1、Designation: D 5521 05Standard Guide forDevelopment of Ground-Water Monitoring Wells in GranularAquifers1This standard is issued under the fixed designation D 5521; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. 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 development of screened wellsinstalled for the purpose of obtaining representative ground-water infor
3、mation and water quality samples from granularaquifers, though the methods described herein could also beapplied to wells used for other purposes. Other well-development methods that are used exclusively in open-borehole bedrock wells are not described in this guide.1.2 The applications and limitati
4、ons of the methods de-scribed in this guide are based on the assumption that theprimary objective of the monitoring wells to which themethods are applied is to obtain representative water qualitysamples from aquifers. Screened monitoring wells developedusing the methods described in this guide shoul
5、d yield rela-tively sediment-free samples from granular aquifer materials,ranging from gravels to silty sands. While many monitoringwells are considered “small-diameter” wells (that is, less thanfour inches in inside diameter), some of the techniquesdescribed in this guide will be more easily applie
6、d to large-diameter wells (that is, four-inches or greater in inside diam-eter).1.3 The values stated in inch-pound units are to be regardedas standard. All other units in parentheses are provided forinformation only.1.4 This standard does not purport to address all of thesafety concerns, if any, as
7、sociated 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 prior to use.1.5 This guide offers an organized collection of informationor a series of options and does not re
8、commend a specificcourse of action. This document cannot replace education orexperience and should be used in conjunction with professionaljudgment. Not all aspects of this guide may be applicable in allcircumstances. This ASTM standard is not intended to repre-sent or replace the standard of care b
9、y which the adequacy ofa given professional service must be judged, nor should thisdocument be applied without consideration of a projects manyunique aspects. The word “Standard” in the title of thisdocument means only that the document has been approvedthrough the ASTM consensus process.2. Referenc
10、ed Documents2.1 ASTM Standards:2D 653 Terminology Relating to Soil, Rock, and ContainedFluidsD 5088 Practice for Decontamination of Field EquipmentUsed at Nonradioactive Waste SitesD 5092 Practice for Design and Installation of Ground-Water Monitoring Wells in Aquifers3. Terminology3.1 Definitions:3
11、.1.1 Many of the terms discussed in this guide are con-tained in Terminology D 653. The reader should refer to thisfor definitions of selected terms.3.2 Definitions of Terms Specific to This Standard:3.2.1 air entrapmenttrapping of air or other gas in porespaces of the formation or filter pack durin
12、g development withcompressed air.3.2.2 air lift pumpa device consisting of two pipes, withone (the air line) inside the other (the eductor pipe), used towithdraw water from a well. The lower ends of the pipes aresubmerged, and compressed air is delivered through the innerpipe to form a mixture of ai
13、r and water. This mixture rises inthe outer pipe to the surface because the specific gravity of thismixture is less than that of the water column.3.2.3 air linea small vertical air pipe used in air-liftpumping. It usually extends from the ground surface to near thesubmerged lower end of the eductor
14、pipe. The length of the airline below the static water level is used in calculating the airpressure required to start air-lift pumping.3.2.4 annular sealmaterial used to provide a seal betweenthe borehole and the casing of a well. The annular seal should1This guide is under the jurisdiction ofASTM C
15、ommittee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.21 on Ground Water andVadose Zone Investigations.Current edition approved Nov. 1, 2005. Published December 2005. Originallyapproved in 1994. Discontinued in 2002 and reinstated as D 552105. Last previousedition approve
16、d in 1994 as D 552194e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Ba
17、rr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.have a hydraulic conductivity less than that of the surroundinggeologic materials and be resistant to chemical or physicaldeterioration.3.2.5 backwashingthe reversal of water flow caused bythe addition of water to a well t
18、hat is designed to loosen bridgesand facilitate the removal of fine-grained materials from theformation surrounding the borehole.3.2.6 bailera long, narrow tubular device with an opentop and a check valve at the bottom that is used to removewater and sediment from a borehole or well.3.2.7 bailing (d
19、evelopment)a development technique us-ing a bailer which is raised and lowered in the well to create astrong inward and outward movement of water from theformation to break sand bridges and to remove fine materialsfrom the well.3.2.8 borehole wallthe face of an open borehole.3.2.9 bridgean obstructi
20、on to fluid and sediment move-ment in the filter pack or formation adjacent to the well due tothe arching of fine sand grains across pore spaces. Thiscondition is caused by one-directional movement of water intothe well during development, as might occur during overpump-ing.3.2.10 bridging (developm
21、ent)the creation of obstructionsto fluid and sediment movement in filter pack or formationmaterials during well development.3.2.11 cable tool drillinga drilling technique in which adrill bit attached to the bottom of a weighted drill stem is raisedand dropped to crush and grind formation materials.
