1、 Standard Test Method Laboratory Screening Tests to Determine the Ability of Scale Inhibitors to Prevent the Precipitation of Calcium Sulfate and Calcium Carbonate from Solution (for Oil and Gas Production Systems) This NACE International standard represents a consensus of those individual members w
2、ho have reviewed this document, its scope, and provisions. Its acceptance does not in any respect preclude anyone, whether he or she has adopted the standard or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not in conformance with this standard. Nothing
3、contained in this NACE International standard is to be construed as granting any right, by implication or otherwise, to manufacture, sell, or use in connection with any method, apparatus, or product covered by Letters Patent, or as indemnifying or protecting anyone against liability for infringement
4、 of Letters Patent. This standard represents minimum requirements and should in no way be interpreted as a restriction on the use of better procedures or materials. Neither is this standard intended to apply in all cases relating to the subject. Unpredictable circumstances may negate the usefulness
5、of this standard in specific instances. NACE International assumes no responsibility for the interpretation or use of this standard by other parties and accepts responsibility for only those official NACE International interpretations issued by NACE International in accordance with its governing pro
6、cedures and policies which preclude the issuance of interpretations by individual volunteers. Users of this NACE International standard are responsible for reviewing appropriate health, safety, environmental, and regulatory documents and for determining their applicability in relation to this standa
7、rd prior to its use. This NACE International standard may not necessarily address all potential health and safety problems or environmental hazards associated with the use of materials, equipment, and/or operations detailed or referred to within this standard. Users of this NACE International standa
8、rd are also responsible for establishing appropriate health, safety, and environmental protection practices, in consultation with appropriate regulatory authorities if necessary, to achieve compliance with any existing applicable regulatory requirements prior to the use of this standard. CAUTIONARY
9、NOTICE: NACE International standards are subject to periodic review, and may be revised or withdrawn at any time in accordance with NACE technical committee procedures. NACE International requires that action be taken to reaffirm, revise, or withdraw this standard no later than five years from the d
10、ate of initial publication. The user is cautioned to obtain the latest edition. Purchasers of NACE International standards may receive current information on all standards and other NACE International publications by contacting the NACE International FirstService Department, 1440 South Creek Drive,
11、Houston, Texas 77084-4906 (telephone +1 281228-6200). Reaffirmed 2007-03-10 Approved November 1974 NACE International 1440 South Creek Drive Houston, Texas 77084-4906 +1 (281) 228-6200 ISBN 1-57590-124-2 2007, NACE International NACE Standard TM0374-2007 (formerly TM0374-2001) Item No. 21208 TM0374-
12、2007 NACE International i _ Foreword Scale is an adherent deposit of inorganic compounds precipitated from water onto surfaces. Most oilfield waters are brines containing large amounts of calcium salts. When calcium is deposited as calcium sulfate or calcium carbonate scale, a loss of production and
13、 increased maintenance expenses can result; therefore, effective scale inhibition is of primary importance to the oil producer. Scale inhibitors can be used in many circumstances to control scale formation, thereby reducing production difficulties. Scale inhibitors are commercially available and are
14、 widely used in oil and gas production systems. The test methods in this standard are designed to provide a relative and quantitative measure of the abilities of scale inhibitors to prevent the precipitation of solids, a necessary and critical stage in the formation of scale. The laboratory screenin
15、g tests described in this standard cannot and do not allow for the wide variation in water chemistry and system properties seen in field operations. As such they must only be regarded as a starting point in the evaluation of scale inhibitors. The existence and use of these methods allow for a unifor
16、m mode of collection of screening test results and facilitate discussion of the results by interested parties. The test methods in this standard have been selected as a means of comparing, under the specified laboratory conditions, the effectiveness of scale inhibitors in preventing precipitation of
