scholarly journals Laboratory Study on EOR in Offshore Oilfields by Variable Concentrations Polymer Flooding

2017 ◽  
Vol 10 (1) ◽  
pp. 94-107 ◽  
Author(s):  
Kaoping Song ◽  
Ning Sun ◽  
Yanfu Pi
Keyword(s):  
Oil Recovery ◽  
Field Application ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Displacement Efficiency ◽  
Constant Concentration ◽  
Sweep Efficiency ◽  
Displacement Effect ◽  
Fracture Pressure ◽  
Recovery Technique

Background: Polymer flooding is the most commonly applied chemical enhanced-oil-recovery technique in offshore oilfields. However, there are challenges and risks in applying the technology of polymer flooding to offshore heavy oil development. Objective: This paper compared the spread law and the displacement effect of different injection modes and validated the feasibility of enhancing oil recovery by variable concentrations polymer flooding. Method: Two types of laboratory experiments were designed by using micro etching glass models and heterogeneous artificial cores. Furthermore, in order to determine a better polymer flooding mode, the displacement results, displacement characteristic curves and oil saturation distribution of heterogeneous artificial cores were also compared, respectively. Results: The experimental results showed that the recovery of variable concentrations polymer flooding was higher than that of constant concentration polymer flooding, under conditions of same total amount of polymer and similar water flooding recovery. Its sweep efficiency and displacement efficiency were also significantly higher than those of constant concentration polymer flooding. Moreover, variable concentrations polymer flooding had lower peak pressure and was at lower risk for reaching the formation fracture pressure. Conclusion: As a consequence, variable concentrations polymer flooding has certain feasibility for heterogeneous reservoir in offshore oilfields, and can improve interlayer heterogeneity to further tapping remaining oil in medium and low permeability layer. Conclusions of this paper can provide reference for the field application of polymer flooding in offshore oilfields.

scholarly journals Experimental Study of Chemical Flooding of Suizhong 36-1 Oilfield

2015 ◽  
Vol 8 (1) ◽  
pp. 392-397 ◽  
Author(s):  
Pi Yanfu ◽  
Guo Xiaosai ◽  
Pi Yanming ◽  
Wu Peng
Keyword(s):  
Oil Recovery ◽  
Pore Volume ◽  
Polymer Flooding ◽  
Oil Field ◽  
Water Flooding ◽  
Chemical Flooding ◽  
Recovery Efficiency ◽  
Displacement Efficiency ◽  
Displacement Effect ◽  
Binary Combination

Aim at the reservoir characteristics of Suizhong 36-1 Oil Field, this paper has developed typical two-dimensional physical model in parallel between the layers and studied the macroscopic displacement effect of polymer flooding and binary compound flooding, and studied the interlayer spread law and oil displacement efficiency of polymer flooding and binary combination flooding by using saturation monitoring system deeply. The results show that: when the multiples of pore volume injected for polymer was 0.3 after water flooding, the recovery efficiency increased by 10.3%, and when the multiples of pore volume injected for binary combination flooding was 0.3 after polymer flooding and the recovery efficiency could also increase by 19.3%, and the effect of enhanced oil recovery was obvious during the binary combination flooding and polymer flooding; Saturation monitoring data showed that there formed oil wall and increased the flow resistance and expanded the swept volume during the stage of polymer flooding and binary combination flooding, effective use of low-permeability layer was the key to improve oil recovery.

scholarly journals Experimental Study on Medium Viscosity Oil Displacement Using Viscoelastic Polymer

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Huiying Zhong ◽  
Qiuyuan Zang ◽  
Hongjun Yin ◽  
Huifen Xia
Keyword(s):  
Oil Recovery ◽  
Polymer Flooding ◽  
Water Soluble ◽  
Water Flooding ◽  
Bohai Bay ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Sweep Efficiency ◽  
Oil Displacement ◽  
Medium Viscosity

