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Analysis

Maintenance Strategy Feature

Tue, 01/22/2013 - 11:21

CORRECTIVE MAINTENANCE

Corrective maintenance is maintenance performed after a problem emerges to identify, isolate, and rectify a fault, with the goal of restoring operability. Corrective maintenance cannot be avoided, since it sometimes has to happen due to extrinsic causes beyond anyone’s control. Over the past decades, Pemex’s limited investment budget, combined with external pressure to maximize oil production, resulted in a situation where investment in infrastructure upkeep drove the company to a corrective maintenance strategy. The company used to conduct minimal preventative maintenance, and would just wait until something broke down to perform maintenance tasks. This process would start by diagnosing why the failure appeared – either through physical inspection or other digital assessment tools – and then repairing or replacing the damaged parts, according to the diagnostic results. Once corrections are made, the system is tested to verify that the problem has been solved, and validate the continued use of the equipment.

For some older equipment, it may make more sense to rely on corrective maintenance, since other types of maintenance are expensive; it may be more cost e†ective to simply repair components as they grow weary or ine†ective, as long as downtime is not detrimental to the company’s bottom line. Downtime can be avoided, though, if regular inspections identify risk of failure in time for maintenance to be planned and scheduled.

PREVENTATIVE MAINTENANCE

Preventative maintenance is maintenance that is carried out to prevent equipment failing or wearing out by providing systematic inspection, detection and prevention of incipient failure. The preventative maintenance e†orts are aimed at preserving the useful life of equipment and avoiding premature equipment failures, minimizing any impact on operational requirements, possible downtime, and even the frequency of corrective maintenance tasks.

The process works through scheduled maintenance programs where the equipment is cleaned, adjusted, lubricated, and tested to verify it is in full working order. Inspections are regularly carried out to identify impending problems and schedule planned repairs prior to equipment failure or decay. Preventative maintenance is usually carried out only on those items where failure would have expensive or unacceptable consequences, and it is recommended for new infrastructure to extend its lifetime and save money in the long-term by preventing as many failures as possible before they happen. The oil and gas business is filled with infrastructure where failure would have dangerous consequences, and this is why Pemex has adopted this type of maintenance over the past decade. Since its shift in maintenance focus, Pemex has gone from having an average of 90 days lost per million hours worked in the period from 2000-2005 to 27 days lost per million hours worked in the period from 2006-2011.

PREDICTIVE MAINTENANCE

Predictive maintenance consists of several techniques that help to determine the condition of equipment in order to predict when maintenance tasks should be performed. This approach helps to save money over preventative maintenance since tasks are performed only when they are justified. The main value of predictive maintenance is to schedule corrective maintenance that can, at the same time, prevent unexpected equipment failures. The key is to possess the right information at the right time, to avoid unnecessary downtime or routine maintenance tasks. This strategy of planning maintenance helps to increase the equipment lifetime and plant safety, while reducing accidents and environmental impact.

New monitoring and customizable parameter-setting technologies allow oil and gas companies to determine the exact time and measurement of their up-keeping necessities. Predictive maintenance keeps industry operators from incurring in unnecessary costs surrounding maintenance, especially when plants or platforms are located in remote areas, both onshore and o†shore. Using predictive maintenance measures thus o†ers competitive advantage in the oil and gas industry, for it allows companies to reduce both operating and maintenance costs. Pemex is currently in the process of changing its culture to include predictive maintenance as its main approach towards its infrastructure upkeep program.