Crisman Annual Report 2009 - Harold Vance Department of ...

Rheological Properties of a New Class of Viscoelastic Surfactant
Objectives
Surfactant-based acid systems were developed over
the last few years for diversion, to overcome the
severe problems caused by polymer residue and
crosslinker precipitate after polymer-based system
treatments during matrix and fracture acidizing.
Surfactant molecules can form rod-like micelles and
significantly increase the viscosity in the presence of
salts. After acid treatments, the surfactant gel can
be broken by mixing with hydrocarbons, external
breakers, or internal breakers or by reducing the
concentration of salts via dilution with water. Acid
additives and Fe (III) contamination can influence
the formation of the rod-shaped micelles and result
in different rheological properties from what we
want. A new class of viscoelastic surfactant (VES)-
amidoamine oxide has been tested in this study.
The effects of acid additives, Fe (III) contamination,
temperatures and shear rates need to be examined
on the rheological properties of this new surfactant.
Approach
Acid additives studied included corrosion inhibitors,
mutual solvents, non-emulsifying surfactants, iron
control agents and a hydrogen sulfide scavenger.
The Grace Instrument M5600 HPHT Rheometer was
used to measure the apparent viscosity of live and
spent acids under different conditions. The wetted
material is Hastelloy C-276, which is acid-resistant.
Measurements were made at temperatures from 75-
220°F, and 300 psi at various shear rates from 0.01-
935 s -1 . An Orion 950 analytical titrator was used to
measure HCl concentration. The centrifuge used in
this study was Z 206 A from Labnet International.
Apparent Viscosity (cp)
1200
1000
800
600
400
200
0
5
10
15
Crisman Annual Report 2009
C HCl
(wt%)
20
8
10
12
15
18
20
25
28
Acid Concentration (wt%)
Viscosity (cp)
108.8632
706.438
984.783
175.0444
12.1892
5.8126
2.8148
2.896
25 30
Fig. 1. Apparent viscosity (10 s -1 ) of surfactant-based live acids that contained
4 wt% surfactant, 1 wt% CI-A and various HCl concentrations.
Apparent Viscosity (cp)
1800
1600
1400
1200
1000
800
600
400
200
Accomplishments
Calcium chloride increased the apparent viscosity
of live acids. Concentration of HCl in the live acid
system affected its apparent viscosity. Live acid
Project Information
2.5.15 Reaction of Organic Acids with Calcite
Related Publications
Li, L., Nasr-El-Din, H.A., Crews, J.B., and Cawiezel, K.E.
2010. Impact of Organic Acids/Chelating Agents on
Rheological Properties of Amidoamine Oxide Surfactant.
Paper SPE 128091 will be presented at the 2010 SPE
International Symposium on Formation Damage Control,
Lafayette, Louisiana, 10-12 February.
Li, L., Nasr-El-Din, H.A., and Cawiezel, K.E. 2009.
Rheological Properties of a New Class of Viscoelastic
Surfactant. Paper SPE 121716 presented at the 2009
SPE International Symposium on Oilfield Chemistry, The
Woodlands, Texas, 20-22 April.
Contacts
Hisham A. Nasr-El-Din
979.862.1473
hisham.nasreldin@pe.tamu.edu
Lingling Li
-1
Shear Rate = 10 s
P = 300 psi
0
50 70 90 110 130 150 170 190 210 230
Temperature (°F)
only CI-A
0.1 wt% FeCl3
0.5 wt% H2S scavenger
0.5 wt% demulsifier
Fig. 2. Effect of some acid additives on the apparent viscosity of spent
acids (pH = 4 ~ 5). All solutions contained CI-A.
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