EN ISO 13503-2:2006

SLOVENSKI STANDARD
01-januar-2007
Industrija za predelavo nafte in zemeljskega plina - Tekočine in materiali za
zaključna dela - 2. del: Merjenje lastnosti podpornih materialov, ki se uporabljajo v
postopkih frakcioniranja in pri filtrskih zasipih s prodom (ISO 13503-2:2006)
Petroleum and natural gas industries - Completion fluids and materials - Part 2:
Measurement of properties of proppants used in hydraulic fracturing and gravel-packing
operations (ISO 13503-2:2006)
Erdöl- und Erdgasindustrie - Komplettierungsflüssigkeiten und -materialien - Teil 2:
Messung der Eigenschaften von Stützmaterialien zum Einsatz bei hydraulischen
Fraktionierungs- und in Kiespackungsvorgängen (ISO 13503-2:2006)
Industries du pétrole et du gaz naturel - Fluides de complétion et matériaux - Partie 2:
Mesurage des propriétés des matériaux de soutenement utilisés dans les opérations de
fracturation hydraulique et de remplissage de gravier (ISO 13503-2:2006)
Ta slovenski standard je istoveten z: EN ISO 13503-2:2006
ICS:
75.100 Maziva Lubricants, industrial oils and
related products
75.180.30 Oprema za merjenje Volumetric equipment and
prostornine in merjenje measurements
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 13503-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2006
ICS 75.100
English Version
Petroleum and natural gas industries - Completion fluids and
materials - Part 2: Measurement of properties of proppants used
in hydraulic fracturing and gravel-packing operations (ISO
13503-2:2006)
Industries du pétrole et du gaz naturel - Fluides de Erdöl- und Erdgasindustrie - Komplettierungsflüssigkeiten
complétion et matériaux - Partie 2: Mesurage des und -materialien - Teil 2: Messung der Eigenschaften von
propriétés des matériaux de soutènement utilisés dans les Stützmaterialien zum Einsatz bei hydraulischen
opérations de fracturation hydraulique et de remplissage de Fraktionierungs- und in Kiespackungsvorgängen (ISO
gravier (ISO 13503-2:2006) 13503-2:2006)
This European Standard was approved by CEN on 22 September 2006.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the Central Secretariat or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,
Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,
Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13503-2:2006: E
worldwide for CEN national Members.

Foreword
This document (EN ISO 13503-2:2006) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum and natural gas industries" in
collaboration with Technical Committee CEN/TC 12 "Materials, equipment and offshore
structures for petroleum, petrochemical and natural gas industries", the secretariat of which is
held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of
an identical text or by endorsement, at the latest by May 2007, and conflicting national standards
shall be withdrawn at the latest by May 2007.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary,
Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Endorsement notice
The text of ISO 13503-2:2006 has been approved by CEN as EN ISO 13503-2:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 13503-2
First edition
2006-11-01
Petroleum and natural gas industries —
Completion fluids and materials —
Part 2:
Measurement of properties of proppants
used in hydraulic fracturing and
gravel-packing operations
Industries du pétrole et du gaz naturel — Fluides de complétion et
matériaux —
Partie 2: Mesurage des propriétés des matériaux de soutènement
utilisés dans les opérations de fracturation hydraulique et de
remplissage de gravier
Reference number
ISO 13503-2:2006(E)
©
ISO 2006
ISO 13503-2:2006(E)
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ii © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Abbreviations . 1
4 Standard proppant sampling procedure .2
4.1 General. 2
4.2 Particle segregation. 2
4.3 Equipment . 2
4.4 Number of required samples — Bulk. 4
4.5 Sampling —Bulk material . 5
4.6 Sampling — Bagged material . 5
5 Sample handling and storage. 5
5.1 Sample reduction. 5
5.2 Sample splitting . 5
5.3 Sample and record retention and storage .5
6 Sieve analysis . 6
6.1 Purpose. 6
6.2 Description . 6
6.3 Equipment and materials . 6
6.4 Procedure . 6
6.5 Calculation of the mean diameter, median diameter and standard deviation. 7
6.6 Sieve calibration . 9
7 Proppant sphericity and roundness . 11
7.1 Purpose. 11
7.2 Description . 12
7.3 Apparatus capability. 12
7.4 Procedure . 12
7.5 Alternate method for determining average sphericity and roundness . 13
8 Acid solubility . 13
8.1 Purpose. 13
8.2 Description . 13
8.3 Equipment and materials . 14
8.4 Procedure . 14
9 Turbidity test . 15
9.1 Purpose. 15
9.2 Description . 16
9.3 Equipment and materials . 16
9.4 Equipment calibration . 16
9.5 Procedure . 16
10 Procedures for determining proppant bulk density, apparent density and absolute density. 17
10.1 Purpose. 17
10.2 Description . 17
10.3 Bulk density. 17
10.4 Apparent density. 19
10.5 Absolute density. 21
ISO 13503-2:2006(E)
11 Proppant crush-resistance test . 21
11.1 Purpose . 21
11.2 Description. 21
11.3 Equipment and materials . 22
11.4 Sample preparation. 22
11.5 Crush-resistance procedure . 23
12 Loss on ignition of resin-coated proppant.25
12.1 Objective . 25
12.2 Apparatus and materials . 25
12.3 Loss-on-ignition procedure for whole-grain proppant . 25
Annex A (informative) Formazin solution preparation. 27
Bibliography . 28

iv © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 13503-2 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries, Subcommittee SC 3, Drilling and completion fluids,
and well cements.
