ASTM D4630-96(2002)
(Test Method)Standard Test Method for Determining Transmissivity and Storage Coefficient of Low-Permeability Rocks by In Situ Measurements Using the Constant Head Injection Test
Standard Test Method for Determining Transmissivity and Storage Coefficient of Low-Permeability Rocks by In Situ Measurements Using the Constant Head Injection Test
SIGNIFICANCE AND USE
Test Method—The constant pressure injection test method is used to determine the transmissivity and storativity of low-permeability formations surrounding packed-off intervals. Advantages of the method are: (a) it avoids the effect of well-bore storage, (b) it may be employed over a wide range of rock mass permeabilities, and (c) it is considerably shorter in duration than the conventional pump and slug tests used in more permeable rocks.
Analysis—The transient water flow rate data obtained using the suggested test method are evaluated by the curve-matching technique described by Jacob and Lohman (1)2 and extended to analysis of single fractures by Doe et al. (2). If the water flow rate attains steady state, it may be used to calculate the transmissivity of the test interval (3).
Units:
4.3.1 Conversions—The permeability of a formation is often expressed in terms of the unit darcy. A porous medium has a permeability of 1 darcy when a fluid of viscosity 1 cp (1 mPa·s) flows through it at a rate of 1 cm3/s (10−6 m3/s)/1 cm2 (10−4 m2) cross-sectional area at a pressure differential of 1 atm (101.4 kPa)/1 cm (10 mm) of length. One darcy corresponds to 0.987 μm2. For water as the flowing fluid at 20°C, a hydraulic conductivity of 9.66 μm/s corresponds to a permeability of 1 darcy.
SCOPE
1.1 This test method covers a field procedure for determining the transmissivity and storativity of geological formations having permeabilities lower than 103 μm2 (1 millidarcy) using constant head injection.
1.2 The transmissivity and storativity values determined by this test method provide a good approximation of the capacity of the zone of interest to transmit water, if the test intervals are representative of the entire zone and the surrounding rock is fully water-saturated.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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 4630 – 96 (Reapproved 2002)
Standard Test Method for
Determining Transmissivity and Storage Coefficient of Low-
Permeability Rocks by In Situ Measurements Using the
1
Constant Head Injection Test
This standard is issued under the fixed designation D4630; 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 2.1.2 storage coeffıcient, S—the storage coefficient of a
formation of thickness, b, is defined as follows:
1.1 This test method covers a field procedure for determin-
ing the transmissivity and storativity of geological formations S 5 S ·b (3)
s
−3 2
having permeabilities lower than 10 µm (1 millidarcy) using
constant head injection.
where:
1.2 The transmissivity and storativity values determined by
S = specific storage.
s
this test method provide a good approximation of the capacity
The ebrss is the specific storage of a material if it were
of the zone of interest to transmit water, if the test intervals are
homogeneous and porous over the entire interval. The specific
representative of the entire zone and the surrounding rock is
storage is given as follows:
fully water-saturated.
S 5rg ~C 1 nC ! (4)
s b w
1.3 The values stated in SI units are to be regarded as the
standard.
1.4 This standard does not purport to address all of the
where:
safety concerns, if any, associated with its use. It is the
C = bulk rock compressibility,
b
responsibility of the user of this standard to establish appro-
C = fluid compressibility, and
w
priate safety and health practices and determine the applica-
n = formation porosity.
bility of regulatory limitations prior to use.
2.2 Symbols:
−1 2
2.2.1 C —bulk rock compressibility (M LT ).
b
2. Terminology
−1 2
2.2.2 C —compressibility of water (M LT ).
w
2.1 Definitions of Terms Specific to This Standard:
2.2.3 G—dimensionless function.
−1
2.1.1 transmissivity, T—the transmissivity of a formation of
2.2.4 K—hydraulic conductivity (LT ).
thickness, b, is defined as follows:
2.2.4.1 Discussion—The use of symbol K for the term
hydraulic conductivity is the predominant usage in ground
T 5 K·b (1)
water literature by hydrogeologists, whereas the symbol k is
commonly used for this term in the rock and soil mechanics
where:
and soil science literature.
K = hydraulic conductivity. −1 −2
2.2.5 P—excess test hole pressure (ML T ).
The hydraulic conductivity, K, is related to the permeability,
3 −1
2.2.6 Q—excess water flow rate (L T ).
k, as follows: 3 −1
2.2.7 Q —maximum excess water flow rate (L T ).
o
K 5 krg/µ (2)
2.2.8 S—storativity (or storage coefficient) (dimensionless).
−1
2.2.9 S —specific storage (L ).
s
2 −1
2.2.10 T—transmissivity (L T ).
where:
2.2.11 b—formation thickness (L).
r = fluid density,
2.2.12 e—fracture aperture (L).
µ = fluid viscosity, and
−2
2.2.13 g—acceleration due to gravity (LT ).
g = acceleration due to gravity.
2
2.2.14 k—permeability (L ).
2.2.15 n—porosity (dimensionless).
1
2.2.16 r —radius of test hole (L).
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
w
RockandisthedirectresponsibilityofSubcommitteeD18.21onGroundWaterand
2.2.17 t—time elapsed from start of test (T).
Vadose Zone Investigations.
2.2.18 a—dimensionless parameter.
Current edition approved Oct. 10, 1996. Published June 1997. Originally
e1
published as D4630–86. Last previous edition D4630–86(1991) .
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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D 4630
−1 −1
2.2.19 µ—viscosity of water (ML T ).
−3
2.2.20 r—density of water (ML ).
3. Summary of Test Method
3.1 Aboreholeisfirstdrilledintotherockmass,intersecting
the geological formations for which the transmissivity and
storativity are desired. The borehole is cored through potential
zonesofinterest,andislatersubjectedtogeophysicalborehole
logging over these intervals. During the test, each interval of
interest is packed off at top and bottom with inflatable rubber
packers attached to high-pressure steel tubing.
3.2 The test itself involves rapidly applying a constant
pressure to the water in the packed-off interval and tubing
string, and recording the resulting changes in water flow rate.
The water flow rate is measured by one of a series of flow
meters of different sensitivities located at the surface. The
initial transient water flow rate is dependent on the transmis-
sivity and storativity of the rock surrounding the test interval
andonthevolumeofwatercontainedinthepacked-offinterval
and tubing string.
4. Significance and Use
4.1 Test Method—The constant pressure injection test
method
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