scholarly journals Key geological factors controlling oil displacement efficiency of CO2 injection in low-permeability reservoirs

2021 ◽  
pp. 014459872199560
Author(s):  
Zhaosheng Wang ◽  
Lianbo Zeng ◽  
Jiangtao Yu ◽  
Zhenguo Zhang ◽  
Siyu Yang ◽  
...  
Keyword(s):  
Low Permeability ◽  
Natural Fractures ◽  
Displacement Efficiency ◽  
High Permeability ◽  
Oil Displacement ◽  
Sand Body ◽  
Oil Displacement Efficiency ◽  
Geological Factors ◽  
Low Permeability Reservoirs ◽  
Sand Bodies

Carbon dioxide (CO2) flooding is an effective method to enhance oil recovery in low-permeability reservoirs. Studying key geological factors controlling oil displacement efficiency is of great significance to the CO2 injection scheme design in low-permeability reservoirs. Focusing on low-permeable H reservoir in Songliao Basin, China, this paper describes the contact and connection of sand bodies, natural fractures and high-permeability zones with core samples, log data and experiment firstly. After that, the impact of interaction of sand body connection, natural fracture and high-permeability zone on oil displacement efficiency is determined by using geological and dynamic data in CO2 injection area. Results indicate that the connection of single sand bodies between injectors and producters wells primarily controls CO2 flooding in low-permeability reservoirs. Furthermore, coupling of sand body connection, natural fractures and high-permeability zones is the key geological factor governing oil displacement efficiency of CO2 injection in low-permeability reservoirs, where well or generally-connected sand bodies can improve the efficiency significantly. Meanwhile, the dominant seepage channels in other directions have no influence on producers, which is beneficial to improve CO2 flooding efficiency.

scholarly journals Immiscible CO2 Flooding Efficiency in Low-Permeability Reservoirs: An Experimental Investigation of Residual Oil Distribution

2021 ◽  
Vol 9 ◽  
Author(s):  
Ying Yang ◽  
Xiao-Feng Zhou ◽  
Le-Yin Sun ◽  
An-Lun Wang ◽  
Jian-guang Wei ◽  
...  
Keyword(s):  
Distribution Patterns ◽  
Low Permeability ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Oil Displacement ◽  
Core Samples ◽  
Oil Distribution ◽  
Oil Displacement Efficiency ◽  
Low Permeability Reservoirs ◽  
Ultralow Permeability

Residual oil distribution plays a critical role in understanding of the CO2 flooding processes, but its quantitative research for reservoirs with different permeability levels rarely has been comprehensively conducted in the laboratory. This article presents the results of an experimental study on the immiscible CO2 displacement efficiency in different permeability core samples and various oil distribution patterns prior to and after immiscible CO2 flooding. Experiments were conducted on four core samples extracted from the selected oil field with a permeability range from 0.210–66.077 mD. The experimental results show that the immiscible CO2 can mobilize oil in ultralow-permeability environment and achieve a reasonable displacement efficiency (40.98%). The contribution of different oil distribution patterns to displacement efficiency varies in reservoirs with different permeabilities. With the increase of core permeability, the contribution of cluster and intergranular pore oil distribution patterns to displacement efficiency increases. However, the oil displacement efficiency of corner and oil film patterns tends to increase with lower permeability. Therefore, immiscible CO2 flooding is recommended for ultralow-permeability case, especially for reservoirs with larger amount of oil in corner and oil film distribution patterns. The oil displacement efficiency calculated by immiscible CO2 flooding experiment results agrees reasonably well with the core frozen slices observation. The results of this study have practical significance that refers to the effective development of low-permeability reservoirs.

