EN ISO 13501:2006

SLOVENSKI STANDARD
01-maj-2007
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Petroleum and natural gas industries - Drilling fluids - Processing systems evaluation
(ISO 13501:2005)
Erdöl- und Erdgasindustrie - Bohrflüssigkeiten - Beurteilung von Verarbeitungssystemen
Industries du pétrole et du gaz naturel - Fluides de forage - Évaluation des systemes de
traitement (ISO 13501:2005)
Ta slovenski standard je istoveten z: EN ISO 13501:2006
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 13501
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2006
ICS 75.180.10
English Version
Petroleum and natural gas industries - Drilling fluids -
Processing systems evaluation (ISO 13501:2005)
Industries du pétrole et du gaz naturel - Fluides de forage - Erdöl- und Erdgasindustrie - Bohrflüssigkeiten - Beurteilung
Évaluation des systèmes de traitement (ISO 13501:2005) von Verarbeitungssystemen
This European Standard was approved by CEN on 13 November 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 13501:2006: E
worldwide for CEN national Members.

Foreword
The text of ISO 13501:2005 has been prepared by Technical Committee ISO/TC 67 "Materials,
equipment and offshore structures for petroleum and natural gas industries” of the International
Organization for Standardization (ISO) and has been taken over as EN ISO 13501:2006 by
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 June 2007, and conflicting national
standards shall be withdrawn at the latest by June 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 13501:2005 has been approved by CEN as EN ISO 13501:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 13501
First edition
2005-12-01
Petroleum and natural gas industries —
Drilling fluids — Processing systems
evaluation
Industries du pétrole et du gaz naturel — Fluides de forage —
Évaluation des systèmes de traitement

Reference number
ISO 13501:2005(E)
©
ISO 2005
ISO 13501:2005(E)
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ii © ISO 2005 – All rights reserved

ISO 13501:2005(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms. 1
4 Requirements . 12
5 Drilled solids removal — System performance . 12
6 Rigsite evaluation of drilled-solids management equipment. 17
7 Practical operational guidelines. 21
8 Conductance of shale-shaker screens.30
9 Shale-shaker screen designation. 35
10 Non-blanked area of shale-shaker screen panel . 43
11 Shale-shaker screen labelling . 45
Annex A (informative) Derivation of capture equation . 49
Bibliography . 51

ISO 13501:2005(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 13501 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.
iv © ISO 2005 – All rights reserved

ISO 13501:2005(E)
Introduction
This International Standard covers equipment which is commonly used in petroleum and natural gas drilling
fluids processing. This equipment can be purchased or rented from multiple sources, and is available
worldwide. No single-source or limited-source equipment is included, either by inference or reference.
International Standards are published to facilitate communications between purchasers and manufacturers, or
provide interchangeability between similar equipment and materials purchased from different manufacturers
and/or at different times, and to provide an adequate level of safety when the equipment or materials are
utilized in the manner and for the purposes intended. This International Standard provides minimum
requirements and is not intended to inhibit anyone from purchasing or using equipment made to other
standards. This International Standard is subject to periodic review and can be revised or withdrawn at such
time as deemed appropriate.
The purpose of this International Standard is to provide a method of assessing the performance of solids
control equipment systems in the field. It includes procedures for evaluation of shale shakers, centrifugal
pumps, degassers, hydrocyclones, mud cleaners and centrifuges, as well as an entire system evaluation.
Shale-shaker screenLabelling and separation potential of shale-shaker screens have been addressed as part
of this International Standard.
This International Standard is based on API RP 13C, third edition, December 2004 (for drilling fluid processing
equipment) and shale-shaker screen API RP 13E, third edition, May 1, 1993 (for shale-shaker screens).
ISO publications may be used by anyone desiring to do so. Every effort has been made to assure the
accuracy and reliability of the data contained in them; however, no representation, warrant or guarantee in
connection with this publication is made by ISO. ISO hereby expressly disclaims any liability, or responsibility
for loss or damage resulting from use of this International Standard or for the violation of any federal, state or
municipal regulation with which this publication may conflict.
