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 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.

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.

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 Investigation of the Effects of Water and Polymer Flooding on Geometric and Multifractal Characteristics of Pore Structures

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5288
Author(s):  
Xianguo Zhang ◽  
Chengyan Lin ◽  
Yuqi Wu ◽  
Tao Zhang ◽  
Hongwei Wang ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Water Injection ◽  
Total Porosity ◽  
Polymer Flooding ◽  
Oil Field ◽  
Water Flooding ◽  
Reservoir Quality ◽  
Thin Sections ◽  
X Ray ◽  
Pore Structures

During water and polymer flooding for enhanced oil recovery, pore structures may vary because of the fluid–rock interactions, which can lead to variations in petrophysical properties and affect oil field production. To investigate the effects of fluid flooding on pore structures, six samples were subjected to brine water, dual-system, and alkaline–surfactant–polymer (ASP) polymer displacement experiments. Before and after experiments, samples were scanned by X-ray CT. Thin sections, X-ray diffraction, and high pressure mercury injection tests were also carried out to characterize mineralogy and fractal dimension of pore systems before experiments. Experiment results show that water flooding with low injection pore volume ratio (IPVR) can improve reservoir quality since total porosity and connected porosity of samples rise after the flooding and the proportion of large pores also increases and heterogeneity of pore structure decreases. However, water flooding with high IPVR has reverse effects on pore structures. Polymer flooding reduces the total porosity, connected porosity, the percentage of small pores and enhances the heterogeneity of pore structures. It can be found that pore structures will change in fluid flooding and appropriate water injection can improve reservoir quality while excessive water injection may destroy the reservoir. Meanwhile, injected polymer may block throats and destroy reservoirs. The experimental results can be used as the basis for oil field development.

scholarly journals Optimisation of Smart Water to Enhance Oil Recovery Efficiency in a Part of Oil Field of Upper Assam Basin, India

2019 ◽  
Vol 9 (2) ◽  
pp. 3620-3626
Keyword(s):  
Oil Recovery ◽  
Ionic Composition ◽  
Oil Field ◽  
Water Flooding ◽  
Rock Surface ◽  
Recovery Efficiency ◽  
Smart Water ◽  
Original Oil In Place ◽  
Brine Salinity ◽  
Secondary Mode

Researchers have proved the significance of water injection by tuning its composition and salinity into the reservoir during smart water flooding. Once the smart water invades through the pore spaces, it destabilises crude oil-brine-rock (COBR) that leads to change in wettability of the reservoir rocks. During hydrocarbon accumulation and migration, polar organic compounds were being adsorbed on the rock surface making the reservoir oil/mixed wet in nature. Upon invasion of smart water, due to detachment of polar compounds from the rock surfaces, the wettability changes from oil/mixed wet to water wet thus enhances the oil recovery efficiency. The objective of this paper is to find optimum salinity and ionic composition of the synthetic brines at which maximum oil recovery would be observed. Three core flood studies have been conducted in the laboratory to investigate the effect of pH, composition and salinity of the injected brine over oil recovery. Every time, flooding has been conducted at reservoir formation brine salinity i.e at 1400 ppm followed by different salinities. Here, tertiary mode of flooding has been carried out for two core samples while secondary flooding for one. Results showed maximum oil recovery by 40.12% of original oil in place (OOIP) at 1050ppm brine salinity at secondary mode of flooding. So, optimized smart water has been proposed with 03 major salts, KCl, MgCl2 and CaCl2 in secondary mode of flooding that showed maximum oil recovery in terms of original oil in place.

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 Wormlike micelles properties and oil displacement efficiency of a salt-tolerant C22-tailed amidosulfobetaine surfactant

2021 ◽  
pp. 014459872199654
Author(s):  
Yu Bai ◽  
Shangqi Liu ◽  
Guangyue Liang ◽  
Yang Liu ◽  
Yuxin Chen ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Carbon Chain ◽  
Mobility Control ◽  
Wormlike Micelles ◽  
Chemical Flooding ◽  
Displacement Efficiency ◽  
Displacement Effect ◽  
Krafft Temperature ◽  
Oil Displacement

