Petroleum Science >2015,??Issue 3:??470-482 DOI: https://doi.org/10.1007/s12182-015-0033-x
An experimental and numerical study of chemically enhancedwater alternating gas injection Open?Access
文章信息
作者：Saeed Majidaie,Mustafa Onur and Isa M. Tan
作者单位：
Leap Energy- Subsurface Consulting Services, Kuala Lumpur, Malaysia;Department of Petroleum and Natural Gas Engineering, Istanbul Technical University, Istanbul, Turkey;Applied Science Department, Universiti Teknologi Petronas, Tronoh, Perak, Malaysia
投稿时间：2015-07-09
引用方式：Majidaie, S., Onur, M. & Tan, I.M. Pet. Sci. (2015) 12: 470. https://doi.org/10.1007/s12182-015-0033-x
文章摘要
In this work, an experimental study combined
with numerical simulation was conducted to investigate the
potential of chemically enhanced water alternating gas
(CWAG) injection as a new enhanced oil recovery method.
The unique feature of this new method is that it uses
alkaline, surfactant, and polymer additives as a chemical
slug which is injected during the water alternating gas
(WAG) process to reduce the interfacial tension (IFT) and
simultaneously improve the mobility ratio. In essence, the
proposed CWAG process involves a combination of
chemical flooding and immiscible carbon dioxide (CO2)
injection and helps in IFT reduction, water blocking
reduction, mobility control, oil swelling, and oil viscosity
reduction due to CO2 dissolution. Its performance was
compared with the conventional immiscible water alternating
gas (I-WAG) flooding. Oil recovery utilizing
CWAG was better by 26 % of the remaining oil in place
after waterflooding compared to the recovery using WAG
conducted under similar conditions. The coreflood data
(cumulative oil and water production) were history matched
via a commercial simulator by adjusting the relative
permeability curves and assigning the values of the rock
and fluid properties such as porosity, permeability, and the
experimentally determined IFT data. History matching of
the coreflood model helped us optimize the experiments
and was useful in determining the importance of the
parameters influencing sweep efficiency in the CWAG
process. The effectiveness of the CWAG process in providing
enhancement of displacement efficiency is evident
in the oil recovery and pressure response observed in the
coreflood. The results of sensitivity analysis on CWAG
slug patterns show that the alkaline–surfactant–polymer
injection is more beneficial after CO2 slug injection due to
oil swelling and viscosity reduction. The CO2 slug size
analysis shows that there is an optimum CO2 slug size,
around 25 % pore volume which leads to a maximum oil
recovery in the CWAG process. This study shows that the
ultralow IFT system, i.e., IFT equaling 10-2 or 10-3 mN/
m, is a very important parameter in CWAG process since
the water blocking effect can be minimized.
with numerical simulation was conducted to investigate the
potential of chemically enhanced water alternating gas
(CWAG) injection as a new enhanced oil recovery method.
The unique feature of this new method is that it uses
alkaline, surfactant, and polymer additives as a chemical
slug which is injected during the water alternating gas
(WAG) process to reduce the interfacial tension (IFT) and
simultaneously improve the mobility ratio. In essence, the
proposed CWAG process involves a combination of
chemical flooding and immiscible carbon dioxide (CO2)
injection and helps in IFT reduction, water blocking
reduction, mobility control, oil swelling, and oil viscosity
reduction due to CO2 dissolution. Its performance was
compared with the conventional immiscible water alternating
gas (I-WAG) flooding. Oil recovery utilizing
CWAG was better by 26 % of the remaining oil in place
after waterflooding compared to the recovery using WAG
conducted under similar conditions. The coreflood data
(cumulative oil and water production) were history matched
via a commercial simulator by adjusting the relative
permeability curves and assigning the values of the rock
and fluid properties such as porosity, permeability, and the
experimentally determined IFT data. History matching of
the coreflood model helped us optimize the experiments
and was useful in determining the importance of the
parameters influencing sweep efficiency in the CWAG
process. The effectiveness of the CWAG process in providing
enhancement of displacement efficiency is evident
in the oil recovery and pressure response observed in the
coreflood. The results of sensitivity analysis on CWAG
slug patterns show that the alkaline–surfactant–polymer
injection is more beneficial after CO2 slug injection due to
oil swelling and viscosity reduction. The CO2 slug size
analysis shows that there is an optimum CO2 slug size,
around 25 % pore volume which leads to a maximum oil
recovery in the CWAG process. This study shows that the
ultralow IFT system, i.e., IFT equaling 10-2 or 10-3 mN/
m, is a very important parameter in CWAG process since
the water blocking effect can be minimized.
关键词
-
Enhanced water alternating gas (CWAG) Enhanced oil recovery Interfacial tension Mobilitycontrol Water blocking