Well stimulation using acidic solutions is widely used to treat carbonate formations. The acidic fluids remove the near-wellbore damage and create channels around the wellbore by dissolving fraction of the carbonate rocks. Many stimulation fluids have been used such as hydrochloric acid (HCl) acid, organic acids, and chelating agents to stimulate carbonate reservoirs. Wormholes that are created by these fluids are very effective and will yield negative skin values and this will enhance the well productivity. In addition to the wormhole creation, the diffusion of these fluids inside the pores of the rock may create significant and permanent changes in the rock mechanical properties. These changes can eventually lead to weakening the rock strength, which may lead to future formation damage due to the wellbore instability. In this paper, the effect of ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) chelating agents on the carbonate rocks elastic properties was investigated. The effect of wormholes created by chelating agent on the rock mechanical properties was investigated. Computed tomography (CT) scan and acoustic measurements were conducted on the core samples before and after matrix stimulation treatments. Experimental results showed that the mechanical properties of strong rocks such as Indiana limestone (IL) cores were not affected when chelating agents were used to stimulate those cores. On the other hand, less strong rocks such as Austin chalk (AC) show significant alteration on the rock elastic properties when chelating agents were used as stimulation fluids.

References

References
1.
Nunes
,
M.
,
Bedrikovetsky
,
P.
,
Newbery
,
B.
,
Paiva
,
R.
,
Furtado
,
C.
, and
de Souza
,
A. L.
,
2010
, “
Theoretical Definition of Formation Damage Zone With Applications to Well Stimulation
,”
ASME J. Energy Resour. Technol.
,
132
(
3
), p.
033101
.
2.
Rae
,
P.
, and
Di Lullo
,
G.
,
2003
, “
Matrix Acid Stimulation—A Review of the State-of-the-Art
,”
SPE European Formation Damage Conference
, The Hague, The Netherlands, May 13–14, Paper No. SPE-82260-MS.
3.
Nasr-El-Din
,
H. A.
,
2005
, “
Formation Damage Induced by Chemical Treatments: Case Histories
,”
ASME J. Energy Resour. Technol.
,
127
(
3
), pp.
214
224
.
4.
Hoefner
,
M. L.
, and
Scott Fogler
,
H.
,
1987
, “
Role of Acid Diffusion in Matrix Acidizing of Carbonates
,”
J. Pet. Technol.
,
39
(
2
), pp.
203
208
.
5.
Metcalf
,
A.
,
Parker
,
C.
, and
Boles
,
J.
,
2005
, “
Acetic Acid Demonstrates Greater Carbonate Dissolution Than Typically Expected
,”
J. Can. Pet. Technology
,
44
(
12
), pp.
22
24
.
6.
Taylor
,
K.
, and
Nasr-El-Din
,
H.
,
2009
, “
Measurement of Acid Reaction Rates With the Rotating Disk Apparatus
,”
J. Can. Pet. Technol.
,
48
(
6
), pp.
66
70
.
7.
Fredd
,
C.
, and
Fogler
,
H. S.
,
1998
, “
Alternative Stimulation Fluids and Their Impact on Carbonate Acidizing
,”
SPE J.
,
13
(
1
), pp.
34
–41.
8.
Frenier
,
W.
,
Fredd
,
C.
, and
Chang
,
F.
,
2001
, “
Hydroxyaminocarboxylic Acids Produce Superior Formulations for Matrix Stimulation of Carbonates at High Temperatures
,”
SPE Annual Technical Conference and Exhibition
, New Orleans, LA, Sept. 30–Oct. 3, Paper No. SPE-71696-MS.
9.
Huang
,
T.
,
Ostensen
,
L.
, and
Hill
,
A.
,
2000
, “
Carbonate Matrix Acidizing With Acetic Acid
,”
SPE International Symposium on Formation Damage Control
, Lafayette, LA, Feb. 23–24, Paper No. SPE-58715-MS.
10.
Jacobs
,
I.
,
1989
, “
Chemical Systems for the Control of Asphaltene Sludge During Oil Well Acidizing Treatments
,”
SPE International Symposium on Oilfield Chemistry
, Houston, TX, Feb. 8–10, Paper No. SPE-18475-MS.
11.
Fredd
,
C.
, and
Fogler
,
H.
,
1997
, “
Chelating Agents as Effective Matrix Stimulation Fluids for Carbonate Formations
,”
International Symposium on Oilfield Chemistry
, Houston, TX, Feb. 18–21, Paper No. SPE 37212-MS.
12.
Al-Katheeri
,
M.