With the growing demand for oil energy and a decrease in the recoverable reserves of conventional oil, the development of viscous oil, bitumen, and shale oil is playing an important role in the oil industry. Bohai Bay in China is an offshore oilfield that was developed through polymer flooding process. This study investigated the pore-scale displacement of medium viscosity oil by hydrophobically associating water-soluble polymers and purely viscous glycerin solutions. The role and contribution of elasticity on medium oil recovery were revealed and determined. Comparing the residual oil distribution after polymer flooding with that after glycerin flooding at a dead end, the results showed that the residual oil interface exhibited an asymmetrical “U” shape owing to the elasticity behavior of the polymer. This phenomenon revealed the key of elasticity enhancing oil recovery. Comparing the results of polymer flooding with that of glycerin flooding at different water flooding sweep efficiency levels, it was shown that the ratio of elastic contribution on the oil displacement efficiency increased as the water flooding sweep efficiency decreased. Additionally, the experiments on polymers, glycerin solutions, and brines displacement medium viscosity oil based on a constant pressure gradient at the core scale were carried out. The results indicated that the elasticity of the polymer can further reduce the saturation of medium viscosity oil with the same number of capillaries. In this study, the elasticity effect on the medium viscosity oil interface and the elasticity contribution on the medium viscosity oil were specified and clarified. The results of this study are promising with regard to the design and optimum polymers applied in an oilfield and to an improvement in the recovery of medium viscosity oil.

An Easy Calculation Method on Sweep Efficiency of Chemical Flooding

2013 ◽  
Vol 275-277 ◽  
pp. 496-501
Author(s):  
Fu Qing Yuan ◽  
Zhen Quan Li
Keyword(s):  
Oil Recovery ◽  
Orthogonal Design ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Solution Viscosity ◽  
Chemical Flooding ◽  
Oil Viscosity ◽  
Sweep Efficiency ◽  
Easy Calculation ◽  
Polymer Compound

According to the geological parameters of Shengli Oilfield, sweep efficiency of chemical flooding was analyzed according to injection volume, injection-production parameters of polymer flooding or surfactant-polymer compound flooding. The orthogonal design method was employed to select the important factors influencing on expanding sweep efficiency by chemical flooding. Numerical simulation method was utilized to analyze oil recovery and sweep efficiency of different flooding methods, such as water flooding, polymer flooding and surfactant-polymer compound flooding. Finally, two easy calculation models were established to calculate the expanding degree of sweep efficiency by polymer flooding or SP compound flooding than water flooding. The models were presented as the relationships between geological parameters, such as effective thickness, oil viscosity, porosity and permeability, and fluid parameters, such as polymer-solution viscosity and oil-water interfacial tension. The precision of the two models was high enough to predict sweep efficiency of polymer flooding or SP compound flooding.

scholarly journals Differences of microscopic seepage mechanisms of water flooding and polymer flooding and prediction models of final oil recovery for conglomerate reservoir

2019 ◽  
Vol 74 ◽  
pp. 13
Author(s):  
Fengqi Tan ◽  
Changfu Xu ◽  
Yuliang Zhang ◽  
Gang Luo ◽  
Yukun Chen ◽  
...  
Keyword(s):  
Pore Structure ◽  
Polymer Solution ◽  
Oil Recovery ◽  
Particle Surface ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Oil Saturation ◽  
Oil Displacement Efficiency

