Low-Tension Gas (LTG) Injection Strategy in High Salinity and High Temperature Sandstone Reservoirs

2015 ◽  
Author(s):  
N. Nguyen ◽  
Guangwei Ren ◽  
K. Mateen ◽  
P. R. Cordelier ◽  
D. C. Morel ◽  
...  
Keyword(s):  
High Temperature ◽  
High Salinity ◽  
Injection Strategy ◽  
Sandstone Reservoirs ◽  
Low Tension

CO2-Soluble Ionic Surfactants and CO2Foams for High-Temperature and High-Salinity Sandstone Reservoirs

2015 ◽  
Vol 29 (9) ◽  
pp. 5750-5760 ◽  
Author(s):  
Zheng Xue ◽  
Krishna Panthi ◽  
Yunping Fei ◽  
Keith P. Johnston ◽  
Kishore K. Mohanty
Keyword(s):  
High Temperature ◽  
High Salinity ◽  
Ionic Surfactants ◽  
Sandstone Reservoirs

Ultralow-Interfacial-Tension Foam-Injection Strategy in High-Temperature Ultrahigh-Salinity Fractured Oil-Wet Carbonate Reservoirs

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2822-2840 ◽  
Author(s):  
Pengfei Dong ◽  
Maura C. Puerto ◽  
Kun Ma ◽  
Khalid Mateen ◽  
Guangwei Ren ◽  
...  
Keyword(s):  
High Temperature ◽  
Oil Recovery ◽  
High Salinity ◽  
Salinity Gradient ◽  
Carbonate Reservoirs ◽  
Sweep Efficiency ◽  
Injection Strategy ◽  
The Matrix ◽  
Ultralow Interfacial Tension ◽  
Ultralow Ift

Summary Oil recovery in many carbonate reservoirs is challenging because of unfavorable conditions, such as oil–wet surface wettability, high reservoir heterogeneity, and high brine salinity. We present the feasibility and injection–strategy investigation of ultralow–interfacial–tension (IFT) foam in a high–temperature (greater than 80°C), ultrahigh–formation–salinity [greater than 23% total dissolved solids (TDS)] fractured oil–wet carbonate reservoir. Because a salinity gradient is generated between injection seawater (SW) (4.2% TDS) and formation brine (FB) (23% TDS), a frontal–dilution map was created to simulate frontal–displacement processes and thereafter it was used to optimize surfactant formulations. IFT measurements and bulk–foam tests were also conducted to study the salinity–gradient effect on the performance of ultralow–IFT foam. Ultralow–IFT foam–injection strategies were investigated through a series of coreflood experiments in both homogeneous and fractured oil–wet core systems with initial oil/brine two–phase saturation. The representative fractured system included a well–defined fracture by splitting the core sample lengthwise. A controllable initial oil/brine saturation in the matrix can be achieved by closing the fracture with a rubber sheet at high confining pressure. The surfactant formulation achieved ultralow IFT (magnitude of 10−2 to 10−3 mN/m) with the crude oil at the displacement front and good foamability at underoptimal conditions. Both ultralow–IFT and foamability properties were found to be sensitive to the salinity gradient. Ultralow–IFT foam flooding achieved more than 50% incremental oil recovery compared with waterflooding in fractured oil–wet systems because of the selective diversion of ultralow–IFT foam. This effect resulted in a crossflow near the foam front, with surfactant solution (or weak foam) primarily diverted from the fracture into the matrix before the foam front, and oil/high–salinity brine flowing back to the fracture ahead of the front. The crossflow of oil/high–salinity brine from the matrix to the fracture was found to create challenges for foam propagation in the fractured system by forming Winsor II conditions near the foam front and hence killing the existing foam. It is important to note that Winsor II conditions should be avoided in the ultralow–IFT foam process to ensure good foam propagation and high oil–recovery efficiency. Results in this work contributed to demonstrating the technical feasibility of ultralow–IFT foam in high–temperature, ultrahigh–salinity fractured oil–wet carbonate reservoirs and investigated the injection strategy to enhance the low–IFT foam performance. The ultralow–IFT formulation helped to mobilize the residual oil for better displacement efficiency and reduce the unfavorable capillary entry pressure for better sweep efficiency. The selective diversion of foam makes it a good candidate for a mobility–control agent in a fractured system for better sweep efficiency.

Robustness of Novel Low-Tension Gas LTG Floods in High Salinity and High Temperature Reservoirs

2019 ◽  
Author(s):  
Nhat Nguyen ◽  
Guangwei Ren ◽  
Khalid Mateen ◽  
Kun Ma ◽  
Haishan Luo ◽  
...  
Keyword(s):  
High Temperature ◽  
High Salinity ◽  
Low Tension

A Novel Hydroxylpropyl Sulfobetaine Surfactant for High Temperature and High Salinity Reservoirs

2013 ◽  
Author(s):  
Fan Zhang ◽  
Desheng Ma ◽  
Qiang Wang ◽  
Youyi Zhu ◽  
Wenli Luo
Keyword(s):  
High Temperature ◽  
High Salinity
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