1、 Standard Practice Corrosion Control of Sucker Rods by Chemical Treatment This NACE International standard represents a consensus of those individual members who have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he or she has adop
2、ted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing contained in this NACE International standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or
3、 use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement of Letters Patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better p
4、rocedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness of this standard in specific instances. NACE International assumes no responsibility for the interpretation or use of this standard by other
5、parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing procedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE International standard are r
6、esponsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standard prior to its use. This NACE International standard may not necessarily address all potential health and safety problems or environmental h
7、azards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standard are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate
8、 regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE tech
9、nical committee procedures. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the date of initial publication and subsequently from the date of each reaffirmation or revision. The user is cautioned to obtain the latest editi
10、on. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International First Service Department, 1440 South Creek Dr., Houston, Texas 77084-4906 (telephone +1 281/228-6200). Reaffirmed 2007-03-11
11、Reaffirmed 2001-03-15 Approved March 1995 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 (281) 228-6200 ISBN 1-57590-121-8 2007, NACE International NACE SP0195-2007 (formerly RP0195-2001) Item No. 21069 SP0195-2007 NACE International i _ Foreword This standard practice presen
12、ts corrosion inhibition, wear reduction, and corrosion prevention techniques for use from the manufacturing of bare steel sucker rods and couplings through installation and service in the well. Although aluminum, fiberglass, coated sucker rods, and high-alloy sucker rods are not specifically address
13、ed in this standard, many recommendations contained herein may be applied to such sucker rods, as appropriate, at the users discretion. Throughout this standard, the words “sucker rod” or “rod” will be used in the above described context. This standard was originally prepared as NACE Publication 1D1
14、671 by NACE Task Group T-1D-3 for inclusion in API(1) RP 11BR.2 Beginning in 1988, it was updated for the revision of API RP 11BR by NACE Task Group T-1D-35, a component of Unit Committee T-1D on Corrosion Monitoring and Control of Corrosion Environments in Petroleum Production Operations, for conve
15、rsion to a standard practice, and this standard was originally issued in 1995. This standard was also balloted to and approved by API as Section 3 of API RP 11BR.(2) It was reaffirmed in 2001 and 2007 by Specific Technology Group (STG) 31 on Oil and Gas ProductionCorrosion and Scale Inhibition and i
16、s issued by NACE International under the auspices of STG 31. In NACE standards, the terms shall, must, should, and may are used in accordance with the definitions of these terms in the NACE Publications Style Manual, 4th ed., Paragraph 7.4.1.9. Shall and must are used to state mandatory requirements
17、. Should is used to state something considered good and is recommended but is not mandatory. May is used to state something considered optional. _ (1) American Petroleum Institute (API), 1220 L Street NW, Washington, DC 20005-4070. (2) This standard was developed by members of NACE International and
18、 API and also is part of API RP 11BR, which can be obtained from API. _ SP0195-2007 NACE International ii _ NACE International Standard Practice Corrosion Control of Sucker Rods by Chemical Treatment Contents 1. General 1 2. Atmospheric Corrosion Control During Transportation and Storage . 1 3. Well
19、 Servicing 1 4. Downhole Corrosion Inhibition . 2 5. Inhibitor Selection 4 6. Evaluation of Inhibitor Programs . 4 References 5 Bibliography . 5 _ SP0195-2007 NACE International 1 _ Section 1: General 1.1 Corrosion can lead to serious multiple failures of oil well sucker-rod strings and other equipm
20、ent. The use of chemical corrosion inhibitors has proved to be a cost-effective approach to minimize corrosion damage and to extend the life of the downhole equipment. This standard addresses corrosion control for atmospheric conditions and downhole environments, treatment procedures, inhibitor sele
21、ction, and evaluation of corrosion inhibitor programs. Other factors to control failure of sucker-rod strings are addressed in API RP 11BR. 1.2 Corrosion inhibitors fall into many chemical classes that may be physical or health hazards. The handling precautions recommended by the manufacturer in the
22、 material safety data sheet (MSDS) shall be followed. In all cases, protection of the environment shall be considered. 1.3 In all operations discussed in this standard, corrosion inhibition is enhanced when sucker rod and coupling surfaces are free of scales and deposits. 1.4 Care should be taken to
23、 prevent air entry into the well to avoid oxygen-accelerated corrosion. Air entry can occur if casing vents are left open to the atmosphere or if the wellhead seals do not hold a vacuum. _ Section 2: Atmospheric Corrosion Control During Transportation and Storage 2.1 A hydrocarbon-removable coating
24、(HRC)(3) such as atmospheric corrosion inhibitor or a temporary protective coating should be used to prevent corrosion damage to sucker rods before they are placed in service. This coating should be applied before transportation of the sucker rods and should be maintained during storage. HRC can als
25、o be used to minimize atmospheric corrosion during field service of the sucker rods. 2.2 The manufacturer should provide sucker rods and couplings free of mill scale and with a suitable HRC applied to all exposed surfaces. The HRC should be adequate to provide protection against corrosion for a mini
26、mum of one year under humid atmospheric conditions at the storage site.(4) Acceptable HRCs shall be readily removable using hydrocarbon solvents. HRCs that do not obscure manufacturer markings are preferred. 2.3 The vendor, supplier, or agent shall inspect shipments and warehouse stocks of sucker ro