ISO 13503 consists of the following parts, under the general title Petroleum and natural gas industries —
Completion fluids and materials:
⎯ Part 1: Measurement of viscous properties of completion fluids
⎯ Part 2: Measurement of properties of proppants used in hydraulic fracturing and gravel-packing
operations
⎯ Part 3: Testing of heavy brines
⎯ Part 4: Procedure for measuring stimulation and gravel-pack fluid leakoff under static conditions
⎯ Part 5: Procedures for measuring the long-term conductivity of proppants
ISO 13503-2:2006(E)
Introduction
[1] [2] [3]
This part of ISO 13503 is a compilation and modification of API RP 56 , API RP 58 and API RP 60 .
The procedures have been developed to improve the quality of proppants delivered to the well site. They are
for use in evaluating certain physical properties used in hydraulic fracturing and gravel-packing operations.
These tests should enable users to compare the physical characteristics of various proppants tested under the
described conditions and to select materials useful for hydraulic fracturing and gravel-packing operations.
The procedures presented in this part of ISO 13503 are not intended to inhibit the development of new
technology, material improvements or improved operational procedures. Qualified engineering analysis and
judgment are required for their application to a specific situation.
In this part of ISO 13503, where practical, US Customary (USC) units are included in brackets for information.
Annex A of this part of ISO 13503 is for information only.

vi © ISO 2006 – All rights reserved

INTERNATIONAL STANDARD ISO 13503-2:2006(E)

Petroleum and natural gas industries — Completion fluids and
materials —
Part 2:
Measurement of properties of proppants used in hydraulic
fracturing and gravel-packing operations
1 Scope
This part of ISO 13503 provides standard testing procedures for evaluating proppants used in hydraulic
fracturing and gravel-packing operations.
NOTE “Proppants” mentioned henceforth in this part of ISO 13503 refer to sand, ceramic media, resin-coated
proppants, gravel-packing media and other materials used for hydraulic fracturing and gravel-packing operations.
The objective of this part of ISO 13503 is to provide a consistent methodology for testing performed on
hydraulic fracturing and/or gravel-packing proppants.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ASTM E11, Standard Specification for Wire Cloth and Sieves for Testing Purposes
3 Abbreviations
API American Petroleum Institute
ASTM American Society for Testing and Materials
ASG apparent specific gravity
FTU formazin turbidity unit
HCI hydrochloric acid
HF hydrofluoric acid
LOI loss on ignition
NTU nephelometric turbidity unit
ISO 13503-2:2006(E)
4 Standard proppant sampling procedure
4.1 General
Before any sample is taken, consider what tests will be performed, as each test requires a different volume. It
is very important that both the supplier and customer obtain the best representative sample possible. Unless
the sample is truly representative of a total shipment or container, testing and correlation with
specifications/standards is very difficult. It is unlikely that sampling/testing methods in the field duplicate the
producer’s system. The standard procedures included within this part of ISO 13503 are to assist in obtaining
representative samples. However, there are inherent variations associated with sampling, testing equipment
and the procedures that can lead to inconsistent results. A sample that is representative of a truckload
[23 000 kg (50 700 lb)] or a railcar load [90 000 kg (198 000 lb)] can be an initial source of wide variation when
making comparisons. All parties shall take care to insure uniform sampling. The customer and the supplier
shall agree on sampling and testing methods/techniques.