The special sedimentary environments of conglomerate reservoir lead to pore structure characteristics of complex modal, and the reservoir seepage system is mainly in the “sparse reticular-non reticular” flow pattern. As a result, the study on microscopic seepage mechanism of water flooding and polymer flooding and their differences becomes the complex part and key to enhance oil recovery. In this paper, the actual core samples from conglomerate reservoir in Karamay oilfield are selected as research objects to explore microscopic seepage mechanisms of water flooding and polymer flooding for hydrophilic rock as well as lipophilic rock by applying the Computed Tomography (CT) scanning technology. After that, the final oil recovery models of conglomerate reservoir are established in two displacement methods based on the influence analysis of oil displacement efficiency. Experimental results show that the seepage mechanisms of water flooding and polymer flooding for hydrophilic rock are all mainly “crawling” displacement along the rock surface while the weak lipophilic rocks are all mainly “inrushing” displacement along pore central. Due to the different seepage mechanisms among the water flooding and the polymer flooding, the residual oil remains in hydrophilic rock after water flooding process is mainly distributed in fine throats and pore interchange. These residual oil are cut into small droplets under the influence of polymer solution with stronger shearing drag effect. Then, those small droplets pass well through narrow throats and move forward along with the polymer solution flow, which makes enhancing oil recovery to be possible. The residual oil in weak lipophilic rock after water flooding mainly distributed on the rock particle surface and formed oil film and fine pore-throat. The polymer solution with stronger shear stress makes these oil films to carry away from particle surface in two ways such as bridge connection and forming oil silk. Because of the essential attributes differences between polymer solution and injection water solution, the impact of Complex Modal Pore Structure (CMPS) on the polymer solution displacement and seepage is much smaller than on water flooding solution. Therefore, for the two types of conglomerate rocks with different wettability, the pore structure is the main controlling factor of water flooding efficiency, while reservoir properties oil saturation, and other factors have smaller influence on flooding efficiency although the polymer flooding efficiency has a good correlation with remaining oil saturation after water flooding. Based on the analysis on oil displacement efficiency factors, the parameters of water flooding index and remaining oil saturation after water flooding are used to establish respectively calculation models of oil recovery in water flooding stage and polymer flooding stage for conglomerate reservoir. These models are able to calculate the oil recovery values of this area controlled by single well control, and further to determine the oil recovery of whole reservoir in different displacement stages by leveraging interpolation simulation methods, thereby providing more accurate geological parameters for the fine design of displacement oil program.

scholarly journals Experimental Study on the Physical Performance and Flow Behavior of Decorated Polyacrylamide for Enhanced Oil Recovery

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 562 ◽  
Author(s):  
Shuang Liang ◽  
Yikun Liu ◽  
Shaoquan Hu ◽  
Anqi Shen ◽  
Qiannan Yu ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Flow Behavior ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Displacement Effect ◽  
Microscale Model ◽  
Water Cut ◽  
Viscosity Stability

With the rapid growth of energy consumption, enhanced oil recovery (EOR) methods are continually emerging, the most effective and widely used was polymer flooding. However, the shortcomings were gradually exposed. A novel decorated polyacrylamide might be a better alternative than polymer. In this work, the molecular structure and the properties reflecting the viscosity of decorated polyacrylamide, interfacial tension, and emulsification were examined. In order to better understand the interactions between decorated polyacrylamide and oil as well as the displacement mechanism, the displacement experiment were conducted in the etched-glass microscale model. Moreover, the coreflooding comparison experiments between decorated polyacrylamide and polymer were performed to investigate the displacement effect. The statistical analysis showed that the decorated polyacrylamide has excellent characteristics of salt tolerance, viscosity stability, and viscosification like polymer. Besides, the ability to reduce the interfacial tension in order 10−1 and emulsification, which were more similar to surfactant. Therefore, the decorated polyacrylamide was a multifunctional polymer. The displacement process captured by camera illustrated that the decorated polyacrylamide flooded oil mainly by means of ‘pull and drag’, ‘entrainment’, and ‘bridging’, based on the mechanism of viscosifying, emulsifying, and viscoelasticity. The results of the coreflooding experiment indicated that the recovery of decorated polyacrylamide can be improved by approximately 11–16% after water flooding when the concentration was more than 800 mg/L, which was higher than that of conventional polymer flooding. It should be mentioned that a new injection mode of ‘concentration reduction multi-slug’ was first proposed, and it obtained an exciting result of increasing oil production and decreasing water-cut, the effect of conformance control was more significant.

scholarly journals Macroscopic visual displacement of a polymer solution for enhanced oil recovery: Hele-Shaw cell experiments and computational simulation

