SPE-159894-PA-P.pdf

Criticality Testing of Drilling-Fluid
Solids-Control Equipment
Bodil Aase, SPE, Tor Henry Omland, SPE, Ellen Katrine Jensen, Anne Turid Lian Vestbakke,
Bjarte Sivert Knudsen, Frode Haldorsen, Arvid Nysted, Eystein Ove Storslett, Iren Steinnes,
Einar Knut Eliassen, Jørund Enger, Øyvind Lie, and Vegard Peikli, SPE, Statoil ASA
Summary
Correct selection and use of solids-control equipment are essential
in not only maintaining drilling fluid at its desired properties but
also in avoiding the generation of unnecessary waste streams dur-
ing drilling.
Since the early 1930s, the shale shaker has been the dominant
device for primary-solids removal. Additional equipment (e.g.,
desilters, desanders, and centrifuges) was often used in the past to
maintain proper solids control, but experience in recent years has
demonstrated that, although dependent on correct operational pro-
cedures, several types of shale shakers have sufficient perform-
ance to act as the sole solids-control devices without the use of
desanders and desilters.
Despite often being the only measure for solids removal, the
selection of shale shakers, the screening, and the establishment of
operational procedures are often based on biased information
(Dahl et al. 2006). In addition, it has been recognized that methods
and criteria for the verification of shale shakers have not been suf-
ficiently qualified and standardized. To address this, a multidisci-
plinary verification test of various solids-control concepts has been
conducted. The objective of the test has been to verify equipment
performance in a standardized, onshore test facility related to
Oil-mist and vapor emission
Ventilation (to obtain a satisfactory working environment)
Flow-handling capacity with various drilling fluids
Leakage rate (i.e., the volume of fluid bypassing the filtration
screen)
Lost-circulation-material feature
Noise and vibration level
Maintenance and equipment robustness
Feature for running lost-circulation-material reclamation
The tests were all planned and run in close cooperation with
the equipment suppliers to ensure test-objective alignment. Sev-
eral findings were made throughout the test period that provided
vital information for design improvements and increased the
industry’s competence with respect to solids control.
Introduction
Drilling operations highly depend on reliable equipment to per-
form efficient drilling operations. Suitable drilling-fluid quality,
efficient solids removal, and low waste production (Bouse and
Carrasquero 1992), as well as health, safety, and environment
(HSE) [especially of the working environment (WE) in the shaker
room], are all aspects relevant for the selection and skilled opera-
tion of solids-control equipment in the oil industry. “Shale shaker”
is referred to as “shaker” in the rest of this publication.
When acquiring new equipment, a crucial part of the prepara-
tion is to perform a market screening. The information collected
during this phase has historically been based on data obtained from
nonstandardized test conditions because it is challenging to provide
a test facility representing a true circulation system or impossible
to obtain equal test conditions, which is the case when performing
tests at a rigsite. When various pieces of solids-control equipment
are tested in different test facilities and with various drilling fluids,
screen configurations, and other test conditions [temperatures, for-
mations, and heating, ventilation, and air-conditioning (HVAC)
systems], it is difficult to compare test results. Examples of irrele-
vant test conditions are the smoke tests of a shaker without drilling
fluid and capacity tests with water instead of drilling fluid.
Because of the criticality of equipment selection, this verifica-
tion test of solids-control equipment has been performed to pro-
vide an offshore drilling and production rig with an objective
basis for equipment selection. The test has been performed as part
of an ongoing rig-upgrade project. The objective of this test has
thus been to verify equipment supplier’s specification on parame-
ters essential for solids-control-equipment performance. In the
test, five different solids-control solutions (or shakers) were
tested. Four conventional shakers and one alternative solids-con-
trol-equipment unit with vacuum technology were tested. The tra-
ditional shakers include one double-deck shaker and three triple-
deck shakers. The shakers are tested at equal conditions (as is
practically possible), with the only changing factor being the
equipment itself. Three main areas of shaker performance were
tested—capacity and filtration efficiency, operation and mainte-
nance friendliness, as well as HVAC and WE.
The shaker test was a multidisciplinary test and is a result of
cooperation between 13 companies. The companies are consul-
tants, equipment suppliers and their distributors, the test center,
and the operator. This cooperation between several discipline
groups has given comparable test results for several aspects of a
shaker’s performances, and consequently creates a unique data-
base for the testing of equipment at the same conditions. The test
also demonstrates the importance of focus on solids-control-
equipment performance to obtain high drilling efficiency and sat-
isfactory HSE conditions.
This paper describes in detail the consequences that proper
testing has on solids-control-equipment selection, how each ele-
ment important for shaker selection was tested, and the results
obtained from the test
Statement of Theory and Definitions. There is an economic in-
centive to base solids-control-equipment selection on reliable tests
because efficient shakers will reduce drilling-fluid loss and waste
generated resulting from drilling-fluid adherence on cuttings. Effi-
cient drilling-fluid solids control may also reduce the risk for the
breakdown of drilling equipment. Significant savings may be
gained by running the equipment efficiently, and it is therefore
crucial to continuously monitor and optimize the solids-control-
equipment operations with respect to such details as screen wear,
screen selection, and flow distribution. Optimization studies (Dahl
et al. 2006) have demonstrated the importance of the operator’s
skills and routines for the inspection, changing, patching, and
washing of screens and the appropriate use of the regulation possi-
bilities of the equipment. When the efficiency of the shaker is
considered as part of the procurement and good operational rou-
tines are implemented and maintained, the drilling cost for the
well will be lower.
Description and Application of Equipment and Process. The
test methodology has been established through cooperative work
Copyright VC 2013 Society of Petroleum Engineers
This paper (SPE 159894) was accepted for presentation at the SPE Annual Technical
Conference and Exhibition, San Antonio, Texas, USA, 8–10 October 2012, and revised for
publication. Original manuscript received for review 9 July 2012. Revised manuscript
received for review 21 November 2012. Paper peer approved 14 January 2013.
148 June 2013 SPE Drilling & Completion
between, and written by, discipline specialists to ensure the qual-
ity and relevance of the applied methodology. Step-by-step proce-
dures were made and followed for each of the tests for all tested
equipment.
The shaker test was performed at an onshore test center that
can simulate the circulation system at a drilling rig. The test cen-
ter is set up to provide equal test conditions for all aspects. The
test center was also equipped with real-time monitoring instru-
ments that continuously collected data for both drilling-fluid prop-
erties (flow rate, specific gravity, temperature, and circulating
volume) and HVAC flow rates. The evaporation level of volatile
organic compounds (VOCs) was monitored by portable VOC-
monitoring instruments, and the VOC instruments were not an
integrated part of the test center and were used on WE tests only.
The total pump capacity of the test center’s drilling-fluid-circula-
tion system is 4050 L/min (LPM).
The four conventional shakers were installed in the test cell
simulating a shaker room on a rig. The approximate size of the
test cell is 5 Â5 Â3 m. The test cell is equipped with a fully ad-
justable HVAC system that can give ventilation flow rate in the
range of 0 to 12 000 m
3
/h, and the test cell has 12 air changes per
hour. However, a droplet separator was installed in the HVAC
system during the test period because of heavy drilling-fluid pol-
lution during the test period. The droplet separator prevented fur-
ther pollution but caused pressure loss, and the highest achieved
ventilation flow rate in the HVAC system after the installation of
the droplet separator was 7500 m
3
/h.
The alternative solids-control equipment with vacuum was
tested in an adjacent test cell that was tailor-made for this unit;
the only difference between the two test cells was that this test
cell was equipped with only ordinary room ventilation.
The test conditions were kept as equal as practically possible
throughout the test. The field-used oil-based drilling fluid used in
the test was from the same batch and was stored in a reserved
tank, circulated, and maintained during the test period. The water-
based drilling fluid used in the test was newly mixed for each
shaker because the durability of the water-based drilling fluid
degrades rapidly and the drilling-fluid properties would change
during the test period. Analysis confirmed that the drilling fluids
used to test the five shakers were comparable and as similar as
practically possible. Test temperatures were 50