For the best representation, continuous sampling is ideal. Although many proppant suppliers utilize automatic
sampling, it is usually impractical at the job site. If sampling is conducted while unloading a container or at the
site, consideration should be given to the number or frequency of samples.
If bulk containers are filled from a flowing stream of proppant material, sampling procedures in accordance
with 4.5 shall be applied. If bulk containers are filled using sacked proppant material, sampling procedures in
accordance with 4.6 shall be applied.
4.2 Particle segregation
It is important to have a basic understanding of segregation when sampling proppant. Depending on the size,
shape, distribution and mechanisms involved, there is usually a certain amount of error or variability involved
in sampling due to segregation. The sampling procedures described here are the result of much experience
and are designed to minimize the effects of segregation of particles by size.
Particles, such as proppants, naturally find the path of least resistance when moved or when force is applied.
During transfer or movement, particles of differing size and mass naturally separate or segregate. The degree
of segregation depends on the mechanisms involved in the transfer or movement.
There are several forces, such as gravity, acting on a stream of particles as it flows. Within a moving stream,
fine particles drop through the voids or gaps and coarser particles move to the outside. The fine particles
migrate and usually rest close to the area where they land. The heavier, coarser particles bounce or roll much
further, stratifying the material by size.
4.3 Equipment
The following equipment shall be used to compile representative proppant material samples.
4.3.1 Box sampling device, with a 13 mm (0,50 in) slot opening.
The length of the 13 mm (0,50 in) slot shall be longer than the thickness of the stream being sampled. The
volume of the sampler shall be large enough so as to not overflow while cutting through the entire stream. A
box sampling device meeting these criteria is shown in Figure 1.
4.3.2 Sample reducer, of appropriate size for handling sack-size samples and reducing the material to 1/16
of the original mass; see Figure 2.
4.3.3 Sample splitter, of appropriate size; see Figure 3.
2 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
Dimensions in centimetres (inches)

Key
1 sampler body, 15,9 × 20,9 × 6,35 (6,25 × 8,25 × 2,5) 3 pipe coupling
2 handle 4 sample opening, 1,27 (0,50)
Figure 1 — Box sampling device
Dimensions in centimetres (inches)

Key
1 main body, 36,8 × 48,3 × 11,4 (14,5 × 19,0 × 4,5) 5 hopper, 36,8 × 24,1 × 15,2 (14,5 × 9,5 × 6,0)
2 splitter plate, 5,1 × 5,1 × 5,1 (2 × 2 × 2) 6 gate, 36,8 × 19,1 × 0,32 (14,5 × 7,5 × 0,125)
3 discharge plate, 36,8 × 30,5 × 0,32 (14,5 × 12 × 0,125) 7 hand knob, 3,8 (1,5) diameter
4 discharge chute, 5,7 × 5,7 × 7,6 (2,25 × 2,25 × 3,0) 8 support stand assembly,
71,1 × 38,1 × 68,6 (28 × 15 × 27)
Figure 2 — Sample reducer
ISO 13503-2:2006(E)
Dimensions in centimetres (inches)

Key
1 main body, 29,2 × 27,9 × 16,5 (11,5 × 11,0 × 6,5)
2 handle
3 gate plate
4 hopper
5 pan
6 splitter vanes, 1,25 (0,5)
Figure 3 — Sample splitter
4.4 Number of required samples — Bulk
4.4.1 Proppants for hydraulic fracturing
A minimum of one sample per 9 000 kg (20 000 lb) or fraction thereof, shall be obtained. A maximum of
10 samples per bulk container shall be obtained, combined and tested.
4.4.2 Gravel-packing media
A minimum of one sample per 4 500 kg (10 000 lb) but no fewer than two samples per job shall be obtained,
combined and tested.
