1、Designation: D4631 18Standard Test Method forDetermining Transmissivity and Storativity of LowPermeability Rocks by In Situ Measurements UsingPressure Pulse Technique1This standard is issued under the fixed designation D4631; the number immediately following the designation indicates the year oforig
2、inal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method covers a field procedure for determin-ing the
3、 transmissivity and storativity of geological formationshaving permeabilities lower than 103m2(1 millidarcy) usingthe pressure pulse technique.1.2 The transmissivity and storativity values determined bythis test method provide a good approximation of the capacityof the zone of interest to transmit w
4、ater, if the test intervals arerepresentative of the entire zone and the surrounding rock isfully water saturated.1.3 UnitsThe values stated in SI units are to be regardedas the standard. The values in parentheses are mathematicalconversions provided for information only and are not consid-ered stan
5、dard. Reporting of test results in units other than SIshall not be regarded as nonconformance with this standard.1.4 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026, unless superseded by this standard.1.4.1 For purpos
6、es of comparing a measured or calculatedvalue(s) with specified limits, the measured or calculatedvalue(s) shall be rounded to the nearest decimal or significantdigits in the specified limits.1.4.2 The procedures used to specify how data are collected/recorded or calculated in this standard are rega
7、rded as theindustry standard. In addition, they are representative of thesignificant digits that generally should 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 objectives; and it is c
8、ommon practice toincrease or reduce significant digits of reported data to becommensurate with these conditions. It is beyond the scope ofthis standard to consider significant digits used in analysismethods for engineering design.1.5 This standard does not purport to address all of thesafety concern
9、s, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.6 This international standard was developed in accor-dance with int
10、ernationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D65
11、3 Terminology Relating to Soil, Rock, and ContainedFluidsD2113 Practice for Rock Core Drilling and Sampling ofRock for Site ExplorationD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD5717 Guide fo
12、r Design of Ground-Water Monitoring Sys-tems in Karst and Fractured-Rock Aquifers (Withdrawn2005)3D6026 Practice for Using Significant Digits in GeotechnicalDataF2070 Specification for Transducers, Pressure andDifferential, Pressure, Electrical and Fiber-Optic3. Terminology3.1 Definitions:3.1.1 For
13、definitions of common technical terms in thisstandard, refer to Terminology D653.3.2 Symbols:1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.21 on Groundwater andVadose Zone Investigations.Current edition approved
14、July 15, 2018. Published August 2018. Originallyapproved in 1986. Last previous edition approved in 2008 as D4631 95(2008),which was withdrawn January 2017 and reinstated July 2018. DOI: 10.1520/D4631-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Se
15、rvice at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.*A Summary of Changes section appears at the end of this standardCopyrigh
16、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International
17、 Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.13.2.1 Cbbulk rock compressibility M1LT2.3.2.2 Cwcompressibility of water M1LT2.3.2.3 Khydraulic conductivity LT1.3.2.3.1 DiscussionThe use of the symbol K for the termhydraulic
18、conductivity is the predominant usage in groundwa-ter literature by hydrogeolists, whereas the symbol k is com-monly used for this term in rock mechanics and soil science.3.2.4 Llength of packed-off zone L.3.2.5 Pexcess test hole pressure ML1T2.3.2.6 Poinitial pressure pulse ML1T2.3.2.7 Sstorativity
19、 (or storage coefficient) (dimensionless).3.2.8 Ssspecific storage L1.3.2.9 Ttransmissivity L2T1.3.2.10 Vwvolume of water pulsed L3.3.2.11 bformation thickness L.3.2.12 efracture aperture L.3.2.13 gacceleration due to gravity LT2.3.2.14 kpermeability L2.3.2.15 nporosity (dimensionless).3.2.16 rwradi
20、us of test hole L.3.2.17 ttime elapsed from pulse initiation T.3.2.18 dimensionless parameter.3.2.19 dimensionless parameter.3.2.20 viscosity of water ML1T1.3.2.21 density of water ML3.4. Summary of Test Method4.1 Aborehole is first drilled into the rock mass, intersectingthe geological formations f
