ASTM D4631-95(2008)
(Test Method)Standard Test Method for Determining Transmissivity and Storativity of Low Permeability Rocks by In Situ Measurements Using Pressure Pulse Technique (Withdrawn 2017)
Standard Test Method for Determining Transmissivity and Storativity of Low Permeability Rocks by In Situ Measurements Using Pressure Pulse Technique (Withdrawn 2017)
SIGNIFICANCE AND USE
Test Method—The pulse test method is used to determine the transmissivity and storativity of low-permeability formations surrounding the packed-off intervals. This test method is considerably shorter in duration than the pump and slug tests used in more permeable rocks. To obtain results to the desired accuracy, pump and slug tests in low-permeability formations are too time consuming, as indicated in Fig. 1 (from Bredehoeft and Papadopulos (1)).
Analysis—The transient pressure data obtained using the suggested method are evaluated by the curve-matching technique described by Bredehoeft and Papadopulos (1), or by an analytical technique proposed by Wang et al (2). The latter is particularly useful for interpreting pulse tests when only the early-time transient pressure decay data are available.
Units:
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 m 3/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.
Viscosity of Water—Table 1 shows the viscosity of water as a function of temperature.
TABLE 1 Viscosity of Water as a Function of Temperature Temperature, °CAbsolute Viscosity, mPa·s 01.79 21.67 41.57 61.47 81.39 10 1.31 12 1.24 14 1.17 16 1.11 18 1.06 20 1.00 22 0.96 24 0.91 26 0.87 28 0.84 30 0.80 32 0.77 34 0.74 36 0.71 38 0.68 40 0.66
SCOPE
1.1 This test method covers a field procedure for determining the transmissivity and storativity of geological formations having permeabilities lower than 10−3 μm2 (1 millidarcy) using the pressure pulse technique.
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. The values in parentheses are for information only.
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.
WITHDRAWN RATIONALE
This test method covers a field procedure for determining the transmissivity and storativity of geological formations having permeabilities lower than 10−3 μm2 (1 millidarcy) using the pressure pulse technique.
Formerly under the jurisdiction of Committee D18 on Soil and Rock, this test method was withdrawn in January 2017 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D4631 − 95 (Reapproved 2008)
Standard Test Method for
Determining Transmissivity and Storativity of Low
Permeability Rocks by In Situ Measurements Using
Pressure Pulse Technique
This standard is issued under the fixed designation D4631; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
ρ = fluid density,
µ = fluid viscosity, and
1.1 This test method covers a field procedure for determin-
g = acceleration due to gravity.
ing the transmissivity and storativity of geological formations
−3 2
havingpermeabilitieslowerthan10 µm (1millidarcy)using 2.1.2 storativity, S—thestorativity(orstoragecoefficient)of
the pressure pulse technique. a formation of thickness, b , is defined as follows:
1.2 The transmissivity and storativity values determined by S 5 S ·b (3)
s
this test method provide a good approximation of the capacity
where:
of the zone of interest to transmit water, if the test intervals are
S = equivalent bulk rock specific storage (ebrss).
s
representative of the entire zone and the surrounding rock is
The ebrss is defined as the specific storage of a material if it
fully water saturated.
were homogeneous and porous over the entire interval. The
1.3 The values stated in SI units are to be regarded as the
specific storage is given as follows:
standard. The values in parentheses are for information only.
S 5 ρg C 1nC (4)
s ~ b w!
1.4 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
where:
responsibility of the user of this standard to establish appro-
C = bulk rock compressibility,
b
priate safety and health practices and determine the applica-
C = fluid compressibility, and
w
bility of regulatory limitations prior to use.
n = formation porosity.
2.2 Symbols:
2. Terminology
−1 2
2.2.1 C —bulk rock compressibility [M LT ].
b
2.1 Definitions of Terms Specific to This Standard:
−1 2
2.2.2 C —compressibility of water [M LT ].
2.1.1 transmissivity, T—the transmissivity of a formation of w
−1
thickness, b, is defined as follows:
2.2.3 K—hydraulic conductivity [ LT ].
2.2.3.1 Discussion—The use of the symbol K for the term
T 5 K·b (1)
hydraulic conductivity is the predominant usage in groundwa-
where:
ter literature by hydrogeolists, whereas the symbol k is com-
K = equivalent formation hydraulic conductivity (efhc).
monly used for this term in rock mechanics and soil science.