C for water-based
drilling fluid and 60

C for oil-based drilling fluid.
Sand was added to the drilling fluid to simulate cuttings
because this is close to inert and would therefore not blend into
the drilling fluid. The sand used in the test was from the same
batch, and its particle-size distribution (PSD) was chosen to fit the
aperture of screens used on the lowest shaker deck during the tests
[Americal Petroleum Institute (API) 170]. The PSD of the test
sand was also representative of the particle size of sandstone for-
mations that are typically drilled in the North Sea by the operator
(Fig. 1). Because the PSD curve of the test sand fits in the middle
of the PSD curves of other sandstone formations that the operator
has drilled in the North Sea, Fig. 1 illustrates that the test sand
should be highly representative of the challenges the screens are
facing during a drilling operation in the field.
Drilling-Fluid-Processing Capacity. To determine the maxi-
mal capacity of the shakers, the flow rate of the circulating dril-
ling fluid was increased in steps while sand was added in each
Brage Stam Model Sand 31/4-a2 #56
Brage 31/4-A-13-T2 #169 Not tested
Camilla_Belinda/Fram 35/11-2 p25 v
Fram Model Sand 35/11-9 #110
Fram Model Sand 25/11-8S #107
Grane Model Sand
Klegg 25/4-9S @ 2241.90 m
Njore 6407/7-4 @ 2983.00 m
Njore 6407/7-4 @ 3087.05 m
Ormen Lange Br6305/5-1 2742,05 m
Oseberg Alfa Model Sand 271
Oseberg J-Structure 30/9-15, p32+33
Oseberg South J-Structure 30/9-15, p22+23+24
Oseberg South 30/9-6, Model Sand 202
Oseberg Vestflanken 30/6-18 @ 3181,30 m
Oseberg Vestflanken 30/6-26 @ 2710.50 m
Oseberg South 30/9-F-6 plugg 94 V
Telemark @ 22719,3 ft
Telemark @ 22743,3 ft
Telemark @ 22749,3 ft
Troll 31/5-J-41 1581.60 m
Troll 31/5-J-41 1586.25 m
Troll M Sand
Tune Model Sand 30/5-2
Tune Model Sand 30/8-1 s
Vale 25/4-6S @ 3848,12 m
Visund Stam Model Sand 194
Visund Stam Model Sand 229
Nord Westflanken 6407/7-6 @ 3805,50 m
Angola Well 4-41-1 @ 1895,15 m
Angola Well 4-41-1 @ 1887,80 sieved at 2 mm
Colette 6507/11-6 @ 3039.75 m
Troll M-sand 1586, 1m 31/2-L41
Troll C-sand @1905,25, 32/2-E6H
Shaker Test Sand, Percent
100
90
80
70
60
C
u
m
.