Distribution of Remaining Oil Controlled by Architecture of Sand Body in Meandering Channel

2013 ◽  
Vol 827 ◽  
pp. 191-194
Author(s):  
Rong Qiang Hu ◽  
Di Ma ◽  
Shi Zhong Ma
Keyword(s):  
Sedimentary Facies ◽  
Seepage Flow ◽  
Flow Unit ◽  
Displacement Efficiency ◽  
Low Contrast ◽  
Meandering Channel ◽  
Oil Displacement ◽  
Sand Body ◽  
Remaining Oil ◽  
Oil Displacement Efficiency

To study the distribution of remaining oil inside meandering channel sand body, the size of sand body architecture was calculated by the use of sedimentary facies, dense well, river parameters, cores, well logs and other data. The architecture of meandering channel that was crescent-shaped in plane and diagonal type in section was identifiable. On the base of study of architecture, the shielding of interlayer was classified into four types by the observation of oiliness interlayer. Framework of seepage flow was identified in meandering channel sand body. Several lateral accretion bodies between the completely choked interlayer constituted the flow unit. Combined with core analysis, the remaining oil in meandering channel sand body distributed in the upper and the middle of flow unit which did not connect with production well. The oil displacement efficiency in the flow unit was a positive rhythm in the flow unit. The oil displacement efficiency was a high-contrast positive rhythm in the lateral accretion body shielded by completely choked interlayer. That was a low-contrast positive rhythm in the lateral accretion body shielded by partly choked or restricted interlayer. All of these would provide guidance for developing the remaining oil.

Field Test of Carbon Dioxide Gas Channeling Foam Plugging

2013 ◽  
Vol 316-317 ◽  
pp. 769-772
Author(s):  
Yun Bo Bao
Keyword(s):  
Carbon Dioxide ◽  
Gas Injection ◽  
Oil Field ◽  
Low Permeability ◽  
Displacement Efficiency ◽  
Oil Displacement ◽  
Carbon Dioxide Gas ◽  
Oil Displacement Efficiency ◽  
Gas Channeling ◽  
Swept Volume

Gas channeling is tending to happen in CO2 immiscible flooding process, and that would seriously influence gas injection development. In order to plugging gas channeling channel effectively, improve inspiration and production profile, and enhance swept volume and oil displacement efficiency of the gas injection, field trials of foam seal channeling are carried out. The tests showed that carbon dioxide foam can effectively plugging the gas channeling channel, expand the swept volume of carbon dioxide gas, reduce invalid circulation, and enhancing oil displacement efficiency. The anti-sealing channeling technology is cost-efficient, and it is suitable for Daqing peripheral low permeability oil field on gas injection development. It has good prospects, and it will provide a strong technical support on gas injection development of low permeability reservoir.

Characteristics and Influence Factors for Oil Displacement Efficiency by the Micro-Model Water Flooding Experiment in Low Permeability Reservoir

2015 ◽  
Vol 1092-1093 ◽  
pp. 1371-1374
Author(s):  
Xiang Chun Zhang ◽  
Wei Sun ◽  
Tian Li Rao ◽  
Hai Zeng Jing ◽  
Yong Jing ◽  
...  
Keyword(s):  
Influencing Factors ◽  
Influence Factors ◽  
Water Flooding ◽  
Low Permeability ◽  
Micro Model ◽  
Displacement Efficiency ◽  
Oil Viscosity ◽  
Oil Displacement ◽  
Piston Displacement ◽  
Oil Displacement Efficiency

Through the displacement experiment of low permeability sandstone micro model of water Erdos basin, summing up the water displacing oil characteristics, and to explore the influencing factors of micro water oil displacement efficiency. The study found that, the water flooding characteristic main performance for: flooding mode mainly by non piston displacement; heterogeneity is strong, the oil displacement efficiency is low; the crude oil viscosity is low, the oil displacement efficiency is high; the main influencing factors are: physical; heterogeneity; displacement ratio. Therefore, for low permeability sandstone reservoir development, process parameters should be selected reasonably, in order to ensure the good development effect.

scholarly journals Research on small-scale sand fracturing and puff technology

2021 ◽  
Vol 329 ◽  
pp. 01001
Author(s):  
Qian Wang ◽  
Zuohao Wu ◽  
Jiapeng Zheng ◽  
Junkai Lu ◽  
Menghong Yu
Keyword(s):  
Sedimentary Environment ◽  
Three Dimensional ◽  
Rate Of Change ◽  
Small Scale ◽  
Model Parameters ◽  
High Permeability ◽  
Sand Body ◽  
Complex Fault ◽  
Low Permeability Reservoirs ◽  
Sand Bodies

