Curtis Pollard VerdeChem

1. Shale Water Management USA 2022 Symposium
Treating Colloidal Iron & Wax in Wet Shale Gas
Brine Production
Curtis Pollard
August 22 - 23, 2022

2. verdechem.com 2
• Soluble Iron Fundamentals & Flow Assurance Issues – one bad actor!
• Field/Case Studies
• Colloidal Wax Poly Dispersions – New Nemesis – another bad actor!
• VerdeChem Chemical Solutions
• Summary
Technical Outline

3. verdechem.com 3
Soluble Iron Fundamentals
&
Flow Assurance Issues

4. verdechem.com 4
Iron we Know and Accept
Scitechdaily.com Azstatepark.com Disneyplus.com

5. verdechem.com 5
Unwanted Production Iron Contaminants
C-Ring Recycled Production Brine for Re-Frack

6. verdechem.com 6
Precipitation of Iron Reaction Products &
Conversion from Ferrous to Ferric

7. verdechem.com 7
Ferric Hydroxide Gels

8. verdechem.com 8
Colloidal Iron and Clays can play a disproportionate role in causing flow assurance problems:
1. Emulsion Stabilization
2. Pad formation in Separators
3. Pipeline solids and sludges
4. Plugging Water Injection and Disposal Wells - Colloidal Charged Particles do not Follow the ’Size Exclusion Rules’ in
formation skin damage plugging mechanisms
A reassessment of the Role of Colloidal Iron in Produced Water from Shale Operations – A Review of Field Data and Literature (Part A & B)
John M. Walsh, PhD, SPE Member, Worley Consulting, former Shell E&P
Kris M. Bansal, PhD, SPE Member, former Conoco Phillips
Featured in the JPT (Journal of Petroleum Technology) Sept. 20 & Nov. 24, 2021
Dr. John Walsh & Dr. Kris Bansal Findings

9. verdechem.com 9
• Colloidal Iron is submicron
• High Charge Density
• Large Surface Area
• Iron cations associate with negatively charged colloidal solids (i.e. clays and silicates)
• Quickly becomes oil wet and acts like a glue to agglomerate/sludge other solids with polar oil
fractions (asphaltenes & maltene resins)
• Stabilize ‘Pickering Style O/W emulsions’ making phase separation more difficult
Charged Iron is often the Glue

10. verdechem.com 10
Field/Case Studies

11. verdechem.com 11
Untreated Oil-Wet Iron Compounds
Iron Hydroxide ppt. Iron Sulfide ppt.
Plugged Bag Filters
Iron Laden Brine/Condensate Emulsions

12. verdechem.com 12
Extraction Analysis by Millipore Paper

13. verdechem.com 13
1 Micron Filter
SEM & EDS Analysis
Element Weight. C (wt%) Atom. C (at%)
O K 25.49 48.29
Al K 2.41 2.71
Si K 15.69 16.94
Cl K 2.98 2.55
K K 0.54 0.42
Ca K 1.82 1.38
Fe K 51.06 27.71
Element Weight. C (wt%) Atom. C (at%)
O K 52.00 71.76
Al K 3.76 3.08
Si K 17.80 13.99
Cl K 1.90 1.18
Ca K 1.87 1.03
Fe K 22.67 8.96

14. verdechem.com 14
Treated Sour Water to Prevent FeS ppt.

15. verdechem.com 15
Rapid Reduction in Required Filter Changes
0
50
100
150
200
250
300
350
400
450
500
January February March April May June July August September October November December January February
10µ 25µ 50µ 100µ
Continuous Injection of
SCi7775 Chemistry Start

16. verdechem.com 16
Colloidal Wax Poly Dispersions
New Flow Assurance Problem

17. verdechem.com 17
• Polymeric Wax Inhibitors are proving effective in keeping downhole wax micro-crystalline and
dispersed so they can be mobilized and brought to surface
• Everyone would agree that moving wax deposition issues from downhole to surface is a prudent
and preferable alternative to wax knifing, costly well shutdowns, and work-overs. The
opportunity cost of lost production is too high
• Micro-crystalline wax tied up with polar polymeric wax inhibitors invariably finds its way into the
brine production treating system. Undersized inlet separators do not help
Treating Wax at Surface Always Preferable

18. The very white opaque Inlet Brine is contaminated with
colloidal wax/organics & sometimes stabilized further by
colloidal iron, silica and clays
Colloidal Wax Poly-Dispersions

19. • Montney Filtered Brine Organic Solids at 16-
21 Inlet Separator
• Broad carbon distribution: C5 to C80
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
C5
C9
C13
C17
C21
C25
C29
C33
C37
C41
C45
C49
C53
C57
C61
C65
C69
C73
C77
C82
C90
Vol
%
Carbon Number
Calculated C100 from ASTM D7169 SimDist.
Data
16-21 Organic Filtered Solids
C100 Scan of Organic Filtered Brine Solids

20. • PAD Pig Trap from 15-20 20” line Nov.
27, 2020
• Amorphous Carbon – 37 %
• Crystalline Carbon – 1.6 %
• Amorphous Iron – 17.4 %
• Crystalline Iron – 7.1 %
Amorphous Carbon from EDS Analysis & Elevated Iron

21. • Cationic surfactants found in water-based corrosion
inhibitors and biocides
• Surfactants render wax surface hydrophilic - hydrated
with water
• Enhanced zeta potential can stabilize poly-dispersed
colloidal wax in brine
Reaction with Cationic Surfactants in Water Leg
Stabilize Colloidal Wax Poly-dispersions

22. verdechem.com 22
VerdeChem Chemical Solutions

23. verdechem.com 23
SCi7775 is a powerful anti-foulant which uses a blend of high-performance additives to
achieve scale control
It is a high activity chelant, which effectively inhibits iron cations in the presence of
calcium and high TDS brines
It has water wetting capacities for removing oil filming and keeping scaling cations
soluble in mixed pH regimes
Capacity to provide Anionic Flocculation to help clarify cationic colloidal poly
dispersions of wax
VerdeChem ICA (Iron Control & Anti-Foulant)

24. • Colloidal wax can pass through process filtration - with
subsequent cooling flocculate downstream
• SCi7775 treatment and soak - flocculate colloidal wax to
surface in water tanks. Any colloidal Iron is effectively
chelated.
• Specialized wax solvents (CD100i) can then solvate the
wax
Anionic Flocculation of Hydrophilic Colloidal Wax

25. • Specialized wax solvent/dispersant (CD100i)
used to solvate the colloidal wax and keep any
remaining wax dispersed
Solvation of Flocculated Colloidal Wax

26. Flocculation and Colloidal Particle Size
Increase after Chemical Treatment

27. PSA Histogram of Colloidal Solids
Before & After Chemical
Before Chemical Treatment After Chemical Treatment

28. SEM IMAGERY OF COLLOIDAL
PARTICLES IN BRINE

29. verdechem.com 29
Summary

30. verdechem.com 30
• Iron is a definitive issue in Flow Assurance Treating
• Colloidal Wax is a new Flow Assurance problem
• VerdeChem ICA Chemistries have proven Effective in Field Applications
• Customization and Optimization of Chemical Treatment Programs - Essential
Summary