v
o
l
%
50
40
30
20
10
0
0 0 1 0 1 1
Grain size, µm
1000 10000
Shaker
test
sand
Fig. 1—PSD of test sand (bold, black line) and the sandstone formations drilled in by the operator, mostly in the North Sea.
June 2013 SPE Drilling & Completion 149
step to keep the same sand content, 1.9% weight/weight (W/W).
This represents a drilling rate of 40 to 50 m/h in a 17 1/2-in. hole.
The flow rate of drilling fluid above the shaker was increased until
the shaker flooded, and the flow rate was decreased until the cut-
tings thrown off from the shaker stabilized, and the maximal
capacity of the shaker was determined to be equal to the flow rate
at this stage.
The three main areas that have been focused on in the shaker
test are capacity and filtration efficiency, operation and mainte-
nance friendliness, and HVAC and WE; how these areas have
been examined is described in the following paragraphs. All
details of the test procedures and test results are not included in
this publication because the testing was so comprehensive.
The shaker-screen configuration also has a significant impact
on capacity (Dahl et al. 2006). To obtain equal test conditions for
all the shakers, the filtration screens were set to have a cutpoint
equal to API 170 (API 2010). For double- and triple-deck shakers,
the manufacturers were allowed to optimize the upper deck(s)
screen configuration to obtain maximal flow because this has no
effect on the fluid quality being filtered through the filtration
screen.
Filtration Efficiency. Samples of drilling fluid from the shak-
ers’ outlet and inlet and of cuttings from the shakers throw-off
were collected at maximal capacity. The drilling-fluid and cut-
tings samples were collected according to a specific sampling and
analysis program, and they are the basis for the assessment of the
shakers’ filtration efficiency. The drilling-fluid samples were ana-
lyzed with particle-size-analysis instruments—Malvern Master-
sizer 2000 (Malvern) and Lasentec Focused Beam Reflectance
Measurement Instrument (FBRM)—whereas the cuttings samples
were analyzed by retort to determine the adherence of drilling
fluid on the cuttings.
Adherence of Drilling Fluid on Cuttings. The filtration effi-
ciency of the shaker is also expressed in the ability to minimize the
loss of drilling fluid as adherence on cuttings. Samples of cuttings
from the shakers’ throw-off were collected at maximal capacity.
The adherence of drilling fluid in the cuttings samples was meas-
ured by the retort analysis of cuttings, and the parameter is oil on
cuttings (OOC). Measurements from the 1990s show a normal
OOC content of 5 to 15% W/W. The analysis results of these tests
are indicative only because of the challenges of collecting repre-
sentative samples and the uncertainty in the analysis method itself.
Screens. To ensure and maintain good filtration and the stable
properties of the drilling fluid, it is important that the screens have
a durable design to resist abrasive wear and fatigue caused by
vibration. The reduced function of the screens may have both
technical and economic impact. When holes occur in the screens,
several negative effects may be observed. Holes in screens coun-
teract cuttings removal. Holes in screens allow cuttings to be
recirculated in the drilling fluid, and the cuttings are degraded into
finer particles as they pass the pumps and re-enter the well. The
finer cuttings give reduced drilling-fluid quality such as excessive
viscosity and a higher loss of fluids over the solids-control equip-
ment. The surface area of the cuttings increases when larger cut-
tings are degraded into many finer particles, and, consequently,
the adherence of drilling fluid on the particles increases. When,
and if, the finer particles eventually can be screened out over the
shale shaker, the results are more drilling fluid lost as adherence
on cuttings and more drilling waste to handle.
The maximal processing capacity and filtration efficiency of
the shaker should be related to screen wear because holes in the
filtering screens might give a higher maximal capacity and a
reduced filtering efficiency. New or fully repaired screens were
installed at the startup of the capacity tests to ensure representa-
tive capacity and filtration results.
Screens were inspected before and after test runs as part of the
test procedures; the API size and the general condition of the
screens were observed before and after each test. Number and
type of holes, tendency to corrosion, clogging, patching method,
and user friendliness of the screens were noted. A post-analysis of
shaker-screen wear was made with optical techniques.
Leakage. The primary function of solids-control equipment is
to remove solids from the circulating fluid. To ensure good solids
removal, it is essential that the drilling fluid returning from the
well pass through the shaker screens and not through leakages in
the shakers. Although drilling fluid is designed to seal off fissures
in the well, and will seal off fissures in the shaker as well, drilling
fluid may bypass the shaker screens by means of alternative flow
routes. The result is reduced solids removal, and low-gravity sol-
ids will be pumped into the well again, thus reducing the quality
of the drilling fluid. The leakage tests were performed by instal-
ling blinded screens in the shaker, filling the shakers with water,
and observing how fast the water was leaking out from the shak-
ers. The leakage test was performed with the shaker turned off
(static-leakage test) and with the shaker running (dynamic-leak-
age test).
The shaker derived from vacuum technology has a rotational
screen; thus, the same leakage-test procedure as for the conven-
tional shakers could not be applied for the vacuum shaker. An al-
ternative procedure was applied on the vacuum shaker in which
leakage between the blinded, rotational screen and the side of the
shaker was examined for the same time interval. Because of dif-
ference in technology, the leakage test could be performed only in
static mode for the vacuum-based shaker.
LCM Recovery. Experience has shown that adding lost-circu-
lation material (LCM) to the drilling fluid can significantly
improve the formation strength (Aston et al. 2004). One of the
practical means for maintaining the correct particle content and
size distribution has led to the development of multiple-deck
shakers that enable the possibility of recirculating particles of a
specific size range back to the drilling fluid (Omland et al. 2007).
By use of this function, the recovered LCM material may be used
again, and the addition of LCM material to the drilling fluid for
each cycle into the well can be avoided. The recycling of the
LCM material has both economic and environmental benefits.
Operation and Maintenance Friendliness. Because the
shaker operator is the primary stakeholder for proper solids con-
trol, user-friendliness and maintenance checks were performed.
This would include an analysis of parameters such as accessibility
to critical components, ease of screen replacements, and ease of
cleaning. The operation- and maintenance-friendliness checks of
the shakers were performed by a maintenance specialist who
assessed these aspects while the shakers were installed and run-
ning in the test center.
HVAC and WE. The shaker room is one of the hot spots for
personnel exposure to chemicals on the drilling rig (Steinsva˚g
et al. 2005, 2011). In the WE part of the test, the compounds in
the test cell were measured with different flow rates of drilling
fluid and HVAC system, and different solutions of enclosure of
the shakers. The WE test was closely linked to the HVAC test.
The organic compounds measured during the shaker test are oil
vapor (OV), oil mist (OM), and VOC. To obtain an acceptable
WE in shaker rooms, various solids-control solutions have differ-
ent ventilation requirements. For each of the tests with oil-based
drilling fluid, analyses were performed detecting the VOC, OV,
and OM levels in the test cell as a function of air-flow rate.
The basis for the test was to use the manufacturer’s standard
shaker products. However, several of the manufacturers supplied
their shakers with custom-made front hoods during the test period
to improve their standard product. Customizations were also per-
formed for some of the hoods to improve the test results.
HVAC. Most of the shakers participating in the test had a
front hood or other solutions for enclosure as a means to limit the
diffusion of compounds in the working atmosphere. The front
hoods and enclosures demonstrate some of the technology devel-
opment caused by the shaker test because front hoods are not
common equipment on shakers. Only one of the tested shakers
delivered a front hood to the test that was already standard equip-
ment and not designed especially for the shaker test. Another sup-
plier manufactured a provisional front hood during the test, and
one shaker included a prototype enclosure. The alternative shaker/
filtering unit derived from vacuum technology has a fully
150 June 2013 SPE Drilling & Completion
enclosed design, and there was no need for further improvements.
And finally, one supplier designed a front hood and tested it after
the shaker test was finished. The front hoods and enclosures from
the different suppliers display diversity of design, but the solu-
tions all have the common purpose to cover openings in front of
and above the shaker to limit diffusion into the shaker room and
to facilitate the extraction of compounds through the HVAC
system.
WE. The objective of the WE test was to verify if the supplier
recommended that HVAC flow rate was sufficient to achieve an
acceptable chemical exposure in close proximity to the shaker.
The levels of VOC, OV, and OM were measured to quantify the
chemical exposure of the WE.
An alternative test methodology was used to carry out the WE
and HVAC tests. The procedure was derived from the parallel use
of the conventional OV/OM sampling with subsequent laboratory
analyses, and a real-time monitoring instrument for VOC. The
test setup required immediate feedback; thus, it was significantly
important to include real-time monitoring to enable the navigation
of variables. Comparing OV/OM results from laboratory analyses
with real-time VOC monitoring represents a new methodology
and a possible technology development.
The OV/OM-sampling method is the standard method accord-
ing to National Institute for Occupational Safety and Health
(NIOSH)/Norwegian National Institute of Occupational Health
(STAMI). The sampling assembly consisted of a membrane-sam-
pling pump that pumped the test-cell air first through a charcoal
tube for collection of OV and second through a filter for collection
of OM at a pump rate of 1.4 LPM. The equipment pieces used to
sample OV and OM were sampling pump SKC EX, charcoal
tubes SKC 226-01, and 37-mm Millipore filter cassettes. The
Millipore filter cassettes were loaded with glass fiber and cellu-
lose-acetate filter. The pump flow rate was measured before and
after sampling with the Bios Defender 717-510MA electronic
flowmeter. Sampling time was 1 hour to avoid overexposure of
the filter. Two parallel samples were taken at each sampling
point—in front of and on the right side of the shaker. The charcoal
tubes and the filters were stored in airtight containers and sent to
an external laboratory where one dedicated chemist extracted and
analyzed samples by high-performance liquid chromatography.
Consequently, it took weeks until the levels of OV and OM were
known; thus, that information was impossible to use as a naviga-
tional tool to determine the next step in the test.
The direct-reading instrument for VOC (MiniRAE 3000 pho-
toionization detector, Rae Instruments) was used to analyze the
variations in the concentrations of organic vapor. Sampling points
were in front of and on the right and left sides of the shaker, and
they produced real-time data and displayed the level of VOC im-
mediately. The MiniRAE indicated whether the HVAC flow rate
was sufficient or not, and consequently the output from the Mini-
RAE was decisive for settling the next step in the WE test on the
basis of the shakers performance at the current drilling-fluid and
HVAC flow rates.
The WE tests were conducted after the maximal capacity of
the shaker had been determined, at 90% of maximal drilling-fluid-
flow rate. The WE test started with the HVAC flow rate as speci-
fied by the supplier, and the HVAC flow rate was increased or
decreased according to the VOC readings from the MiniRAE de-
tector. The OM/OV method was first used to document the levels
at the supplier’s specification for HVAC flow rate, and second
used to document at which HVAC flow rate the OV/OM were at
an acceptable or lowest possible level.
The acceptance criteria (AC) for OV and OMare given as occu-
pational exposure limits (OELs). The operator’s OELs applicable
for Norway are given in Table 1. Currently, there is no specific
limit or AC for the measured VOC level, but for evaluation pur-
poses in this project, 30 ppm was used as the acceptance criterion.
However, the operator’s design criterion is one-sixth of that value.
Noise and Vibration. Specific noise and vibration analyses
were performed with the equipment running in normal operating
mode. If different operation settings were possible, the noise tests
were to cover all relevant operation conditions including running
dry. Noise measurements were carried out with ventilation extrac-
tion as specified by the supplier. The tests were performed with
90 and 100% of maximal-capacity fluid flow, and with the shakers
running without drilling fluid.
According to the operators’s WE requirements, the area noise-
level limit for a shaker area is 85–90 dBA (dB A-weighted).
Where the lower limit is unfeasible, a maximal area noise-level
limit of 90 dBA shall apply. The reason for unfeasibility of 85
dBA shall be documented. The operator’s requirement for A-
weighted noise exposure level normalized to a nominal 12 h
working day is L
EX,12h
¼ 83 dBA. Sound power level (SWL) was
measured according to the standard ISO 9614-2. Sound pressure
level (SPL) at a 1.0-m distance from the unit was derived from
the measured SWL.
Vibration measurements were carried out on the shaker skid
(primary structure) to evaluate vibration-transmission effects. The
mean value of the vibration level of all the support points is given
in octave bands from 31.5 to 2,000 Hz (structural noise/vibra-
tions) and in third octave bands from 1 to 80 Hz (human
vibrations).
Presentation of Data, Results, and Discussions. According to
agreements with the shaker suppliers, all performance results are
presented anonymously, and please note that the results presented
in the charts cannot be related to a specific shaker. The perform-
ance results displayed on the y-axis of the plot are randomly dis-
tributed on the x-axis, and the results illustrate the diversity in
performance.
Drilling-Fluid-Processing Capacity. The results from the
capacity test illustrate that oil-based drilling fluids typically are
easier to process than water-based drilling fluids, and all shakers
except one obtained a higher capacity with oil-based drilling fluid
(Fig. 2). The highest flow rate for oil-based drilling fluid is 3950
LPM, and the highest for water-based drilling fluid is 3320 LPM.
One shaker has a pronouncedly higher processing capacity than
the other shakers. The lowest drilling-fluid processing rates are
1150 LPM for oil-based and 900 LPM for water-based drilling
fluid.
Please note that the maximal capacities found on the shaker
test represent maximal flow for the drilling fluids used in the
shaker test. The variation of the results indicates a difference in
the drilling-fluid-processing capacity of the participating shakers.
TABLE 1—AC OF OV, OM, AND VOC
AC OV 30 mg/m
3a
OM 0.6 mg/m
3a
VOC 30 ppm
b
a
The measured levels of OM/OV are adjusted for a 12-hour offshore schedule.
For an 8-hour shift, the OELs are 1 and 50 mg/m
3
, respectively.
b
For VOC, there are no official OELs. For evaluation purposes in this project, 30
ppm was used as the acceptance criterion.
4500
4000
3500
3000
2500
2000
1500
500
0
Shakers-random Order, different in every Figure
Capacity Test
WBM
OBM
D
r
i
l
l
i
n
g