27、ds and couplings for visible signs of physical damage and corrosive attack. The vendor also shall take necessary action to clean rust spots and repair damage to the HRC. 2.4 The purchaser should inspect sucker rods and couplings upon receipt for physical damage and corrosion attack. The purchaser sh
28、ould also make periodic inspections of the sucker rods and couplings and maintain the HRC integrity during storage. 2.5 Used sucker rods that are stored for future service should be cleaned and coated for protection against atmospheric corrosion. Corrosion protection for less than one year can be ob
29、tained by dipping or spraying the rods and couplings with a suitable HRC. However, storage for more than one year requires the use of HRC similar to those recommended in Paragraph 2.2. _ Section 3: Well Servicing 3.1 Sucker rods should be protected after removal from the well during well-servicing o
30、perations. This is especially important in areas where hydrogen sulfide (H2S), carbon dioxide (CO2), or both are produced. However, the corrosion damage may frequently be caused by atmospheric oxidation. In some cases, protection from atmospheric oxidation can be achieved by pumping oil with a high
31、concentration of corrosion inhibitor into the tubing immediately before the rods are pulled. Alternatively, the rods may be coated with a mixture of oil and corrosion inhibitor after the rods are laid down. 3.2 Failures in threaded connections because of improper makeup or corrosion fatigue can occu
32、r when well fluids enter the couplings during pumping. Corrosion inhibitor should be applied during sucker-rod connection makeup to minimize corrosion inside the coupling. The couplings and pin ends can be dipped, brushed, or sprayed with a mixture of oil-soluble, film-forming corrosion inhibitor in
33、 refined oil or with inhibited grease.3 Sealants, such as thread dope, which contain a high level of solids, should not be used for sucker-rod threads. The _ (3) For the purposes of this standard, HRC refers to a material that is removed from the sucker-rod surface because it is soluble in produced
34、hydrocarbon. The material is not necessarily formulated in a hydrocarbon solvent. SP0195-2007 2 NACE International procedure for selecting an inhibitor can be found in NACE Standard MR0174.4 The sucker-rod manufacturer may be consulted for assistance in selecting commercial lubricants. Use of too mu
35、ch inhibitor-oil mix in the coupling cavity interferes with proper makeup. The procedure for proper makeup of sucker rods is found in API RP 11BR. Proper circumferential displacement develops sufficient sealing force at the shoulders, which tends to exclude well fluids from the threads. 3.3 When a n
36、ew rod string is run or each time the rods are pulled and rerun, the corrosion inhibitor film should be established (or reestablished) on downhole equipment. The rods should be examined for physical and corrosion damage each time they are run. 3.3.1 To provide initial protection to rods during and f
37、ollowing installation, one approach is to add an oil-soluble corrosion inhibitor mixture (19 to 38 L 5 to 10 gal U.S. of chemical in diesel or lease crude) to the tubing before running the rods (or to the casing before running tubing and rods). As the rods pass through this inhibitor mixture, a prot
38、ective film is applied. If there is no packer, additional benefit may be obtained from the inhibitor by circulating one tubing volume of fluid into the annulus before the well is returned to production. 3.3.2 An alternate initial treating practice is to add 19 to 38 L (5 to 10 gal U.S.) of inhibitor
39、 to the casing/tubing annulus and circulate the well to displace the annular volume before beginning production to the battery. 3.4 After the well is placed back on production, the selected treatment program should be resumed. _ Section 4: Downhole Corrosion Inhibition 4.1 There are many corrosion-i
40、nhibiting products and application techniques that are effective in protecting downhole production equipment. Selection of a particular method should be based on the specific application and the economics of the treatment program. These economic evaluations should consider the effectiveness of the t
41、reatment program as it relates to equipment replacement frequency and lost production. 4.2 Batch-and-Flush Treatment 4.2.1 The batch-and-flush treatment is most widely used for rod-pumped wells. Normally in this technique, an oil-soluble, water-dispersible corrosion inhibitor is injected into the we
42、ll annulus and flushed down to the fluid level. The flush fluids may be chemically oxygen-scavenged produced brine, chemically oxygen-scavenged fresh water, crude oil from a treater truck, or produced fluids bypassed from the wells flowline. Water-soluble inhibitors are generally less film-persisten
43、t than oil-soluble inhibitors, and therefore are normally not recommended for the batch-and-flush treatment. 4.2.2 Specific design of a treatment program (i.e., inhibitor selection, inhibitor dosage, treatment frequency) should include considerations such as oil/water ratio, fluid corrosiveness, flu
44、id level above the pump, and rod loading. Inhibitor selection is covered in Section 5. Typical inhibitor dosage and frequency are as follows: 4.2.2.1 One common practice for selecting inhibitor dosage for the initial program is to use an inhibitor concentration that is equal to 25 ppmv(5) based on t
45、he total fluid production between treatments. A minimum inhibitor volume of 4 L (1 gal U.S.) per treatment should be used. For example, a well producing 64 m3/d (400 barrels of fluid per day BFPD) would require about 11 L (3 gal U.S.) of inhibitor per week. 4.2.2.2 Treatment frequency usually varies
46、 with the well production rate. Typical treatment frequencies are every other week for wells producing less than 16 m3/d (100 BFPD), weekly for wells producing 16 to 48 m3/d (100 to 300 BFPD), and twice weekly for wells producing 48 to 80 m3/d (300 to 500 BFPD). When the total produced fluid is more
47、 than 80 m3/d (500 BFPD), some operators consider continuous treatments. 4.2.2.3 Adjustments in dosage and frequency to optimize treatment effectiveness should be based on corrosion-monitoring results (see Section 6 on Evaluation of Inhibitor Programs). 4.2.3. Flush volumes are often calculated based on well depth and annular pumping fluid level.5 For example, in low-fluid-level wells (less than 150 m 500 ft above the pump), typical flush volumes are 80 to 160 L (0.5 to 1.0 bbl) of flush (produced water or oil) per 300 m (1,000 ft) of well depth
