Cesium formate brine - Keeping the Home Fires Burning

How the use of cesium formate brine has been enhancing the safe extraction of the UK’s natural gas reserves from 3 miles underneath the North Sea

1. Keeping the
Home Fires
Burning
How the use of cesium formate
brine has been enhancing the safe
extraction of the UK’s natural gas
reserves from 3 miles underneath
the North Sea
25/01/2022

2. John Downs
Senior Scientist -Shell Research
Rijswijk, The Netherlands 1990-94
John Downs -Formate Brine Ltd, Tealby 2
John developed cesium formate brine for drilling and
completing deep gas wells
25/01/2022

3. Cesium formate brine is a clear high-density aqueous fluid used to
drill and complete deep gas wells
John Downs -Formate Brine Ltd, Tealby 3
Cesium formate is extracted from
pollucite ore mined in Canada
The heavy brine is
transported and stored
in 1 m
3
IBCs
Used in North Sea since
1999
2.3x heavier
than water
25/01/2022

4. Technical note : Drilling fluids are circulated down the hollow drill pipe, out through
the drill bit and up the annulus of the wellbore during wellbore construction
John Downs -Formate Brine Ltd, Tealby 4
Wellbore stabilization*
Well pressure control*
Lubrication
Hole cleaning
Fluid loss control
Non-damaging to reservoir
Safe
Power transmission
Low environmental impact
Allow formation evaluation
Compatible with metals
and elastomers
A lot rests on the shoulders of drilling fluids –they have to fulfil many functions
Aids rock cutting
Scavenges acid gases
* Typically want to keep wellbore pressure @ a steady500 psi above pore pressure in the surrounding rock
25/01/2022

5. Drilling fluids need to be made up to 2.3 times heavier than water in order to
balance downhole pressures and stabilise the borehole
John Downs -Formate Brine Ltd, Tealby 5
A 96-year old technology is still used to increase the density of traditional drilling fluids :
•Finely ground barite ore is dispersed in oil or water at concentrations
of up to 40% w/v
•The resulting slurry provides weight but degrades just about every
aspect of drilling and well performance !
25/01/2022

6. Loss of well control resulting from the drilling fluid in your wellbore having
the wrong weight (density) can have truly catastrophic consequences
John Downs -Formate Brine Ltd, Tealby 6
Macondo field, offshore USA -10
th
April 2010 -loss of well control leadingto well blow out
11 fatalities, loss of rig, environmental disaster, $ 43 billion bill for BP
Well control incidents were common in deep gas well drilling
operations in the North Sea before the arrival of cesium formate brine
25/01/2022

7. Natural gas –a
hugely
important
source of
energy and
chemicals for
the UK.
HEAT
•Natural gas provides around 80% of the UK’s domestic,
commercial and industrial heat
•84% of the UK’s homes (22 million) are heated by gas.
Domestic heating accounted for 38% of the UK’s gas
demand in 2020
•61% of UK cooking hobs are fuelled by gas
•Glass recycling furnaces in UK use 1 million cubic metres
of gas every day
John Downs -Formate Brine Ltd, Tealby
725/01/2022

8. Natural gas –a hugely
important source of
energy and chemicals
in the UK.
POWER GENERATION
•35.7% of the UK’s electricity was
provided by gas in 2020
•43.1 % of the UK’s electricity was
provided from renewables in 2020
-but when the wind is not blowing gas
fills the energy gap
•Electricity generation accounted for
29% of the UK’s gas demand in 2020
John Downs -Formate Brine Ltd, Tealby
825/01/2022

9. Natural gas – a hugely important source of energy and
chemicals in the UK.
CHEMICALS FOR
AGRICULTURE & FOOD
PRODUCTION
•Natural gas is a key feedstock in the
production of ammonia used in
nitrogen-based fertilizers
•CO
2, a by-product of ammonia
synthesisfrom natural gas , has
important applications in food
production
25/01/2022

10. Natural gas –a hugely
important source of
energy and chemicals
in the UK.
CHEMICALS FOR
MANUFACTURING
•500,000 jobs in the UK’s
chemical and pharmaceutical
industries depend on natural
gasas a raw material
John Downs -Formate Brine Ltd, Tealby
1025/01/2022

