1、Designation: D 6167 97 (Reapproved 2004)Standard Guide forConducting Borehole Geophysical Logging: MechanicalCaliper1This standard is issued under the fixed designation D 6167; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This guide covers the general procedures necessary toconduct caliper logging of boreholes, wells, access tubes,
3、caissons, or shafts (hereafter referred as boreholes) as com-monly applied to geologic, engineering, ground-water, andenvironmental (hereafter referred as geotechnical) investiga-tions. Caliper logging for mineral or petroleum exploration anddevelopment are excluded.1.2 This guide defines a caliper
4、log as a record of boreholediameter with depth.1.2.1 Caliper logs are essential in the interpretation ofgeophysical logs since they can be significantly affected byborehole diameter.1.2.2 Caliper logs are commonly used to measure boreholediameter, shape, roughness, and stability; calculate boreholev
5、olume; provide information on borehole construction; anddelineate lithologic contacts, fractures, and solution cavitiesand other openings.1.3 This guide is restricted to mechanically based deviceswith spring-loaded arms, which are the most common calipersused in caliper logging with geotechnical app
6、lications.1.4 This guide provides an overview of caliper logging,including general procedures, specific documentation, calibra-tion and standardization, and log quality and interpretation.1.5 To obtain additional information on caliper logs seeSection 9 of this guide.1.6 This guide is to be used in
7、conjunction with GuideD 5753.1.7 This guide should not be used as a sole criterion forcaliper logging and does not replace professional judgement.Caliper logging procedures should be adapted to meet theneeds of a range of applications and stated in general terms sothat flexibility or innovation is n
8、ot suppressed.1.8 The geotechnical industry uses English or SI units. Thecaliper log is typically recorded in units of inches, millimetres,or centimetres.1.9 This guide does not purport to address all of the safetyand liability problems (for example, lost or lodged probes andequipment decontaminatio
9、n) associated with its use.1.10 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations
10、prior to use.2. Referenced Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock and ContainedFluidsD 5088 Practice for Decontamination of Field EquipmentUsed at Nonradioactive Waste SitesD 5608 Practice for Decontamination of Field EquipmentUsed at Low Level Radioactive Waste SitesD
11、 5753 Guide for Planning and Conducting Borehole Geo-physical Logging3. Terminology3.1 Definitions: Definitions shall be in accordance withTerminology D 653, Section 12, Ref (1),3or as defined below:3.1.1 accuracy, nhow close a measured log values ap-proaches true value. It is determined in a contro
12、lled environ-ment. A controlled environment represents a homogeneoussample volume with known properties.3.1.2 depth of investigation, nthe radial distance from themeasurement point to a point where the predominant measuredresponse may be considered centered, that is not to be confusedwith borehole d
13、epth (for example, distance) measured from thesurface.3.1.3 measurement resolution, nthe minimum change inmeasured value that can be detected.1This guide is under the jurisdiction of ASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.01 on Surface and SubsurfaceC
14、haracterization.Current edition approved July 1, 2004. Published August 2004. Originallyapproved in 1997. Last previous edition approved in 1997 as D 6167 - 97e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book
15、of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The boldface numbers given in parentheses refer to a list of references at theend of the text.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Uni
16、ted States.3.1.4 repeatability, nthe difference in magnitude of twomeasurements with the same equipment and in the sameenvironment.3.1.5 vertical resolution, nthe minimum thickness thatcan be separated into distinct units.3.1.6 volume of investigation, nthe volume that contrib-utes 90 % of the measu
17、red response. It is determined by acombination of theoretical and empirical modeling. The vol-ume of investigation is non-spherical and has gradationalboundaries.4. Summary of Guide4.1 This guide applies to borehole caliper logging and is tobe used in conjunction with Guide D 5753.4.2 This guide bri
18、efly describes the significance and use,apparatus, calibration and standardization, procedures, andreports for conducting borehole caliper logging.5. Significance and Use5.1 An appropriately developed, documented, and executedguide is essential for the proper collection and application ofcaliper log
