1、American Petroleum Institute Methods for Measuring Naturally Occurring Radioactive Materials (NORM) in Petroleum Production Equipment Exploration and Production Department API Publication 7102 Novem ber, 1 997 . STD*API/PETRO PUBL 7LU2-ENGL 11797 E4 0732?40 ObO11bUO BT5 SI+!- Strategies for Today? E
2、nvironnentaZ Partnership One of the most significant long-term trends affecting the future vitality of the petroleum industry is the publics concerns about the documenting performance; and communicating with the public. API ENVIRONMENTAL, HEALTH AND SAFETY MISSION AND 1 GUIDING PRINCIPLES c The memb
3、ers of the American Petroleum Institute are dedicated to continuous efforts to improve the compatibility of our operations with the environment while economically ,devel- oping energy resources and supplying high quality products and services to consumers. We recognize our responsibility to work wit
4、h the public, the government, and others to develop and to use natural resources in an environmentally sound manner while protecting the health and safety of our employees and the public. To meet these responsibilities, API members pledge to manage our businesses according to the following principle
5、s using sound science to prioritize risks and to implement cost-effective management practices: To recognize and to respond to cornmuniiy concerns about our raw materials, prod- ucts and operations. To operate our plants and facilities, and to handle our raw materials and products in a manner that p
6、rotects the environment, and the safety and health of our employees and the public, To make safety, health and environmental consider-ations a priority in our planning, and our develop-ment of new products and processes. To advise promptly, appropriate officials, employ-ees, customers and the public
7、 of- information on significant industry-related safety, health and environmental hazards, and to recommend protective measures. To counsel customers, transporters and others in the safe use, transportation and dis- posal of our raw materials, products and waste mareriab. resources by using energy e
8、fficiently. To extend knowledge by conducting or supporting research on the safety, health and environmental effects of our raw materials, products, processes and waste materials. To economically develop and produce natural re-sources and to conserve those To commit to reduce overall emissioq and wa
9、ste generation. To work with others to resolve problems created by handling and disposal of hazardous substances from our operations. To participate with government and others in creating responsible laws, regulations and standards to safeguard the community, workplace and environment. To promote th
10、ese principles and practices by sharing experiences and offering assis- tance to others who produce, handle, use, transport or dispose of similar raw materi- als, petroleum products and wastes. a STD.API/PETRO PUBL 7102-ENGL 1777 0732290 Ob01bL 731 D Methods for Measuring Naturally Occurring Radioac
11、tive Materials (NORM) in Petroleum Production Equipment Exploration and Production Department API PUBLICATION 71 02 PREPARED BY: Rogers however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsib
12、ility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict. Suggested revisions are invited and should be submitted to the director of the Manufactur- ing, Distribution and Marketing Department, America
13、n Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. STD.API/PETRO PUBL 7102-ENGL 1777 0732270 Ob01b03 50Li TABLE OF COXTESTS Chamer 1 ISTRODCCTION 1.1 Origin and Xature of XORM 1.2 Project Objectives and Scope 1.3 Report Organization 2 3 SCISTILLATION DETECTOR CHARACTERISTICS 2.1 Ins
14、trument Calibration 2.2 Variability of Detector Response 2.2.1 Variability Between Detectors 2.2.2 Environmental Effects on Detector 2.2.3 Electronic Variability of Detectors Variability DEVELOPMENT OF CORRELATIONS 3.1 Theoretical Development of the Detector Correlation 3.2 Laboratory Measurements 3
15、.2.1 Radioactive Sources 3.2.2 Equipment Configurations Tested 3.3 Results and Analyses Pace So. 1-1 1- 1 1-3 1-3 2-1 2-1 2-3 2-3 2-6 2-10 3-1 3-1 3-4 3-5 3-7 3-9 3-9 3.3.1 Determination off 3.3.2 Determination of t 3-15 3.3.3 Development of the Correlation for Radium ,. -a 3-ZU 3-25 Concentration 3
16、.3.4 Implementation of the Correlation 3.3.5 Correlation for Thin Scales and Gas Plant Equipment 3.3.6 Correlations for Soil 3-28 3-30 VARIATIOXS IN SOURCE AND DETECTOR GEOMETRY, AND CORRELATION SENSITIVITIES 4.1 Geometries and Orientations Considered 4-1 4-1 4 4.2 Minimum Detectable Concentrations
17、with a One-Inch Na1 Detector 4-8 4-13 4.3 The Lse of Alternative Detectors ii ChaDter TABLE OF CONTESTS 4.3.1 Detector Configurations 4.3.2 Results 5 FELD APPLICATION OF THE CORRELATIOXS 5.1 Field Measurement Data 5.2 5.3 5.4 5.5 5.6 5.7 Field Test of Gas Plant Correlation Tests of Wall Thickness an