F
l
u
i
d

F
l
o
w

R
a
t
e
,
l
i
t
e
r
s
/
m
i
n
u
t
e
1000
Fig. 2—Maximal capacities for oil-based drilling fluid and water-
based drilling fluid (WBM) for the various solids-control
equipment.
June 2013 SPE Drilling & Completion 151
Filtration Efficiency. The analysis of PSD was performed to
assess the filtration efficiency of the shakers. In the beginning, the
PSD analysis was performed with the Malvern instrument, and
the D 90 results of the PSD analysis are shown in Fig. 3. As dril-
ling fluids are added with significant amounts of weighting mate-
rial that has the majority of particles in the lower size range (less
than 70 lm), this would mask the filtration-efficiency results. The
samples of drilling fluid were therefore prepared for analysis by
the removal of the largest and smallest particles by sieving
because the instrument provided relative measurements of the
number of particles only.
The results from the Malvern analysis were, however, incon-
clusive; only minor differences in PSD from the drilling fluid
going into the shaker (inlet) and coming out from the shaker (out-
let) were found. This is a result of the huge number of barite par-
ticles in the fluid, thus masking the true PSD of the drilling-fluid
samples (Fig. 3).
Because of the inaccurate data representation with the Malvern
instrument providing relative PSD only, it was decided to analyze
PSD with the FBRM. This instrumentation has been used exten-
sively at both laboratory and field conditions and has demon-
strated accurate particle-sizing measurements. The FBRM also
provides the possibility of representing the particle count for the
specific size range of interest.
The advantage demonstrated by the FBRM analysis indicates
that this instrument should be used more in future PSD analysis,
and this experience may be useful for both drilling operations and
further research projects.
The drilling-fluid samples analyzed by FBRM were samples
parallel to the ones analyzed by the Malvern instrument. With
API 170 screens on the lowest shaker deck, it is expected to
achieve a D100 separation from the drilling fluid of the particles
larger than 82.5 to 98.0 lm (API 2010); see the PSD results in
Figs. 4 through 6.
The blue columns represent the drilling fluid coming into the
shaker (inlet), and the red columns represent the filtered drilling
fluid coming out of the shaker (outlet). The particle counts from
the outlet samples (red columns) in Figs. 4 through 6 are of most
interest, being taken from filtered drilling fluid.
The blue columns in Figs. 4 through 6 that represent the dril-
ling fluid coming into the shaker (inlet) display, thus, varying the
content of particles (barite and sand). The variation in solids load-
ing in the inlet-samples content may have been caused by differ-
ent sample-collection points in the central or peripheral flow at
the shaker inlets.
On one of the shakers, it was not possible to collect samples
from the inlet; thus, only the PSD result from the outlet from this
shaker is presented in Figs. 4 through 6.
The test results show that all shakers in the test have a satisfac-
tory removal of particles in the size interval just above the desig-
nated cutpoint (Figs. 4 and 5). As expected, the removal of
particles is higher in the size interval 100 to 200 lm, but there is a
corresponding lower content of these larger particles in the dril-
ling fluid going into the shaker. The test results in Figs. 4 and 5
indicate that the D
100
for the particles sized 100 to 200 lm is a
theoretical value because all shakers in the test have particles of
this size interval in their outlet samples.
Even though the results are satisfactory for all participants,
some shakers have a somewhat higher particle count in the size
ranges 80 to 100 lm and 100 to 200 lm. This higher particle
count in some shakers may be related to more extensive screen
wear in these shakers.
Particles reduction was also observed on 9- to 80-lm particles
(Fig. 6). The reduction of the coarser particles is expected, but not
of the finer particles. These fine particles are expected to remain
in the drilling fluid. This phenomenon is often described as the
“piggy-back effect” in which finer particles attach to the coarser
ones and are thereby removed from the fluid system.
Adherence on Cuttings. Adherence of drilling fluid on cut-
tings was measured by retort analysis as OOC by an external labo-
ratory; see results in Fig. 7.
All shakers seemed to be performing adequately; best OOC
result is 3% W/W, and poorest OOC result is 8% W/W.
Shakers-random Order, different in every Figure
150
Filtration Efficiency - Malvern Lab Analysis
Inlet
Outlet
100
50
0
D