4 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
4.5 Sampling —Bulk material
All samples shall be obtained from a flowing stream of proppant by a manual or automatic sampler. Samples
shall not be taken from a static pile. The sampling device shall be used with its length perpendicular to the
flowing proppant stream. The sampler shall be passed at a uniform rate from side to side through the full
stream width of moving proppant. This shall be done as the material is moving to or from a conveyor belt into
a blender, truck, railcar or bulk container. Two metric tons of proppant material shall be allowed to flow prior to
taking the first sample. The number of samples taken shall comply with 4.4. During sampling, the sampling
receptacle shall be passed completely across the moving proppant stream in a brief interval of time so as to
take the entire stream with each pass. Under no circumstances shall the sampling receptacle be allowed to
overflow.
4.6 Sampling — Bagged material
4.6.1 Bags up to 50 kg (110 lb)
Only whole bags shall be used for sampling bagged proppant materials.
4.6.2 Totes/bulk bags/super sacks weighing up to 2 000 kg (4 400 lb)
Unless the product can be sampled in a free-flowing state, the sampling of large bags presents the same
problems as for a static pile. Follow the same sample frequency as described in 4.4, using the sampling
method described in 4.5, except for allowing approximately 50 kg (110 lb) to be discharged from the bulk bag
before sampling.
5 Sample handling and storage
5.1 Sample reduction
Place the contents of the combined bulk sample of proppant, or an entire sack up to 50 kg (110 lb), in the 16:1
sample reducer (see Figure 2) or equivalent. Obtain a reduced sample of approximately 1/16 of the original
mass of the total sack’s contents, typically 3 kg (6,6 lb).
5.2 Sample splitting
An appropriately-sized sample reducer and sample splitter shall be used to permit samples to be prepared for
testing. Place the reduced sample, obtained according to 5.1, or the sample obtained during bulk material
loading operations (refer to 4.5), in the sample splitter (refer to Figure 3) and split the sample to a
testing-aliquot size of approximately 1 kg (2,2 lb). Sufficient proppant material shall be split to permit
performance of recommended tests as specified in this part of ISO 13503.
5.3 Sample and record retention and storage
The proppant supplier shall maintain records of all tests conducted on each shipment for a minimum of one
year. Physical samples of an amount sufficient to conduct all tests recommended herein, but in no cases less
than 0,25 kg (0,5 lb), shall be retained in storage for a minimum of six months. Any material subsequently
taken for testing shall be split from the retained sample. Samples shall be sealed in a type of container that is
sufficient to protect the sample from contamination and moisture. Samples shall be stored in a cool dry place.
ISO 13503-2:2006(E)
6 Sieve analysis
6.1 Purpose
The purpose of the procedure in Clause 6 is to ensure a consistent methodology for sieve analysis and to
provide a consistent procedure for sieve evaluation.
6.2 Description
The procedure and equipment described in 6.3 to 6.6 are the most widely utilized in the gas and oil industry.
Alternate methods may be used but shall be correlated with these standard methods.
6.3 Equipment and materials
6.3.1 Sieve sets, two, complying with the requirements of the ASTM Series, 200 mm (8 in) diameter or
equivalent.
One set is a working set of sieves, and the other a master set to be used for standardization only.
Refer to ASTM E11.
6.3.2 Testing sieve shaker, providing simultaneous rotating and tapping action, that accepts the sieves
specified in Table 1.
The shaker shall be calibrated to the following specifications: 290 rev/min, 156 taps/min, height of tapper
33,4 mm (1,3 in) and timer accurate to ± 5 s.
6.3.3 Balance, minimum 100 g (0,22 lb) capacity with a precision of 0,1 g or better.
6.3.4 Brushes, nylon or equivalent.
6.4 Procedure
6.4.1 Stack a minimum of seven sieves, recently checked against a master set, plus a pan and cover, in a
stack of decreasing sieve-opening sizes from top to bottom. Table 1 establishes sieve sizes for use in testing
designated example proppant sizes. Table 1 should be used as a guide and does not attempt to preclude the
use of other grades that are or can become available.
6.4.2 Using a split sample of 80 g to 120 g, obtain an accurate sample to within 0,1 g.
6.4.3 Weigh each sieve and record the mass. Pour the split sample onto the top sieve, place the stack of
sieves plus pan and lid in testing sieve shaker and agitate for 10 min.
6.4.4 Remove the sieve stack from the testing sieve shaker.
6.4.5 Weigh and record the mass retained on each of the sieves and in the pan.
Calculate the percent mass of the total proppant sample retained on each sieve and in the pan. The
cumulative mass shall be within 0,5 % of the sample mass used in the test. If not, the sieve analysis shall be
repeated using a different sample.
