Comparative study of oil recovery efficiency enhanced by
surfactants, microemulsion, and nanoemulsion
1,2
Tereza Neuma de Castro Dantas * , 2 Tamyris Thaise Costa de Souza,
2 Afonso Avelino Dantas Neto e 2 Eduardo Lins de Barros Neto
1I N S T I T U T E
O F C H E M I S T R Y, P O S T - G R A D U AT I O N P R O G R A M , F E D E R A L U N I V E R S I T Y O F R I O G R A N D E D O
NORTE, UFRN, BRAZIL
2 D E PA R T M E N T
O F C H E M I C A L E N G I N E E R I N G , P O S T - G R A D U AT I O N P R O G R A M , F E D E R A L U N I V E R S I T Y O F
RIO GRANDE DO NORTE, UFRN, BRAZIL
* terezaneuma1011@yahoo.com.br ; tereza@eq.ufrn.br
Introduction
As the reservoir natural energy starts to exhaust, it is necessary to provide additional
energy in order to improve the recovery rate. These techniques are called enhanced
recovery methods (EOR).
In the conventional methods, water or gas are injected in order to keep the reservoir’s
energy up. The method’s limitations, such as the viscosity of the retained oil and the
high interface tension (fluid/oil), compromises the operations efficiency.
The enhanced recovery methods were created to act when the conventional methods
are no longer efficient. The main objective of these methods is the interaction
between the injected fluid and the oil retained inside the reservoir pores. There are
three major categories of EOR: thermal, miscible, and chemical methods.
Introduction
The oil industry, despite the high levels of technology, still needs help on
recovering oil from reservoirs.
UFRN – Science and Technology in
Surfactants Research Group has
developed studies on the use of:
These solutions act directly in the
rock/oil interface, changing the
following properties:
- Surfactant solutions;
- Microemulsions;
- Nanoemulsions.
-
Interface tension;
Wettability;
Miscibility;
Viscosity.
Objective
This presentation has, as its main objective, to show the results
obtained with the development of new technologies of enhanced oil
recovery
using
surfactant
nanoemulsions as injection fluids.
solutions,
microemulsions,
and
SURFACTANT
Natural or synthetic substances that have a water soluble (polar head
group - hydrophilic) and a water insoluble component (tail group hydrophobic), responsible for its adsorption in the liquid-liquid, liquidgas or solid-solid interfaces of a given system.
Microemulsions and Nanoemulsions
Microemulsions and nanoemulsions are liquid dispersions containing surfactant
aggregates.
Nanoemulsion
Microemulsion
oThermodynamically unstable
oThermodynamically stable
o Transparent aspect
X
o Transparent aspect
o Requires low energy to prepare it – low costs
o Requires more energy to be prepared
o Greater amount of surfactant
o Lower amount of surfactant
o Very low interface tension
o Low interface tension
Methodology
Confining pressure apparatus for hydrostatic tests in porous media
Experiments using cores of sandstone and carbonate rocks
1st – Brine saturation – injection of KCL 2%
at a constant rate of 0.5mL/min;
2nd – Oil saturation – injection of oil (Ubarana
Oilfield) at a constant rate of 0.5mL/min;
3rd – Brine injection – conventional recovery
4th – Injection of chemical fluid – enhanced oil
recovery
Results
Sandstone rock study
Micromulsion
12.5% - Surfactant
2% - Oil Phase
73% - Aqueous phase
Obtained nanoemulsion: 2.5% of Surfactant
Ternary phase diagram
Nanoemulsion obtaining – Low Energy
Results
Sandstone rock study
Microemulsion x Nanoemulsion
12.5%
2.5%
Results
Sandstone rock study
MICROEMULSION
NANOEMULSION
Polymer solution
% POLYMER
0
0.1
0.5
0
0.1
0.5
0.5
%
Conventional
Efficiency
71.3
62.5
68.0
57.5
56.7
57.0
53.2
% Advanced
Efficiency
56.9
61.3
87.5
39.4
52.6
85.0
30.1
% Total
efficiency
87.6
85.50
96.0
74.4
79.4
93.5
67.5
Microemulsion
12.5% - Surfactant
Nanoemulsion
2.5% - Surfactant
Results
Carbonate rock study
Micromulsion
12.5% - Surfactant
2% - Oil Phase
73% - Aqueous phase
Results
Carbonate rock study
Conventional
efficiency
(%)
Advanced
efficiency
(%)
Total
efficiency
(%)
ST
54.0
12.5
60.0
ST
(KCl 2wt%)
62.0
27.5
72.0
Micro
64.0
59.0
85.0
Micro
(KCl 2wt%)
68.0
52.0
84.0
ST – Surfactant solution
Micro - Microemulsion
Results
Carbonate rock Study
Study of nanoemulsion systems that
were obtained by infinite dilution of
microemulsiom systems.
Results
Carbonate rock study
Nanoemulsion 1% - Surfactant
Conventional efficiency(%)
59.0
Advanced efficiency (%)
28.0
Total efficiency (%)
70.0
Conclusions
o The presented results show the overall potential for surfactant solution, microemulsions, and nanoemulsions
application in enhanced oil recovery;
o The methods using the developed systems present some extra advantages when compared with other
methods, considering that they interact directly with the oil and, consequently, promote the displacement by
miscibility and/or reduction of the interface tension between the fluid and the oil, increasing oil production
after the conventional treatment;
o The nanoemulsion application presents as advantage the use of small amounts of surfactant in its
composition.