Theefhcisthehydraulicconductivityofamaterialifitwere
2.2.4 L—length of packed-off zone [ L].
homogeneous and porous over the entire interval. The hydrau-
−1 −2
2.2.5 P—excess test hole pressure [ ML T ].
lic conductivity, K, is related to the equivalent formation, k,as
−1 −2
2.2.6 P —initial pressure pulse [ML T ].
o
follows:
2.2.7 S—storativity (or storage coefficient) (dimensionless).
K 5 kρg/µ (2)
−1
2.2.8 S —specific storage [ L ].
s
where:
2 −1
2.2.9 T—transmissivity [L T ].
2.2.10 V —volume of water pulsed [L ].
1 w
ThistestmethodisunderthejurisdictionofASTMCommitteeD18onSoiland
Rock and is the direct responsibility of Subcommittee D18.21 on Groundwater and
2.2.11 b—formation thickness [ L].
Vadose Zone Investigations.
2.2.12 e—fracture aperture [ L].
Current edition approved Sept. 15, 2008. Published October 2008. Originally
−2
approved in 1986. Discontinued April 1995 and reinstated as D4631–95. Last
2.2.13 g—acceleration due to gravity [ LT ].
previous edition approved in 2000 as D4631–95 (2000). DOI: 10.1520/D4631-
95R08. 2.2.14 k—permeability [L ].
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D4631 − 95 (2008)
2.2.15 n—porosity (dimensionless). formationsaretootimeconsuming,asindicatedinFig.1(from
Bredehoeft and Papadopulos (1)).
2.2.16 r —radius of test hole [L].
w
4.2 Analysis—Thetransientpressuredataobtainedusingthe
2.2.17 t—time elapsed from pulse initiation [T].
suggested method are evaluated by the curve-matching tech-
2.2.18 α—dimensionless parameter.
nique described by Bredehoeft and Papadopulos (1),orbyan
2.2.19 β—dimensionless parameter.
analytical technique proposed by Wang et al (2). The latter is
−1 −1
2.2.20 µ—viscosity of water [ML T ].
particularly useful for interpreting pulse tests when only the
−3
2.2.21 ρ—density of water [ ML ].
early-time transient pressure decay data are available.
4.3 Units:
3. Summary of Test Method
4.3.1 Conversions—The permeability of a formation is of-
3.1 Aboreholeisfirstdrilledintotherockmass,intersecting
ten expressed in terms of the unit darcy.Aporous medium has
the geological formations for which the transmissivity and
a permeability of 1 darcy when a fluid of viscosity 1 cP (1
storativity are desired. The borehole is cored through potential
3 −6 3 2
mPa·s) flows through it at a rate of 1 cm /s (10 m /s)/1 cm
zonesofinterest,andislatersubjectedtogeophysicalborehole
−4 2
(10 m )cross-sectionalareaatapressuredifferentialof1atm
logging over these intervals. During the test, each interval of
(101.4kPa)/1cm(10mm)oflength.Onedarcycorrespondsto
interest is packed off at top and bottom with inflatable rubber
0.987 µm . For water as the flowing fluid at 20°C, a hydraulic
packers attached to high-pressure steel tubing. After inflating
conductivity of 9.66 µm/s corresponds to a permeability of 1
the packers, the tubing string is completely filled with water.
darcy.