2020 ◽  
Vol 66 (3 May-Jun) ◽  
pp. 273
Author(s):  
S. De Santiago ◽  
O. Olivares-Xometl ◽  
N. V. Likhanova ◽  
I. V. Lijanova ◽  
P. Arellanes-Lozada
Keyword(s):  
Oil Recovery ◽  
Flow Direction ◽  
Computational Simulation ◽  
Homogeneous Medium ◽  
Oil Production ◽  
Field Application ◽  
Polymer Flooding ◽  
Water Flooding ◽  
The Matrix ◽  
The One

Numerous laboratory studies and field application tests have shown that polymer flooding is an effective method to improve the oil recovery by displacing residual oil after water flooding. In this work, a series of visual model displacement experiments was conducted in Hele-Shaw cells to determine the effectiveness of polymer flooding in homogeneous and fractured media with a fracture parallel or perpendicular to the flow direction. The matrix with parallel fracture to the flow direction presented a delay in the oil production process during water and polymer flooding with respect to the homogeneous medium and the one with perpendicular fracture, where the highest recovery numbers during waterflooding and polymer flooding were achieved for the medium with perpendicular fracture to the flow direction, reaching 56 % of cumulative oil recovery. The displacement results and multiphasic simulation show that the homogeneous medium is an attractive candidate for additional recovery application with polymer flooding after water flooding when the oil production reached almost zero, although the production rate is lower than the one obtained for a porous medium with a fracture perpendicular to the flow direction.

scholarly journals Nuclear Magnetic Resonance Evaluation Study for Effect of Foam flooding in Heterogeneous Cores

2020 ◽  
Vol 213 ◽  
pp. 01025
Author(s):  
Shuai Hua ◽  
Yuan Li ◽  
Qinfeng Di
Keyword(s):  
Oil Recovery ◽  
Foam Stability ◽  
Dynamic Change ◽  
Water Flooding ◽  
Sweep Efficiency ◽  
Displacement Effect ◽  
Oil Displacement ◽  
Profile Control ◽  
Foam Flooding ◽  
Heterogeneous Cores

Foam flooding demonstrated the ability to solve the viscous fingering problem of gas flooding and increase the sweep efficiency in enhancing oil recovery. It is commonly used in development of heterogeneous reservoirs. While the characteristics of fluid migration in pores and between layers were still unclear. In this paper, Dynamic change of oil and water with different foam quality was tested during foam flooding by NMR method. Oil displacement effect of water flooding and foam flooding was compared. The results showed the foam quality affected the foam stability and profile control effect. Compared with water flooding, the foam could increase the recovery rate of the low-permeability layer, and the foam system with high stability had a high sweep efficiency and a high oil displacement efficiency in the heterogeneous cores.

A Comprehensive Study on Factors Affecting Preformed Particle Gel in Enhanced Oil Recovery

2020 ◽  
Vol 13 ◽  
Author(s):  
Imran Akbar ◽  
Zhou Hongtao ◽  
Liu Wei ◽  
Asadullah Memon ◽  
Ubedullah Ansari
Keyword(s):  
Oil Recovery ◽  
Fractured Reservoirs ◽  
Water Flooding ◽  
Displacement Efficiency ◽  
Void Space ◽  
High Permeability ◽  
Sweep Efficiency ◽  
Factors Affecting ◽  
Low Salinity ◽  
Preformed Particle Gel

: The Preformed Particle gels (PPGs) has been widely used and injected in low permeability rich oil zones as di-verting agent to solve the conformance issues, distract displacing fluid into out of sorts swept zones and reduce the perme-ability of thief zones and high permeability fractured zones. However, the PPG propagation and plugging mechanism is still remain unpredictable and sporadic in manifold void space passages. PPGs have two main abilities, first, it increases the sweep efficiency and second, it decreases the water production in mature oilfields. But the success or failure of PPG treatment largely depends on whether it efficiently decreases the permeability of the fluid paths to an expected target or not. In this study, the different factors were studied that affecting the performance of PPG in such reservoirs. PPGs were treated in different ways; treated with brine, low salinity, and high salinity brine and then their impacts were investigated in low/high permeability and fractured reservoirs and void space conduit models as well. From the literature, it was revealed that the sweep efficiency can be improved through PPG but not displacement efficiency and little impact of PPG were found on displacement efficiency. Similarly, on the other hand, Low salinity water flooding (LSWF) can increase the displacement efficiency but not sweep efficiency. Hence, based on above issues, few new techniques and directions were introduced in this work for better treatment of PPG to decrease water cut and increase oil recovery.