17、 calcium sulfate and calcium carbonate from solution. Because the prices of scale inhibitors change with time and may be unknown to the tester, no attempt has been made to dilute the scale inhibitor to a common cost base. This standard was originally prepared in 1974 by Task Group T-1D-9 and was rev
18、ised in 1990 by Task Group T-1D-31, a component of Unit Committee T-1D on Corrosion Monitoring and Control of Corrosion Environments in Petroleum Production Operations. It was reviewed and reaffirmed in 1995 by members of T-1D, and in 2001 and 2007 by members of Specific Technology Group (STG) 31 on
19、 Oil and Gas ProductionCorrosion and Scale Inhibition. It is 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
20、.9. Shall and must are used to state mandatory requirements. Should is used to state something considered good and is recommended but is not mandatory. May is used to state something considered optional. _ TM0374-2007 ii NACE International _ NACE International Standard Test Method Laboratory Screeni
21、ng Tests to Determine the Ability of Scale Inhibitors to Prevent the Precipitation of Calcium Sulfate and Calcium Carbonate from Solution (for Oil and Gas Production Systems) Contents 1. General . 1 2. Calcium Sulfate Precipitation Test 1 3. Calcium Carbonate Precipitation Test 2 4. Percent Inhibiti
22、on Calculation 4 Table 1 Calcium Sulfate Retained in Solution (as Calcium Sulfate, mg/L) . 2 Table 2 Calcium Carbonate Retained in Solution (as Calcium Carbonate, mg/L) 4 References 4 _ TM0374-2007 NACE International 1 _ Section 1: General 1.1 The test methods described in this standard are static l
23、aboratory screening tests designed to give a measure of the ability of scale inhibitors to prevent the precipitation of calcium sulfate and calcium carbonate from solution at 71C (160F). 1.2 These test methods are recommended only for ranking the performance of different scale inhibitors under labor
24、atory conditions set by these methods. They are not intended to provide actual field treating rates. 1.3 Many factors, such as reaction kinetics, fluid velocity and composition, variable temperatures and pressures, scale adherence, and solids dispersion can significantly affect actual scale depositi
25、on under field conditions. Detailed consideration of these parameters is deemed to be outside the scope of this standard. However, field conditions, field brine composition, and other variables noted above should be considered at some point in scale inhibitor evaluation prior to final scale inhibito
26、r selection for field use. 1.4 Tests should be conducted at various scale inhibitor concentrations in order to obtain a better understanding of performance under laboratory conditions set by these methods. The scale inhibitor concentration required for a field application is likely to be different f
27、rom that determined under these laboratory conditions. 1.5 This standard lists the necessary apparatus, reagents, and procedures for conducting these laboratory screening tests. _ Section 2: Calcium Sulfate Precipitation Test 2.1 This section lists the apparatus, solutions, and procedure for conduct
28、ing the calcium sulfate precipitation screening test. 2.2 Apparatus and Solutions 2.2.1 Constant-temperature water bath or forced-draft oven with the capability of maintaining the specified temperature within 1C (2F). 2.2.2 Clean and dust-free glass test cells (approximately 125-mL 4-oz bottles with
29、 positive seals). 2.2.3 Synthetic brines prepared with distilled or deionized water, as follows: 2.2.3.1 Calcium-containing brine: 7.50 g/L NaCl (ACS (1)reagent grade); 11.10 g/L CaCl 2 2H 2O (ACS reagent grade). 2.2.3.2 Sulfate-containing brine: 7.50 g/L NaCl (ACS reagent grade); 10.66 g/L Na 2SO 4
30、 (ACS reagent grade). 2.2.3.3 Note: Very small quantities of insoluble materials may remain after the specified reagents have completely dissolved. For consistency of results, solutions shall be filtered through a 0.45- m filter. 2.2.4 Apparatus for reproducibly delivering 50 0.5 mL (e.g., graduated
31、 cylinders or volumetric pipets). 2.2.5 One percent by weight (1 wt%) and 0.1 wt% dilutions of the as-received scale inhibitors to be tested, prepared with deionized water. 2.2.6 Graduated measuring pipets in the following sizes: 0.1, 0.5, and 1.0 mL. 2.2.7 Standard reagents and apparatus for determ
32、ination of calcium concentration in accordance with ASTM (2)D 511, 1ASTM D 1126, 2 APHA (3)Standard Methods for the Examination of Water and Wastewater (Part 300), 4or another accepted test method. 2.3 Test Procedure 2.3.1 Pipet the desired amount of scale inhibitor into each test cell using the 1 w