19、s. This guide is to be used in conjunction with GuideD 5753.5.2 The benefits of its use include the following: improvingselection of caliper logging methods and equipment, caliperlog quality and reliability, and usefulness of the caliper log datafor subsequent display and interpretation.5.3 This gui
20、de applies to commonly used caliper loggingmethods for geotechnical applications.5.4 It is essential that personnel (see the Personnel sectionof Guide D 5753) consult up-to-date textbooks and reports onthe caliper technique, application, and interpretation methods.6. Interferences6.1 Most extraneous
21、 effects on caliper logs are caused byinstrument problems and borehole conditions.6.2 Instrument problems include the following: electricalleakage of cable and grounding problems, temperature drift,wear of mechanical components including the hinge pins andin the linear potentiometer (mechanical hyst
22、eresis), damagedor bent arms, and lack of lubrication of the mechanicalcomponents.6.3 Borehole conditions include heavy drilling mud, bore-hole deviation, and drilling-related borehole irregularities.7. Apparatus7.1 A geophysical logging system has been described in thegeneral guide (see the Apparat
23、us section of Guide D 5753).7.2 Caliper logs may be obtained with probes having asingle arm, three arms (averaging or summation), multipleindependent arms (x-y caliper), multiple-feeler arms, bowsprings, or gap wheels. Single-arm and three-arm averagingprobes are most commonly used for geotechnical
24、investiga-tions.7.2.1 A single-arm caliper commonly provides a record ofborehole diameter while being used to decentralize anothertype of log, such as a side-collimated gamma-gamma probe(see Fig. 1). The caliper arm generally follows the high side ofa deviated hole. The single-arm decentralizing cal
25、iper may nothave the resolution needed for some applications.7.2.2 The three-arm averaging or summation caliper hasarms of equal length oriented 120 apart (see Fig. 2). All armsmove together, which provides an average diameter measure-ment. This caliper provides higher resolution than the single-arm
26、 caliper measurement (see Fig. 3).7.2.3 Multiple independent arm calipers generally havethree or four independent arms of equal length; these arms aresometimes oriented. Horizontal resolution, that provides accu-rate borehole-diameter measurement regardless of boreholeshape, is related to the number
27、 of independent arms. In general,calipers with four or more independent arms will have higherresolution than three-arm averaging (see Fig. 3). The fourindependent-arm caliper log may show borehole elongation(elliptical borehole shape) and better indicates the actualirregularity of the borehole.7.3 C
28、aliper probes using arms are typically spring loaded.The arms are retracted and opened with an electric motor andFIG. 1 Probe for Making Side-Collimated Gamma-Gamma Logswith Single-Arm Caliper (2)FIG. 2 Three-Arm Averaging CaliperD 6167 97 (2004)2retention spring. The arms and gears are lubricated.
29、Caliperprobes closed by hand are held closed with an electric solenoidor weighted retention ring that is released with a sudden drop.Typically, the caliper arms are mechanically connected to alinear or rotary potentiometer such that changes in the angle ofthe arms causes changes in resistance. These
30、 changes inresistance are proportional to average borehole diameter. Insome probes, the voltage changes are converted to a varyingpulse rate or digitized downhole to eliminate or minimize cabletransmission noise. Different arm length can be used tooptimize sensitivity for the borehole-diameter range
31、 expected.7.4 The concepts of volume of investigation and depth ofinvestigation are not applicable to caliper logs since it is asurface-contact measurement.7.5 Vertical resolution of caliper measurements is a functionof the size of the contact surface (arm tip or pad), the responseof the mechanical
32、and electronic components, and digitizinginterval used. The theoretical limit of vertical resolution isequal to the width of the caliper pad or tip. Selection of armlengths and angle, and tip diameter will affect sensitivity.Shorter arms generally will provide more detail of the rugosity(borehole ro
33、ughness as defined by Ref. (2) of the boreholewall than longer arms. However, size of caliper probe andborehole diameter may also determine arm lengths used.7.6 Measurement resolution of typical caliper probes is 0.05in. (0.13 cm) of borehole diameter.7.7 A variety of caliper logging equipment is av
34、ailable forgeotechnical investigations. It is not practical to list all of thesources of potentially acceptable equipment.8. Calibration and Standardization of Caliper Logs8.1 General:8.1.1 National Institute of Standards and Technology(NIST) calibration and standardization procedures do not existfo