11. FROM SELF-SUFFICIENCY
IN 2004 THE UK CAN
NOW ONLY MEET HALF
ITS OWN GAS NEEDS
John Downs -Formate Brine Ltd, Tealby 1125/01/2022

12. NATURAL GAS SUPPLIED BY
PIPELINE FROM GAS
FIELDS OFFSHORE
NORWAY MAKES UP MOST
OF THE SHORTFALL –WITH
LNG SHIPMENTS FROM
OTHER COUNTRIES
PROVIDING THE REST
John Downs -Formate Brine Ltd, Tealby 1225/01/2022

13. THE NATURAL GAS SUPPLIED
TO THE UK FROM THE
NORWEGIAN NORTH SEA
GAS FIELDS IS MAINLY
CARRIED BY THE VESTERLED
AND LANGELED PIPELINES
John Downs -Formate Brine Ltd, Tealby 1325/01/2022

14. John Downs -Formate Brine Ltd, Tealby 14
The sequence of gas field developments in
North Sea since 1960’s
High-Pressure High-Temperature (HPHT) from 1997
Located in Central
and Viking Grabens
Buried > 4,000 meters
below sea bed
Pressure of reservoir
fluids and gases
> 10,000 psi
Reservoir temperature
> 149
o
C
Small/intermediate conventional linked to infrastructure
Large conventional –starting 1967
25/01/2022

15. UK continues to produce gas but its output has been
steadily decreasing over the past 20 years, with more than
half of its gas now imported.
Natural gas piped from the North Sea and the East Irish
Sea to refineries on land makes up 44% of the UK’s gas
production.
Around 47% of the UK’s gas supply now comes from
across Europe –nds, Belgium, and Russia - through long
distance pipelines.
While 9% of the UK’s gas is imported as liquid natural gas
transported around the world in tankers at temperatures
below -160C by ship, mainly from Qatar.
The UK has been hit badly by the gas shortage due to 85%
of its homes using gas central heating - one of Europe’s
biggest users of natural gas.
Factors holding back deep
HPHT gas field developments
in the North Sea during 1980’s
and early 90 ’s
1)Economics
•Slow drilling and costly equipment for hydrothermal sour/acid gas duty make deep gas wells up to 12 times
more expensive than conventional gas wells
•Drilling the last 10% of a deep gas well accounts for 50% of total well cost *
John Downs -Formate Brine Ltd, Tealby 15
•* US Department of Energy website -Onshore gas well costs in USA
•** Snead (2005) -The Economics of Deep Drilling in Oklahoma
Gas well cost versus depth**
25/01/2022

16. Solids-weighted drilling muds increase
costs and reduce revenues
High solids content of barite-weighted muds slows
everything down, creates additional operational costs/risk
and damages the reservoir
•Well control problems caused by high ECD and barite sag
•Reduced drilling penetration rate and bit life
•Differential sticking
•Slow pipe and casing running speeds
•Long mud conditioning and flow-check times
•Failures/plugging of completion tools, seals and screens
•Formation damage !!
•Mud maintenance : barite looks same as fine drilled solids

17. UK continues to produce gas but its output has been
steadily decreasing over the past 20 years, with more than
half of its gas now imported.
Natural gas piped from the North Sea and the East Irish
Sea to refineries on land makes up 44% of the UK’s gas
production.
Around 47% of the UK’s gas supply now comes from acrs ,
Belgium, and Russia -through long distance pipelines.
While 9% of the UK’s gas is imported as liquid natural gas
transported around the world in tankers at temperatures
below -160C by ship, mainly from Qatar.
The UK has been hit badly by the gas shortage due to 85%
of its homes using gas central heating - one of Europe’s
biggest users of natural gas.
Factors holding back deep
HPHT gas field developments
in the North Sea during 1980’s
and early 90 ’s
2) Safety
•Drilling into highly-pressured formations
with conventional (unstable) drilling fluids
containing oil and barite is hazardous
-45% of HPHT wells drilled in 1987
experienced well control incidents
(unplanned influxes = «kicks» )
-HPHT well control incidents were
still at 15% level in 2003
•Failure of casing, tubulars, blow- out
preventers and other safety-critical
equipment
John Downs -Formate Brine Ltd, Tealby 17
Well blowout on Ocean Odyssey drilling rig while drilling a
HPHT exploration well in the UK North Sea on 22
nd
September
1988
25/01/2022

18. Conventional high-density clear completion fluids (bromide brines) are hazardous
and corrosive
The brines are hazardous for the rig crew and for the environment –and they are corrosive to
metals too.

