ASTM D4104-96
(Test Method)Standard Test Method (Analytical Procedure) for Determining Transmissivity of Nonleaky Confined Aquifers by Overdamped Well Response to Instantaneous Change in Head (Slug Tests)
Standard Test Method (Analytical Procedure) for Determining Transmissivity of Nonleaky Confined Aquifers by Overdamped Well Response to Instantaneous Change in Head (Slug Tests)
SCOPE
1.1 This test method covers the determination of transmissivity from the measurement of force-free (overdamped) response of a well-aquifer system to a sudden change of water level in a well. Force-free response of water level in a well to a sudden change in water level is characterized by recovery to initial water level in an approximate exponential manner with negligible inertial effects.
1.2 The analytical procedure in this test method is used in conjunction with the field procedure in Test Method D4044 for collection of test data.
1.3 Limitations -Slug tests are considered to provide an estimate of transmissivity. The determination of aquifer storage coefficient is less reliable. Although the assumptions of this test method prescribe a fully penetrating well (a well open through the full thickness of the aquifer), the slug test method is commonly conducted using a partially penetrating well. Such a practice may be acceptable for application under conditions in which the aquifer is stratified and horizontal hydraulic conductivity is much greater than vertical hydraulic conductivity. In such a case the test would be considered to be representative of the average hydraulic conductivity of the portion of the aquifer adjacent to the open interval of the well.
1.4 The values stated in SI units are to be regarded as standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D 4104 – 96
Standard Test Method
(Analytical Procedure) for Determining Transmissivity of
Nonleaky Confined Aquifers by Overdamped Well Response
to Instantaneous Change in Head (Slug Tests)
This standard is issued under the fixed designation D4104; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Determining of Hydraulic Properties by Well Techniques
D4044 Test Method (Field Procedure) for Instantaneous
1.1 This test method covers the determination of transmis-
Change in Head (Slug Test) for Determining Hydraulic
sivity from the measurement of force-free (overdamped) re-
Properties of Aquifers
sponse of a well-aquifer system to a sudden change of water
D4750 Test Method for Determining Subsurface Liquid
level in a well. Force-free response of water level in a well to
Levels in a Borehole or Monitoring Well (Observation
a sudden change in water level is characterized by recovery to
Well)
initial water level in an approximate exponential manner with
D5912 Test Method (Analytical Procedure) for Determin-
negligible inertial effects.
ing Hydraulic Conductivity of an Unconfined Aquifer by
1.2 The analytical procedure in this test method is used in
Overdamped Well Response in Instantaneous Change in
conjunctionwiththefieldprocedureinTestMethodD4044for
Head (Slug Test)
collection of test data.
1.3 Limitations—Slug tests are considered to provide an
3. Terminology
estimate of transmissivity. Although the assumptions of this
3.1 Definitions:
test method prescribe a fully penetrating well (a well open
3.1.1 aquifer, confined—an aquifer bounded above and
through the full thickness of the aquifer), the slug test method
below by confining beds and in which the static head is above
is commonly conducted using a partially penetrating well.
the top of the aquifer.
Such a practice may be acceptable for application under
3.1.2 confining bed—a hydrogeologic unit of less perme-
conditions in which the aquifer is stratified and horizontal
able material bounding one or more aquifers.
hydraulic conductivity is much greater than vertical hydraulic
3.1.3 control well—wellbywhichtheaquiferisstressed,for
conductivity. In such a case the test would be considered to be
example, by pumping, injection, or change of head.
representative of the average hydraulic conductivity of the
3.1.4 head, static—theheightaboveastandarddatumofthe
portion of the aquifer adjacent to the open interval of the well.
surface of a column of water (or other liquid) that can be
1.4 The values stated in SI units are to be regarded as
supported by the static pressure at a given point.
standard.
3.1.5 hydraulic conductivity—(field aquifer tests), the vol-
1.5 This standard does not purport to address all of the
umeofwaterattheexistingkinematicviscositythatwillmove
safety concerns, if any, associated with its use. It is the
in a unit time under a unit hydraulic gradient through a unit
responsibility of the user of this standard to establish appro-
area measured at right angles to the direction of flow.
priate safety and health practices and determine the applica-
3.1.6 observation well—a well open to all or part of an
bility of regulatory limitations prior to use.
aquifer.
2. Referenced Documents 3.1.7 overdamped-well response—characterized by the wa-
ter level returning to the static level in an approximately
2.1 ASTM Standards:
exponential manner following a sudden change in water level.
D653 Terminology Relating to Soil, Rock, and Contained
(See for comparison underdamped-well response.)
Fluids
3.1.8 slug—avolumeofwaterorsolidobjectusedtoinduce
D4043 Guide for Selection of Aquifer-Test Method in
a sudden change of head in a well.