9
0
,

µ
m
Fig. 3—PSD results from the Malvern analysis for the various
shakers.
Filtration Efficiency -
FBRM Lab Analysis, 80–100 µm
5
4
3
2
1
0
Shakers - random Order, same in FBRM Figure
Inlet Outlet
P
a
r
t
i
c
l
e
s
/
s
e
c
o
n
d
Fig. 4—Particle counts for each of the shakers for the size
range of 80 to 100 lm with the FBRM.
0
Inlet Outlet
Shakers - random Order, same in FBRM Figure
Filtration Efficiency-
FBRM Lab Analysis, 9–80 µm
P
a
r
t
i
c
l
e
s
/
s
e
c
o
n
d
5000
10000
15000
20000
25000
30000
Fig. 6—Particle counts for each of the shakers for the size
range of 9 to 80 lm with the FBRM.
0
Shakers - random Order, same in FBRM Figure
Filtration Efficiency -
FBRM Lab Analysis, 100–200 µm
P
a
r
t
i
c
l
e
s
/
s
e
c
o
n
d
Inlet Outlet
0,2
0,4
0,6
0,8
1
1,2
1,4
Fig. 5—Particle counts for each of the shakers for the size
range of 100 to 200 lm with the FBRM.
152 June 2013 SPE Drilling & Completion
Retrieving representative drilling fluid and cuttings samples is
often a challenge, and the results of the filtration-efficiency tests
should be used as indication only, and a further investigation of
filtration efficiency will require a higher number of samples to be
collected and analyzed.
Screen Wear. In these shaker tests, screens were inspected
before and after test runs. The holes and number of plugs used to
seal off holes were registered after each test (Fig. 8).
These screen-wear results are influenced by how many screens
the supplier brought to the test, but these observations were per-
formed during the test and the number of holes, no holes, and
number of screens with plugs were as displayed in Fig. 8. There is
large variety in the percentage of screens with holes—from 100%
intact screens down to 33% only.
More data on screens and screen wear were collected during
the test, such as a tendency to corrosion, clogging of screens by
solids, method for patching screens, and the characterization of
holes (rips, abrasions, size, position, and more). These data are,
however, too detailed to be included here.
Leakage. Leakage tests were performed to detect the average
leakage rate that can be expected during drilling operations by
each shaker. Both static- (equipment turned off) and dynamic-
leakage (equipment running) tests were performed; see leakage
rates in Fig. 9.
The leakage rates for the four conventional shakers are rela-
tively similar, between 2.5 and 3.5 LPM, on both the static and
the dynamic test. No leakage was observed during the alternative
leakage test of the vacuum-technology shaker. See Fig. 9 for
results of the leakage tests. The static test was performed only on
the alternative solids-control unit.
One of the shakers on the test turned out to be a demo unit that
had the final quality check that was performed before offshore in-
stallation. This shaker needed adjustments to avoid excessive
leakage, and after the adjustments, this shaker had good leakage
results. This incident brings out the importance of a quality check
before the installation on a drilling facility.
LCM-Recovery Function. An LCM-recovery demonstration
was performed for shakers as an optional part of the test because
not all the participating shakers have this function. Three of the
shakers performed a successful demonstration of the LCM func-
tion, in which the LCM particles added to the drilling fluid were
screened out and recovered.
Operation and Maintenance Friendliness and Screen Wear.
The operation and maintenance check was performed while the
shakers were installed and running in the test center. The perform-
ances of the shakers are ranked by a scale from poor to excellent;
see summary of results in Tables 2 and 3.
Some shakers have a limited possibility to observe screens
during operation because of the narrow opening between the
decks, which may also be a benefit because the shaker operator
has to pull out the screens to allow a better visual inspection of
screen wear and to observe them. Some shakers have very tight
0
Shakers - random Order, different in FBRM Figure
Oil on Cuttings
O
i
l

o
n

C
u
t
t
i
n
g
s
,

%
Oil on Cuttings
2
4
6
8
10
Fig. 7—OOC results from retort analysis.
0
Shakers - random Order, different in every Plot
No holes, % With plugs, % With holes, %
Screen Wear
10
20
30
40
50
60
70
80
90
100
S
c
r
e
e
n
s
,

%

o
f

u
s
e
d

s
c
r
e
e
n
s
Fig. 8—Screen wear of screens used in shaker tests.
0
L
e
a
k
a
g
e