22、Inunconsolidated formations, casing is usually driven as drillingproceeds to prevent collapse of noncohesive materials into theborehole.3.2.12 catheada rotating power unit on a drilling rigemploying either a plain spool or an automatic spool used tohoist drill pipe, casing, small tools, or other dri
23、lling equipment.3.2.13 centrifugal pump (submersible)a downhole pumpconsisting of a sealed electric motor that drives impellersthrough a rotating shaft and seal arrangement at high revolu-tions per minute.3.2.14 centrifugal pump (surface)a pump that moves aliquid by accelerating it radially outward
24、from within a rotatingimpeller to a surrounding circular-shaped chamber.3.2.15 developmentsee well development.3.2.16 drilling fluida water- or air-based fluid used in thewell drilling operation to remove cuttings from the borehole, toclean and cool the bit, to reduce friction between the drill stri
25、ngand the sides of the borehole and to hold the borehole openduring the drilling operation.3.2.17 eductor pipethe vertical discharge pipe used inair-lift pumping, submerged at least one third but usually twothirds of its length below the pumping water level in the well.3.2.18 filter cakethe solids f
26、rom a drilling fluid that aredeposited on the walls of a borehole in a geologic formationduring the process of drilling. Also called mudcake.3.2.19 filter-packed wella well in which the natural for-mation materials adjacent to the well screen has been replacedby a filter pack material.3.2.20 formati
27、on damagereduction of formation hydrau-lic conductivity at the borehole wall caused by the drillingprocess. May consist of compaction, clay smearing, cloggingof pores with drilling mud filtrate, or other drilling-relateddamage.3.2.21 hydraulic jettinga well-development method thatemploys a jetting t
28、ool with nozzles and a high-pressure pumpto force water outwardly through the well screen, the filterpack, and sometimes into the adjacent geologic unit, for thepurpose of dislodging fine sediment and correcting formationdamage done during drilling.3.2.22 indicator parameterschemical parameters, inc
29、lud-ing pH, specific conductance, temperature and dissolved oxy-gen content, which are used to determine when formationwater is entering a monitoring well.3.2.23 jettingsee hydraulic jetting.3.2.24 monitoring wella well that is constructed by one ofa variety of techniques that may serve a variety of
30、 purposes: (1)extracting ground water for physical, chemical, or biologicaltesting; (2) measuring water levels; (3) measuring formationhydraulic parameters; or (4) measuring formation fluid chemi-cal or physical parameters.3.2.25 naturally developed wella well in which the for-mation materials colla
31、pse around the well screen, and fineformation materials are removed using standard developmenttechniques.3.2.26 overpumpinga well-development technique thatinvolves pumping the well at a rate that exceeds the designcapacity of the well.3.2.27 rawhidingstarting and stopping a pump intermit-tently to
32、produce rapid changes in the pressure head in the well.3.2.28 sandlockingrefers to the accumulation of sand andother sediment on development tools while they are working inthe well screen, resulting in the tools becoming lodged in thescreen. Also refers to the accumulation of sand and othersediment
33、in the impeller section of a submersible pump,resulting in the impellers binding.3.2.29 sloughingcaving of formation materials into anunstabilized open borehole.3.2.30 spuddingthe operation, in cable-tool drilling, ofdrilling a collar hole and advancing a casing through overbur-den. Also a general t
34、erm in rotary or diamond core drillingapplied to drilling through overburden.3.2.31 sumpa blank extension of easing beneath the wellscreen that provides a space for sediment brought into the wellduring development to accumulate.3.2.32 surge blocka plunger-like tool consisting of disksof flexible mat
35、erial (for example, neoprene) sandwiched be-tween rigid (for example, metal) disks that may be solid orvalved, and that is used in well development. See surging.3.2.33 surginga well-development technique in which asurge block is alternately raised and lowered within the wellcasing or screen, or both