3.1.9 specific storage—the volume of water released from
ortakenintostorageperunitvolumeoftheporousmediumper
This test method is under the jurisdiction of ASTM Committee D-18 on Soil
unit change in head.
andRockandisthedirectresponsibilityofSubcommitteeD18.21onGroundWater
and Vadose Zone Investigations.
Current edition approved Oct. 10, 1996. Published January 1997. Originally
published as D4104–91.
2 3
Annual Book of ASTM Standards, Vol 04.08. Annual Book of ASTM Standards, Vol 04.09.
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D4104–96
3.1.10 storage coeffıcient—the volume of water an aquifer and:
releases from or takes into storage per unit surface area of the
2 2
D~u! 5 @uJ ~u! 22aJ ~u!# 1 @uY ~u! 22aY ~u!#
0 1 0 1
aquifer per unit change in head. For a confined aquifer, the
NOTE 1—See D5912 and Hvorslev (2) Bouwer and Rice (3), and
storage coefficient is equal to the product of specific storage
Bouwer (4).
and aquifer thickness. For an unconfined aquifer, the storage
coefficient is approximately equal to the specific yield.
5. Significance and Use
3.1.11 transmissivity—the volume of water at the existing
5.1 Assumptions of Solution of Cooper et al (1):
kinematic viscosity that will move in a unit time under a unit
5.1.1 Theheadchangeinthecontrolwellisinstantaneousat
hydraulic gradient through a unit width of the aquifer.
time t =0.
3.1.12 underdamped-well response—responsecharacterized
5.1.2 Well is of finite diameter and fully penetrates the
by the water level oscillating about the static water level
aquifer.
following a sudden change in water level. (See for comparison
5.1.3 Flow in the nonleaky aquifer is radial.
overdamped-well response.)
5.2 Implications of Assumptions:
3.1.13 For definitions of other terms used in this test
5.2.1 The mathematical equations applied ignore inertial
method, see Terminology D653.
effects and assume the water level returns the static level in an
3.2 Symbols:
approximate exponential manner. The geometric configuration
3.2.1 J [nd]—zero-order Bessel function of the first kind.
of the well and aquifer are shown in Fig. 1.
3.2.2 J [nd]—first-order Bessel function of the first kind.
−1 5.2.2 Assumptions are applicable to artesian or confined
3.2.3 K [LT ]—hydraulic conductivity.
2 −1
conditions and fully penetrating wells. However, this test
3.2.4 T [L T ]—transmissivity.
method is commonly applied to partially penetrating wells and
3.2.5 S [nd]—storage coefficient.
in unconfined aquifers where it may provide estimates of
3.2.6 Y [nd]—zero order Bessel function of the second
hydraulic conductivity for the aquifer interval adjacent to the
kind.
open interval of the well if the horizontal hydraulic conduc-
3.2.7 Y [nd]—first order Bessel function of the second
tivity is significantly greater than the vertical hydraulic con-
kind.
ductivity.
3.2.8 r [L]—radius of control-well casing or open hole in
c
5.2.3 AspointedoutbyCooperetal(1)thedeterminationof
interval where water level changes.
storage coefficient by this test method has questionable reli-
3.2.9 r [L]—radius of control well screen or open hole
w
ability because of the similar shape of the curves, whereas, the
adjacent to water bearing unit.
determination of transmissivity is not as sensitive to choosing
3.2.10 u—variable of integration.
the correct curve. However, the curve selected should not
3.2.11 H [L]—change in head in control well.
imply a storage coefficient unrealistically large or small.
3.2.12 H [L]—initial head rise (or decline) in control well.
o
3.2.13 t—time.
6. Procedure
3.2.14 b—Tt/r .
c
2 2
6.1 The overall procedure consists of conducting the slug
3.2.15 a—r S/r .
w c
test field procedure (see Test Method D4044) and analysis of
the field data, that is addressed in this test method.
4. Summary of Test Method
4.1 This test method describes the analytical procedure for
analyzing data collected during an instantaneous head (slug)
test using an overdamped well. The field procedures in
conducting a slug test are given in Test Method D4044. The
analytical procedure consists of analyzing the recovery of
water level in the well following the change in water level
induced in the well.
4.2 Solution—The solution given by Cooper et al (1) is as
follows:
2H `
o
H 5 @@exp ~2bu /a!@J ~ur/r ! (1)
* 0 w
p
uY u! 22aY u! 2 Y ur/r !
@ ~ ~ # ~
0 1 0 w
@uJ ~u! 22aJ ~u!##/D~u!##du
0 1
where:
2 2
a5 r S/r ,
w c
b5 Tt/r ,
c
The boldface numbers in parentheses refer to a list of references at the end of FIG. 1 Cross Section Through a Well in Which a Slug of Water is
the text. Suddenly Injected
D4104–96
6.2 The integral expression in the solution given in (Eq 1) 7.2 Prepare a semilogarithmic plot of the same scale as that
cannot be evaluated analytically. A graphical solution for of the type-curve. Plot the w
...
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