Experimental investigations on the fluid flow mechanism in porous media of enhanced oil recovery by alkli/surfactant/polymer flooding

2005 ◽  
Vol 48 (4) ◽  
pp. 454 ◽  
Author(s):  
Jialu WANG
SPE Journal ◽  
2009 ◽  
Vol 14 (02) ◽  
pp. 237-244 ◽  
Author(s):  
Pingping Shen ◽  
Jialu Wang ◽  
Shiyi Yuan ◽  
Taixian Zhong ◽  
Xu Jia

Summary The fluid-flow mechanism of enhanced oil recovery (EOR) in porous media by alkali/surfactant/polymer (ASP) flooding is investigated by measuring the production performance, pressure, and saturation distributions through the installed differential-pressure transducers and saturation-measurement probes in a physical model of a vertical heterogeneous reservoir. The fluid-flow variation in the reservoir is one of the main mechanisms of EOR of ASP flooding, and the nonlinear coupling and interaction between pressure and saturation fields results in the fluid-flow variation in the reservoir. In the vertical heterogeneous reservoir, the ASP agents flow initially in the high-permeability layer. Later, the flow direction changes toward the low- and middle-permeability layers because the resistance in the high-permeability layer increases on physical and chemical reactions such as adsorption, retention, and emulsion. ASP flooding displaces not only the residual oil in the high-permeability layer but also the remaining oil in the low- and middle-permeability layers by increasing both swept volume and displacement efficiency. Introduction Currently, most oil fields in China are in the later production period and the water cut increases rapidly, even to more than 80%. Waterflooding no longer meets the demands of oilfield production. Thus, it is inevitable that a new technology will replace waterflooding. The new technique of ASP flooding has been developed on the basis of alkali-, surfactant-, and polymer-flooding research in the late 1980s. ASP flooding uses the benefits of the three flooding methods simultaneously, and oil recovery is greatly enhanced by decreasing interfacial tension (IFT), increasing the capillary number, enhancing microscopic displacing efficiency, improving the mobility ratio, and increasing macroscopic sweeping efficiency (Shen and Yu 2002; Wang et al. 2000; Wang et al. 2002; Sui et al. 2000). Recently, much intensive research has been done on ASP flooding both in China and worldwide, achieving some important accomplishments that lay a solid foundation for the extension of this technique to practical application in oil fields (Baviere et al. 1995; Thomas 2005; Yang et al. 2003; Li et al. 2003). In previous work, the ASP-flooding mechanism was studied visually by using a microscopic-scale model and double-pane glass models with sand (Liu et al. 2003; Zhang 1991). In these experiments, the water-viscosity finger, the residual-oil distribution after waterflooding, and the oil bank formed by microscopic emulsion flooding were observed. In Tong et al. (1998) and Guo (1990), deformation, threading, emulsion (oil/water), and strapping were observed as the main mechanisms of ASP flooding in a water-wetting reservoir, while the interface-producing emulsion (oil/water), bridging between inner pore and outer pore, is the main mechanism of ASP flooding in an oil-wetting reservoir. For a vertical heterogeneous reservoir, ASP flooding increases displacement efficiency by displacing residual oil through decreased IFT, simultaneously improving sweep efficiency by extending the swept area in both vertical and horizontal directions. Some physical and chemical phenomena, such as emulsion, scale deposition, and chromatographic separation, occur during ASP flooding (Arihara et al. 1999; Guo 1999). Because ASP flooding in porous media involves many complicated physicochemical properties, many oil-recovery mechanisms still need to be investigated. Most research has been performed on the microscopic displacement mechanism of ASP flooding, while the fluid-flow mechanism in porous media at the macroscopic scale lacks sufficient study. In this paper, a vertical-heterogeneous-reservoir model is established, and differential-pressure transducers and saturation-measuring probes are installed. The fluid-flow mechanism of increasing both macroscopic sweep efficiency and microscopic displacement efficiency is studied by measuring the production performance and the variation of pressure and saturation distributions in the ASP-flooding experiment. An experimental database of ASP flooding also is set up and provides an experimental base for numerical simulation.


Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2751 ◽  
Author(s):  
Sameer Al-Hajri ◽  
Syed Mahmood ◽  
Hesham Abdulelah ◽  
Saeed Akbari

Polymer flooding is an important enhanced oil recovery technology introduced in field projects since the late 1960s. The key to a successful polymer flood project depends upon proper estimation of polymer retention. The aims of this paper are twofold. First, to show the mechanism of polymer flooding and how this mechanism is affected by polymer retention. Based on the literature, the mobility ratio significantly increases as a result of the interactions between the injected polymer molecules and the reservoir rock. Secondly, to provide a better understanding of the polymer retention, we discussed polymer retention types, mechanisms, factors promoting or inhibiting polymer retention, methods and modeling techniques used for estimating polymer retention.


Author(s):  
E.F. Veliyev ◽  

Polymer flooding is one of the main enhanced oil recovery methods that have been actively used since the late 1960s. However, despite the significant gained experience of both laboratory and field research, this technology still continues to develop from year to year, revealing more and more new factors and challenges that are necessary aspects for successful implementation. Estimation of retained polymer amount by the porous medium is one of the key factors. The article discusses the main mechanisms and factors affecting retention process, as well as methods for determining the amount of retained polymer when flooding the solution through porous medium in laboratory conditions.


Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3732 ◽  
Author(s):  
Yaohao Guo ◽  
Lei Zhang ◽  
Guangpu Zhu ◽  
Jun Yao ◽  
Hai Sun ◽  
...  

Water flooding is an economic method commonly used in secondary recovery, but a large quantity of crude oil is still trapped in reservoirs after water flooding. A deep understanding of the distribution of residual oil is essential for the subsequent development of water flooding. In this study, a pore-scale model is developed to study the formation process and distribution characteristics of residual oil. The Navier–Stokes equation coupled with a phase field method is employed to describe the flooding process and track the interface of fluids. The results show a significant difference in residual oil distribution at different wetting conditions. The difference is also reflected in the oil recovery and water cut curves. Much more oil is displaced in water-wet porous media than oil-wet porous media after water breakthrough. Furthermore, enhanced oil recovery (EOR) mechanisms of both surfactant and polymer flooding are studied, and the effect of operation times for different EOR methods are analyzed. The surfactant flooding not only improves oil displacement efficiency, but also increases microscale sweep efficiency by reducing the entry pressure of micropores. Polymer weakens the effect of capillary force by increasing the viscous force, which leads to an improvement in sweep efficiency. The injection time of the surfactant has an important impact on the field development due to the formation of predominant pathway, but the EOR effect of polymer flooding does not have a similar correlation with the operation times. Results from this study can provide theoretical guidance for the appropriate design of EOR methods such as the application of surfactant and polymer flooding.


2021 ◽  
Vol 21 (1) ◽  
pp. 124
Author(s):  
Ahmad Tawfiequrahman Yuliansyah ◽  
Bardi Murachman ◽  
Suryo Purwono

The need for energy, especially the petroleum-based one, is steadily increasing along with population growth and technological advancement. Meanwhile, oil exploitation from oil reservoirs using primary and secondary techniques can only obtain about 30%-50 % out of the original oil in place. Enhanced Oil Recovery (EOR) is a method for increasing oil recovery from a reservoir by injecting materials that are not found in the reservoir, such as surfactant, polymer, etc. This research aims to develop a mathematical model representing two-phase flow through porous media in the EOR process. This model was extended from mass balance and fluid flow in porous media equations. The reliability of the model was then validated by water flooding and polymer flooding experiment. A porous media, constituted by a silica sand pack, was saturated with 2 % brine and sequentially flooded with HPAM polymer solution at various concentrations (5,000-15,000 ppm). The volume of the oil coming out from the media at any time intervals was measured. Validation of the model was carried out by optimizing the model parameters to obtain the best curve-fitting on the plot of the percentage of cumulative recovered oil against time. The results showed that the proposed mathematical model was reliable enough to express both water and polymer-flooding processes.


Author(s):  
Jianlong Xiu ◽  
Tianyuan Wang ◽  
Ying Guo ◽  
Qingfeng Cui ◽  
Lixin Huang ◽  
...  

2007 ◽  
Author(s):  
Jialu Wang ◽  
Shiyi Yuan ◽  
Pingping Shen ◽  
Taixian Zhong ◽  
Xu Jia

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Ruissein Mahon ◽  
Gbenga Oluyemi ◽  
Babs Oyeneyin ◽  
Yakubu Balogun

Abstract Polymer flooding is a mature chemical enhanced oil recovery method employed in oilfields at pilot testing and field scales. Although results from these applications empirically demonstrate the higher displacement efficiency of polymer flooding over waterflooding operations, the fact remains that not all the oil will be recovered. Thus, continued research attention is needed to further understand the displacement flow mechanism of the immiscible process and the rock–fluid interaction propagated by the multiphase flow during polymer flooding operations. In this study, displacement sequence experiments were conducted to investigate the viscosifying effect of polymer solutions on oil recovery in sandpack systems. The history matching technique was employed to estimate relative permeability, fractional flow and saturation profile through the implementation of a Corey-type function. Experimental results showed that in the case of the motor oil being the displaced fluid, the XG 2500 ppm polymer achieved a 47.0% increase in oil recovery compared with the waterflood case, while the XG 1000 ppm polymer achieved a 38.6% increase in oil recovery compared with the waterflood case. Testing with the motor oil being the displaced fluid, the viscosity ratio was 136 for the waterflood case, 18 for the polymer flood case with XG 1000 ppm polymer and 9 for the polymer flood case with XG 2500 ppm polymer. Findings also revealed that for the waterflood cases, the porous media exhibited oil-wet characteristics, while the polymer flood cases demonstrated water-wet characteristics. This paper provides theoretical support for the application of polymer to improve oil recovery by providing insights into the mechanism behind oil displacement. Graphic abstract Highlights The difference in shape of relative permeability curves are indicative of the effect of mobility control of each polymer concentration. The water-oil systems exhibited oil-wet characteristics, while the polymer-oil systems demonstrated water-wet characteristics. A large contrast in displacing and displaced fluid viscosities led to viscous fingering and early water breakthrough.


2021 ◽  
Vol 48 (1) ◽  
pp. 169-178
Author(s):  
Xiangguo LU ◽  
Bao CAO ◽  
Kun XIE ◽  
Weijia CAO ◽  
Yigang LIU ◽  
...  

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