Water-Based Nanofluid-Alternating-CO2 Injection for Enhancing Heavy Oil Recovery: Underlying Mechanisms that Influence its Efficiency

2021 ◽  
Author(s):  
Changxiao Cao ◽  
Zhaojie Song ◽  
Shan Su ◽  
Zihan Tang ◽  
Zehui Xie ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Phase Inversion ◽  
Core Flooding ◽  
Heavy Component ◽  
Water Emulsion ◽  
Heavy Oil Reservoirs ◽  
Oil Water ◽  
Underlying Mechanisms

Abstract The efficiency of CO2 water-alternating-gas (WAG) flooding is highly limited in low-permeability heavy oil reservoirs due to the viscosifying action of W/O emulsification and high mobility contrast between oil and CO2. Here we propose a new enhanced oil recovery (EOR) process which involves water-based nanofluid-alternating-CO2 (NWAG) injection, and investigate the synergistic effect of nanofluid and CO2 for enhancing heavy oil recovery. Firstly, the oil-nanofluid and oil-water emulsions were prepared, and the bulk rheology and interfacial properties of emulsion fluid were tested. Then, core flooding tests were conducted to examine the NWAG flooding efficiency and its underlying mechanisms. The results showed that the bulk viscosity and viscoelasticity of oil-nanofluid emulsion reported much lower than those of oil-water emulsion, and nanofluid presented a positive contribution to the phase inversion from W/O to O/W emulsification. Compared with oil-water emulsion, the interfacial storage modulus of oil-nanofluid emulsion was obviously increased, which confirmed that more of crude oil heavy components with surface activity (e.g., resin and asphaltene) were adsorbed on interfacial film with the addition of silica nanoparticles (NPs). However, the interfacial viscosity of oil-nanofluid emulsion was much lower than that of oil-water emulsion, showing the irregularity of interfacial adsorption. This implied that the self-assembly structure of crude oil heavy component of the oil-water interface was destroyed due to the surface activity of silica NPs. During the core flooding experiments, NWAG injection could reduce the displacement pressure by 57.14% and increase oil recovery by 23.31% compared to WAG injection. By comparing produced-oil components after WAG and NWAG injection, we found that more of crude oil light components were extracted by CO2 during NWAG flooding, showing that the interaction between CO2 and crude oil was improved after oil-nanofluid emulsification. These findings clearly indicated two main EOR mechanisms of NWAG injection. One was the phase inversion during the nanofluid flooding process. The addition of silica NPs promoted phase-inversion emulsification and thus improved the displacement efficiency. The other was the enhanced interaction between CO2 and crude oil after oil-nanofluid emulsification. Because of the enhanced adsorption of crude oil heavy component on the oil-water interface, the proportion of light hydrocarbon increased in the bulk phase, and so the interaction between CO2 and oil phase was improved. This work could provide a new insight into the high-efficiency exploitation of low-permeability heavy oil reservoirs.

Research of Lifting Technology of Combustion In Situ

2011 ◽  
Vol 347-353 ◽  
pp. 3219-3222
Author(s):  
Xi Shun Zhang ◽  
Xiao Dong Wu ◽  
Shu Qin Ma
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Gas Production ◽  
Technical Support ◽  
Recovery Ratio ◽  
Heavy Component ◽  
In Situ Combustion ◽  
Dynamic Displacement

In-situ combustion (fire flooding) is one of important methods to improve heavy oil recovery ratio, utilizing the reservoir itself heavy component burning as dynamic displacement of crude oil, improving the crude oil character, flooding efficiency is high, applicability is extensive, and other recover techniques can not match. But the technical support is difficult and broad, and is the key in restricting the effect of in-situ combustion, especially for the effectiveness of development. With the increase of fire flooding development, flowing wells turns to artificial lifting wells, the gas production increases deeply, and the lifting technology faces a lot of new problems. Aiming at the problems of combustion in-situ, the relevant technologies were researched, then some methods and measures suiting to heavy oil fire flooding technology were proposed. And it provided reference for researching of deep heavy oil fire flooding lifting technology in the future.