r
a
t
e
,

l
i
t
e
r
s
/
m
i
n
u
t
e
s
Shakers - random Order, different in every Figure
Static Dynamic
Leakage Test
0.5
1
1.5
2
2.5
3
3.5
4
Fig. 9—Leakage test.
TABLE 2—OPERATION AND MAINTENANCE TEST, PART ONE
Shakers,
Random
Order
Operation and Maintenance Screen
Access Daily
Maintenance
Inspection of
Screens During
Operation
Need for Lifting
Equipment During
Maintenance
Ease of
Replacing
Screen
Operation
Time To
Change Screens
Excellent Excellent Yes
a
Excellent Excellent
Excellent Excellent Yes
a
Excellent Excellent
Excellent Poor Yes
a
Excellent Excellent
Excellent Excellent Yes
a
Excellent Excellent
Excellent Excellent Yes
a
Good þ Excellent
a
Use of lifting equipment only necessary when engine is lifted.
June 2013 SPE Drilling & Completion 153
anchorage solutions for the screens that require that force and spe-
cial tools sometimes have to be used. The cleaning of the bottom
tray and the screens is less convenient in some shakers, and clean-
ing requires extra attention.
The overall result for the participating shakers is that the main-
tenance and operation friendliness are prioritized in the design of
the shakers. All five vendors have good products, and each of
them can be recommended on the basis of operational, access,
and maintenance solutions.
HVAC and WE. All solids-control solutions were tested at the
manufacturers’ recommended HVAC extract air-flow rates. With
the smoke test and VOC readings, the HVAC extract air flows
were thereafter adjusted to obtain the best possible WE atmos-
phere in the room.
As a result of differences in the design of shakers and front
hoods/enclosures, it was difficult to test all shakers within the exact
same parameters. It was determined that each shaker had to be
tested as dictated by the differences in design of each unit (Fig. 10).
Because of the installation of a filter in the test center’s HVAC
system, the highest achieved ventilation flow rate after the instal-
lation of the filter was 7400 m
3
/h, and not 120 00 m
3
/h, which
was the initial HVAC capacity. As a consequence, it was not pos-
sible to determine the test-optimized value for one of the shakers
tested later in the test period. Test-optimized value is the ventila-
tion flow rate that gave the best achieved WE results for the
shakers.
The vendors specification for HVAC requirement (blue col-
umns) for the tested units, the test-optimized value (red columns),
and the corresponding ventilation flow rates for shakers tested
with and without front hoods or other enclosures are displayed in
Fig. 10.
One shaker had an open design, and a provisional front hood
was built by the supplier during the test. However, it was not pos-
sible to determine the test-optimized value resulting from high
evaporation level and limitations in the HVAC system, and the
test-optimized value is set to be equal to the vendors recommen-
dation because this was the highest achieved ventilation flow rate
for this unit; thus, it was not possible to obtain a satisfactory WE
at this ventilation flow rate. The ventilation requirement for this
unit is higher than the vendors-recommended ventilation flow
rate.
One shaker had a front hood as extra equipment and was tested
with and without a front hood; even with a front hood mounted on
the shaker, measurements displayed that the unit required a higher
ventilation flow rate than recommended by the vendor.
One shaker was tested in a prototype enclosure with the front
hatches open and closed. It was not possible to test this unit with-
out the enclosure because the shakers’ connection to the HVAC
system was part of the enclosure. It turned out that this vendor
recommended a higher ventilation flow rate than test results
revealed that this unit actually needed.
One solids-control unit that is enclosed and derived from vac-
uum technology obtained an excellent WE atmosphere at a low
ventilation flow rate, and the vendor-recommended ventilation
flow rate is sufficient.
Only one shaker was tested without a front hood/enclosure and
with a supplier-recommended ventilation flow rate that proved to
be insufficient. Test-optimized ventilation flow rate for this shaker
was almost double the supplier-recommended value.
A surprising discovery during the HVAC tests is that several
of the shaker vendors did not know the ventilation requirement
for their shaker; one vendor believed that the shaker needed a
high ventilation flow rate when measurements showed that it
needed a low rate. Other suppliers realized that they had underes-
timated the required ventilation flow rate for their shakers.
The comparisons of ventilation flow rates for the shakers
revealed that there was insufficient accordance in vendor-recom-
mended values and test-optimized values (Fig. 10).
Comparisons of HVAC measurements indicate that the installa-
tion of a front hood/enclosure on the shakers had a better effect on
the level of OV/OM/VOC than increased ventilation flow rate, and
that the effect of the front hood/enclosure seemed to be improved
when sufficient ventilation flowrate was applied simultaneously.
WE. The objective of the WE test was to verify if the sup-
plier-recommended HVAC flow rate was sufficient to achieve an
acceptable chemical exposure in close proximity to the shaker.
The levels of VOC, OV, and OM were measured to quantify the
chemical exposure.
OV and OM were sampled with a pump. Two parallel samples
were taken at the sampling points, which were in front of and on
the right side of the shaker. VOC was sampled with the direct-
reading instrument MiniRAE 3000, and sampling points were in
front of and on the right and left sides of the shaker. Representa-
tive, selected test results from the WE test are displayed in Figs.
11 and 12 (measurements in front of shaker and measurements on
the right side of shaker, respectively).
In Fig. 11, the OM levels from the shaker with the highest
level are truncated. The actual values for low- and high-ventila-
tion flow rates, given as exposure indices [exposure level (E)/
AC)], would have been 337 and 297, respectively.
TABLE 3—OPERATION AND MAINTENANCE TEST, PART TWO
Shakers,
Random
Order
Cleaning of Screens and Bottom Tray Possibilities for Adjustment
Robustness
Cleaning of
Screen
Cleaning of
Bottom Tray
Adjustment of
Flow and Cuttings
Excellent Excellent Good Excellent
Excellent Excellent Excellent Excellent
Excellent Good þ Excellent Excellent
Excellent Excellent Excellent Excellent
Poor Good Excellent Excellent
0
Yes No
Front Hood
Yes No
Front Hood
Yes No
Front Hood
Yes No
Front Hood
Yes No
Front Hood
Shakers - random Order, different in every Figure
Vendor Recommendation Test Optimized Rate
Ventilation Flow Rate - HVAC System
V
e
n
t
i
l
a
t
i
o
n