3.2 The test itself involves applying a pressure pulse to the
4.3.2 Viscosity of Water—Table 1 shows the viscosity of
water in the packed-off interval and tubing string, and record-
water as a function of temperature.
ing the resulting pressure transient. A pressure transducer,
located either in the packed-off zone or in the tubing at the
5. Apparatus
surface,measuresthetransientasafunctionoftime.Thedecay NOTE 1—A schematic of the test equipment is shown in Fig. 2.
characteristics of the pressure pulse are dependent on the
5.1 Source of Pressure Pulse—A pump or pressure intensi-
transmissivity and storativity of the rock surrounding the
fier shall be capable of injecting an additional amount of water
intervalbeingpulsedandonthevolumeofwaterbeingpulsed.
to the water-filled tubing string and packed-off test interval to
Alternatively,undernon-artesianconditions,thepulsetestmay
produce a sharp pressure pulse of up to 1 MPa (145 psi) in
be performed by releasing the pressure on a shut-in well,
magnitude, preferably with a rise time of less than 1% of one
thereby subjecting the well to a negative pressure pulse.
half of the pressure decay (P/P =0.5).
o
Interpretationofthistestmethodissimilartothatdescribedfor
5.2 Packers—Hydraulically actuated packers are recom-
the positive pressure pulse.
mended because they produce a positive seal on the borehole
wall and because of the low compressibility of water they are
4. Significance and Use
alsocomparativelyrigid.Eachpackershallsealaportionofthe
4.1 Test Method—The pulse test method is used to deter-
borehole wall at least 0.5 m in length, with an applied pressure
mine the transmissivity and storativity of low-permeability
at least equal to the excess maximum pulse pressure to be
formations surrounding the packed-off intervals. This test
method is considerably shorter in duration than the pump and
slug tests used in more permeable rocks. To obtain results to 2
The boldface numbers in parentheses refer to a list of references at the end of
the desired accuracy, pump and slug tests in low-permeability this standard.
FIG. 1 Comparative Times for Pressure Pulse and Slug Tests
D4631 − 95 (2008)
TABLE 1 Viscosity of Water as a Function of Temperature
5.4 Hydraulic Systems—The inflatable rubber packers shall
Temperature, °C Absolute Viscosity, mPa·s be attached to high-pressure steel tubing reaching to the
0 1.79 surface. The packers themselves shall be inflated with water
2 1.67
using a separate hydraulic system. The pump or pressure
4 1.57
intensifier providing the pressure pulse shall be attached to the
6 1.47
8 1.39 steel tubing at the surface. If the pump is used, a fast-operating
10 1.31
valve shall be located above, but as near as practical to the
12 1.24
upper packer. That valve should be located less than 10 m
14 1.17
16 1.11 above the anticipated equilibrium head in the interval being
18 1.06
testedtoavoidconditionsinthetubingchangingduringthetest
20 1.00
from a full water column to a falling water-level column
22 0.96
24 0.91
because of formation of a free surface at or near zero absolute
26 0.87
pressure (Neuzil (3)).
28 0.84
30 0.80
6. Procedure
32 0.77
34 0.74
6.1 Drilling Test Holes:
36 0.71
38 0.68 6.1.1 Number and Orientation—The number of test holes
40 0.66
shall be sufficient to supply the detail required by the scope of
the project. The test holes shall be directed to intersect major
fracture sets, preferable at right angles.
6.1.2 Test Hole Quality—The drilling procedure shall pro-
vide a borehole sufficiently smooth for packer seating, shall
contain no rapid changes in direction, and shall minimize
formation damage.
6.1.3 Test Holes Cored—Core the test holes through zones
of potential interest to provide information for locating test
intervals.
6.1.4 Core Description—Describe the rock core from the
test holes with particular emphasis on the lithology and natural
discontinuities.
6.1.5 Geophysical Borehole Logging—Log geophysically
the zones of potential interest. In particular, run electrical-
induction and gamma-gamma density logs. Run other logs as
required.
6.1.6 Washing Test Holes—The test holes must not contain
any material that could be washed into the permeable zones
during testing, thereby changing the transmissivity and stor-
ativity. Flush the test holes with clean water until the return is
free from cuttings and other dispersed solids.
6.2 Test Intervals:
6.2.1 Selection of Test Intervals—Test intervals are deter-
mined from the core descriptions, geophysical borehole logs,
and, if necessary, from visual inspection of the borehole with a
borescope or television camera.
FIG. 2 Schematic of Test Equipment
6.2.2 Changes in Lithology—Test each major change in
lithology that can be isolated between packers.