Standards are published to facilitate the broad availability of proven, sound engineering and operating
practices. Users of this International Standard should be aware that further or differing requirements may be
needed for individual applications. This International Standard is not intended to inhibit a vendor from offering,
or the purchaser from accepting, alternative equipment or engineering solutions for the individual application.
This may be particularly applicable where there is innovative or developing technology. Where an alternative
is offered, the vendor should identify any variations from this International Standard and provide details.”
Any manufacturer marking equipment or materials in conformance with the marking requirements is solely
responsible for complying with all the applicable requirements of that standard. ISO does not represent,
warrant, or guarantee that such products do in fact conform to the applicable International Standard.

INTERNATIONAL STANDARD ISO 13501:2005(E)

Petroleum and natural gas industries — Drilling fluids —
Processing systems evaluation
1 Scope
This International Standard provides a standard procedure for assessing and modifying performance of solids
control equipment systems commonly used in the field in petroleum and natural gas drilling fluids processing.
This procedure is not intended for the comparison of similar types of individual pieces of equipment.
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.
ISO 3310-1, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ANSI/AWWA Standard C700, Cold-water meters — Displacement type, bronze main case
API, Manual of Petroleum Measurement Standards
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this document, the following terms and definitions apply.
3.1 Terms and definitions
3.1.1
addition section
compartment(s) in the surface drilling fluid system between the removal section and the suction section which
provides a well-agitated compartment(s) for the addition of commercial products such as chemicals,
necessary solids and liquids
3.1.2
agitator
mechanical stirrer
mechanically driven mixer that stirs the drilling fluid by turning an impeller near the bottom of a mud
compartment to blend additives, suspend solids and maintain a uniform consistency of the drilling fluid
3.1.3
aperture
〈screen cloth〉 opening between the wires in a screen cloth
3.1.4
aperture
〈screen surface〉 opening in a screen surface
ISO 13501:2005(E)
3.1.5
apex
opening at lower end of a hydrocyclone
3.1.6
API sand
〈physical description〉 particles in a drilling fluid that are too large to pass through a 74 µm sieve (API 200
screen)
NOTE 1 Its amount is expressed as a volume fraction (percent) of drilling fluid.
NOTE 2 Particle size is a descriptive term; the particles can be shale, limestone, wood, gold or any other material.
3.1.7
API screen number
mesh, obsolete
mesh count, obsolete
number in an API system used to designate the D100 separation range of a mesh screen cloth
cf. D100 separation (3.1.23)
NOTE 1 The term mesh was formerly used to refer to the number of openings (and fraction thereof) per linear inch in a
screen, counted in both directions from the centre of a wire. This term is being replaced by the API screen number.
NOTE 2 Mesh count was formerly used to describe the fineness of a square or rectangular mesh screen cloth. For
example, a mesh count such as 30 × 30 or often 30 mesh indicates a square mesh, while a designation such as
70 x 30 mesh indicates rectangular mesh. This term is being replaced by the API screen number.
NOTE See 9.6 for further information.
3.1.8
backing plate
support plate attached to the back of screen cloth(s)
3.1.9
baffle
plate or obstruction built into a compartment to change the direction of fluid flow
3.1.10
barite
baryte
natural barium sulfate (BaSO ) used for increasing the density of drilling fluids
NOTE International Standards require a minimum specific gravity of 4,20 for barite, but do not specify that the
material must be barium sulfate. Commercial ISO 13500 barite can be produced from a single ore or a blend of ores, and
can be a straight-mined product or processed by flotation methods. It can contain accessory minerals other than barium
sulfate (BaSO ). Because of mineral impurities, commercial barite can vary in colour from off-white to grey to red or brown.
Common accessory minerals are silicates such as quartz and chert, carbonate compounds such as siderite and dolomite,
and metallic oxide and sulfide compounds.