Investigation into the Functions of Alkali and Surfactant in Chemical Flooding for Enhanced Heavy-Oil Recovery

2012 ◽  
Vol 524-527 ◽  
pp. 1816-1820 ◽  
Author(s):  
Ji Jiang Ge ◽  
Hai Hua Pei ◽  
Gui Cai Zhang ◽  
Xiao Dong Hu ◽  
Lu Chao Jin
Keyword(s):  
Oil Recovery ◽  
Heavy Oil ◽  
Chemical Flooding ◽  
Surfactant Flooding ◽  
Core Flooding ◽  
Sweep Efficiency ◽  
Water Emulsion ◽  
Tertiary Oil Recovery ◽  
Fingering Phenomena ◽  
Oil In Water Emulsion

In this study, a comparative study of alkaline flooding and alkali-surfactant flooding were conducted for Zhuangxi heavy oil with viscosity of 325 mPa•s at 55 °C. The results of core flooding tests show that the tertiary oil recovery of alkali-surfactant flooding are lower than those of alkaline-only flooding, in spite of the coexistence of the surfactant and alkali can reduce the IFT between the heavy oil and aqueous phase to an ultralow level. Further flood study via glass-etching micromodel tests demonstrates that injected alkaline-only solution can penetrate into the oil phase and creates some discontinuous water droplet inside the oil phase that tend to lower the mobility of the injected water and lead to the improvement of sweep efficiency. While for alkali-surfactant flooding, heavy oil is easily emulsified in brine by an alkaline plus very dilute surfactant formula to form oil-in-water emulsion, and then entrained in the water phase. Therefore, viscous fingering phenomena occur during the alkali-surfactant flooding, resulting in relatively lower sweep efficiency.

scholarly journals Study of Influences of Fracture Additives on Stability of Crude Oil Emulsion

2018 ◽  
Vol 11 (1) ◽  
pp. 118-128
Author(s):  
Hongbo Fang ◽  
Mingxia Wang ◽  
Xiaoyun Liu ◽  
Weinan Jin ◽  
Xiangyang Ma ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Crude Oil ◽  
Oil Recovery ◽  
Oil Field ◽  
Stable Emulsion ◽  
Water Emulsion ◽  
High Efficient ◽  
Fracture Fluid ◽  
Oil Water ◽  
The Stability

Background: A hydraulic fracture is a key technology to increase production of the low permeability oil fields. Fracture additives such as gels, friction reducers, pH adjusters and clay stabilizers were injected into the underground. While more than 50% of the fracture fluid remains underground. The residue of fracture fluid comes out with the produced liquid (a mixture of crude oil and water) in the subsequent oil recovery process, which results in a highly stable crude oil-water emulsion. Objective: The stability and stable mechanism of the emulsion with fracture fluid have been experimentally investigated. Materials and Methods: The influences of fracture additives and components of crude oil on the stability of emulsion were investigated by bottle test and microscopic examination. The interfacial tension and modulus of dilation were explored by a spinning drop interfacial tension meter and an interface expansion rheometer, respectively. Results: The fracture additives played the key role on the emulsion stability. On one hand, the interface energy of oil-water was reduced by friction reducer (IFT was decreased from 24.0 mN/m to 1.9 mN/m), which was a favor for the formation of an emulsion. On the other hand, the dilational modulus of crude oil-water film was increased by hydroxypropyl guar and pH adjuster (Na2CO3) to form a viscoelastic film, which resulted in a highly stable emulsion. Conclusion: The residual fracture fluid accompanied by produced liquid resulted in a highly stable emulsion. The emulsion with fracture additives was difficult to be broken, which may affect the normal production of the oil field. A positive strategy such as developing demulsifier with high efficient should be put onto the schedule.