Affected by complex fault blocks, sedimentary environment and reservoir physical properties, Jidong Oilfield generally develops small-scale sand bodies, accounting for 24.2% of the produced reserves of medium and low permeability reservoirs. Such sand bodies rely on elastic energy to develop and are difficult to use effectively. In this paper, through the three-dimensional hydraulic physical model experiment and the analysis of the oil layer-dry layer-mudstone mixed sand body, the reasons that affect the model parameters are obtained. The results show that: the length of the high-permeability reservoir area, the length of the intermediate-permeability dry layer area, the rate of change of permeability parameters, the viscosity of the construction fluid, and the construction displacement have an impact on the effect of fracturing enhanced injection energy storage.

scholarly journals Study on oil displacement efficiency of offshore sandstone reservoir with big bottom water

2021 ◽  
Author(s):  
Jie Tan ◽  
Ying-xian Liu ◽  
Yan-lai Li ◽  
Chun-yan Liu ◽  
Song-ru Mou
Keyword(s):  
Bottom Water ◽  
High Water ◽  
Displacement Efficiency ◽  
Oil Displacement ◽  
Oil Displacement Efficiency ◽  
Sandstone Reservoir ◽  
Sandstone Reservoirs ◽  
High Water Cut Stage ◽  
High Water Cut ◽  
Water Cut

AbstractX oilfield is a typical sandstone reservoir with big bottom water in the Bohai Sea. The viscosity of crude oil ranges from 30 to 425 cp. Single sand development with the horizontal well is adopted. At present, the water content is as high as 96%. The water cut of the production well is stable for a long time in the high water cut period. The recoverable reserves calculated by conventional methods have gradually increased, and even the partial recovery has exceeded the predicted recovery rate. This study carried out an oil displacement efficiency experiment under big water drive multiple to accurately understand an extensive bottom water reservoir's production law in an ultra-high water cut stage. It comprehensively used the scanning electron microscope date, casting thin section, oil displacement experiment, and production performance to analyze the change law of physical properties and relative permeability curve from the aspects of reservoir clay minerals, median particle size, pore distribution, and pore throat characteristics. Therefore, the development law of horizontal production wells in sandstone reservoirs with big bottom water is understood. It evaluates the ultimate recovery of sandstone reservoirs with big bottom water. It provides a fundamental theoretical basis and guidance for dynamic prediction and delicate potential tapping of sandstone reservoirs with big bottom water at a high water cut stage.

Experimental Study on the Displacement Performance of Heat-Resistant Polymer

2014 ◽  
Vol 675-677 ◽  
pp. 1495-1499 ◽  
Author(s):  
Tao Ping Chen ◽  
Biao Qiu
Keyword(s):  
Polymer Flooding ◽  
Displacement Efficiency ◽  
Oil Viscosity ◽  
Permeability Ratio ◽  
Ratio Increase ◽  
Displacement Effect ◽  
Oil Displacement ◽  
Heat Resistant ◽  
Homogeneous Core ◽  
Oil Displacement Efficiency

The displacement performance of heat-resistant polymer is evaluated with the artificial cores and natural cores under 95°C. The best concentration of BH heat-resistant polymer is 1500 mg/L, and the best slug is 0.6 PV on the condition of the average permeability is 600×10-3μm2 of the homogeneous core and the oil viscosity is 2.3mPa • s. Under the best concentration and the PV size, BH heat-resistant polymer solution has better displacement effect for the artificial double core whose permeability ratio is less than 4. When permeability ratio exceed 4, the displacement affect no longer increase. When the mobility ratio increase from 0.05 to 0.2, for the artificial cores, the recovery of polymer flooding reduce by 3.17%, and for the natural cores, the recovery of polymer flooding reduce by 2.26%. The recovery of BH polymer that is aged for 90 days after vacuumed is 32.29%. Comparing with the fresh BH polymer, it is lower by 6.56%. That is to say that the aged BH polymer still has good oil displacement efficiency.

Sign in / Sign up

Export Citation Format

Share Document