6.2.3 Sampling Discontinuities—Discontinuities are often
the major permeable features in hard rock. Test jointed zones,
applied to the packed-off interval and less than the formation fault zones, bedding planes, and the like, both by isolating
fracture pressure at that depth. individual features and by evaluating the combined effects of
several features.
5.3 Pressure Transducers—The test pressure may be mea-
6.2.4 Redundancy of Tests—To evaluate variability in trans-
sured directly in the packed-off test interval or between the
missivity and storativity, conduct several tests in each rock
fast-acting valve and the test interval with an electronic
type,ifhomogeneous.Iftherockisnothomogeneous,eachset
pressure transducer. In either case the pressure shall be
of tests should encompass similar types of discontinuities.
recorded at the surface as a function of time. The pressure
transducer shall have an accuracy of at least 63 kPa (60.4 6.3 Test Water:
psi), including errors introduced by the recording system, and 6.3.1 Quality—Water used for pressure pulse tests shall be
a resolution of at least 1 kPa (0.15 psi). clean and compatible with the formation. Even small amounts
D4631 − 95 (2008)
of dispersed solids in the injection water could plug the rock
α and β = dimensionless parameters given by:
face of the test interval and result in a measured transmissivity
to:
value that is erroneously low.
α 5 πr S/V C ρg (6)
w w w
6.3.2 Temperature—The lower limit of the test water tem-
β 5 πTt/V C ρg (7)
perature shall be 5°C below that of the rock mass to be tested. w w
and:
Cold water injected into a warm rock mass causes air to come
out of solution, and the resulting bubbles will radically modify
where:
the pressure transient characteristics.
V = volume of water being pulsed,
w
6.4 Testing: r = well radius,
w
t = time elapsed from pulse initiation,
6.4.1 Filling and Purging System—Allow sufficient time
C = compressibility of water,
afterwashingthetestholeforanyinducedformationpressures
w
T = transmissivity,
to dissipate. Once the packers have been set, slowly fill the
S = storage coefficient,
tubing string and packed-off interval with water to ensure that
ρ = density of water, and
no air bubbles will be trapped in the test interval and tubing.
g = gravitational acceleration.
6.4.2 Pressure Pulse Test—This range of pressures is in
most cases sufficiently low to minimize distortion of fractures
TablesofthefunctionF(αβ)havebeenprovidedbyCooper,
adjacent to the test hole, but in no case should the pressure et al (4), Papadopulos (5), and Bredehoeft and Papadopulos
exceed the minimum principal ground stress. Record the
(1).
resulting pressure pulse and decay transient detected by the
7.1.1 In Fig. 3 the pressure, p, shown before (to the left of)
pressure transducer as a function of time. A typical record is
Time t represents the unknown natural pressure in the interval
shown in Fig. 3.
eventually to be tested. The drill hole encounters that interval
6.4.2.1 Before the pressure pulse test can be started it is
at Time t and from then until Time t the pressure variation
1 2
necessary to reliably estimate the natural pressure in the test
reflects the effects of drilling and test hole development. If the
interval. See 7.1.1 and Fig. 3 for a description of a method to
interval consists of rocks or sediments of low hydraulic
preparethesystemforthepulsetest.Afterthepressureisat,or
conductivity, there might be a long time period before the
estimated to be approaching at a predictable rate, near-
water level in an open hole would stabilize to the equilibrium
equilibrium conditions, then rapidly pressurize the tubing,
level. For that reason before a pulse test can be conducted we
typically to between 300 and 600 kPa (50 to 100 psi), and then
want to establish a condition that provides a reasonable
shut in.
estimate of the undisturbed pressure for the interval. The
following procedure is intended to provide that condition. At
7. Calculation and Interpretation of Test Data
Time t the packers are inflated, and then the system is filled
7.1 The type of matching technique developed by Brede- withwaterandshutin.Bythisoperationthechangeinpressure
inthepacked-offintervalwillreflectacompressivesystemand
hoeft and Papadopulos (1) involves plotting normalized pres-
sure (the ratio of the excess b
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.