6 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
a
Table 1 — Sieve sizes
Sieve-opening sizes
µm
3 350/ 2 360/ 1 700/ 1 700/ 1 180/ 1 180/ 850/ 600/ 425/ 425/ 212/

1 700 1 180 1 000 850 850 600 425 300 250 212 106
Typical proppant/gravel-pack size designations
6/12 8/16 12/18 12/20 16/20 16/30 20/40 30/50 40/60 40/70 70/140
b
Stack of ASTM sieves
4 6 8 8 12 12 16 20 30 30 50
First primary sieve
6 8 12 12 16 16 20 30 40 40 70
in bold type
8 10 14 14 18 18 25 35 45 45 80
10 12 16 16 20 20 30 40 50 50 100
12 14 18 18 25 25 35 45 60 60 120
Second primary
16 20 30 40 50 70 140
14 20 30 70
sieve in bold type
16 20 30 30 40 40 50 70 100 100 200
pan pan pan pan pan pan pan pan pan pan pan
a
Sieve series as defined in ASTM E11.
b
Sieves stacked in order from top to bottom.

6.5 Calculation of the mean diameter, median diameter and standard deviation
6.5.1 General
The mean diameter, d , shall be used to characterize the proppant distribution for hydraulic fracturing. The
av
median diameter, d , shall be used to characterize gravel-packing distributions. This is in addition to the
mesh-size characterization described in 6.4.
6.5.2 Mean diameter
The mean diameter, d , expressed in millimetres, is calculated as given in Equation (1):
av
dn=⋅dn (1)
av∑∑
where n·d is the product of mid-size diameter (d) multiplied by frequency of occurrence (n).
EXAMPLE Calculation of the mean diameter for a 16/30 proppant with the following size distribution; see Table 2:
+12 mesh (1 700 µm) 0,0 %
+16 mesh (1 180 µm) 1,2 %
+18 mesh (1 000 µm) 37,9 %
+20 mesh (850 µm) 48,7 %
+25 mesh (710 µm) 11,9 %
+30 mesh (600 µm) 0,3 %
+40 mesh (425 µm) 0,0 %
Pan 0,0 %
TOTAL 100,0 %
ISO 13503-2:2006(E)
Table 2 — Parameters for mean diameter calculation
US mesh size Particle-size Mid size Frequency of n·d
interval d occurrence
n
µm µm
% by mass
10 to 12 2 000 to 1 700 1 850 0,0 0
12 to 16 1 700 to 1 180 1 440 1,2 1 728
16 to 18 1 180 to 1 000 1 090 37,9 41 311
18 to 20 1 000 to 850 925 48,7 45 047
20 to 25 850 to 710 780 11,9 9 282
25 to 30 710 to 600 655 0,3 197
TOTAL 100,0 97 565
Therefore, the mean diameter, dn=⋅dn = 97 565/100,0 = 975,7 µm = 0,976 mm (0,038 in).
av∑∑
6.5.3 Median diameter
In gravel-packing, the median diameter, d (the fiftieth mass percentile), which is commonly used, is
calculated as follows.
Determine the percent of the sample retained on each screen. This is done by dividing the mass retained on
the screen by the total cumulative mass (not the original mass) and multiplying by 100. Determine the
cumulative percent retained for each screen by adding the percent retained on that screen with the percents
retained on the larger screens that are above it. The cumulative percent of the material retained by all the
screens and the pan should be 100 %.
Plot a particle-size distribution curve with cumulative percent on the y-axis versus log of sieve opening on the
x-axis, which is inverted so that the scale is smaller to the right and larger to the left. The sieve size can be
plotted as microns, millimetres or inches. A plot of the example in 6.5.2 is plotted in Figure 4. Reading the
graph at 50 % cumulative mass (on the y-axis) gives the d grain-size diameter (on the x-axis) of 0,97 mm
(0,038 in).
d is also the median diameter, which is the size at which 50 % of the particles are smaller and 50 % are
larger. In this example, the mean and median are very close together. This might not be the case in highly
skewed distributions.
From Figure 4 other common criteria, such as d , and standard deviation, σ, can be determined. Reading
the graph at 90 % cumulative mass (on the y-axis) gives the d grain-size diameter (on the x-axis) of 0,82 mm
(0,032 in).
