Directorate (NPD) does not impose prescriptive requirements, relying on DH safety assessments during the operation of the installation. In the majority of cases, the practice adopted reflects that on the UKCS. There has been an occasion in the Norwegian sector where production via a gas export pipeline was maintained during the approach, set-up and departure, but information suggests that the DH concerned carried out additional risk reduction measures to satisfy themselves that risks were controlled ALARP.
8 During the review of current practice, a study of previously accepted UK safety cases has demonstrated case specific levels of risk to assets, people and the environment. Factors affecting the level of risk include:
9 Should a DH be considering an approach and/or departure by a jack-up to an installation, the key issue is whether the risks are ALARP and not intolerable.
10 ALARP is demonstrated by ensuring that all reasonably practicable measures have been implemented, usually based on the current practice of the DH in the UKCS and/or common industry practice for the operation under consideration. To date, current practice on the UKCS has largely resulted in the option of an approach and/or departure without the installation remaining in production.
11 However, it may be possible for the DH to argue for an option that results in a change to the risk profile in which some risks may increase (e.g. a live approach) in comparison with their current practice. This may be acceptable to the HSE providing the DH can successfully demonstrate that there are changed circumstances that justify adopting such an option, and provided that the new option has risks which are ALARP.
12 Changed circumstances are likely to be case specific, as is evident by the variation in approach accepted by the HSE in safety cases. Offshore Information Sheet 2/2006 does provide a few generic examples of changed circumstances, e.g. the introduction of new processes, new technology, or unavoidable alteration to the conditions under which equipment is operated.
13 It is possible that in a case where a live approach and/or departure is proposed, the DH can make a case for changed circumstances, leading to changing the current practice. Examples of changed circumstances, in this situation, may include:
14 When a proposed option generates direct economic benefit, such as when increased production results, the DH should also consider the level of economic benefit as a measurement against which expenditure on further risk reduction measures could be evaluated. In other words, any risk reduction measures would be assessed using ALARP arguments, but with an allowance for a greater disproportionality ratio in ICAF versus CPLS to account for the cash benefit of the increased production. Incorporating the economic benefit of increased production, provides emphasis on the precautionary approach, especially where higher risk levels are being proposed, economic benefit is direct and multiple fatalities are reasonably foreseeable.
15 Justification for moving to a less protected, (increased risk) situation through the application of Quantitative Risk Assessments (QRA) and Cost Benefit Analysis (CBA) arguments, evaluated using industry risk reduction approaches e.g. Implied Cost to Avert a Fatality (ICAF), versus Cost Per Life Saved (CPLS) ratios, are unacceptable (the so called Reverse ALARP argument).
16 Sections 2 and 3 of the HSWA are relevant to defining the key legal obligations of the DH. In particular, the obligation of the DH is defined by a duty to provide and maintain plant and systems of work that are, so far as is reasonably practicable, safe and without risks to health (section 2) and the requirement for every employer to conduct his undertaking in such a way to ensure, so far as is reasonably practicable, that persons not in his employment who may be affected thereby are not thereby exposed to risks to their health and safety (section 3).
17 Application of sections 2 and 3 of the HSWA, essentially requires employers to be able to show that they are taking all reasonably practicable measures based on estimating the disproportionality of sacrifice (cost) to risk reduction. In addition all reasonably foreseeable hazards must be considered by employers to discharge their duty to comply with the Act.
18 SCR 2.12 requires a demonstration that the management system of the duty holder will ensure compliance with the relevant statutory provisions (including HSWA s.2 and s.3), and that all hazards with the potential to cause a major accident have been identified, these risks evaluated and measures have been, or will be, taken to control those risks to ensure that the relevant statutory provisions will be compiled with. Failure to comply with the accepted safety case is a breach of SCR r. 16.
19 Offshore Information Sheet 2/2006 , provides guidance on how to make a demonstration that risks are controlled to ensure that the relevant statutory provisions have been, or will be met.
20 Good practice generally represents a preferred approach to the control of risk.Offshore Information Sheet 2/2006 , describes how good practice can be used to provide a risk benchmark for deciding whether risks are controlled ALARP. For the purposes of evaluation by the DH, and assessment by HSE, good practice is demonstrated by a combination of the following:
21 It is also a key consideration of Offshore Information Sheet 2/2006 , that good practice, as established by the above considerations, has provided a risk benchmark. Where a duty holder wishes to adopt a different approach to controlling risks, and can show that the risks from the proposed approach are broadly similar to that which would have been achieved through the adoption of good practice, and are ALARP for that approach, they will normally be doing enough to comply with the law. But note paras 9 - 15 above, in respect of making a case for changed circumstances
22 A review of safety cases and current UK practice has shown that it is reasonably practicable in the UKCS for jack-up approach, rig set-up and departure operations to be done whilst shutting-in production from the wells and import/export from risers and pipelines on the installation being approached. Similar practice is evident in the US and the majority of operations in Norway.
23 Depressurisation and venting of the topsides and/or riser systems while being the preferred inherently safer option may not always be reasonably practicable during similar jack-up rig operations. However, the DH must consider these options and demonstrate that they are not reasonably practicable. HSE will review each safety case on its merits.
24 Approach, set-up and departure, (or combinations thereof), to and/or from a live installation, may in specific circumstances be acceptable, but the DH would be required to provide a rigorous demonstration that changed circumstances apply, and that a detailed evaluation of all reasonably practicable risk reduction measures has been undertaken. Where the DH proposes a change to current practice, such as not shutting-in the plant, which involves additional risk, further reasonably practicable reduction measures would need to be identified and implemented, to control risks ALARP.
For further information contact OSD 4.2