18、d NORM Thickness Terms Field Test of the Radium Correlation for Large Equipment Field Test of the Radium Correlation for Tubing Field Test of the Radium Correlation for Yard Pipe and Similar Diameter Equipment Field Test of the Radium Correlation for soils 6 SUMMARY AND CONCLUSIONS Page So. 4- 13 4-
19、13 5- 1 a- 1 a- 1 5-2 5-6 5-10 5-10 5-10 6- 1 Tzible So. 2- 1 2-2 3- 1 3-2 3-3 3-4 3-5 3-6 3-7 3-8 3-9 3-10 3-11 3- 12 4- 1 , 4-2 4-3 STD-API/PETRO PUBL 7102-ENGL 1997 M 0732290 ObO1bOS 387 LIST OF TABLES Comparison of Resolutions of the 609 KeV Peak Jleasured with Five Different Detectors Gamma Mea
20、surements on Three Tubing Samples Using Six Different Scintillation Detectors Under Iden tical Conditions Radium-226 Analyses in Selected Bags of Uranium Tailings Used in the Laboratory Correlation Measurements Characteris tics of Oil Field Production Tubing Scintillometer Measurements of oil Scale
21、in Small Flat Plate Geometry Scintillometer Measurements of Tailings in Small Flat Plate Geometry Additional Scintillometer Measurements in Small Flat Plate Geometry Scintillometer Measurements of Tailings in Large Flat Plate Geometry Scintillometer Measurements of Tailings in 20 cm Pipe Geometry Sc
22、intillometer Measurements of oil Scale in Tubing Summary of Correlation Constant Values Summary of Correlation Results Test Pile Data for Correlation of Gamma Levels with Radium in Contaminated Soil Gamma Level Data for Correlation of Gamma Levels with Radium Contaminated Soils Results of Tapered So
23、urce Analysis Comparison of Detector Configurations Comparison of Ks of Different Detectors Using 5 cm Tubing Geometry Pace So. 2-8 2-9 3-6 3-10 3- 12 3-13 3-14 3-18 3-21 3-22 3-23 3-26 3-33 3-34 4-7 4- 14 4- 16 iv STD-APIIPETRO PUBL 7102-ENGL 1997 m 0732290 Ob01bOb 213 m LIST OF FIGVRES Fioure So.
24、1-1 Principal Components of the Cranium-238 and Thorium-232 Decay Chains 2- 1 2-2 Operating Voltage Plateau for Detector $1 Spectra Produced by a 1000 pCi/g Ra-226 Source, Using 1“ Na1 Detector #1 2-3 2-4 2-5 2-6 2- 7 2-8 3- 1 3-2 3-3 3-4 3-3 3-6 3-7 3-8 Spectra Produced by a 1000 pCilg Ra-226 Sourc
25、e, Using 1“ Na1 Detector #2 Spectra Produced by a 1000 pCYg Ra-226 Source, Using 1“ NaI Detector #3 Spectra Produced by a 1000 pCi/g Ra-226 Source, Using 1“ Na1 Detector #4 Spectra Produced by a 1000 pCi/g Ra-226 Source, Using 1“ Na1 Detector #5 Voltage Plateau Curves for the Five Scintillation Dete
26、ctors Detector Response vs. Varied Thresholds Major Factors Affecting the Measurement of Radiations from NOFM Counting Configuration for Large Diameter Equipment Simulation Counting Configuration for Medium Diameter Equipment Simulation Counting Configuration and Sample Points Used to Measure Tubing
27、 Detector Response to Well Tubing Comparison of Calculated ft$ for Tailings, Small Plate Geometry Comparison of Calculated f s with observed fis for oil Scaie, Small Plate kometry Comparison of Calculated fis with Observed fis for Tailings, Large Plate Geometry B as a Function of Equipment Diameter
28、Pace So. 1-2 2-2 2-4 2-4 2-5 2-5 2-7 2-11 2-12 3-2 3-8 3-8 3-11 3-16 3-17 3-19 3-24 V STD-API/PETRO PUBL 7LCIZ-ENGL L797 0732270 ObOLb07 L5T LIST OF FIGURES (Continued) Fimre So. 3-9 3- 10 3-11 3-12 4- 1 4-2 4-3 4-4 4- a 4-6 4-7 5- 1 5-2 5-3 5-4 5-5 5-6 Comparison of Correlation Radium Concentration
29、s u;ith Measured Concentrations in the Laboratory Variable “A“ as a Function of NORM Thickness Variable E as a Function of Equipment Wail Thickness Variable E as a Function of Equipment Wall Thickness Detector Response for Different Detector Orientations Detector Response as a function of Distance F
30、rom Surface Gradually Tapered Source Abruptly Tapered Source Configuration Bulk Detection Limits for Plate and Tubing Geometries Surface Detection Limits for Plate and Tubing home tries Effect of Background Intensity on Bulk Limit of Detection for 1“ Na1 Detector Comparison of Predicted and Measured
31、 NORM Surface Concentrations for Gas Plant Equipment Ratio Predicted to Measured NORM Surface Concentrations for Gas Plant Equipment as a Function of Wall Thickrress Ratio o Trer,:ted to Measured Radium Concentrations for Thick Equipment Walls Ratio of Vorrelation to Measured Radium Concentrations a
32、s a Function of NORM Thickness Ratio of Correlation to Measured Radium Concentrations for Yew XORM Thickness Correction Comparison of Correlation Radium Concentrations with Measured Concentrations for Large Equipment Paze So. 3-27 3-29 3-31 3-33 4-2 4-4 4-5 4-6 4-10 4-11 4-12 5-3 5-4 5-7 5-8 5-9 vi
33、Figure So. 5- 7 STD.API/PETRO PUBL 7102-ENGL 1997 = 0732270 ObOLbO 09b LIST OF FIGCRES (Continued) 5-8 5- 9 Comparison of Correlation Radium Concentrations with Measured Concentrations for Tubing Comparison of Correlation Radium Concentrations with Measured Concentrations for Intermediate Diameter E
