Page 24: of Offshore Engineer Magazine (Oct/Nov 2013)

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Asset Integrity

Fig 3. – For decommissioning, SIM is used to take into account the integrity of the topside and the jacket.

Removal

Removal option Removal option assurance

Knowledge screening – topside screening – jacket

Bank

Reverse Lift analysis

Cut and ¦ Structure engineering removal weight

Transportation

Combined

Single lift by ¦ Structure analysis module lifts dual crane configuration

Load in ¦ Changes to Single analysis

Refloat structure topside lift

Manual ¦ Structure calculations

New concept condition (Piece small) removal vessel (lift point/ trailer supports) continental shelf would be required to stop at cessation of production. SIM develop and maintain a safety and envi- plays a vital role in the safe and suc- ronmental management system (SEMS). cessful decommissioning of offshore

The SEMS fnal rule is designed to infrastructure. improve workplace safety offshore. The SIM system provides a central

The rule will hold operators location for platform knowledge, con- accountable for overall facility safety, taining information about the struc- including ensuring that all contractors ture, its weight, confguration, changes and subcontractors have safety policies and modifcations, and current condi- and procedures in place that support tion. The retention and availability of the implementation of the opera- this information forms a critical part tor’s SEMS program, and align with of decommissioning planning. When the principles of managing safety, set considering removal options as part of forth in API RP 75, the recommended the decommissioning process, SIM is practice for offshore oil, gas, and sulfur used to take into account the integ- facilities and associated equipment. rity of the topside and the jacket, so

Applying a SIM system can help options can be assessed according to operators manage these challenges, and the robustness of the structure for safe ensure that the required systems and removal, transportation, and load-in, tools are available for asset life exten- Fig. 3.

sion or demonstration of enhanced If effectively implemented and structural capacity beyond the original maintained, the SIM system is there to design values. provide the required structural integ-

The realization of enhanced struc- rity assurance from design to complete tural integrity can involve advanced decommissioning. structural analysis techniques such as: n

In-place assessments Mohammad n Reserve strength ratio (RSR) Nabavian is head assessments of advanced n Boat impact assessments integrity at Wood n Finite element analysis Group PSN. His n Dynamic and post-buckling experience includes assessments design and analysis n Blast assessments of new offshore n Fatigue/fracture mechanics structures for the North Sea, Middle- n Reliability assessments East, and deep waters of the Gulf of

There are various assessment triggers Mexico, as well as, appraisal of which can be used to inform the need existing mature platforms, involving for such analyses. damage assessment and engineering beyond the confnes of current codes.

He earned an MSc and PhD from

Decommissioning

The requirement for SIM does not Cranfeld University.

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