3.1.11
blinding
reduction of open area in a screening surface caused by coating or plugging
3.1.12
bonding material
material used to secure screen cloth to a backing plate or support screen
2 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
3.1.13
centrifugal pump
machine for moving fluid by spinning it using a rotating impeller in a casing with a central inlet and a tangential
outlet
NOTE The path of the fluid is an increasing spiral from the inlet at the centre to the outlet, tangent to the impeller
annulus. In the annular space between the impeller vane tips and the casing wall, the fluid velocity is roughly the same as
that of the impeller vane tips. Useful work is produced by the pump when some of the spinning fluid flows out of the casing
tangential outlet into the pipe system. Power from the motor is used to accelerate the fluid entering the inlet up to the
speed of the fluid in the annulus. Some of the motor power is expended as friction of the fluid in the casing and impeller.
3.1.14
centrifuge
device, rotated by an external force, for the purpose of separating materials of various masses (depending
upon specific gravity and particle sizes) from a slurry to which the rotation is imparted primarily by the rotating
containing walls
NOTE In a weighted drilling fluid, a centrifuge is usually used to eliminate colloidal solids.
3.1.15
check section
suction section
last active section in the surface system which provides a location for rig pump and mud hopper suction, and
ideally is large enough to check and adjust drilling fluid properties before the drilling fluid is pumped downhole
3.1.16
clay mineral
soft variously coloured earth, commonly hydrous silicate of alumina
NOTE Clay minerals are essentially insoluble in water but disperse under hydration, grinding, heating or velocity
effects. Particle sizes of clay mineral can vary from sub-micrometre to larger than 100 µm.
3.1.17
clay particle
colloidal particles of clay mineral having less than 2 µm equivalent spherical diameter
cf. colloidal solid (3.1.20)
3.1.18
coating
〈substance〉 material adhering to a surface to change the properties of the surface
cf. blinding (3.1.11)
3.1.19
coating
〈physical process〉 procedure by which material forms a film that covers the apertures of the screening surface
cf. blinding (3.1.11)
3.1.20
colloidal solid
particle of diameter less than 2 µm
NOTE This term is commonly used as a synonym for clay particle size.
ISO 13501:2005(E)
3.1.21
conductance
permeability per unit thickness of a static (not in motion) shale-shaker screen
1)
NOTE It is expressed in units of kilodarcies/millimetre.
3.1.22
cuttings
formation pieces dislodged by the drill bit and brought to the surface in the drilling fluid
NOTE Field practice is to call all solids removed by the shaker screen “cuttings,” although some can be sloughed
material.
3.1.23
D100 separation
particle size, expressed in micrometres, determined by plotting the percentage of aluminium oxide sample
separated by the test screen on the plot of cumulative mass fraction (as percent) retained versus U.S. Sieve
Opening (expressed in micrometres) for the sieve analysis of the aluminium oxide test sample
NOTE 100 % of the particles larger than the D100 separation are retained by the test screen.
3.1.24
decanting centrifuge
centrifuge which removes solids from a feed slurry by rotating the liquid in cylindrical bowl at high speed and
discharges the larger particles as a damp underflow
NOTE Colloidal solids are discharged with the liquid overflow, or light slurry. The decanting centrifuge has an internal
auger that moves solids that have settled to the bowl walls out of a pool of liquid and to the underflow.
3.1.25
density
mass divided by volume
NOTE 1 In the SI system, density is expressed in kilograms per cubic metre (kg/m ); In United States Customary units
it is expressed as pounds per gallon (lb/gal) or pounds per cubic foot (lb/ft ).
NOTE 2 Drilling fluid density is commonly referred to as “drilling fluid weight” or “mud weight.”
3.1.26
desander
hydrocyclone, having an inside diameter of 152 mm (6 in) or larger, that removes a high proportion of the
particles of diameter 74 µm and larger from a drilling fluid
3.1.27
desilter
hydrocyclone having an inside diameter less than 152 mm (6 in)
3.1.28
dilution
method of decreasing the drilled-solids content of a slurry by addition of a material(s) other than drilled solids,
usually a clean drilling fluid

1) The darcy is not an SI unit. The SI unit of permeability to fluid flow is defined as the amount of permeability that
3 2
permits 1 m of fluid of a viscosity of 1 pascal per second to flow through a section 1 m thick with a cross section of 1 m in
1 second at a pressure difference of 1 pascal. That unit has no special name. The SI unit of permeability = 1,013 25 × 10
darcy.
