Petroleum Wellhead BOP Systems

Hello,

I would class BOP's as safety equipment. "Mud" is used to equalise the fluid, be it gas or other, while drilling, the BOP's are there to stave off an accident or blow out.

Right, wrong?

I work in a factory/service organization that services and sells BOP's as well as manufactures the hydraulic pump and control systems to operate them.

I can understand why they would be considered valves. I consider them to be mission critical safety devices. You don't drill without them, or the supporting control systems. The rams are a form of gate valve. the Annular is a metal/rubber torus, made to constrict on the pipe, but still a form of valve. The major function of the BOP is control and seal the pressures in the wellbore, and then using choke and kill to divert the gases to flare, or other valves to pump mud back down, and suppress the gas.

BOP's have rubber seals, and can be in a closed position while drilling or stripping, but I wouldn't say that they really mechanical grip the pipe. they seal off against it. It is a form of rotary seal. Other drill platform devices grip the pipe. I can see a 'centering function' as being somewhat appropriate, but not a required one.

So basically, they are very powerful, heavy, precision hydraulic valves, made to control specific condtions and arrangements. They do not directly bore or sink, and I wouldn't consider them part of the boring or sinking equipment. Is a mud pump part of boring or sinking equipment? Then really, the whole rig is, even the generator. I would think that they are classified as valves because that is their basic mechanical function. their nature, so to speak.

I think that the API website would be an excellent place to start looking for classification information, taxation, or tariff information.

http://www.api.org/policy/tax/

chrisg288@hotmail.com

Chris,

I'm a naval architect and would like to know a little bit more about BOP.

According to "A Primer of Offshore Operations" (2nd Ed.) by Ron Baker and published by Petroleum Extension Service, Division of Continuing Education, The U. of Texas at Austin (1985), "Blowout preventers (BOPs) on land rigs are located beneath the rig at the land's surface; on jackup or platform rigs, atthe water's surface; .....".

How could one put a BOP on water's surface?

Thanks and best regards.

Our company does not specialize in Subsea drilling systems, but we have one person here who has experience, and there are a couple of books here. He worked as a consultant on the Hibernia project.

As I understand it, the BOP's are subsea, and are part of a package (Lower Marine Riser Package or LMRP) that is planted on the ocean floor, while the hydraulic pumping unit (controls) for the bops are on the surface (platform, ship, island) The accumulator bottles can be in both locations. Difficulties with hydraulic pressure systems arise due to the pressures experienced at depth, and must be compensated for.

There is plenty of information on the web too.

Chris

You might try http://www.pennwell.com/books_videos.cfm?navid=3005

I got a good primer on well control including BOP's through them some years ago

Classification for tariff purposes under the Harmonized Tariff System is governed by the language describing the particular headings. Ancillary equipment used in drilling operations (pumps, motors, piping, winches, etc.) get classified as those things because there are headings with language that more clearly describes them. With the BOPs, the choices seem to include "boring or sinking machinery," "valves," "mechanical seals," or "other machinery." My goal, just to be up front, is to find arguments for classifying them as "boring or sinking machinery."

The language of the "valve" heading is: "Taps, cocks, valves and similar appliances, for pipes, boiler shells, tanks, vats or the like, including pressure-reducing valves and thermostatically controlled valves." As far as the safety function, there is not really a generic heading for "safety equipment." There is a subheading within the "valves" heading for "safety and relief valves" and that, perhaps, is an option but the U.S. duty rate is 2% (millions or dollars). Other than that, however, there are no valve subheadings that speak to the industry or the purpose...there are just generic references to various classes of valve types. The "other" provision, for valves not more specifically described, is dutiable at 2%.

There are specific provisions for "seals" and mechanical sealing devices. The tariff language for that heading is: "Gaskets and similar joints of metal sheeting combined with other material or of two or more layers of metal; sets or assortments of gaskets and similar joints, dissimilar in composition, put up in pouches, envelopes or similar packings; mechanical seals." If BOPs are deemed to be mechanical seals, the duty rate is 3.9% (even more millions of dollars). There are no "seal" subheadings that speak to the industry or the purpose...there is just a subheading for "mechanical seals." Thus, do BOPs "valve" or do they "seal"? To me, the sealing function seems more accurately descriptive than the "valve" function but the tariff result is even less desirable. Also, I have been advised that a key function of the BOP stack is to prevent the ejection of the drill string during a kick. That's neither "valvish" or "sealish."

If neither the "valve" nor the "seal" language captures the BOPs, there is a heading for "other machinery" that provides for: "Machines and mechanical appliances having individual functions, not specified or included elsewhere in this chapter." That duty rate is 2.5%.

The duty rate for The duty rate for "boring or sinking machinery" is FREE and classification as such is my goal. I would argue that BOPs are not really valves because their function is more to prevent a flow in the annulus than to regulate it. If a valve were desired in the BOP stack, the obvious choice would be a ball valve. A BOP stack typically includes rams that shear the drill string and any other piping in the annulus. Pipe shearing is certainly not a "valve" function. Nor is it a "seal" function. Does the drill rotate when the pipe rams or annular BOP is engaged? If so, when fully engaged or only partially engaged? In any event, it seems that BOPs are "valvish" and "sealish" but, perhaps, not precisely either. On the other hand, they do have a specific purpose and that purpose is intimately related to the drill string. BOPs are devices that were designed solely for use in boring or sinking holes into the earth. Granted, they don't contribute to making the hole but they are machinery intended to deal with certain consequences of making the hole and only useful to drillers when drilling.

Thus, the choices seems to be between classifying based on their being "valvish," "sealish," "not elsewhere described," or machinery whose function relates to "boring or sinking." Any creative ideas out there?

I would say that according to the general rule number 3 c or the 4th in the HTS the subheading for the BOP's is 8481.80.

regards from mexico

3. When, by application of rule 2(b) or for any other reason, goods are, prima facie, classifiable under two or more headings,

classification shall be effected as follows:

(a) The heading which provides the most specific description shall be preferred to headings providing a more general

description. However, when two or more headings each refer to part only of the materials or substances contained in mixed

or composite goods or to part only of the items in a set put up for retail sale, those headings are to be regarded as equally

specific in relation to those goods, even if one of them gives a more complete or precise description of the goods.

(b) Mixtures, composite goods consisting of different materials or made up of different components, and goods put up in sets for

retail sale, which cannot be classified by reference to 3(a), shall be classified as if they consisted of the material or

component which gives them their essential character, insofar as this criterion is applicable.

(c) When goods cannot be classified by reference to 3(a) or 3(b), they shall be classified under the heading which occurs last in

numerical order among those which equally merit consideration.

4. Goods which cannot be classified in accordance with the above rules shall be classified under the heading appropriate to the

goods to which they are most akin.