System of pipes for use in oil wells

Inactive Publication Date: 2006-06-15
EI DU PONT DE NEMOURS & CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011] It is an advantage of the present invention to be able to tailor the use of such linings so that particular problems may be addressed by particular sections of pipe. In addition, with the present invention, certain sections of pipe need not be lined at al.
[0012] The lining system on the interior surface and/or exterior of the pipe either minimizes or eliminates (i) the deposition of asphaltenes, paraffin wax, and inorganic scale, so as to minimize or eliminate pluggage of the oil pipe and (ii) corrosion of the interior surface of the pipe. The reduction in deposition can be characterized by being at least 40%, preferably at least 50%, of at least one of asphaltenes, paraffin wax, and inorganic scale as compared to the interior surface of the pipe without the lining being present. Reductions of at least 60%, 70%, 80% and even at least 90% may be realized. Preferably these reductions apply to at least two of the deposition materials, and more preferably, to all three of them. The reduced deposition performance of the lined pipes of the present invention is in contrast to the result obtained for unlined pipes, as well as for epoxy resin-lined oil pipe, where surprisingly the deposition is greater than for the unlined pipe. This deposition reduction is accompanied by the added benefit of salt water impermeability as well as corrosion resistance, as compared to unlined oil pipe.
[0013] The lining comprises a fluoropolymer, which has non-stick properties. In one embodiment, the lining may comprise a perfluoropolymer, and in particular, a pure perfluoropolymer. The pipe of this embodiment of the present invention has a continuous adherent perfluoropolymer coating, or lining, on its interior surface, with the exposed surface of the perfluoropolymer providing a non-

Problems solved by technology

In addition, the lining on the interior surface of the pipe is impermeabl

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Example

Comparative Example B

ETFE Primer / ETFE Overcoat

[0112] A layer of primer 2 (aqueous ETFE) is applied to a prepared stainless steel sleeve and a prepared carbon steel panel, followed by baking at 150° C. for 10 minutes. The dry film thickness (DFT) of the primer layer is 12-19 micrometers (p). A layer of overcoat B (powder ETFE) is applied over the dried primer layer. It is baked at 316° C. for 20 minutes. The total DFT is 100-125 micrometers and the total thickness of the overcoat is 81-113 micrometers. When the coated sleeve is subjected to the Paraffin Deposition Test, a deposition of 0.0327 g / cm2 is obtained. When the coated carbon steel panel is subjected to the PWA test and Cross-Hatch Adhesion Test, the panel passes both tests.

[0113] Aqueous primers are not preferred for use in this invention because of the potential for reduced corrosion resistance over a prolonged period of time. ETFE overcoats are inferior to the perfluoropolymer overcoats of this invention.

Example

Comparative Example C

Uncoated Substrate

[0114] An uncoated prepared stainless steel sleeve is subjected to the Paraffin Deposition Test, a deposition of 0.0296 g / cm2 is obtained.

Example

Example 1

FEP Primer / Modified PFA Overcoat

[0115] A layer of primer 1 (liquid FEP) is applied to a prepared stainless steel sleeve and a prepared carbon steel panel, followed by baking at 150° C. for 10 minutes. The dry film thickness (DFT) of the primer layer is 12-19 micrometers. A layer of overcoat 1 (PFA modified with PEVE powder) is applied over the dried primer layer. It is baked at 399° C. for 20 minutes. The total DFT is 60-75 micrometers. A second layer of overcoat is applied. It is baked at 371° C. for 20 minutes. The total DFT is 100-125 micrometers and the total thickness of the overcoat is 81-113 micrometers. An insulating layer is applied to the exterior of the sleeve.

[0116] When the coated sleeve is subjected to the Paraffin Deposition Test, a deposition of only 0.0168 g / cm2 is obtained. When the coated carbon steel panel is subjected to the PWA test and Cross-Hatch Adhesion Test, the panel passes both tests.

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Abstract

The present invention relates to pipes that convey any flowable medium, such as chemicals, food and in particular, oil and gas, and more particularly to a system of pipes having different coatings or linings for the interior and exterior surfaces of such pipes, depending on the environment in which the pipes are used. The pipes may be coated with different materials, which may be of different thicknesses, with various configurations of coatings or linings. Such coating may be done on the interior and/or the exterior of the pipes.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority under 35 U.S.C. §119 from U.S. Provisional Application Ser. No. 60 / 630,942, filed Nov. 24, 2004.FIELD OF THE INVENTION [0002] This invention relates to pipes that convey any flowable medium, such as chemicals, food and in particular, oil and gas, and more particularly to a system of pipes having different coatings or linings for the interior and exterior surfaces of such pipes, depending on the environment in which the pipes are used. BACKGROUND OF THE INVENTION [0003] Pipes used in the production and transportation of flowable media are subject to corrosion and plugging. An example of such a pipe is oil pipe which is generally large and for reasons of economy is manufactured from carbon steel rather than more expensive corrosion resistant alloys. Corrosion is induced by the hot underground environment in which down-hole pipes convey oil from deeply buried deposits to the earth's surface. Materials such a...

Claims

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Application Information

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IPC IPC(8): F16L11/04
CPCF16L55/1656F16L58/02Y10T428/1393F16L58/10F16L58/04Y10T137/0402
Inventor MOHAN, PIDATALA K.MESTEMACHER, STEVEN A.FARNSWORTH, KIMBERLY DAWNMCKEEN, LAURENCE WAINOOBAL, W. DOUGLAS
Owner EI DU PONT DE NEMOURS & CO
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