F
l
o
w

R
a
t
e
,

m
3
/
h
r
1000
2000
3000
4000
5000
6000
7000
8000
Fig. 10—Ventilation flow rate; vendors-recommended value
(blue) and test-optimized value (red) with and without front
hood/other enclosure of shaker.
154 June 2013 SPE Drilling & Completion
In Figs. 11 and 12, the average OV, OM, and VOC levels from
each of the shakers have been compared. The results are presented
as exposure indices (e.g., measured E/AC) for measurements
obtained at the front and the right side of the shakers, respectively.
The results given in Figs. 11 and 12 have to be interpreted
with caution. However, they show considerable and consistent
differences in OV, OM, and VOC levels between the five shakers.
None of the shakers fulfilled the design criteria (1/6 ÂAC).
However, there was one shaker that came very close to having
emissions in the low category (1/6 to 1/2 ÂAC) for both OV and
OM. Another shaker had OV measurements in the high category
(1/5 ÂAC). These two shakers were designed with a technical
barrier of Priority 1 (efficient enclosure of emission sources). The
first of these shakers represents new technology that is derived
from vacuum methods, and the second shaker uses conventional
technology equipped with an enclosure.
On the basis of the results from the five shakers tested, one
enclosed solids-control unit was highly recommended because of
its ability to control the emissions of OV and OM at the pollutant
source, resulting in low measured concentration in the vicinity of
the shaker. The second-best shaker was also equipped with an en-
closure providing an enclosed handling of the emissions, although
the test results show higher OV and OM concentrations in the
atmosphere than expected.
The other three shakers need to develop further toward a closed
system in which the emissions can be better controlled. It was not
possible to fulfill the design criteria, nor the AC, with an open
shaker. Even with a hood, the tested shakers did not have accepta-
ble emission levels, especially for OV. A recommendation is to de-
velop the open and semiclosed shakers toward better/full enclosure
to handle and control the OVand the OM emissions at their source.
Comparisons of the WE measurements revealed that more-
open shaker designs caused higher levels of OV/OM/VOC in the
atmosphere. All conventional shakers in the test were encouraged
to develop toward a more closed design.
A positive effect of the test was that the suppliers now see WE
performance as an area of competition. These WE tests have
stimulated innovation to improve the WE. All participants with
the potential to improve their performance on HVAC and WE
have designed and produced front hood or other means of enclo-
sure and have performed smoke tests of their shakers with front
hoods/enclosures on their own sites.
Noise and Vibration. SWL has been measured to obtain the
noise emission from one shaker. The area noise level in a shaker
room has then been calculated from the measured SWL. See the
results of the shakers SWL at 90 and 100% of maximal drilling-
fluid-flow rate, and shakers running dry without drilling fluid
(Fig. 13).
The small size of the test cell caused challenges related to mea-
surement accuracy, but after noise absorbents were mounted on
the test-cell walls, noise-measurement conditions were improved.
The SWL results given in Fig. 13 were the basis for the calcu-
lation of predicted SPL for comparison with the area noise levels
of a shaker room. Only one of the tested shakers has the potential
to meet the required area noise limit of 85 dBA in a shaker area.
Three of the tested shakers have the potential to meet an area
noise level of 90 dBA, and one of the shakers operates at more
than this highest allowable limit. Noise at these high levels has a
large impact on operational restrictions for individuals to fulfill
their personal-exposure requirements.
Vibration-measurement results are reported according to
standards NORSOK S-005 and S-002. Vibration measurements
were also performed on the mud container below the shaker and
were compared with Category 3, and the measurement made on
the shaker skid (the highest-level measurement) was compared
with Category 4. See Fig. 14 for a comparison of the vibration
measurements.
All measurements are within acceptable limits. The shaker
representing new technology has the lowest vibration levels on
the skid. However, on the reference point, the difference between
the units was small, suggesting a good effect of the vibration iso-
lators used on all units.
Comment on Results. To facilitate access to the shakers’ per-
formances in the various aspects of the shaker test, a ranking was
0
Low High
Rate
Low High
Rate
Low High
Rate
Low High
Rate
Low High
Rate
Shakers - same Order in OV/OM/VOC Figures
Comparison of OV, OM, and VOC Levels Sampled in
Front of the Shaker With Low and High Ventilation Flow Rate
Oil Vapor,
mg/m
3
Oil Mist,
mg/m
3
Average VOC,
ppm
5
10
15
20
25
30
40
E
x
p
o
s
u
r
e

I
n
d
e
x

E
/
A
c
c
e
p
t

C
r
i
t
e
r
i
a

A
C
35
Fig. 11—Average of selected OV, OM, and VOC levels from each
of the shakers measured in the front of the shakers.
18
16
14
12
10
8
6
4
2
0
Low High
Rate
Low High
Rate
Low High
Comparison of OV, OM, and VOL Levels Sampled on
Right Side of Shaker With Low and High Ventilation Flow Rate
Shakers - same Order in OV/OM/VOC Figures
Oil Vapor,
mg/m
3
Oil Mist,
mg/m
3
Average VOC,
ppm
Rate
Low High
Rate
Low High
Rate
E
x
p
o
s
u
r
e

I
n
d
e
x

E
/
A
c
c
e
p
t

C
r
i
t
e
r
i
a

A
C
Fig. 12—Average of selected OV, OM, and VOC levels from each
of the shakers measured at the right side of the shakers.
70
Shakers - random Order, different in every Figure
0,9 1 Dry
Comparison of Measures Sound Power Level (SWL)
75
80
85
90
95
100
105
S
o
u
n
d