33、t% and 0.1 wt% dilutions. The 0.1 wt% dilution shall be used for tests in which scale inhibitor loadings are less than 10 mg/L. Run duplicates of each concentration. _ (1)American Chemical Society (ACS), 1155 16 thSt. NW, Washington, DC 20036. (2)ASTM International (ASTM), 100 Barr Harbor Dr., West
34、Conshohocken, PA 19428. (3)American Public Health Association (APHA), 800 I St. NW, Washington, DC 20001-3710. TM0374-2007 2 NACE International 2.3.2 Prepare duplicate blanks as follows: 2.3.2.1 Set aside two samples of the calcium- containing brine (50 mL each). Determine the calcium ion concentrat
35、ion of the blanks before precipitation in accordance with Paragraph 2.3.8 and divide each value by 2. 2.3.2.2 Prepare and handle the blanks after precipitation as described in Paragraphs 2.3.3 through 2.3.8, but do not include a scale inhibitor. 2.3.3 Add 50 mL of sulfate-containing brine to the tes
36、t cell and mix well. Add 50 mL of calcium-containing brine to the test cell. 2.3.4 Cap the test cell immediately and agitate to mix the brines and the scale inhibitor thoroughly. 2.3.5 Place all test cells and blanks in a forced-draft oven or immerse to 75% of their lengths in a water bath at 71 1C
37、(160 2F) for 24 hours. 2.3.6 Remove the test cells after the 24-hour exposure and avoid agitation. Allow the test cells to cool to 25 5C (77 9F) for a time not to exceed two hours. 2.3.7 Pipet 1 mL of the test brine to a suitable vessel, avoiding the transfer of calcium sulfate crystals, and dilute
38、with distilled water, deionized water, or as otherwise specified in the calcium determination method to be used. 2.3.8 Determine the calcium ion concentration by procedures given in ASTM D 511, ASTM D 1126, APHA Standard Methods for the Examination of Water and Wastewater (Part 300), or another acce
39、pted test method. NOTE: Calcium ion concentration values for duplicate test samples often differ by 2% or more. A 5% difference is considered unacceptable and shall be cause for rerunning the test. 2.3.9 Report the average of the duplicate calcium ion concentration values as mg/L calcium sulfate ret
40、ained in solution for each inhibitor test concentration and the blank. 2.3.10 Percent inhibition may be calculated in accordance with Paragraph 4.1 and reported. 2.3.11 Representative data from the evaluation of three scale inhibitors are given in Table 1. These data are examples only and do not ref
41、lect experimental precision. These data indicate that scale inhibitor A is most effective. Note: Costs of the scale inhibitors have not been considered. TABLE 1Calcium Sulfate Retained in Solution (as Calcium Sulfate, mg/L) Scale Inhibitor 1 mg/L 3 mg/L 5 mg/L 10 mg/L 20 mg/L A 5,140 5,140 5,140 5,1
42、40 5,140 B 4,080 4,352 4,896 5,068 5,140 C 4,896 5,103 5,140 5,140 5,140 Blank (after precipitation): 3,808 mg/L Blank (before precipitation): 5,140 mg/L _ Section 3: Calcium Carbonate Precipitation Test 3.1 This section lists the apparatus, solutions, and procedure for conducting the calcium carbon
43、ate precipitation screening test. 3.2 Apparatus and Solutions 3.2.1 A pressure-regulated source of carbon dioxide (CO 2). All recognized grades of CO 2 are suitable for this test. 3.2.2 Constant-temperature water bath or forced-draft oven with the capability of maintaining the specified temperature
44、within 1C (2F). 3.2.3 Clean and dust-free glass test cells (approximately 125-mL 4-oz bottles with positive seals). Caution: The amount of vapor space above the test solutions in Paragraph 3.3.5 will affect the test results. To maximize the validity and reproducibility of test results, choose test c
45、ells that vary in capacity (volume) when sealed by 5% or less; that is, V r = V 0.025 V, where V r equals the desired range of test cell capacities and V equals the mean test capacity. 3.2.4 Fritted-glass gas dispersion tube(s) (medium or coarse porosity rating). TM0374-2007 NACE International 3 3.2
46、.5 Synthetic brines prepared with distilled or deionized water, as follows: 3.2.5.1 Calcium-containing brine: 12.15 g/L CaCl 2 2H 2O (ACS reagent grade); 3.68 g/L MgCl 2 6H 2O (ACS reagent grade); 33.0 g/L NaCl (ACS reagent grade). 3.2.5.2 Bicarbonate-containing brine: 7.36 g/L NaHCO 3 (ACS reagent
47、grade); 33.0 g/L NaCl (ACS reagent grade). 3.2.5.3 Note: Very small quantities of insoluble materials may remain after the specified reagents have completely dissolved. For consistency of results, the solutions shall be filtered through a 0.45-m filter. 3.2.6 Apparatus for reproducibly delivering 50
48、 0.5 mL (e.g., graduated cylinders or volumetric pipets). 3.2.7 One percent by weight (1 wt%) and 0.1 wt% dilutions of the as-received scale inhibitors to be tested, prepared with deionized water. 3.2.8 Graduated measuring pipets in the following sizes: 0.1, 0.5, and 1.0 mL. 3.2.9 Standard reagents and apparatus for determina