4 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
3.1.29
dilution factor
ratio of the actual volume of clean drilling fluid required to maintain a targeted drilled-solids concentration to
the volume of drilling fluid required to maintain the same drilled-solids fraction over the same specified interval
of footage with no drilled-solids removal system
3.1.30
drilled solids
formation solids which enter the drilling-fluid system, whether produced by the drill bit or from the side of the
borehole
3.1.31
drilled-solids fraction
average volume fraction of drilled solids maintained in the drilling fluid over a specified interval of footage
3.1.32
drilled-solids removal system
all equipment and processes used while drilling a well that remove the solids generated from the hole and
carried by the drilling fluid
NOTE These processes include settling, screening, desanding, desilting, centrifuging and dumping.
3.1.33
drilled-solids removal system performance
measure of the removal of drilled solids by surface solids-control equipment
NOTE The calculation is based on a comparison of the dilution required to maintain the desired drilled-solids content,
with that which would have been required if none of the drilled solids were removed.
3.1.34
drilling fluid
any liquid or slurry pumped down the drill string and up the annulus of a hole during the drilling operation
3.1.35
eductor
〈fluid stream〉 device utilizing a fluid stream discharging under high pressure from a jet through an annular
space to create a low pressure region
NOTE When properly arranged, it can evacuate degassed drilling fluid from a vacuum-type degasser or pull solids
through a hopper.
3.1.36
eductor
〈pressure jet〉 device using a high velocity jet to create a low pressure region (Bernoulli Principle) which draws
liquid or dry material to be blended with the drilling fluid
3.1.37
effluent
discharge of liquid, generally a stream, after some attempt at separation or purification has been made
3.1.38
equalizer
opening for flow between compartments in a surface fluid-holding system which allows all compartments to
maintain the same fluid level
3.1.39
flow capacity
rate at which equipment, such as a shaker, can process drilling fluid and solids
NOTE It is a function of many variables, including shaker configuration, design and motion, drilling fluid rheology,
solids loading, and blinding by near-size particles.
ISO 13501:2005(E)
3.1.40
flow line
piping or trough which directs drilling fluid from the rotary nipple to the surface drilling-fluid system
3.1.41
flow rate
volume of liquid or slurry which moves through a pipe in one unit of time
NOTE It is expressed as cubic metres per minute, gallons per minute, barrels per minute, etc.
3.1.42
foam
〈phase system〉 two-phase system, similar to an emulsion, in which the dispersed phase is air or gas
3.1.43
foam
〈floating material〉 bubbles floating on the surface of the drilling fluid
NOTE The bubbles are usually air-cut drilling fluid but can be formation gasses.
3.1.44
gumbo
cuttings that agglomerate and form a sticky mass as they are circulated up the wellbore
3.1.45
head
height that a fluid column would reach in an open-ended pipe if the pipe were attached to the point of interest
NOTE The head at the bottom of a 300 m (1 000 ft) well is 300 m (1 000 ft), but the pressure at that point depends
upon the density of the drilling fluid in the well.
3.1.46
high specific gravity solids
solids added to a drilling fluid specifically to increase drilling-fluid density
NOTE Barite (specific gravity = 4,2) and haematite (specific gravity = 5,05) are the most common.
3.1.47
hook strip
hooks on the edge of a screen section of a shale shaker which accept the tension member for screen
mounting
3.1.48
hopper
mud hopper
large funnel- or coned-shaped device into which dry components are poured to uniformly mix the components
with liquids or slurries that are flowing through the lower part of the cone
3.1.49
hydrocyclone
cone
cyclone
liquid-solids separation device utilizing centrifugal force for settling
NOTE Fluid enters tangentially and spins inside the hydrocyclone The heavier solids settle to the walls of the
hydrocyclone and move downward until they are discharged at the hydrocyclone apex. The spinning fluid travels partway
down the hydrocyclone and back up to exit out the top of the hydrocyclone through a vortex finder.