34、quipment Comparison of Correlation Radium Concentrations with Measures Concentrations in Soils and Pits Pace So. 5-11 5- 12 5-13 vi i EXECUTIVE SL,LMARY The use and capabilities of common field-sumey equipment have been charactenzed for measuring naturally-occurring radioactive materials (NORM) in s
35、ludges and scales accumulated in oil and gas production equipment. A correlation was developed between radium concentrations in scales and sludges and the external radiation measured with scintillation detectors and Geiger-Mueller (GM) tubes. The correlation was validated with field measurements, an
36、d was used to estimate the lowest limits of detection of radium in the equipment. Characteristics of the field-survey instruments and of the NORM distribution in the oil and gas production equipment Sect the achievable measurement precisions and accuracies. One-inch Na1 scintillation probes commonly
37、 used for field gamma surveys should be calibrated with proper threshold current and voltage, and checked daily with check sources before use. Measurement variations using six different probes were within less than fifteen percent when properly used, despite major variations in detector energy respo
38、nses and resolutions. Freezing temperatures reduced detector efficiency by 9 percent, and only partial recovery was achieved upon warming. Count rates decreased by 2 percent for every doubling of the meter threshold setting. Correlations were developed to quantitatively relate survey readings to NOR
39、M radium concentrations in equipment scales and sludges. From fundamental radiation principles, the correlations depended on the NORM density, volume, thickness, and nuclide composition. They also depended on the thickness of the surrounding equipment wall, on the detector efficiency, and on the geo
40、metric efficiency (measurement position). Using laboratory measurements on NOK! sources in simulated equipment, correlation constants were defined for the geometric efficiency, and effects of NORM thickness, XORM density and XORM radial extent, wall thickness, and other variables. NORM sources prepa
41、red from oil-field scales and uranium tailings were characterized and placed in sealed bags in steel pipes and plates to simulate varying equipment diameters and wall thicknesses. NORM source thicknesses and areas were varied by the placement of over 143 source bags used in the simulations. Sections
42、 of well tubing containing scale were used to directly calibrate small-diameter tube measurements. Using two types of NORM, radium variations of an order of magnitude, and steel thicknesses up to 4 cm, the laboratory ES- 1 STD.API/PETRO PUBL 7L02-ENGL 1797 0732290 Ob01bLO 744 gamma measurements pred
43、icted radium concentrations averaging within 20 percent of reference values. Other, separate correlations also were developed for thin scales in gas plant equipment and for YORM contamination in exposed surface soils. Variations in detector and source geometry strongly affect measurements of externa
44、l gamma radiation. Survey instruments tested in perpendicular, parallel, and 45“ angular orientations indicated 10%-15% lower readings may result from parallel or angular detector orientations, compared to perpendicular, for 20-cm pipe sources. The effect is smaller for large equipment (flat plate g
45、eometry), and greater for small-source geometry. Distance between the source and detector has greater effects, reducing gamma measurements by over 30% for a one-inch separation from well tubing, and by nearly 90% for a one-foot separation. Again, the effect is smaller for large-diameter equipment, a
46、mounting to about 40% for one-foot separation from a large flat source. Using a source with tapered thickness (O to 8 cm thick), errors of -21% to +16% were obtained from measurements in the thick and thin regions, respectively. Using a source with step changes from zero, 1-inch, and 3-inches of NOR
47、M thickness, maximum errors of -44% to +45% were obtained from measurements near the thickness boundaries. Detection limits for one-inch NaI scintillation probes in the optimum position (perpendicular, surface contact) were computed using the correlation for well tube and flat plate geometries. Base
48、d on field detection limits of 50% above background count rates (because of spatial and temporal variations dominating background), radium detection limits of 9 pCi/g to 160 pCi/g were estimated for tubing, and 6 pCi/g to 100 pCi/g for flat sources, with the range depending on the thickness of the N
49、ORM deposit (2.5 cm to 0.1 cm). If extra care is taken to achieve field detection limits of only 10% above background count rates, the radium detection limits can be reduced by as much as a factor of five. Detection limits for the 1-inch Na1 probe were reduced by a factor of 2.5 by collimating the probe, and by a factor of 5 when operating the collimated probe in the delta measurement mode. A 2-inch probe had essentially identical detection limits to the 1-inch probe because of the spatial and temporal variability of backgrounds. Collimation
