Service companies install RFID tags on frac equipment

June 28, 2010
Recent advancements in radio-frequency identification tags are allowing new uses of the tags such as for identifying equipment at hydraulic fracturing job sites.

Recent advancements in radio-frequency identification tags are allowing new uses of the tags such as for identifying equipment at hydraulic fracturing job sites.

Konrad Konarski, cofounder of the Oil & Gas RFID Solution Group told OGJ that "RFID technology today is not what we have seen 10 or even 5 years ago. The technology that was introduced into the market a decade ago was low-frequency RFID, imported from other industrial sectors.

"Today the technology has evolved into a dedicated niche for the oil and gas sector, with ultrahigh-frequency capability, read ranges that can exceed multiple feet, and tag designs that can withstand the harshest environmental stresses."

Konarski said two of the companies now supplying the new RFIDs are FMC Technologies Inc. and Weir SPM.

As far as the Oil & Gas RFID Solution Group, he said members include BP PLC, ExxonMobil Corp., FMC Technologies, Weir SPM, and several other companies with the group's aim being to support development of best practices and data standards that could help enable further collaboration between supply-chain partners interested in using the technology.

RFID uses

Konarski explained that RFIDs are a wireless method of identification similar to the barcode and made their debut in upstream almost 2 decades ago with applications that included drill pipe tagging and downhole-tool actuation.

Fig. 1 shows how a passive RFID tag energized by an antenna works.

The RFID tags attached to oil field parts provide a means of automating the identification process and decrease the time for processing equipment into and out of the field. The tags replace an old identification method of engraved serial numbers on metal bands that required reorientation of heavy objects and careful inspection of the band to identify the part ID, Konarski said.

Konarski noted that in a fracturing job ideally each component, such as swivels, pup joints, valves, etc., would have an RFID tag but the reality is that this takes time. He said currently both FMC and WEIR are working in different areas of the world to deploy the tags

He said that this means that in the field only certain parts are RFID enabled, while other parts from the old inventory are not RFID enabled. In regions in which there is a focus on RFID-tag commissioning several hundred tags might be on a job site, Konarski said.

The cost of the tags is $5-8, but Konarski expects prices to decrease to $2-3 by 2011 as the numbers manufactured increase from the hundreds of thousands into the millions.

RFID description

Konarski provided the following description of the tags.

Companies attach the bands on locations on the parts that do not obstruct assembly and disassembly. This typically is below thread lines in areas where the OD is smallest, or smaller than the largest OD of that particular part.

Installation may be flush and tight on the part, based on oil field service company request. Attachments that enable partial loss, however, provide better flexibility and turn aside impact well.

The RFID is in a vulcanized rubber band that is attached to the part with a stainless-steel braided aircraft wire (Fig. 2).

From a form perspective (Fig. 2), the shape of the tags is a dome-like structure that is a common shape used to distribute impact force. The size of this form can change depending on the equipment.

The material for the tag is a vulcanized rubber, selected deliberately because of its durometer hardness, which is relatively high yet malleable enough to bend around products. Also the material resists corrosive chemicals and sunlight, much like a rubber tire.

A stainless-steel braided aircraft wire (extremely strong) covered in a teflon reinforced cover attaches the tag to the part. The wire thickness and length may vary with the parts.

Previously service companies used serial bands to identify parts (Fig. 3).

Installation of the tags is almost identical to the old serial bands used by the industry (Fig. 3). An iron nico-press crimp device pulls the tag in place and the size of the crimp depends on the width of the stainless-steel wire. The final attachment for the RFID tags is much stronger and more effective than the serial bands.

The tags can come fully manufactured (size, aircraft wire length, and width), or the manufacturer can deliver them in a subassembly, in which the vulcanized rubber tag is separate from the coated wire, and subsequently the wire is cut and fitted into a predrilled hole in the tag depending on the part being commissioned.

All electronics on the RFID tag are Class 1 Gen 2 UHF. This means all the tags function under the same frequency and all use the same air protocol (communication language) and therefore are all readable by Class 1 Gen 2 compliant RFID readers.

The data scheme is basically the structure of the identifier-data that is in the tag memory. The tags have an established standard that specifies what data are stored in what part of the tag memory.

This standard also is for multivendor data that are encoded on the tag as it moves through the supply-chain. All Class 1 Gen 2 tags can be reencodable by the standard. They contain 512 bits of memory and are reencodable an unlimited number of times.

The data scheme has various user memory spaces that can be password protected and reencoded only with the corresponding password, thus protecting each vendor and its respective memory. On that note, these tags are the newest and most sophisticated passive RFID tags available, with read ranges of more than 5 ft and complex engineer packages used for rugged environments and are interoperable across any geographical region.

The RF provides global interoperability, which means that the antennas of the tags can capture signals across various RF spectrums allocated to the passive UHF RFID band (865-868 Mhz in Europe and 902-928 Mhz in North America). These consequently modulate this signal and return their data based on commands sent from the readers (transmitted devices tuned and located at the corresponding region).

For example, the tag can travel from one region to another, and each region of the world can have different frequency regulations. The readers in these regions will transmit activation energy to these tags and the tags will respond at the corresponding allowable frequency based on that original activation transmission, thus allowing for global interoperability.

Tag manufacturers classify the parts into different categories that include swivels, valves, pup joints, and specialty. The first three come in different diameters and wall thickness but generally are identical in shape.

The location of the attachment is therefore always consistent and the wire lengths and sometimes thicknesses that are based on the part size. For instance a large-diameter pup joint would require a longer wire. A small valve would require a smaller wire, but also potentially a thinner wire, to allow for it to lay flush beneath the final attachment thread (Fig. 4).

This small valve has an RFID that lies flush beneath the final thread (Fig. 4).

The specialty parts use a custom epoxy with a very small form factor. Specialty parts are those parts that do not have any easy attachable surfaces. They represent fewer than 5% of all products.

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