6 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
3.1.50
impeller
spinning disc in a centrifugal pump with protruding vanes used to accelerate the fluid in the pump casing
3.1.51
manifold
length of pipe with multiple connections for collecting or distributing drilling fluid
3.1.52
Marsh funnel viscosity
funnel viscosity
viscosity measured with the instrument used to monitor drilling fluid
NOTE A Marsh funnel is a tapered container with a fixed orifice at the bottom so that, when filled with 1 500 cm of
fresh water, 946 cm (one quart) will drain in 26 s. It is used for comparison values only and not to diagnose drilling fluid
problems. See ISO 10414-1 (API RP 13B-1) and ISO 10414-2 (API RP 13B-2).
3.1.53
mud
slurry of insoluble and soluble solids in either a water, synthetic or oil continuous-phase fluid
cf. drilling fluid (3.1.34).
3.1.54
mud balance
beam-type balance used in determining drilling fluid density
NOTE See ISO 10414-1 and ISO 10414-2.
3.1.55
mud cleaner
combination of hydrocyclones and screens in series with the underflow of the hydrocyclones
NOTE The hydrocyclone overflow returns to the drilling fluid, while the underflow of the hydrocyclones is processed
through a vibrating screen. The screen is usually of size API 150 or finer. The screen solids discharge is discarded while
the liquid and solids passing through the screen are returned to the drilling fluid.
3.1.56
mud compartment
subdivision of the removal, addition or check/suction sections of a surface system
3.1.57
mud gun
submerged nozzle used to stir drilling fluid with a high-velocity stream
3.1.58
near-size particle
particle whose size is close to the size of the openings in the screen through which its passage is under
evaluation
3.1.59
oil-based drilling fluid
drilling fluid in which the continuous phase is not miscible with water, and water or brine is the dispersed
phase
NOTE Oil-based drilling fluids are usually referred to as non-aqueous drilling fluids, or NAF.
ISO 13501:2005(E)
3.1.60
overflow
centrate
discharge stream from a centrifugal separation that contains a higher percentage of liquids than does the feed
3.1.61
particle
discrete unit of solid material that consists of a single grain or of any number of grains stuck together
3.1.62
particle size distribution
mass, or net volume, classification of solid particles into each of the various size ranges as a percentage of
the total solids of all sizes in a fluid sample
3.1.63
plastic viscosity
measure of the high-shear-rate viscosity which depends upon the number, shape and size of solids and the
viscosity of the liquid phase
NOTE Plastic viscosity is calculated by subtracting the 300 r/min concentric cylinder viscometer reading from the
600 r/min concentric cylinder viscometer reading (see ISO 10414-1 and ISO 10414-2).
3.1.64
plugging
wedging or jamming of openings in a screening surface by near-size particles, preventing passage of
undersize particles and leading to the blinding of the screen (see blinding)
3.1.65
possum belly
compartment, or back tank, on a shale shaker into which the flow line discharges, and from which drilling fluid
is either fed to the screens or is bypassed, if necessary
3.1.66
removal section
first section in the surface drilling-fluid system, consisting of a series of compartments to remove gas and
undesirable solids
3.1.67
retort
instrument used to distil oil, water and other volatile material in a drilling fluid
NOTE The amount of volatile fluid is used to determine oil, water and total solids contents as volume fraction percent,
expressed as a percent (see ISO 10414-1 or ISO 10414-2).
3.1.68
sand trap
first compartment and the only unstirred or unagitated compartment in a surface system, and intended as a
settling compartment
3.1.69
screen cloth
type of screening surface woven in square, rectangular or slotted openings
3.1.70
screening
mechanical process resulting in a division of particles on the basis of size by their acceptance or rejection by a
screening surface
8 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
3.1.71
shale shaker
mechanical device that separates cuttings and large solids from a drilling fluid
NOTE The separation methods can include vibrating screens, rotating cylindrical screens, etc.