,
Nasr-EL-Din
,
H. A.
,
Taylor
,
K. C.
, and
Al-Grainees
,
A. H.
,
2002
, “
Determination and Fate of Formic Acid in High Temperature Acid Stimulation Fluids
,”
International Symposium and Exhibition on Formation Damage Control
, Lafayette, LA, Feb. 20–21, Paper No. SPE-73749-MS.
13.
Buijse
,
M.
,
de Boer
,
P.
,
Breukel
,
B.
, and
Burgos
,
G.
,
2004
, “
Organic Acids in Carbonate Acidizing
,”
SPE Prod. Facil.
,
19
(
3
), pp.
128
134
.
14.
Chang
,
F. F.
,
Nasr-El-Din
,
H. A.
,
Lindvig
,
T.
, and
Qui
,
X. W.
,
2008
, “
Matrix Acidizing of Carbonate Reservoirs Using Organic Acids and Mixture of HCl and Organic Acids
,”
SPE Annual Technical Conference and Exhibition
, Denver, CO, Sept. 21–24, Paper No. SPE-116601-MS.
15.
Dill
,
R. W.
, and
Keeney
,
B. R.
,
2003
, “
Optimizing HCl-Formic Acid Mixtures for High Temperature Stimulation
,”
SPE Annual Fall Technical Conference and Exhibition
, Houston, TX, Oct. 1–3, Paper No. SPE-7567-MS.
16.
Alkhaldi
,
M. H.
,
Nasr-El-Din
,
H. A.
, and
Sarma
,
H. K.
,
2009
, “
Application of Citric Acid in Acid Stimulation Treatments
,”
Canadian International Petroleum Conference
, Calgary, AB, Canada, June 16–18, Paper No. PETSOC-2009-015.
17.
Rabie
,
A. I.
,
Shedd
,
D. C.
, and
Nasr-El-Din
,
H. A.
,
2014
, “
Measuring the Reaction Rate of Lactic Acid With Calcite and Dolomite by Use of the Rotating-Disk Apparatus
,”
SPE J.
,
19
(06), pp.
1192
1202
.
18.
Robert
,
J.
, and
Crowe
,
C.
,
2000
, “
Carbonate Acidizing Design
,”
Reservoir Stimulation
, Wiley, Chichester, UK, Chap. 17.
19.
Broaddus
,
G.
,
1988
, “
Well-and Formation-Damage Removal With Nonacid Fluids
,”
J. Pet. Technol.
,
40
(06), pp.
685
687
.
20.
Cikes
,
M.
,
Branka
,
V.
,
Mihovil
,
T.
, and
Oljeg
,
J.
,
1990
, “
A Successful Treatment of Formation Damage Caused by High-Density Brine
,”
SPE Prod. Eng.
,
5
(02), pp.
175
179
.
21.
Clemmit
,
A.
,
Ballance
,
D.
, and
Hunton
,
A.
,
1985
, “
The Dissolution of Scales in Oilfield Systems
,”
Offshore Europe
, Aberdeen, UK, Sept. 10–13, Paper No. SPE-14010-MS.
22.
Paul
,
J.
, and
Fieler
,
E.
,
1992
, “
A New Solvent for Oilfield Scales
,”
SPE Annual Technical Conference and Exhibition
, Washington, D.C., Oct. 4–7, Paper No. SPE-24847-MS.
23.
Vetter
,
O.
,
1976
, “
Oilfield Scale—Can We Handle It?
,”
J. Pet. Technol.
,
28
(
12
), pp.
1402
1408
.
24.
Mahmoud
,
M.
, and
Nasr-El-Din
,
H. A.
,
2014
, “
Challenges During Shallow and Deep Carbonate Reservoirs Stimulation
,”
ASME J. Energy Resour. Technol.
,
137
(
1
), p.
012902
.
25.
Fredd
,
C. N.
, and
Fogler
,
H. S.
,
1998
, “
The Influence of Chelating Agents on the Kinetics of Calcite Dissolution
,”
J. Colloid Interface Sci.
,
204
(
1
), pp.
187
197
.
26.
Husen
,
A.
,
Frenier
,
W. W.
,
Xiao
,
Z.
, and
Ziauddin
,
M.
,
2002
, “
Chelating Agent-Based Fluid for Optimal Stimulation of High-Temperature Wells
,”
SPE Annual Technical Conference and Exhibition
, San Antonio, TX, Sept. 29–Oct. 2, Paper No. SPE-77366-MS.
27.
Mahmoud
,
M.
, and
Nasr-El-Din
,
H. A.
,
2014
, “
Modeling Flow of Chelating Agents During Stimulation of Carbonate Reservoirs
,”
Arabian J. Sci. Eng.
,
39
(
12
), pp.
9239
9248
.
28.
LePage
,
J.
,
De Wolf
,
C.
,
Josine
,
B.
