Oil Displacement Efficiency of Residual Oil after Polymer Flooding can be Enhanced by Betaine Surfactant

2010 ◽  
Author(s):  
Huifen Xia ◽  
Liang Qin ◽  
Hongyu Sui ◽  
Gang Wang
Keyword(s):  
Polymer Flooding ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Oil Displacement ◽  
Oil Displacement Efficiency

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.

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.

The Effect of Following Water after Polymer Flooding on the Displacement Efficiency with Alternately Injecting Slug of Gel and Polymer/Surfactant

2013 ◽  
Vol 734-737 ◽  
pp. 1290-1293 ◽  
Author(s):  
Ji Hong Zhang ◽  
Yu Wang ◽  
Xi Ling Chen ◽  
Zi Wei Qu ◽  
Dong Ke Qin
Keyword(s):  
Polymer Flooding ◽  
Experimental Results ◽  
Compound System ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Flat Panel ◽  
Oil Displacement ◽  
Panel Model ◽  
Displacement Experiments ◽  
Polymer Surfactant

Aiming at the development of remaining oil after polymer flooding, the author develops an oil displacement technology, alternately injecting the slug of the gel and polymer/surfactant compound system, which can advanced improve the remained oil after polymer flooding. By using the artificial large flat-panel model, the oil displacement experiments are carried on to study the injection characteristics and the displacement efficiency of the alternately injecting the slug of gel and polymer/surfactant compound system, and whether the following water should be injected after polymer flooding has been discussed. The experimental results show that, the recovery of alternately injecting the gel and polymer/surfactant slug after polymer flooding could enhance recovery more than 10% on the basis of polymer flooding, the following water after polymer flooding has a little impact on the final recovery but increasing time and the difficulty of development. Therefore, these results provide the technology that alternately injecting the slug of the gel and polymer/surfactant could advance develop the residual oil and enhance the recovery after polymer flooding.

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.

Effects of Mobile Water on Multiple-Contact Miscible Gas Displacements

1983 ◽  
Vol 23 (03) ◽  
pp. 447-455 ◽  
Author(s):  
D.L. Tiffin ◽  
W.F. Yellig
Keyword(s):  
Water Saturation ◽  
Water Injection ◽  
Residual Oil ◽  
Displacement Efficiency ◽  
Mobile Water ◽  
Oil Displacement ◽  
Oil Displacement Efficiency ◽  
Gas Flooding ◽  
Water Trapping ◽  
First Contact

Abstract Miscible gas flooding using an alternate gas/water injection process (AGWIP) is presently being applied for enhanced oil recovery (EOR) in several waterflooded reservoirs. A mobile-water saturation in the vicinity of the miscible displacement front can occur in this process. To design field applications of miscible gas floods process. To design field applications of miscible gas floods properly, it is necessary to understand the effects of properly, it is necessary to understand the effects of water saturations above the connate saturation on the oil-displacement efficiency. Previous research on AGWIP has involved water-wet long-core flow tests using an injected solvent that is first-contact miscible with the inplace oil. Miscible floods employing CO2, enriched gas, methane, and flue gases, however, are rarely first-contact miscible with reservoir oils; the oil miscibility is normally achieved by a multiple-contact mechanism. This paper discusses the effects of mobile water on multiple-contact miscible displacements under water- and oil-wet conditions. Tests were conducted in 8-ft (244-cm) water- and oil-wet Berea cores in which CO2 and water were injected both separately and simultaneously to displace a reservoir oil. The data presented focus on effects of water in the oil-moving zone (OMZ) where the CO2 is generating miscibility with the oil and mobilizing residual oil to waterflooding. Special emphasis is placed on understanding the effect of mobile-water saturation on the oil-displacement efficiency and the component transfer between phases necessary to develop miscibility in the CO2/reservoir-oil system. This study demonstrates that reservoir wettability is a key factor in the performance of AGWIP. Gas/water injection can, under certain conditions, have adverse effects on characteristics of the OMZ. These effects are in part caused by the water trapping portions of the oil and part caused by the water trapping portions of the oil and solvent. It was observed that mobile water did not change the mass transfer process by which miscibility develops in a multiple-contact miscible displacement. Introduction Miscible gas flooding has been and will be used as a commercial EOR process. In most reservoir applications the injected gas has a lower viscosity than the reservoir oil being displaced. This leads to an inherently unfavorable gas/oil mobility ratio. AGWIP has been used to control mobility. To improve sweep of the injected miscible gas, and to utilize this relatively expensive fluid more effectively. In many field applications of this process, volumes of miscible gas and water are injected process, volumes of miscible gas and water are injected alternately into the reservoir until the desired cumulative slug volume of miscible gas has been injected. The AGWIP process may lead to a high mobile-water saturation in the reservoir, particularly in waterflooded reservoirs. Several authors have discussed the effects of this mobile water on the first-contact miscible oil-displacement process. These studies have shown that the in-place oil can be shielded from the injected solvent by the mobile water in water-wet porous media. The ability of the injected solvent to displace residual oil in laboratory systems was detrimentally affected by high mobile-water saturations. In simulated oil-wet porous media, this solvent trapping was either much less severe or nonexistent. Simulated oil-wet conditions were obtained in a water-wet core by displacing a glycerin/water solution by simultaneous injection of water and oil. SPEJ P. 447

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.

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