19. UK continues to produce gas but its output has been
steadily decreasing over the past 20 years, with more than
half of its gas now imported.
Natural gas piped from the North Sea and the East Irish
Sea to refineries on land makes up 44% of the UK’s gas
production.
Around 47% of the UK’s gas supply now and Russia -
through long distance pipelines.
While 9% of the UK’s gas is imported as liquid natural gas
transported around the world in tankers at temperatures
below -160C by ship, mainly from Qatar.
The UK has been hit badly by the gas shortage due to 85%
of its homes using gas central heating - one of Europe’s
biggest users of natural gas.
Factors holding back deep
HPHT gas field developments
in the North Sea during 1980’s
and early 90 ’s
3) Drilling fluid damage to gas
reservoirs reduces production
John Downs -Formate Brine Ltd, Tealby 19
25/01/2022

20. Conventional clear completion fluids (bromide brines) can block gas wells under
HPHT conditions
Bromide brines can block oil and gas production completely by reacting with oil-based drilling muds
residues in the well under HPHT conditions
“In the latest problem to solve, zinc bromide standardly used in well completions for years
became the culprit. It turns out that in a high pressure, high temperature environment as
found at Davy Jones, the zinc bromide acts differently than it usually does and becomes
like putty. When it comes into contact with drilling mud, it sets up like cement.That’s just
what you don’t need in a small ultra deep well that you need to flow.”
“McMoRan'sDavy Jones #1 Well Close But Still NoBanana”
McMoranspent $ 1 billion on this Davy Jones well –and blocked it with Zn bromide
Forbes magazine article –14 June 2012 :

21. John Downs of Shell Research developed cesium formate brine as an
improved drilling and completion fluid for deep HPHT gas wells, 1990-94
John Downs -Formate Brine Ltd, Tealby 21
John’s strategy : Use heavy cesium formate brine in place of a) water or
oil weighted up with fine barite particles and b) bromide brines
25/01/2022
White papers from 1992/93

22. Properties of cesium formate brine that are beneficial in drilling
and completion fluids for deep HPHT gas wells
•Density up to 2.3 g/cm
3
–no solids !
•Only monovalent ions (Na
+
, K
+
, Cs
+
, HCOO
-
)
•Low brine viscosity , typically ~5 cP (in water)
•Low water activity= ~0.3 at higher densities
•Non-toxic and readily biodegradable
•Can be buffered at pH 9-10
•Protect polymers at high temperature
•Less corrosive than other brines
•Low TCT and good hydrate inhibition
•Good lubricity
•Poor solvent for methane
John Downs -Formate Brine Ltd, Tealby 22
25/01/2022
NO OIL !
NO BARITE !
NO BROMIDE !

23. Cesium formate is leased out to users and recycled after use. The
sole supplier, Sinomine Specialty Fluids, receives United Nations
recognition for its leasing business model
Cs formate recycling unit in Aberdeen

24. First field trials of cesium formate brine
in HPHT Shearwater and Dunbar wells,
UK North Sea, during late- 1999
Cesium formate brine was used as
a clean/clear completion and
workover fluid in these first trials

25. The first sustained use of K/Cs formate brine was in the world’s largest HPHT gas
field development
Cesium formate brine was used by TOTAL in 34 well
construction operations in 8 deep gas fields in period
1999-2010
Elgin/Franklin field –UK North Sea –operated by TOTAL

26. 26Case History –HPHT gas condensate wells drilled and completed with Cs formate brine -Kvitebjornwells A- 5 and A-14
Sustained use of cesium formate brine as a drilling and completion fluid in the
the Kvitebjornfield, 2004-2010
•Kvitebjornis a HPHT gas/condensate field in the Norwegian North Sea
•Owners: Equinor, Spirit Energy (Centrica), PGNiGand Total
•Water depth: 190 metres
•Reservoir: Brent Group – Middle Jurassic sandstones
•Av. porosity 20%, permeability 50- 90 mD, net/gross 0.63
•Reservoir thickness: 125- 165 metres
•Reservoir depth: 4,000 metres TVD
•Reservoir temperature/pressure: 150
o
C/ 770 bar
•Drainage strategy: Pressure depletion
•No aquifer or mobile water in main reservoir
•Production start-up date: 2004 -5 from initial 5 (of 14) wells
•All 15 development wells drilled and completed with cesium formate fluids
(SPE
105733)