36、, to create a strong inward and outwardmovement of water through the well screen.3.2.34 tool stringthe drill pipe or drill rod and all attacheddrilling or development tools used in the borehole or well.3.2.35 turbiditycloudiness in water due to suspended andcolloidal material.3.2.36 well casinga dur
37、able pipe placed in a borehole toprevent the walls of the borehole from caving, and to seal offD5521052surface drainage or undesirable water, gas, or other fluids andprevent their entrance into the well.3.2.37 well developmentthe act of repairing damage to theborehole caused by the drilling process
38、and removing fine-grained materials or drilling fluids, or both, from formationmaterials so that natural hydraulic conditions are restored andwell yields are enhanced.3.2.38 well screena filtering device that allows groundwater to flow freely into a well from the adjacent formation,while minimizing
39、or eliminating the entrance of fine-grainedmaterial into the well.4. Significance and Use4.1 A properly designed, installed, and developed ground-water monitoring well, constructed in accordance with PracticeD 5092 should provide the following: representative samplesof ground water that can be analy
40、zed to determine physicalproperties and water-quality parameters of the sample orpotentiometric levels that are representative of the total hy-draulic head of that portion of the aquifer screened by the well,or both. Such a well may also be utilized for conducting aquifertests used for the purpose o
41、f determining the hydraulic prop-erties of the geologic materials in which the well has beencompleted.4.2 Well development is an important component of moni-toring well completion. Monitoring wells installed in aquifersshould be sufficiently developed to ensure that they serve theirintended objectiv
42、es. Well development methods vary with thephysical characteristics of the geologic formation in which themonitoring well is screened, the construction details of thewell, the drilling method used during the construction of theborehole in which the well is installed, and the quality of thewater. The
43、development method for each individual monitoringwell should be selected from among the several methodsdescribed in this guide and should be employed by the wellconstruction contractor or the person responsible for monitor-ing well completion.4.3 The importance of well development in monitoringwells
44、 cannot be overestimated; all too often development is notperformed or is carried out inadequately. Proper and carefulwell development will improve the ability of most monitoringwells to provide representative, unbiased chemical and hydrau-lic data. The additional time and money spent performing thi
45、simportant step in monitoring well completion will minimizethe potential for damaging pumping equipment and in-situsensors, and increase the probability that ground-water samplesare representative of water contained in the monitored forma-tion.5. Purposes of Monitoring Well Development5.1 Monitoring
46、 wells are developed primarily for the fol-lowing reasons:5.1.1 To rectify damage done during drilling to the boreholewall and the adjacent formation (that is, clogging, smearing, orcompaction of formation materials) that may result in alocalized reduction in hydraulic conductivity of the formationn
47、ear the borehole (see Fig. 1);5.1.2 To remove fine-grained materials from the formationand filter pack (where applicable) that may result in theacquisition of turbid, sediment-laden samples;5.1.3 To stabilize formation and artificial filter pack mate-rials (where applicable) adjacent to the well scr
48、een (see Fig.23);5.1.4 To retrieve lost drilling fluid (if drilling fluid was usedin the borehole installation process) that may alter the qualityof water in the vicinity of the well and interfere with waterquality analysis (see Fig. 3); and5.1.5 To maximize well efficiency and hydraulic communi-cat
49、ion between the well and the adjacent formation to providefor the acquisition of representative ground-water samples andformation hydraulic test data.6. Conducting a Monitoring Well-Development Program6.1 Well Development ProcessThe well development pro-cess consists of three phases: predevelopment, preliminarydevelopment, and final development.6.1.1 Predevelopment refers to techniques used to mitigateformation damage during well construction. This is particularlyimportant when using direct or reverse rotary drilling systemsthat depend on drilli