3.1.72
sieve
laboratory screen with wire-mesh or electronically-punched holes of known dimensions
3.1.73
sieve analysis
classification by mass of solid particles passing through or retained on a sequence of screens with decreasing
aperture sizes
NOTE Sieve analysis can be carried out by wet or dry methods.
3.1.74
slug tank
small compartment, normally adjacent to the suction compartment, used to mix special fluids to pump
downhole
NOTE Slug tanks are most commonly used to prepare a small volume of weighted drilling fluid before a drillstem trip
in and out of the borehole.
3.1.75
suction compartment
〈general〉 any compartment from which a pump removes fluid
3.1.76
suction compartment
〈specific〉 area of the check/suction section that supplies drilling fluid to the suction of the drilling-fluid pumps
3.1.77
sump
pan or lower compartment below the lowest shale-shaker screen
3.1.78
tensioning
stretching of a screening surface of a shale shaker to the proper tension while positioning it within the vibrating
frame
3.1.79
total dilution
volume of drilling fluid that would be built to maintain a specified volume fraction of drilled solids over a
specified interval of footage if there were no solids removal system
3.1.80
total non-blanked area
net unblocked area that will permit the passage of fluid through a screen
NOTE 1 It is expressed in square metres (square feet).
NOTE 2 Some screen designs can eliminate as much as 40 % of the gross screen panel area from fluid flow due to
backing-plate and bonding-material blockage.
3.1.81
trip tank
gauged and calibrated vessel used to account for fill and displacement volumes as pipe is pulled from and run
into the hole
NOTE Close observation allows early detection of formation fluid entering a wellbore and of drilling fluid loss to a
formation.
ISO 13501:2005(E)
3.1.82
underflow
〈centrifugal separator〉 discharge stream from a centrifugal separator that contains a higher percentage of
solids than does the feed
3.1.83
underflow
〈screen separator〉 discharge stream from a screen separator that contains a lower percentage of solids than
does the feed
3.1.84
unoccluded
unobstructed area of a screen opening
3.1.85
unweighted drilling fluid
drilling fluid that does not contain commercial suspended solids added for the purpose of increasing the
density of the drilling fluid
3.1.86
viscosity
ratio of shear stress to shear rate
NOTE 1 In the SI system, viscosity is expressed in pascal seconds (Pa⋅s).
NOTE 2 If the shear stress is expressed in the CGS system (dynes per square centimetre) and the shear rate is
2 −1 −1 −1
expressed in reciprocal seconds, the viscosity is expressed in poise, P. 1 P = 1 dyn·s/cm = 1 g⋅cm ⋅s = 10 Pa⋅s.
3.1.87
volume of solids drilled
volume of solids drilled over a specified interval
3.1.88
vortex
cylindrical or conical shaped core of air or vapour lying along the central axis of the rotating slurry inside a
hydrocyclone
3.1.89
water-based drilling fluid
drilling fluid in which water is the suspending medium for solids and is the continuous phase, whether oil is
present or not
3.1.90
weighted drilling fluid
drilling fluid to which high specific-gravity solids have been added to increase its density
3.1.91
weighting material
high specific-gravity solids used to increase the density of drilling fluids
NOTE This material is commonly barite or haematite, and in special applications may be limestone
10 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
3.2 Symbols and abbreviated terms
ACS American Chemical Society
AlO aluminium oxide (Al O ) having a specific gravity of 3,5 to 3,9
2 3
API American Petroleum Institute
ASTM American Society for Testing and Materials
AWWA American Water Works Association
CAS Chemical Abstracts Service
C conductance of screen cloth, expressed in kD/mm
gal gallon (USC unit of volume)
k dilution factor
kD kilodarcy
lbf/in pounds force per square inch (USC unit of pressure)
m mass of empty container
m mass of container plus sample
m mass of dried/retorted container
USC United States Customary
V volume of total drilling fluid system, expressed in m (gal)
a
V volume of base fluid added to drilling fluid system, expressed in m (gal)
b
3 3
V volume of drilling fluid built, expressed in m (ft )
c
3 3
V volume of solids drilled, expressed in m (ft )
d
3 3
V volume of total dilution, expressed in m (ft )
e
V/t flow rate (volume per time), expressed as m /h, (gal/min)