, and
Nasr-El-Din
,
H. A.
,
2011
, “
An Environmentally Friendly Stimulation Fluid for High-Temperature Applications
,”
SPE J.
,
16
(
1
), pp.
104
110
.
29.
Mahmoud
,
M.
,
Mohamed
,
I. M.
,
Nasr-El-Din
,
H. A.
, and
De Wolf
,
C. A.
,
2011
, “
When Should We Use Chelating Agents in Carbonate Stimulation?
,”
SPE/DGS Saudi Arabia Section Technical Symposium and Exhibition
, Al-Khobar, Saudi Arabia, May 15–18, Paper No. SPE-149127-MS.
30.
Mahmoud
,
M. A.
,
Nasr-El-Din
,
H. A.
,
De Wolf
,
C.
, and
LePage
,
J. N.
,
2010
, “
An Effective Stimulation Fluid for Deep Carbonate Reservoirs: A Core Flood Study
,”
International Oil and Gas Conference and Exhibition in China
, Beijing, China, June 8–10, Paper No. SPE-131626-MS.
31.
Brandås
,
L. T.
,
2012
, “
Relating Acoustic Wave Velocities to Formation Mechanical Properties
,” Master's thesis, The Norwegian University of Science and Technology, Trondheim, Norway.
32.
Olabode
,
A.
, and
Radonjic
,
M.
,
2014
, “
Shale Caprock/Acidic Brine Interaction in Underground CO2 Storage
,”
ASME J. Energy Resour. Technol.
,
136
(
4
), p.
042901
.
33.
Mohamed
,
I. M.
,
He
,
J.
, and
Nasr-El-Din
,
H. A.
,
2013
, “
Experimental Analysis of CO2 Injection on Permeability of Vuggy Carbonate Aquifers
,”
ASME J. Energy Resour. Technol.
,
135
(
1
), p.
013301
.
34.
Nguyen
,
M.
,
Bemer
,
E.
, and
Dormieux
,
L.
,
2011
, “
Micromechanical Modeling of Carbonate Geomechanical Properties Evolution During Acid Gas Injection
,”
45th U.S. Rock Mechanics/Geomechanics Symposium
, San Francisco, CA, June 26–29, Paper No. ARMA-11-207.
35.
Lu
,
J.
, and
Andrew
,
W. K.
,
2014
, “
Progression of Injectivity Damage With Oily Waste Water in Linear Flow
,”
J. Pet. Sci.
,
11
(
4
), pp.
550
562
.
36.
Buret
,
S.
,
Nabzar
,
L.
, and
Jada
,
A.
,
2010
, “
Water Quality and Well Injectivity: Do Residual Oil-in-Water Emulsions Matter?
,”
SPE J.
,
15
(
2
), pp.
557
568
.
37.
Fjar
,
E.
,
Holt
,
R. M.
,
Raaen
,
A. M.
,
Risnes
,
R.
, and
Horsrud
,
P.
,
2008
,
Petroleum Related Rock Mechanics
, Vol. 53,
Elsevier
, Oxford, UK.
38.
Eberli
,
G. P.
,
Baechle
,
G. T.
,
Flavio
,
S. A.
, and
Incze
,
M. L.
,
2003
, “
Factors Controlling Elastic Properties in Carbonate Sediments and Rocks
,”
Leading Edge
,
22
(
7
), pp.
654
660
.
39.
Mokhtar
,
E. A.
,
Sandra
,
V.
,
Ahmed
,
A. H.
, and
Mariam
,
N. M.
,
2010
, “
Rock Physics Characterization Using Acoustic Velocity Measurements On Late Cretaceous Carbonate Rocks From the Middle East
,”
Abu Dhabi International Petroleum Exhibition and Conference
, Abu Dhabi, UAE, Nov. 1–4, Paper No. SPE-138649-MS.
40.
Alam
,
M. M.
,
Fabricius
, I
. L.
,
Hjuler
,
M. L.
, and
Christensen
,
H. F.
,
2012
, “
Influence of Effective Stress Coefficient on Mechanical Failure of Chalk
,”
46th U.S. Rock Mechanics/Geomechanics Symposium
, Chicago, IL, June 24–27, Paper No. ARMA-12-286.
41.
Blanton
, III,
T. L.
,
1981
, “
Deformation of Chalk Under Confining Pressure and Pore Pressure
,”
European Offshore Petroleum Conference and Exhibition, London
, Oct. 24–27, Paper No. SPE-8076.
42.
Chertov
,
M.
,
2013
, “
On the Limitations of Effective Medium Approaches for Estimating Fracture Width in Anisotropic Rocks
,”
47th U.S. Rock Mechanics/Geomechanics Symposium
, San Francisco, CA, June 23–26, Paper No. ARMA-2013-261.
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