Technologies for Reusing Resources in Abandoned Oilfield after Tertiary Oil Recovery

2013 ◽  
Vol 368-370 ◽  
pp. 249-256
Author(s):  
Xian Jie Shao ◽  
Yuan Yuan Kang ◽  
Cai Feng Wang ◽  
Er Shuang Gao ◽  
Xin Hui Che ◽  
...  
Keyword(s):  
Production Rate ◽  
Oil Recovery ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Chemical Flooding ◽  
Displacement Efficiency ◽  
Steam Flooding ◽  
Lab Experiments ◽  
High Production Rate ◽  
Water Cut

In traditional views, oilfield is abandoned after water flooding and chemical flooding. But the recovery is only 50%~60%，that is to say, more than 40% of the resource is still left underground. Therefore, how to utilize this part of resource economically and effectively is a key problem to be tackled. Based on the lab experiments and theoretical researches on viscosity-temperature relationship, displacement and relative permeability under high temperature, the mechanism of enhancing oil recovery through steam flooding in super-high water cut stage of water injection oilfield was analyzed. The experimental results showed that steam flooding in 200°C after polymer flooding could increase oil displacement efficiency by 14.5%. Water flooding and polymer flooding had been implemented in Sabei development area of Daqing Oilfield since it was brought into development in 1963. The recovery had reached above 70% and the water cut had exceeded 98%. There was no economic benefit to develop continually, the oilfield faced abandonment. Steam flooding test was carried out to enhance oil recovery on this basis. According to the geological characteristics and development status, special technical measures were taken based on the lab experiments and numerical simulation including high-pressure steam injection to improve heat utilization, forced fluid withdrawal to increase production rate, insulated tubing and nitrogen insulation to keep the bottom hole steam dry, and tracking analysis to adjust injection-production parameters duly. The ultimate recovery reached 81.6％ which increased 10.7% on the original basis, the field test was successful technically. Steam flooding is characterized with quick effect, high production rate and high producing degree of residual oil. This successful technology provides a direction for secondary development after polymer flooding in water flooding oilfield.

scholarly journals Chemical Migration and Emulsification of Surfactant-Polymer Flooding

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Jierui Li ◽  
Weidong Liu ◽  
Guangzhi Liao ◽  
Linghui Sun ◽  
Sunan Cong ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Sweep Efficiency ◽  
Equal Concentration ◽  
Multiple Sample ◽  
Water Cut ◽  
And Migration ◽  
Swept Volume ◽  
Chemical Migration

With a long sand-packed core with multiple sample points, a laboratory surfactant-polymer flooding experiment was performed to study the emulsification mechanism, chemical migration mechanism, and the chromatographic separation of surfactant-polymer flooding system. After water flooding, the surfactant-polymer flooding with an emulsified system enhances oil recovery by 17.88%. The water cut of produced fluid began to decrease at the injection of 0.4 pore volume (PV) surfactant-polymer slug and got the minimum at 1.2 PV. During the surfactant-polymer flooding process, the loss of polymer is smaller than that of surfactant, the dimensionless breakthrough time of polymer is 1.092 while that of surfactant is 1.308, and the dimensionless equal concentration distance of the chemical is 0.65. During surfactant-polymer flooding, the concentration of surfactant controls the formation of the emulsion. From 50 cm to 600 cm, as the migration distance increases, the concentration of surfactant decreases, and the emulsification strength and duration decrease gradually. With the formation of emulsion, the viscosity of the emulsion is relatively stable, which is beneficial to enhanced oil recovery. With the shear of reservoirs and migration of surfactant-polymer slug, the emulsion is formed to improve the swept volume and sweep efficiency and enhance oil recovery.

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