27. Some of the UK North Sea
HPHT gas fields developed
using cesium formate brine
1/25/2022 John Downs -Formate Brine Ltd, Tealby 27

28. Some of the Norwegian North Sea gas
fields developed using cesium formate
brine
The majority of the Norwegian fields developed
using cesium formate are HPHT or semi- HPHT
Considerable use of solids- free oil-based
completion fluids weighted up with Cs formate
brine emulsified within the oil

29. Replacing traditional barite slurries with clear cesium
formate brine in deep HPHT gas well construction ops had
an immediate impact
•Well delivery time and costs were reduced
•Well/operational safety was greatly improved
•Hydrocarbon production exceeded expectations
•More precise reservoir definition from well
Logging

30. Replacing traditional barite slurries with clear cesium
formate brine in deep HPHT gas well construction ops
had an immediate impact
Well delivery time and costs were reduced
Confirmed by benchmarking study carried
out by Ridge consultancy in 2012
25/01/2022 John Downs -Formate Brine Ltd, Tealby 30

31. Replacing traditional barite slurries with
clear cesium formate brine in deep
HPHT gas well construction ops had an
immediate impact
Well/operational safety was greatly
improved
Zero well control incidents in wells drilled and/or
completed with Cs formate , 1999-2022
25/01/2022 John Downs -Formate Brine Ltd, Tealby 31

32. Replacing traditional barite
slurries with clear cesium
formate brine in deep HPHT
gas well construction ops had
an immediate impact
Hydrocarbon production
rates exceeded expectations
Gas production from the Kvitebjorn
field has so far exceeded the original
reserves estimate by > 50%
25/01/2022 John Downs -Formate Brine Ltd, Tealby 32

33. 33
Delivering Reserves -Long term (14 years) production from Kvitebjornwells A- 5 and A-14
0
2
4
6
8
10
12
14
0 1000 2000 3000 4000 5000
Cumulative Gas Production [G Sm
3
]
Time since start-up (days)
Well A-5
Well shut-inMay 2007 to
January 2009 (619 days)
Revised gas reserves estimate in 2006 after drill- in with Cs formate brine
A-5 completed with 6
5
/
6 inchsingle-wrap sand screens
Original gas reserves estimate in 2004
0
2
4
6
8
10
12
14
0 1000 2000 3000 4000 5000
Cumulative Gas Production [G Sm
3
]
Time since start-up (days)
Well A-14
Revised gas reserves estimate in 2006 after drill-in with Cs formate brine
Four well shut-insDec 2006 to Aug
2011 (total 765 days)
A-14 completed with a perforated 7" cemented liner
Both HPHT wells have produced 2 x more gas than the original reserves figure estimated in 2004 prior to
drill-in with Cs formate brine
Initial skin = 3 and estimated initial PI = 140,000 Sm
3
gas /day/bar
Initial skin = 15 and initial PI = 94,022 Sm 3
gas /day/bar

34. Replacing traditional barite slurries with clear cesium formate brine in
deep HPHT gas well construction ops had an immediate impact
Providing more precise reservoir definition
John Downs -Formate Brine Ltd, Tealby
3425/01/2022
Photoelectric absorption of low
energy γ-rays by formation
components with high atomic
number (Z)

35. 1st July 2021 – Start-up of Martin Linge field, developed with cesium formate
brine. Recoverable gas reserves equivalent to 1/3 of UK annual needs
John Downs -Formate Brine Ltd, Tealby
3525/01/2022
Photoelectric absorption of low
energy γ-rays by formation
components with high atomic
number (Z)

36. Further information www.formatebrines.com
John Downs -Formate Brine Ltd, Tealby 3625/01/2022
Photoelectric absorption of low
energy γ-rays by formation
components with high atomic
number (Z)