21、or which the transmissivity andstorativity are desired. The borehole is cored through potentialzones of interest, and is later subjected to geophysical boreholelogging over these intervals. During the test, each interval ofinterest is packed off at top and bottom with inflatable rubberpackers attach
22、ed to high-pressure steel tubing. After inflatingthe packers, the tubing string is filled with water.4.2 The test itself involves applying a pressure pulse to thewater in the packed-off interval and tubing string, and record-ing the resulting pressure transient. A pressure transducer,located either
23、in the packed-off zone or in the tubing at thesurface, measuring the transient as a function of time. Thedecay characteristics of the pressure pulse are dependent on thetransmissivity and storativity of the rock surrounding theinterval being pulsed and on the volume of water being pulsed.Alternative
24、ly, under non-confining conditions, the pulse testmay be performed imposing a pressure pulse and then releasingthe pressure on a shut-in well, thereby subjecting the well to anegative pressure pulse. Interpretation of this test method islike that described for the positive pressure pulse.5. Signific
25、ance and Use5.1 Test MethodThe pulse test method is used to deter-mine the transmissivity and storativity of low-permeabilityformations surrounding the packed-off intervals. This testmethod is considerably shorter in duration than the pumpingand slug tests used in more permeable rocks. To obtain res
26、ultsto the desired accuracy, pumping and slug tests in low-permeability formations are too time consuming, as indicatedin Fig. 1 (from Bredehoeft and Papadopulos (1).45.2 transmissivity, Tthe transmissivity of a formation ofthickness, b, is defined as follows:T 5 Kb (1)where:K = equivalent formation
27、 hydraulic conductivity (efhc).The efhc is the hydraulic conductivity of a material if it werehomogeneous and porous over the entire interval. The hydrau-lic conductivity, K, is related to the equivalent formation, k,asfollows:K 5 kg/ (2)4The boldface numbers in parentheses refer to a list of refere
28、nces at the end ofthis standard.FIG. 1 Comparative Times for Pressure Pulse and Slug TestsD4631 182where: = fluid density, = fluid viscosity, andg = acceleration due to gravity.5.3 storativity, Sthe storativity (or storage coefficient) of aformation of thickness, b, is defined as follows:S 5 Ssb (3)
29、where:Ss= equivalent bulk rock specific storage (ebrss).The ebrss is defined as the specific storage of a material if itwere homogeneous and porous over the entire interval. Thespecific storage is given as follows:Ss5 gCb1nCw!(4)where:Cb= bulk rock compressibility,Cw= fluid compressibility, andn = f
30、ormation porosity.5.4 AnalysisThe transient pressure data obtained using thesuggested method are evaluated by the curve-matching tech-nique described by Bredehoeft and Papadopulos (1),orbyananalytical technique proposed by Wang et al (2). The latter isparticularly useful for interpreting pulse tests
31、 when only theearly-time transient pressure decay data are available.5.5 Units:5.5.1 ConversionsThe permeability of a formation is of-ten expressed in terms of the unit darcy. A porous medium hasa permeability of 1 darcy when a fluid of viscosity 1 cP (1mPas) flows through it at a rate of 1 cm3/s (1
32、06m3/s)/1 cm2(104m2) cross-sectional area at a pressure differential of 1 atm(101.4 kPa)/1 cm (10 mm) of length. One darcy corresponds to0.987 m2. For water as the flowing fluid at 20C, a hydraulicconductivity of 9.66 m/s corresponds to a permeability of 1darcy.NOTE 1A darcy (or darcy unit) and mill
33、idarcy (md or mD) are unitsof permeability. They are not SI units, but are widely used in petroleumengineering and geology. A darcy has dimensional units in length.5.5.2 Viscosity of WaterTable 1 shows the viscosity ofwater as a function of temperature.NOTE 2The quality of the result produced by thi
34、s standard isdependent on the competence of the personnel performing it and thesuitability of the equipment and facility used. Agencies that meet thecriteria of Practice D3740 are generally considered capable of competentand objective testing/sampling/observation/ and the like. Users of thisstandard
35、 are cautioned that compliance with Practice D3740 does not itselfguarantee reliable results. Reliable results depend on many factors; D3740provides a means of evaluating some of those factors.NOTE 3The function of wells in any unconfined setting in a fracturedterrain might make the determination of