w mass fraction
w mass fraction of suspended solids removed, expressed as percent
a
w mass fraction of suspended solids in the feed to a piece of separator equipment
w mass fraction of suspended solids in the overflow from a piece of separator equipment
w mass fraction of suspended solids in the underflow from a piece of separator equipment
w mass fraction of weighting material
w mass fraction of low gravity solids, expressed as a percent
η efficiency, drilled solids removal system performance
ϕ base fluid volume fraction of total drilling fluid system (V ) determined by retort and salinity
a a
measurement, expressed as percent
ϕ drilled solids volume fraction of total drilling fluid system (V ) determined by retort, salinity and
b a
bentonite measurement, expressed as percent
3 3
ρ density, kg/ m (lb/gal, lb/ft )
ISO 13501:2005(E)
4 Requirements
4.1 This International Standard is organized such that a method of assessing the performance of an
equipment set is presented first. A procedure for assessing the performance of individual equipment pieces is
then presented. A collection of proven operating guidelines for the equipment and the overall system is then
given. The principles shall be used to design a new system or to modify the operation of the equipment and
removal system on an existing drilling rig, and thereby comply with this International Standard.
4.2 Use of this practice allows direct comparison of the results achieved by modifications made to the
system at the drill site. Improved removal performance can be recognized through lower trouble costs and
improved drilling performance.
4.3 Shale-shaker screen designations and labelling are included as a means for manufacturers to mark
screens in a consistent manner. The screen identification tag describes the equivalent screen aperture
opening, the conductance and the non-blanked area of the screen. Screen manufacturers shall use this
designation to comply with this International Standard.
5 Drilled solids removal — System performance
5.1 Principle
5.1.1 This procedure gives a method to determine the drilled solids removal efficiency by a set of
drilling-fluid processing equipment.
5.1.2 The drilled-solids removal efficiency refers to the volume fraction of drilled rock discarded compared
with the volume of drilled solids generated.
5.1.3 Dumping drilling fluid removes 100 % of the drilled solids but is not a desirable removal method
because of the amount of drilling fluid lost. The solids removal efficiency refers to the ability of the equipment
to reduce the concentration of drilled solids in the system. Dumping drilling fluid does not reduce the
concentration of drilled solids in the system.
5.1.4 The dilution factor (k) is a term created to describe the drilled solids removal system performance. The
drilled solids removal system is defined as all equipment and processes used while drilling a well that remove
the solids generated from the hole and carried by the drilling fluid. These processes consist of dumping of
whole drilling fluid (including lost circulation), settling, screening, desanding, desilting and centrifuging.
Drilled-solids removal system performance is defined as a measure of the removal of drilled solids by surface
solids-control equipment. The dilution factor is calculated by monitoring the amount of base fluid (oil or water)
added to the system and/or the volume of clean drilling fluid added to the system to dilute the remaining drilled
solids after processing the drilling fluid through the solids control equipment.
5.2 Apparatus
5.2.1 Meters
Water meters shall comply with American Water Works Association Standard C705 as referenced in
ANSI/AWWA C700-77.
Metering of oils shall be carried out in accordance with the API Manual of Petroleum Measurement Standards,
Chapter 5. Turbine meter operation is contained in Section 3.
5.2.2 Drilling-fluid density determination apparatus, of sufficient accuracy to permit measurement within
3 3 3
± 0,01 g/cm or ± 10 kg/m (0,1 lb/gal, 0,5 lb/ft ).
The mud balance is the instrument generally used for drilling-fluid density determinations. The mud balance
and procedures are described in ISO 14014-1 or ISO 10414-2.
12 © ISO 2005 – All rights reserved

ISO 13501:2005(E)
5.2.3 Apparatus for water, oil and solids determination.
The apparatus is described in ISO 10414-2.