The standard deviation, σ, is calculated from the expression d /d = 0,85 mm/0,97 mm = 0,88.
84,13 50
8 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
Key
X size, expressed in millimetres
Y cumulative percent
Figure 4 — Graphical determination of d , d and d
50 90 84,13
6.6 Sieve calibration
6.6.1 Purpose
It is necessary to check sieves against a master set because sieves are not perfect and are subject to wear.
This is true for both new and used sieves and for matched and unmatched sieves. Optical examination of any
sieve shows the openings vary in both size and shape. Calibration is a means by which the extent and the
effect of the opening differences can be determined. It is also a means to compensate for manufactured
differences in sieves to ensure consistency in sieve analysis.
6.6.2 Description
A stack of master sieves is used to check working sieves. This master stack should be used very sparingly to
prevent major changes in the openings. The master stack consists of certified sieves that are optically
calibrated on an annual basis, typically by the original equipment manufacturer, to ensure that the sieves are
in accordance with latest revision of ASTM E11. If any sieve fails the ASTM E11 specification, the sieve shall
be replaced with a new certified sieve. Storage of sieves shall be done in such a manner as to prevent
deterioration and/or damage.
ISO 13503-2:2006(E)
6.6.3 Procedure
Place a calibration sample (see 6.6.4) into the master sieve stack and complete sieve analysis according to
6.4. The load retained on each master sieve is considered the master load for calculation purposes.
This calibration sample is then placed into the working sieve stack and sieve analysis is completed according
to 6.4. The load retained on each working sieve is considered the working load for calculation purposes. If the
total test sample mass exceeds ± 0,2 % difference from the master stack to the working stack, repeat the test.
Calculate the difference, D, as given in Equation (2), the % difference, D', as given in Equation (3), absolute
deviation, δ , as given in Equation (4), and % absolute deviation, δ' , as given in Equation (5). If the percent
A A
absolute deviation exceeds 10 % between the master sieve set and the working/supplier sieve, the difference
should be considered when comparing results to sieve recommendations. If the absolute deviation exceeds
25 %, the working sieve shall be replaced.
D = m − m (2)
Ws Ms
D' = (D/m ) × 100 (3)
Ms
where
D is the difference, expressed in millimetres;
D' is the difference, expressed in percent;
m is the mass retained on each sieve in the master set;
Ms
m is the mass retained on each sieve in the working set.
Ws
NOTE For the top sieve of the stack, the absolute deviation equals the difference. This number can be positive or
negative.
Absolute deviation is calculated from Equation (4):
δ = δ + D (4)
A,S(I) A,S(I−1) S(I)
where
δ is the absolute deviation of the sieve of interest, expressed in millimetres;
A,S(I)
δ is the absolute deviation of the preceding sieve;
A,S(I−1)
D is the difference for the sieve of interest.
S(I)
Percent absolute deviation, δ' , is calculated from Equation (5):
A,S(I−1±D)
δ' = (δ /m ) × 100 (5)
A,S(I−1±D) A,S(I−1±D) Ms
where δ is the absolute deviation of preceding sieve ± D , the difference for the sieve of interest.
A,S(I−1±D) S(I)
NOTE The word “absolute” is not referring to the mathematical absolute function.
EXAMPLE Example calculation for 25-mesh sieve; see Table 3:
⎯ from Equation (2): D = 10,5 − 10,1 = 0,4
⎯ from Equation (3): D' = (0,4/10,1) 100 = 4,0
⎯ from Equation (4): δ = 1,8 + 0,4 = 2,2
A,S(I)
⎯ from Equation (5): δ' = (2,2/10,1) 100 = 22,0
A,S(I−1±D)
10 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
Table 3 —Absolute deviation example
Sieve mesh m m D D' δ δ'
Ms Ws A,S(I) A,S(I)
size g g mm % mm %
12 9,4 10,0 0,6 6,4 0,6 6
16 10,9 11,7 0,8 7,3 1,4 13
18 9,5 9,2 −0,3 −3,1 1,1 12
20 9,5 10,2 0,7 7,4 1,8 19
25 10,1 10,5 0,4 4,0 2,2 22
30 10,0 9,9 2,1 21
−0,1 −1,0
35 11,4 10,9 −0,5 −4,4 1,6 14
40 9,3 9,2 1,5 16
−0,1 −1,1
50 10,1 9,2 −0,9 −8,9 0,6 6
70 8,8 8,9 0,1 1,1 0,7 8
Pan 0,9 0,4 — — — —
6.6.4 Preparing calibration samples
A sieve calibration sample is prepared by blending sized samples. To prepare the sized samples, first
determine the specific mesh material(s) needed. Assemble a sieve stack that covers these mesh sizes and
place a pan at the bottom.
