12 - Oilfield Mineral Scale Management
Submitting InstitutionsHeriot-Watt University,
University of Edinburgh
Unit of AssessmentGeneral Engineering
Summary Impact TypeTechnological
Research Subject Area(s)
Engineering: Environmental Engineering, Resources Engineering and Extractive Metallurgy, Interdisciplinary Engineering
Summary of the impact
One of the major problems experienced in the oil production industry is
the formation of mineral scale deposited downhole within an oil reservoir
and topside. The scale creates a blockage causing a detrimental effect to
the productivity of the well. ERPE Research in scale management has led to
the following impacts in the REF2014 period:
- Helped Shell save £3M per well per year by reducing the frequency of
scale inhibiting treatments i.e. squeezes, from a treatment every six
months to a yearly treatment.
- All scale service companies are required to demonstrate competence in
ERPE written SQUEEZE software within tender processes. For a single
contractor (Nalco Champion) in 2012 this resulted in an addition $3.5M
(£2.3M) of revenue.
- [text removed for publication]
The ERPE team of Mackay (Prof), Sorbie (Prof), Todd (Prof) have been on
staff throughout the REF2014 period.
Overall, the most important outputs from the ERPE research were:
- Demonstration of the importance of reservoir mineralogy in determining
how scale inhibitors are retained in reservoirs.
- The modelling of adsorption and precipitation scale inhibitor squeeze
treatments in North Sea fields.
- The development of the methodology to assess the scale risk in fields
at the Front End Engineering and Design stage of a project.
One of the major problems experienced in the oil production industry is
the formation of mineral scale. Scale is deposited downhole within an oil
reservoir and topside, throughout the water production lifecycle of a
producer well. This creates formation damage (restriction / blockage
within the rock matrix) and blockage of the production tubing, reducing
the productivity of the well. Various forms of inorganic scales can be
found in the North Sea and elsewhere and these are normally prevented
using a process known as a "squeeze" treatment, where scale inhibitor
chemicals are applied to the rock formation to stop scale deposition in
the pipelines and to protect the wellbore area, or by continual chemical
injection, which treats the topside precipitated calcium carbonate and
barium sulphate scale.
Scaling problems arise in high pressure, high temperature (HP/HT) fields
in the North Sea and around the World, and also in systems where low
temperatures are prevalent such as long line tie-backs. In order to treat
the scale that is formed under such severe conditions as these, a solid,
scientifically-based understanding of the chemical processes leading to
scale formation is required.
Since 1993, ERPE has developed a detailed predictive understanding of the
way in which scale forms and can be treated in a wide variety of operating
environments. ERPE has achieved this understanding through manufacture of
specialised laboratory equipment, field condition experiments (up to 200 C
and 1500 bar), and development of computer software that can model scale
at the level of pore, core, well and field.
To give some context for the amount of data that ERPE has generated and
analysed, our industrial partners, (e.g. BP, Petrobras, Shell, Total,
Statoil, Talisman, etc), have provided water compositional analysis data
and samples of core taken from numerous wells in their fields; ERPE has
received 65,000 lines of 8-12 ion field brine analysis data from operators
and undertaken reservoir simulation studies on 40 offshore fields for 16
companies and over 100 reservoir condition corefloods. The data has been
used to investigate the fundamental mechanisms by which generic chemicals
inhibit various scales and how they are retained on various mineral
substrates. [1,2,3] The work has been carried out under a wide range of
conditions leading to a widespread applicability of the results of the
ERPE's SQUEEZE software encapsulates the results of 20 years of detailed
laboratory experiments and experience in upscaling laboratory measurements
to field conditions. The SQUEEZE software enabled ERPE researchers to
conduct appropriate experiments to study field problems, often iterating
with modelling to ensure requisite data are collected and analysed .
These predictions were then compared with observed field data, and the
models further refined as necessary. Knowledge gained from analysis of
produced water compositions and reservoir simulation calculations
regarding brine displacement through the reservoir, and the impact this
has on production conditions, is also used to inform recommendations for
field practice , a process that is now routinely carried out by
industry during the Front End Engineering and Design (FEED) phase of
References to the research
The references identified with * are the ones which best indicate the
quality of the underpinning research.
 * Jordan, M.M., Sorbie, K.S., Jiang, P., Yuan, M., Todd, A.C. and
Taylor, K.: "Mineralogical Controls on Inhibitor Adsorption/Desorption
in Brent Group Sandstone and Their Importance in Predicting and
Extending Field Squeeze Lifetimes", Society of Petroleum Engineers
European Production Operations Conference and Exhibition, 15-17 March
1994, Aberdeen, DOI: 10.2118/27607-MS
12 Google Scholar (GS) citations.
This paper showed that the one of the main factors determining how scale
inhibitors are retained in reservoirs is the reservoir mineralogy.
 Neville, A., Bepoix, M., Graham, G. , and Morizot, A.P.: "Assessing
the Potential of Atomic Force Microscopy to Study the Formation of
Electrodeposited Calcareous Scales in Uninhibited and Inhibited
Conditions", Society of Petroleum Engineers International Symposium
on Oilfield Scale, 30-31 January 2002, Aberdeen, DOI: 10.2118/74653-MS
This work identified the nature of crystal growth in oilfield
environments, and as a result that chemicals need not function by
preventing growth across the entire crystal surface area, but just need to
target the active growth site on the crystal, reducing the volumes of
chemical required for inhibition.
