Drilling and Production

A lot of experienced drillers are feeling like newcomers around some rig floors lately. Iron roughnecks, automated pipe handling systems, and air-conditioned drillers' cabins are making the place nearly unrecognizable to old timers gone but a few years from the field. And if drilling equipment innovators like Varco Technologies and its subsidiary, M/D Totco, have their way, that sense of unfamiliarity is only going to increase.

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Futuristic drilling stations are replacing old drilling environments.


Drilling automation marches on

A lot of experienced drillers are feeling like newcomers around some rig floors lately. Iron roughnecks, automated pipe handling systems, and air-conditioned drillers' cabins are making the place nearly unrecognizable to old timers gone but a few years from the field. And if drilling equipment innovators like Varco Technologies and its subsidiary, M/D Totco, have their way, that sense of unfamiliarity is only going to increase.

Varco is the outfit mainly respon sible for making topdrives a must-have piece of equipment on all new and upgraded drilling rigs. Now, they are introducing a product they call V-ICIS, an acronym for Varco Integrated Control and Information System and pronounced vee-eye-sis by its friends.

The high-tech drilling system brings control of all the rig's automated drilling equipment to a single command-control center. The futuristic look of the center is reminiscent more of a pilot's cabin than a driller's station. Through touch-screen or joystick controls, drillers, drillers' assistants, and other function operators monitor and control all drill floor operations (top drive, iron roughneck, pipe-handling), pressure control equipment (BOP, choke, diverter), mud systems (fluid transfer, chemical dosing, shaker load), drawworks, SCR controls, and more in comfort.

The artificial brains of the operation is a Windows NT system (a Microsoft product not to be confused with Windows 95 or Windows 3.1). It is an operating and data management system that was designed for, and is in common use on, major process control systems in a number of industries.

The system has been designed for easy expansion and can easily incorporate any additional piece of automated equipment, either from Varco or other product manufacturers, that contractors may wish to add to their drilling units.

V-ICIS comprises multiple, networked operator workstations. Typically, the driller's station will consist of 3-5 workstations, the assistant driller's station will have 2-3, and the pipe transfer station will have two.

And despite its high-tech image, the whole thing has been thought out with people in mind. Lest the driller become too complacent with the repetitive motions of making hole from a lounge chair, for instance, and as a safety feature, the system requires the operator to use two hands or give redundant commands to make particularly sensitive maneuvers.

The whole thing is tied into a file server with access to the Internet and company Intranet systems. Using a secure information transfer system, data can be transferred directly from the drilling equipment, monitoring systems, and diagnostics to interested parties either

on- or off-site. The server also has the capability of communicating with other systems management components and provides a firewall to regulate information traffic and to prevent viruses and unauthorized entrance to the network.

Experienced drillers may occasionally find themselves waxing nostalgic for the old drill floor look. But most, in honest moments, will remember that not long ago dictums from higher-ups to improve ROP and cut costs often translated into sloppy, and even dangerous, work environments. Recent innovations, typified by the likes of V-ICIS and others, changes that. Calls for faster and cheaper are now being answered with brain, not brawn.

Insulated pipe may slow paraffin

One of the very few things known about paraffin formation is that it doesn't happen when fluids are kept above a certain temperature known as the cloud point. Like all well fluids, those produced from subsea wellheads leave the ground well above that point. But as it travels sometimes miles from wellhead to host platform, deepwater production must pass through pipelines bathed in near-freezing waters. Inevitably, of course, flowstream temperatures drop dramatically and paraffin begins to form on the pipe's inner wall.

Currently, the response of choice is pre-emptive pigging. It is a solution that requires the inclusion of two flowlines per well in order to create a pigging circuit, intermittent shut-in of prolific wells, and platforms equipped with pig launching stations.

It also incurs risk. Pigging more often than necessary results in too-frequent, costly downtime. Pigging delayed can result in a pig buried in more paraffin than it can move. The results of such a mishap have already been felt by one US Gulf of Mexico operator who reportedly was forced to replace miles of pipeline when the original became hopelessly blocked.

Even in areas that experience little paraffin formation, either because pipelines are relatively short, or because of the fluids' natural resistance to paraffin formation, are not immune. In the event of unscheduled shutdowns, fluids caught in transit can be exposed to cold for periods of time sufficient to instigate paraffin formation where before there had been none.

Though it is unlikely designers will ever risk a deepwater project without pigging provisions, a Houston-based company thinks it may offer some measure of relief. Oil Tech Services claims in its literature it "has the technology to produce a Vacuum Insulated Tubular System capable of maintaining product temperatures for longer periods of time than any other known insulated tubular system."

Oil Tech VP Roy Lee said the system, which includes downhole as well as pipeline components, can be thought of in its simplest form, "as a long, skinny thermos bottle." The pipe-in-a-pipe system uses a "getter" (a chemical designed to capture stray gas) in the annulus and several layers of insulation. The annular space is "outgassed" at a temperature just below that necessary to activate the getter. Then the temperature is raised to the getter activation temperature to capture residual gas. It is not a perfect vacuum but, according to Lee, it approaches one.

The company guarantees an overall U factor (BTU/hr-ft - degree ft) of 0.03-0.05, including the loss at the connections of the 120-ft joints. By comparison, said Lee, other insulation systems typically offer a much less attractive heat loss factor of about 0.2-0.4.

Insulating the offending flowlines is not a new concept, of course but it has generally lost out to less costly methods. Lee thinks his company, which has teamed up with the installation capabilities of Stolt Comex Seaway, has overcome that drawback. For one project, for instance, his company recently quoted a contractor about $1 million per mile FOB the plant on a 32-mile flowline scheduled to be installed at about $3.5 million per mile. As Lee put it, "That leaves a lot of running room for installation."

None of Oil Tech's lines are in deepwater yet. But three are being considered by majors in the Gulf. If successful, they could go a long way toward relieving the anxiety of a lot of deepwater production engineers.

Copyright 1997 Oil & Gas Journal. All Rights Reserved.

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