5.2.3.1 Retort instrument.
5.2.3.2 Liquid receiver.
5.2.3.3 Fine steel wool.
5.2.3.4 High-temperature-resistant silicone grease.
5.2.3.5 Pipe cleaners.
5.2.3.6 Putty knife or spatula.
5.2.3.7 Defoaming agent.
5.2.4 Chloride (salinity) determination apparatus.
The apparatus described in ISO 10414-1 or ISO 10414-2 is appropriate for water-based or oil-based fluids.
5.2.4.1 Silver nitrate solution, as appropriate. (CAS No. 7761-88-8).
5.2.4.2 Potassium chromate indicator solution, 5 g/100 cm . (CAS No. 7778-50-9).
5.2.4.3 Sulfuric or nitric acid solution, standardized 0,02 N (N/50). (CAS No. 7665-93-9 or CAS
No. 7697-37-2).
5.2.4.4 Phenolphthalein indicator solution, 1 g/100 cm of 50 % alcohol in water solution. (CAS
No. 77-09-8).
5.2.4.5 Calcium carbonate, precipitated, chemically pure grade. (CAS No. 471-34-1).
5.2.4.6 Distilled water.
3 3
5.2.4.7 Serological (graduated) pipettes, one of capacity 1 cm and one of capacity 10 cm .
3 3
5.2.4.8 Titrating vessel, of capacity 100 cm to 150 cm , preferably white.
5.2.4.9 Stirring rod.
5.3 Sampling
5.3.1 Remove a one-litre (one quart) sample of drilling fluid from the suction pit following all processing by
solids control equipment.
5.3.2 Clear the sample of any foreign objects, such as leaves or twigs.
5.3.3 Record the well depth or interval at which the measurement is being made.
5.4 Procedure
5.4.1 Suction pit drilling fluid density chloride content, and solids by retort
Measure and record the drilling fluid density chloride content and solids by retort in accordance with
procedures outlined in ISO 10414-1 for water-based drilling fluids or ISO 10414-2 for oil-based drilling fluids.
ISO 13501:2005(E)
5.4.2 Base fluid additions to the drilling fluid
5.4.2.1 Metering devices can provide the actual volume of base fluid used within the accuracy of the
equipment. The most commonly used meters for measuring base fluid consumption are the mechanical
turbine propeller and compound types.
5.4.2.2 Magnetic and Doppler meters are more dependent on suspended solids in fluid streams to
provide volume measurements.
5.4.2.3 The sizing of the meter is critical for accuracy. Tables of acceptable line sizes per volume
throughput are included in the AWWA C700 series standards. These standards are meter body type specific,
so a knowledge of the meter composition is required. The test for all meters should be volumetric or by mass,
if accurate scales are available.
5.4.2.4 Use strainers upstream of the meter and check frequently for clogging.
5.4.2.5 Record the volume of base fluid added to the drilling fluid system, as V . The recorded value shall
b
be within 0,25 % (volume fraction) of the actual volume.
5.4.3 Base fluid fraction
The base fluid fraction is the average value for the interval in question. The averaging method is critical. It is
important to use the same method to enable interval and well comparisons.
Using different averaging methods can result in inaccurate comparisons. The base fluid fraction can be
calculated from solids analysis methods using retort and salinity measurements, as outlined in ISO 10414-1.
Record the base fluid fraction as ϕ .
a
5.4.4 Drilled solids fraction
5.4.4.1 The drilled-solids fraction can be calculated by several methods, from simple solids analysis
which correct for salinity and bentonite concentrations to complex material balance methods which correct for
additional components such as commercial additives.
5.4.4.2 The drilling-solids fraction is averaged for the interval, therefore, the averaging method is critical.
Sensitivity studies of the effect of the drilled-solids fraction on the final dilution factor show that a significant
variance is possible when using different methods of averaging. Comparisons are valid only when using
identical averaging methods.
5.4.4.3 Select the desired method of determining the drilling-fluid components, and perform the analyses.
5.4.4.4 Calculate the drilled-solids fraction, and record as ϕ .
b
5.4.5 Volume of drilling fluid built
The volume of drilling fluid built is determined from the base fluid v
...