In the midst of a multi-billion dollar upgrade of one of the world's largest offshore fields, Mexico's national oil company, Pemex, is refurbishing rather than replacing a number of rig systems, saving money and time.
At the Madero fabrication yard on the Panuco River in Tampico, Mexico, separated drill rig modules are set up like an assembly line for refurbishment. Workers at the Cigsa-owned yard are rebuilding the 15-20-year-old units, which are intended to function like newbuild structures when completed. The modules will be equipped with a wide variety of new equipment - everything from drawworks to lifeboats.
The work is being completed by a partnership between Enron Offshore Services and Technology and Cigsa, an in-country offshore fabricator. Over the summer, workers were completing the Pemex drill module PM 4036. Restoration of the decks and accommodations systems, along with new equipment, was recently completed.
Also, the Enron/Cigsa team had recently completed and loaded out the refurbished PM 4037 modules in the spring. Some of the modules are almost 20 years old. The equipment is in need of repair and the superstructures have suffered under the tropical heat and corrosive salt air of the Gulf of Mexico.
Another 20 years
When the work is finished, Enron and Cigsa say the drill rig modules will be good for another 20 years. Besides the quicker turnaround time for a refurbed unit, over a newbuild, about 10 months as opposed to 15 months, the cost savings are substantial. Refurbished modules will cost about $18-20 million, compared to $50 million for comparable newbuild systems, according to Carlos Gonzalez, Cigsa's General manager for the Madero Yard.
Gonzalez has become well-acquainted with these specific systems. He said he was involved in their original construction 15 years ago by LanDermott. The modules were originally installed on jackets that are no longer producing. The wells below these jackets have since been plugged and abandoned, but the rig modules were saved for re-use.
This will be the first time Pemex has refurbished modules, rather than ordering newbuilds, but the cost savings for refurbishment was such that it just made financial sense to go this route.
Refurbishment
The drill rig modules are cut individually from the jackets and loaded on barges to be shipped to the Madero yard in Tampico. Once in place at the yard, the modules undergo extensive structural reworking. Crews inspect and replace beams and steel plate, and renew welds. All of the metal is sandblasted clean and repainted.
The equipment aboard is either repaired, or in some cases, replaced. This goes for everything from the mud pumps to the drawworks. All the electronic wiring is replaced and updated, as are the electronic controls. Other upgrades in equipment, according to Gonzalez, reflect advancements in computer technology, motion control systems, and the use of steel cantinary riser systems.
Gonzalez said the hardware for these upgrades is being imported from the US under the North American Free Trade Agreement with very low tariffs. This offers the Enron/Cigsa partnership quite a cost savings over equipment built and exported from other countries, which can carry tariffs as high as 18%.
In addition to the latest in drilling and controls technology, the safety equipment on the modules is replaced and modernized. New cranes capable of lifting twice as much as the out-dated 25-ton cranes are installed in anticipation of the heavier skids now standard in the industry.
The modules under refurbishment are arranged in a row on skids near one another. Not only is this convenient for painting and sandblasting operations, but it is important during the precommissioning phase. During pre com mission ing, the modules' electrical systems must be connected and powered up prior to load out.
Other work
Enron and Cigsa handle the refurbishment and load-out, but Pemex is responsible for re-installing the modules onto the platform. In addition to the two platform modules being refurbished at the Madero yard, Pemex has two others under refurbishment at a competitor's yard.
Gonzalez said Pemex has plans to refurbish several more topsides systems in connection to the Cantarell upgrade. As many as four will be cut from their jackets and brought to shore for a similar overhaul next year. Gonzalez said Cigsa and Enron are ready for the business.
Although the one set of modules dominates the space at the yard, Gonzalez said this facility can handle two full sets of modules at one time and further projects at its El Prieto yard, located up the river. Once completed, the refurbished modules will be fitted offshore to platforms similar to Akal TJ, which Enron and Cigsa fabricated at the El Prieto yard.
