1、Designation:D740014Standard Test Methods forDownhole Seismic Testing1This standard is issued under the fixed designation D7400;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicate
2、s the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 These test methods are limited to the determination ofthe interval velocities from arrival times and relative arrivaltimes of compression(P)and vertically(SV)and horizo
3、ntally(SH)polarized shear(S)seismic waves which are generatednear surface and travel down to an array of vertically installedseismic sensors.Apreferred method intended to obtain data foruse on critical projects where the highest quality data isrequired is included.Also included is an optional method
4、intended for use on projects which do not require measure-ments of a high degree of precision.1.2 Various applications of the data will be addressed andacceptable procedures and equipment,such as seismic sources,receivers,and recording systems will be discussed.Other itemsaddressed include source-to
5、-receiver spacing,drilling,casing,grouting,a procedure for borehole installation,and conductingactual borehole and seismic cone tests.Data reduction andinterpretation is limited to the identification of various seismicwave types,apparent velocity relation to true velocity,examplecomputations,use of
6、Snells law of refraction,and assump-tions.1.3 There are several acceptable devices that can be used togenerate a high-quality P or SV source wave or both and SHsource waves.Several types of commercially available receiv-ers and recording systems can also be used to conduct anacceptable downhole surv
7、ey.Special consideration should begiven to the types of receivers used and their configuration.Heavily-damped sensors should not be used so that spectralsmearing,phase shifting,and latency response between sensorsis avoided.These test methods primarily concern the actual testprocedure,data interpret
8、ation,and specifications for equipmentwhich will yield uniform test results.1.4 All recorded and calculated values shall conform to theguide for significant digits and rounding established in PracticeD6026.1.4.1 The procedures used to specify how data are collected/recorded and calculated in these t
9、est methods are regarded asthe industry standard.In addition,they are representative of thesignificant digits that should generally be retained.The proce-dures used do not consider material variation,purpose forobtaining the data,special purpose studies,or any consider-ations for the users objective
10、s;and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations.It is beyond the scopeof these test methods to consider significant digits used inanalysis methods for engineering design.1.4.2 Measurements made to more significant digit
11、s orbetter sensitivity than specified in these test methods shall notbe regarded a nonconformance with this standard.1.5 This standard is written using SI units.Inch-pound unitsare provided for convenience.The values stated in inch poundunits may not be exact equivalents;therefore,they shall beused
12、independently of the SI system.Combining values fromthe two systems may result in nonconformance with thisstandard.1.5.1 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units.In this system,the pound(lbf)represents a unit of force(weight),while the unit for massis sl
13、ugs.The rationalized slug unit is not given,unless dynamic(F=ma)calculations are involved.1.5.2 It is common practice in the engineering/constructionprofession to concurrently use pounds to represent both a unitof mass(lbm)and of force(lbf).This implicitly combines twoseparate systems of units;that
14、is,the absolute system and thegravitational system.It is scientifically undesirable to combinethe use of two separate sets of inch-pound units within a singlestandard.As stated,this standard includes the gravitationalsystem of inch-pound units and does not use/present the slugunit for mass.However,t
15、he use of balances or scales recordingpounds of mass(lbm)or recording density in lbm/ft3shall notbe regarded as nonconformance with this standard.1.6 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 standar
16、d to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.09 on Cyclic andDynamic Properties of Soils.Current edition approved Nov.1,2014.Published November 2014.Originallyapproved in 2007.Last previous edition approved in 2008 as D7400 08.DOI:10.1520/D7400-14.*A Summary of Changes section appea