Wormlike micelles formed by amidosulfobetaine surfactants present advantage in increasing viscosity, salt-tolerance, thermal-stability and shear-resistance. In the past few years, much attention has been paid on rheology behaviours of amidosulfobetaine surfactants that normally bear C18 or shorter tails. Properties and oil displacement performances of the wormlike micelles formed by counterparts bearing the long carbon chain have not been well documented. In this paper, the various properties of C22-tailed amidosulfobetaine surfactant EHSB under high salinity (TDS = 40g/L) are investigated systematically, including solubility, rheology and interfacial activity. Moreover, its oil displacement performance is studied for the first time. These properties are first compared with those of C16-tailed counterpart HDPS. Results show that the Krafft temperature( TK) of EHSB decreases from above 100°C to 53°C with the increase of TDS to 40 g/L. Increasing concentration of EHSB in the semidilute region induces micelle growth from rod-like micelles to wormlike micelles, and then the worms become entangled or branched to form viscoelastic micelle solution, which will increase the viscosity by several orders of magnitude. The interfacial tension with oil can be reduced to ultra-low level by EHSB solution with concentration below 4.5 mM. Possessing dual functions of mobility control and reducing interfacial tension, wormlike micelles formed by EHSB present a good displacement effect as a flooding system, which is more than 10% higher than HPAM with the same viscosity. Compared with the shorter tailed surfactant, the ultra-long tailed surfactant is more efficient in enhancing viscosity and reducing interfacial tension, so as to enhance more oil recovery. Our work provides a helpful insight for comprehending surfactant-based viscoelastic fluid and provides a new viscoelastic surfactant flooding agent which is quite efficient in chemical flooding of offshore oilfield.

Experimental Investigation of Microscopic/Macroscopic Efficiency of Polymer Flooding in Fractured Heavy Oil Five-Spot Systems

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Mohammad Hossein Sedaghat ◽  
Mohammad Hossein Ghazanfari ◽  
Mohammad Parvazdavani ◽  
Saeid Morshedi
Keyword(s):  
Experimental Investigation ◽  
Oil Recovery ◽  
Polymer Concentration ◽  
Synthetic Polymers ◽  
Polymer Flooding ◽  
Water Flooding ◽  
Recovery Efficiency ◽  
Recovery Method ◽  
Geometrical Properties ◽  
Glass Type

This paper concerns on experimental investigation of biopolymer/polymer flooding in fractured five-spot systems. In this study, a series of polymer injection processes were performed on five-spot glass type micromodels saturated with heavy crude oil. Seven fractured glass type micromodels were used to illustrate the effects of polymer type/concentration on oil recovery efficiency in presence of fractures with different geometrical properties (i.e., fractures orientation, length and number of fractures). Four synthetic polymers as well as a biopolymer at different levels of concentration were tested. Also a micromodel constituted from dead-end pores with various geometrical properties was designed to investigate microscopic displacement mechanisms during polymer/water flooding. The results showed that polymer flooding is more efficient by using hydrolyzed synthetic polymers with high molecular weight as well as locating injection well in a proper position respect to the fracture geometrical properties. In addition, by monitoring of microscopic efficiency, pulling, stripping, and oil thread flow mechanisms were detected and discussed. The results showed that flow rate, fluid type, polymer concentration, and geometrical properties of pores influence the efficiency of mentioned mechanisms. Furthermore, it was detected that polymer's velocity profile play a significant role on oil recovery efficiency by influencing both macroscopic and microscopic mechanisms. This study demonstrates different physical and chemical conditions that affect the efficiency of this enhanced oil recovery method.

Research on the Remaining Oil Starting Mechanism in Different Pores of Polymer Surfactants Using NMR Analysis

2014 ◽  
Vol 1010-1012 ◽  
pp. 1727-1734
Author(s):  
Yi Qiang Li ◽  
Zhe Yu Liu ◽  
Yan Yue Li ◽  
Yi Bo Xu
Keyword(s):  
Relaxation Time ◽  
Oil Recovery ◽  
Water Flooding ◽  
Good Effect ◽  
Chemical Flooding ◽  
Displacement Effect ◽  
Oil Displacement ◽  
Remaining Oil ◽  
Polymer Surfactants ◽  
Polymer Surfactant

With its unique structure and properties, polymer surfactants have been used in chemical flooding. Compared with ordinary polymer, polymer surfactants have a higher recovery degree. However, remaining oil starting mechanism in different pores using different polymer surfactants after water flooding is still unclear. NMR (Nuclear Magnetic Resonance) has a good effect on determination of rock oil saturation and analysis of pore structure. In this paper, oil displacement experiment using kerosene which contains no hydrogen was conducted and the problem caused by the similarity between oil phase relaxation time and water relaxation time in large pores was overcome. Through the change of NMR relaxation time, oil distribution situation in different pores of ordinary polymer, refining III polymer surfactant, and Haibo III polymer surfactant after polymer flooding was measured accurately. This paper also quantitatively analyzed the contribution degree to oil recovery in pores of different sizes, and evaluated oil displacement effect of the above three kinds of oil displacement systems. The results show that when only the swept volume is considered, recovery degree of Haibo III polymer surfactant is higher, reaching 53.66%. In different systems, middle pores contribute most to recovery degree. At the same time, the remaining oil in middle pores and large pores accounts more, which is the main attack direction towards tapping the potential of remaining oil in the oilfield.

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