P
o
w
e
r

L
e
v
e
l
,

d
B
A
Fig. 13—Comparison of measured SWL for the different units.
June 2013 SPE Drilling & Completion 155
performed by the discipline specialists on their respective areas.
Because of an anonymity agreement with the shaker vendors, this
ranking is not included in this publication.
Conclusions
Drilling-Fluid-Processing Rate. There is a significant difference
in the drilling-fluid-processing capacities; that for oil-based dril-
ling fluid spans from 3950 to 1150 LPM, and corresponding
results for water-based drilling fluid are 3320 and 900 LPM.
The filtration efficiency of the shakers was examined by PSD
analysis, first with the Malvern that was inconclusive and then by
FBRM that produced useful data. The advantage demonstrated by
the FBRM analysis indicates that this instrument should be used
more in future PSD analysis, and this experience may be useful
for both drilling operations and further-research projects.
The adherence of drilling fluid on cuttings was measured as
OOC. This is of economic and environmental importance,
because less drilling fluid lost as adherence on cuttings implies a
reduced loss of drilling fluid and less drilling waste. All shakers
showed good results relative to adherence-of-drilling-fluid-on-cut-
tings/OOC corresponding measurements from 1990s operations,
which demonstrates the improvement of solids-control equipment
and better procedures for shaker operation since that time.
The challenge of representative drilling-fluid and cuttings
samples should be taken into account when reading the results,
and a larger number of drilling-fluid and cuttings samples should
be collected and analyzed to achieve more-reliable filtration
results.
The screen-wear registration displayed variation in the durabil-
ity of the screens because some screens were more prone to
develop holes. The screen data collected are too detailed to in-
corporate in this publication, but further testing would benefit
from allocating resources on consecutive registration of screen
wear because screen data are complex.
The leakage rates from the shakers were satisfactory for all
participants, but experience performed during the test brings out
the importance of checking this aspect before a solids-control unit
is set in operation.
The maintenance and operation checks revealed that the over-
all result for the participating shakers is that the user friendliness
is prioritized in the design. Some shakers have minor issues
related to the change of screens and cleaning.
The introduction of the front hood on the shakers seems to sig-
nificantly improve the WE atmosphere in the test room. This test
of shakers in an enclosed environment indicates that the WE chal-
lenges in shaker rooms are very difficult to resolve with an HVAC
solution only. The real exposures of personnel working in shaker
modules will depend on such details as working operations, time
spent in the module, and personnel protections.
The new method used for the first time on the shaker test, in
which an active sampling of OV and OM is performed in parallel
with direct-reading instruments for VOC to monitor the variations
in concentrations of organic vapor and the chemical WE as a con-
sequence of changes in ventilation flow rate and front hood or en-
closure, represents technology development. This method was
used for the first time in the shaker test, and the possibility to
obtain real-time data of the VOC level was used as a navigational
tool during the test, because results from OV and OM samples
were available only after some time. The VOC levels were used
to determine the required HVAC flow rate during the tests.
The recommendation from the HVAC-test results is that the
conventional shakers should be equipped with a front hood, and
the extract ventilation from the shaker should maintain an under-
pressure inside the shaker and preferably a 1.5-m/s air velocity
through any openings. The front-hood design should be further
developed to improve the effect of capturing the OV and OM.
The control of hazardous emissions in the WE shall be
achieved by technical measures/barriers (in order of priority):
• Efficient enclosure of emission sources.
• Efficient extraction/exhaust-ventilation systems to remove pol-
lutants near the source.
• General ventilation/dilution of contaminants.
Noise tests revealed that only one of the tested shakers had the
potential to meet the required area noise-level limit of 85 dBA,
three shakers had the potential to meet the highest allowable area
noise-level limit of 90 dBA, and one shaker exceeded this highest
allowable limit. All measurements of vibration were within ac-
ceptable limits.
The shaker test triggered competition among the equipment
suppliers and stimulated technology development and product
improvement. This was especially the case for the solutions
related to HVAC and WE. The publication of the anonymous test
results will make benchmarking possible for the participants.
Tests of the various aspects of shaker performance called for
the development of new test methodology. Covering different dis-
ciplines, the test initiated by the rig modification project was a
result of a multidisciplinary cooperation. The internal specialists
were representing the discipline areas of drilling and well facili-
ties, WE technology, operation and maintenance including HVAC
and drilling fluids. Other internal contributors were representing
the contracts department, the legal department and the department
for intellectual-properties rights. The external participants are
from the test center, drilling-fluid supplier, five shaker vendors
and their distributors in Norway, external laboratory, and consul-
tant companies for measurement of HVAC, occupational hygiene,
and noise/vibration.
During the phases of this project, lessons have been learned
that have given increased competence on test methodology. With
many specialists working together on the same test, new ideas
have been conceived, and some of them have resulted in product
improvements of the solids-control equipment. Some shaker ven-
dors have discovered that there was potential for improvement on
their shakers, and the test experience and results have become a
basis for product improvement.
Because all shakers were tested with test conditions as equal
as practically possible and the only variable factor was the shak-
ers, the test has produced a unique database of comparable results.
The test results are valid for the test conditions, and performance
may be better on other tests, but the unique aspect was that these
results were truly comparable results and revealed the differences
in shaker performance.
The variation in performance among the shakers supports the
legitimacy of the test, and it demonstrates the need for a standar-
dized-test methodology for shakers. The test methodology is con-
sidered the main outcome of the shaker test, and this publication
may be a step toward a standardized methodology applied on this
and similar equipment. In the future, a standardized test method-
ology for shakers would facilitate the selection of the most suita-
ble equipment for the shaker customers.
Acknowledgments
Thanks to the shaker vendors and their distributors—Cubility Test
Center, OHS/Proactima, Sinus, Mollier, STAMI, and Hallibur-
ton—for great service and cooperation before, during, and after
the shaker test. The shaker test could not have been carried out
0
Ref point Skid frame
Shakers - random Order, different in every Figure
Comparison of vibration Measurements
V
a
r
i
a
t
i
o
n

c
a
t
e
g
o
r
y
(
N
o
r
s
o
k

S
-
0
0
2

l
i
m
i
t
s
)
1
2
3
4
5
Fig. 14—Human-vibration measurements compared with the
vibration category. The red line is the limit for the red dots, and
the blue line is the limit for the blue dots.
156 June 2013 SPE Drilling & Completion
without their great support and team spirit. Thanks to Jamie Stuart
Andrews of Statoil, who supplied data for Fig. 1.
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Anne Turid Lian Vestbakke is a principal engineer within tech-
nical working environment, and she has been working with
drilling-upgrade projects at Statoil ASA; currently, she is work-
ing as an HSE Engineer within Drilling and Well in Statoil. Vest-
bakke is a certified occupational hygienist and holds an MS
degree in offshore engineering–environmental control from
the University of Stavanger.
Vegard Peikli is a specialist within working environment tech-
nology; he works as the HSE Manager in the Platform Removal
Portfolio at Statoil. Peikli is a certified occupational hygienist
and holds an MS degree from the Norwegian University of Sci-
ence and Technology.
Arvid Nysted works as principal engineer at Statoil ASA in
HVAC. Nysted holds a BS degree in mechanical engineering–
HVAC from the University of Stavanger.
Eystein Ove Storslett works as Advisor in Statoil ASA. Area of
work is HVAC. He holds an engineering degree in HVAC from
Trondheim College of Engineering, and a Cand. Mag. Degree
from the University of Stavanger.
Iren Steinnes works as a senior drilling engineer at Statoil ASA in
planning exploration wells. She holds an MSc degree in petro-
leum technology from the University of Stavanger.
Øyvind Lie works as HVAC Leading Adviser at Statoil ASA and
holds a BSc degree in mechanical engineering from Sta-
vanger Ingeniørhøgskole and a BSc degree in business man-
agement from Regional University Stavanger.
Einar Eliassen is employed by Odfjell Drilling in the position of
senior tool pusher, and has gained 35 years’ experience in the
field of offshore drilling. He is currently employed as a consul-
tant drilling equipment engineer at Statoil ASA, on the Snorre
A Drilling facility project, in the role of drilling equipment engi-
neer and user representative.
Bjarte Sivert Knudsen works as senior engineer at Statoil ASA in
the area of drilling facilities. He holds a BS degree in mechani-
cal engineering– production technology from the Bergen Uni-
versity College.
Frode Haldorsen has amassed more than 23 years of work ex-
perience in the oil and gas industry, covering both offshore
and onshore projects, representing client and contractor
companies. He is currently employed in the role of project
manager for Statoil ASA. Haldorsen holds an MS degree in civil
engineering from the Norwegian Institute of Technology and
a Master of Management degree from the Norwegian School
of Management.
Ellen Jensen works as a leading adviser in industrial hygiene at
Statoil ASA. She holds a PhD degree from the Norwegian Uni-
versity of Science and Technology in indoor air quality, and an
MSc degree from the same university in chemical engineering.
Jensen has been an international certified occupational hy-
gienist since 2002.
Jørund Enger works as specialist noise control engineer at Life-
tec A/S in the area of noise management in offshore develop-
ment projects for Statoil ASA. He holds an MS degree in
building acoustics from the University of Trondheim.
Tor H. Omland works as a leading adviser at Statoil ASA in the
area of responsibility for drilling fluids and total fluid manage-
ment. He holds a PhD degree in drilling engineering and an
MSc degree in petroleum engineering from the University of
Stavanger and is an SPE member.
Bodil Aase works as a principal engineer at Statoil ASA in the
areas of fluids, solids-control equipment, and drilling waste. She
holds an MS degree in offshore engineering–environmental
control and a BS degree in chemical–environmental biotech-
nology from the University of Stavanger and is an SPE member.
June 2013 SPE Drilling & Completion 157