 * Yuan, Ming Dong, Sorbie, K.S., Todd, A.C., Atkinson, L.M., Riley,
H, Gurden, S. "The Modelling of Adsorption and Precipitation Scale
Inhibitor Squeeze Treatments in North Sea Fields" Society of
Petroleum Engineers International Symposium on Oilfield Chemistry, 1993,
New OrleansSPE Journal, 25613 (1993) DOI: 10.2118/25163-MS
27 GS citations
The research that led to this paper established the SQUEEZE model as the
standard tool for assessing scale inhibitor core floods, which are used by
industry every time a new chemical is introduced to a field for scale
 Mackay, E.J., Matharu, A.P., Sorbie, K.S., Jordan, M.M., and Tomlins,
R.: "Modelling Scale-Inhibitor Treatments in Horizontal Wells:
Application to the Alba Field", SPE Production & Facilities
(May 2000) 15 (2) 107-114. DOI: 10.2118/63013-PA
48 GS citations
This paper was the first to describe how to design scale inhibitor squeeze
treatments in an existing horizontal well using reservoir modelling, and
has been the basis on which all subsequent modelling of scale squeezes in
horizontal wells has been carried out since.
* Sorbie, K.S. and Mackay, E.J.: "Mixing of Injected, Connate and
Aquifer Brines in Waterflooding and its Relevance to Oilfield Scaling"
Journal of Petroleum Science and Engineering (July 2000) 27 (1-2) 85-106.
10.1016/S0920-4105(00)00050-4 108 GS citations.
This paper established the methodology now used by operating companies to
assess the scale risk in fields at the Front End Engineering and Design
stage of a project.
Details of the impact
[text removed for publication]
In the REF2014 period Shell has used SQUEEZE software to go from a
treatment every six months to a treatment every 12 months, saving £3M per
well per annum. A partial list of the wells for which this OPEX reduction
has been achieved is Pierce B1, Guillemot P3, and some Bittern wells,
leading to savings well in excess of £10M per year. [S4]
As a result of ERPE research, service companies tendering for work are
required to demonstrate expertise in designing field treatment programmes
using the SQUEEZE software. In the last three years, 102 industry
representatives have undergone SQUEEZE training at our Edinburgh campus
and at industry offices in Aberdeen, Norway, Dubai, Malaysia and USA. As
examples of service company use of SQUEEZE software, we provide two
quotes: Clariant Oil state that they "use the most recently updated
version of the SQUEEZE modelling software (currently SQUEEZE 8) to plan
all the scale inhibitor squeeze operations that we manage for our
clients. Across the global organization this equates to approximately
300 squeezes per year and protects over 500,000,000 barrels of produced
water resulting in many billions of dollars of protected oil
Nalco Champion "...use the latest version of the SQUEEZE software for
all our squeeze designs, which annually numbers approximately 250
squeeze treatments. Along with our current customer contracts we are
required by operators to demonstrate expertise in the use of the SQUEEZE
software in tendering for chemical squeeze business. In the past 12
months Nalco Champion has been able to secure contracts worth over
$3,000,000 based on our ability to use the current version of this ERPE
developed software." [S2]
Prevention by inhibition is by far more cost effective than cure taking
into account typical workover costs in the UK N Sea of ca. £25 M/well
excluding the associated loss of production. ERPE is a recognized world
leader JIP supporting the industry in terms of learning on this key scale
management area. A Production Chemistry Team Leader at Talisman Sinopec
Energy UK Ltd commented that "All the scale management activity in the
North Sea that our company undertakes is impacted by the research that
has been undertaken by ERPE over the past decade....Talisman-Sinopec
Energy UK Limited has some fifty four wells under active scale squeeze
management protecting 36,798 barrels of oil production per day. This
production typically equates to a significant portion of the company's
annual production and revenue." [S5]
Sources to corroborate the impact
[S1] Senior Manager within Application Development Team, Clariant Oil
will advise that their company uses the SQUEEZE (Version 8) modelling
software to plan all scale inhibitor squeeze operations that we manage for
[S2] Consultant, Oil Field Chemicals Team, Nalco Champion, an Ecolab
Company will corroborate that they use SQUEEZE (Version 8) software for
all squeeze designs, annually approximately 250 squeeze treatments. They
must demonstrate expertise in the use of SQUEEZE software in tendering for
chemical squeeze business.
[S3] Scale Specialist, Total will confirm that they undertook some
modelling of squeeze treatments for a specific well at ERPE. The value of
production of gas condensate from this well was approximately £1million
daily. A 90 day shut in to install a chemical injection capillary was the
alternative. Total decided to model the treatments using SQUEEZE software.
[S4] Production Chemist Shell, will confirm that ERPE's work with Shell
has shown that squeezes in some of their fields cost £3million, and they
have used the SQUEEZE software to go from a treatment every six months to
a treatment every 12 months, saving £3m per well per annum in those
[S5] Senior member of staff within the Production Chemistry Team,
Talisman Sinopec Energy UK Ltd The company has 54 wells under active scale
squeeze management protecting 36,798 barrels of oil production per day.
Prevention by inhibition is more cost effective than cure taking into
account typical workover costs in the UK N Sea of ca. £25 millions/well
excluding the associated loss of production.