35、r caliper logging.8.1.2 Caliper logs can be used in a qualitative (for example,comparative) or quantitative (for example, borehole diametercorrections) manner depending upon the project objectives.8.1.3 Caliper calibration methods and frequency shall besufficient to meet project objectives.8.1.3.1 C
36、alibration and standardization should be performedeach time a caliper probe is suspected to be damaged, modified,repaired, and at periodic intervals.8.2 Calibration is the process of establishing values forcaliper response and is accomplished with a physical model ofa known diameter. Calibration dat
37、a values related to thephysical properties (for example, borehole diameter, rough-ness) may be recorded in units (for example, counts persecond), that can be converted to units of length (for example,inches, millimetres, or centimetres.)8.2.1 At least two, and preferably more, values, whichapproxima
38、te the anticipated operating range, are needed toestablish a calibration curve (for example, 4- and 10-in. (10.2-and 25.4-cm) rings) if the borehole diameter to be logged is 5in. (12.7 cm).8.2.2 Physical models of measured diameter that may beused to calibrate the caliper response may include rings
39、or barsmade of rigid materials that are not easily deformed and resistwear.8.2.2.1 Calibration of caliper probes is done most accuratelyin rings of different diameters.8.2.2.2 A calibration bar is a plate that is drilled and markedat regular intervals and machined to fit over the body of theprobe (s
40、ee Fig. 4). One arm is placed in the appropriate hole forthe range to be logged.8.2.2.3 Calibration can be checked by using casing ofmeasured diameter logged in the borehole.8.3 Standardization is the process of checking loggingresponse to show evidence of repeatability and consistency.8.3.1 Calibra
41、tion serves as a check of standardization.8.3.2 A representative borehole may be used to periodicallycheck caliper response providing the borehole environmentdoes not change with time. Caliper response may not repeatexactly because the probe may rotate, causing the arms tofollow slightly different p
42、aths within the borehole.9. Procedure9.1 See the Procedure section of Guide D 5753 for planninga logging program, data formats, personnel qualifications, fielddocumentation, and header documentation.9.2 Caliper specific information (for example, arm length)should be documented.9.3 Identify caliper l
43、ogging objectives.9.4 Select appropriate equipment to meet objectives.9.4.1 Caliper equipment decontamination is addressed ac-cording to project specifications (see Practice D 5088 fornon-radioactive waste sites and Practice D 5608 for low levelradioactive waste sites). Some materials commonly used
44、forcaliper-arm lubrication may be environmentally sensitive.9.5 Select the order in the logging sequence in which thecaliper probe is to be run (see 8.2.2.1 of Guide D 5753).FIG. 3 Caliper Logs From Probes Having Four Independent Arms,Three Averaging Arms, and a Single Arm, Madison LimestoneTest Wel
45、l 1, Wyoming (2)D 6167 97 (2004)39.5.1 Caliper probes are run before any probe utilizingnuclear sources and more expensive centralized probes.9.5.2 Caliper probes are run after any television camera andfluid property probes are run.9.6 Caliper operation and calibration are checked at the startof eac
46、h borehole or at an interval consistent with projectobjectives. (see the Procedure section of Guide D 5753). Aftercalibration, the caliper arms are closed before lowering.9.7 Select and document the depth reference.9.7.1 The selected depth reference needs to be stable andaccessible (for example, top
47、 of borehole casing).9.8 Determine and document probe zero reference point (forexample, top of probe or cablehead) and depth offset to calipermeasurement point.9.8.1 The measurement point of a caliper is the end ofcaliper arms and it changes as the arms open and close with thesine of arm angle multi
48、plied by length of arm. Typically, themeasurement point varies less than a few tenths of a foot (a fewcentimetres).9.8.2 The measurement point will change if the arm lengthis changed.9.9 Select horizontal and vertical scales for log display.9.10 Select digitizing interval (or sample rate if applicab
49、le)to meet project objectives (see 8.3.1.2 of Guide D 5753).9.10.1 Maximum vertical resolution requires the selectionof a digitizing interval at least as small as the arm tip contactheight.9.10.2 Typically, this interval is no larger than 0.1 ft (0.03m) for high-resolution applications.9.11 The caliper probe is lowered to the bottom of theborehole.9.11.1 Any time the caliper probe is lowered in the bore-hole, the arms should be closed to avoid damaging equipmentor borehole.9.11.2 Selection of probe speed while lowering is based onknowledge of borehole depth, stability, and o