Place 100 g ± 20 g of media that has been identified as a source for test material onto the top sieve and cover
with a lid. Place the sieve stack into the sieve shaker and shake for 10 min. The mass of media used should
be optimized without exceeding 35 g on any sieve.
Remove the stack from the sieve shaker and then remove the lid. Carefully remove the top sieve and invert
onto a recovery pan. Place the material from the recovery pan into a storage container labelled specifically for
this mesh-sized material. Return the sieve to the recovery pan. Brush any remaining material from the sieve
and discard this material. Repeat for each sieve.
Select the sieve mesh sizes to be tested based on Table 1. For each sieve mesh size, weigh out
approximately 10 g of correspondingly sized material. Blend the sized material together to form a calibration
standard.
7 Proppant sphericity and roundness
7.1 Purpose
The purpose of this procedure is to evaluate and report proppant shapes.
ISO 13503-2:2006(E)
7.2 Description
Key
X roundness
Y sphericity
Figure 5 — Chart for visual estimation of sphericity and roundness
The common particle shape parameters that have been found to be useful for visually evaluating proppants
are sphericity and roundness. This procedure finds its greatest utility in the characterization of new proppant
deposits and new sources of man-made proppants. The most widely-used method of determining roundness
and sphericity is the use of the Krumbien/Sloss chart (see Figure 5). Sphericity is a measure of how close a
proppant particle approaches the shape of a sphere. Roundness is a measure of the relative sharpness of
corners or of curvature. These measurements must be determined separately. Distinct measurement methods
utilizing photographic or digital technology are available and are acceptable.
7.3 Apparatus capability
The apparatus shall have the following capabilities:
a) 10 times to 40 times magnification microscope or equivalent;
b) analytical balance, accuracy to 0,001 g.
7.4 Procedure
7.4.1 Using the split sample (see 5.2) and the sample splitter, further reduce the sample to 5 g to 15 g. If a
small sample splitter is available, then the reduced sample amount can be safely reduced further to 1 g or 2 g.
7.4.2 Place the reduced sample onto a suitable background, spread it out to a one-particle-thickness layer,
and view it through a microscope at low magnification (10 times to 40 times magnification). Choose a darker
background colour for a light-coloured proppant and, conversely, choose a lighter background colour for dark
particles.
12 © ISO 2006 – All rights reserved

ISO 13503-2:2006(E)
7.4.3 Randomly select at least 20 individual particles in the field of view for evaluation of particle sphericity.
7.4.4 Determine the sphericity of each selected particle by comparison to the chart provided, refer to
Figure 5. Record the assigned sphericity number for each particle selected.
7.4.5 Calculate the arithmetic average of the recorded sphericity numbers and report as average particle
sphericity to the nearest 0,1 units.
7.4.6 Using the same individual particles selected in 7.4.3, determine the roundness of each particle.
Record the assigned roundness number for each particle selected.
7.4.7 Calculate the arithmetic average of the recorded roundness numbers and report as average particle
roundness to the nearest 0,1 units.
7.5 Alternate method for determining average sphericity and roundness
7.5.1 Use of photomicrographs
Photomicrographs of a representative proppant sample are used to provide identical, suitably enlarged
reproductions for the determination of average sphericity and roundness for the reduced proppant sample. A
scanning electron microscope, a reflected-light microscope fitted with a camera, a fixed camera with bellows
and a wide-angle lens, digital camera and/or other appropriate photographic equipment can be successfully
used to produce suitable photomicrographs of known magnification. The choice of equipment to use becomes
a matter of individual preference and availability.
7.5.2 Procedure
Follow the procedure in 7.4, except use the photographic equipment of choice. Numbering each selected
particle in the image limits confusion and assures the same particles are used for both the sphericity and the
roundness determinations.
7.5.3 Suggested magnification for photomicrographs
For designated proppant size ranges, the magnifications are shown in T
...