36、 k problematic because the wellsmight only intersect tributary or subsidiary channels or conduits. Theproblems determining the k of a channel or conduit notwithstanding, thepartial penetration of tributary channels may make determination of ameaningful number difficult. If plots of k in carbonates a
37、nd other fracturedsettings are made and compared, they may show no indication that thereare conduits or channels present, except when with the lowest probabilityone maybe intersected by a borehole and can be verified, such problemsare described by Worthington (3) Smart, 1999 (4). Additional guidance
38、can be found in D5717.6. Calibration, Verification, Functional Checks6.1 Prior to use, the test equipment will be verified foroperation, freedom from leakage and data recording.6.2 Pressure transducers will be checked for operation andverified against known devices or calibrated using knownstandards
39、 (F2070).7. ApparatusNOTE 4A schematic of the test equipment is shown in Fig. 2.TABLE 1 Viscosity of Water as a Function of TemperatureTemperature, C Absolute Viscosity, mPas0 1.792 1.674 1.576 1.478 1.3910 1.3112 1.2414 1.1716 1.1118 1.0620 1.0022 0.9624 0.9126 0.8728 0.8430 0.8032 0.7734 0.7436 0.
40、7138 0.6840 0.66FIG. 2 Schematic of Test EquipmentD4631 1837.1 Source of Pressure PulseA pump or pressure intensi-fier shall be capable of injecting an additional amount of waterto the water-filled tubing string and packed-off test interval toproduce a sharp pressure pulse of up to 1 MPa (145 psi) i
41、nmagnitude, preferably with a rise time of less than 1 % of onehalf of the pressure decay (P/Po= 0.5).7.2 PackersHydraulically actuated packers are recom-mended because they produce a positive seal on the boreholewall and because of the low compressibility of water they arealso comparatively rigid.
42、Each packer shall seal a portion of theborehole wall 0.5 m in length or more, with an applied pressureequal to the excess maximum pulse pressure or more to beapplied to the packed-off interval and less than the formationfracture pressure at that depth.7.3 Pressure TransducersThe test pressure may be
43、 mea-sured directly in the packed-off test interval or between thefast-acting valve and the test interval with an electronicpressure transducer. In either case the pressure shall berecorded at the surface as a function of time. The pressuretransducer shall have an accuracy when practicable of 63 kPa
44、(60.4 psi), including errors introduced by the recordingsystem, and a resolution when practicable of 1 kPa (0.15 psi).7.4 Hydraulic SystemsThe inflatable rubber packers shallbe attached to high-pressure steel tubing reaching to thesurface. The packers themselves shall be inflated with waterusing a s
45、eparate hydraulic system. The pump or pressureintensifier providing the pressure pulse shall be attached to thesteel tubing at the surface. If the pump is used, a fast-operatingvalve shall be located above, but as near as practical to theupper packer. That valve should be located less than 10 mabove
46、 the anticipated equilibrium head in the interval beingtested to avoid conditions in the tubing changing during the testfrom a full water column to a falling water-level columnbecause of formation of a free surface at or near zero absolutepressure (Neuzil (5).7.5 WaterWater used in this test shall b
47、e potable. It will beclean and compatible with the formation without dispersedsolids.8. Procedure8.1 Drilling Test Holes:8.1.1 Number and OrientationThe number of test holesshall be sufficient to supply the detail needed by the scope ofthe project. The test holes shall be directed to intersect major
48、fracture sets, preferable at right angles.8.1.2 Test Hole QualityThe drilling procedure shall pro-vide a borehole sufficiently smooth for packer seating, shallcontain no rapid changes in direction, and shall minimizeformation damage.8.1.3 Test Holes CoredCore the test holes through zonesof potential
49、 interest to provide information for locating testintervals (D2113). The selection of drilling fluids shouldconsider the quality of the borehole that will be achieved, andthe ease or difficulty of later washing and cleaning of theborehole surface without plugging with additives or cuttings.The use of polymer drilling fluids is recommended.8.1.4 Core DescriptionDescribe the rock core from thetest holes with particular emphasis on the lithology and naturaldiscontin