Application of the Marangoni Effect in Nanoemulsion on Improving Waterflooding Technology for Heavy-Oil Reservoirs

SPE Journal ◽  
2017 ◽  
Vol 23 (03) ◽  
pp. 831-840 ◽  
Author(s):  
Danian Zhang ◽  
Xuan Du ◽  
Xinmin Song ◽  
Hongzhuang Wang ◽  
Xiuluan Li ◽  
...  
Keyword(s):  
Shear Stress ◽  
Kinetic Energy ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Marangoni Effect ◽  
Production Method ◽  
Heavy Oil Recovery ◽  
Oil Sand ◽  
Water Emulsion ◽  
Oil Water

Summary Waterflooding is considered an important cold-production method because it is economically advantageous for heavy-oil-reservoir development; however, its efficiency is not remarkable because of the adverse oil/water-mobility ratio and cold damage from solid-state adsorption. To address this problem, oil/water emulsion is critical for improving the recovery by significantly altering oil mobility. Previous research is mainly focused on the effect of surfactants, salinity, and water/oil ratio on emulsion formation, rather than on the effect of kinetic energy under low or no shear stress on emulsification. In this study, experiments are conducted using a microscope to observe oil/water interfacial turbulence (Marangoni effect) when oil is dropped into a nanoemulsion. The purpose of this study is to form an emulsion using the interfacial turbulence under low or no shear stress, to improve heavy-oil recovery under waterflooding. The interfacial movement between a nanoemulsion and oil and the mechanism of formation of the emulsion are investigated. The Marangoni effect and mass transfer are observed by use of a microscope and low field nuclear magnetic resonance (NMR), respectively. Nanoemulsion, along with other methods of chemical enhanced oil recovery (EOR), is compared by conducting coreflooding and sandpack-flooding experiments after waterflooding. The results show that the Marangoni effect can help to emulsify and remove the oil from oil sand by converting interfacial energy into kinetic energy. On the basis of flooding-experiment results, we conclude that slug injection with a combination of nanoemulsion flooding and polymer flooding is an effective method for improving heavy-oil recovery.

Characterization of Oil−Water Emulsion and Its Use in Enhanced Oil Recovery

2010 ◽  
Vol 49 (24) ◽  
pp. 12756-12761 ◽  
Author(s):  
Ajay Mandal ◽  
Abhijit Samanta ◽  
Achinta Bera ◽  
Keka Ojha
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Water Emulsion ◽  
Oil Water

Industrial Application of Nickel Tallate Catalyst During Cyclic Steam Stimulation in Boca De Jaruco Reservoir

2021 ◽  
Author(s):  
Alexey V. Vakhin ◽  
Irek I. Mukhamatdinov ◽  
Firdavs A. Aliev ◽  
Dmitriy F. Feoktistov ◽  
Sergey A. Sitnov ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Industrial Application ◽  
Laboratory Scale ◽  
Catalyst Precursor ◽  
Hydrothermal Conditions ◽  
Cyclic Steam Stimulation ◽  
Steam Stimulation

Abstract A nickel-based catalyst precursor has been synthesized for in-situ upgrading of heavy crude oil that is capable of increasing the efficiency of steam stimulation techniques. The precursor activation occurs due to the decomposition of nickel tallate under hydrothermal conditions. The aim of this study is to analyze the efficiency of in-situ catalytic upgrading of heavy oil from laboratory scale experiments to the field-scale implementation in Boca de Jaruco reservoir. The proposed catalytic composition for in-reservoir chemical transformation of heavy oil and natural bitumen is composed of oil-soluble nickel compound and organic hydrogen donor solvent. The nickel-based catalytic composition in laboratory-scale hydrothermal conditions at 300°С and 90 bars demonstrated a high performance; the content of asphaltenes was reduced from 22% to 7 wt.%. The viscosity of crude oil was also reduced by three times. The technology for industrial-scale production of catalyst precursor was designed and the first pilot batch with a mass of 12 ton was achieved. A «Cyclic steam stimulation» technology was modified in order to deliver the catalytic composition to the pay zones of Boca de Jaruco reservoir (Cuba). The active forms of catalyst precursors are nanodispersed mixed oxides and sulfides of nickel. The pilot test of catalyst injection was carried out in bituminous carbonate formation M, in Boca de Jaruco reservoir (Cuba). The application of catalytic composition provided increase in cumulative oil production and incremental oil recovery in contrast to the previous cycle (without catalyst) is 170% up to date (the effect is in progress). After injection of catalysts, more than 200 samples from production well were analyzed in laboratory. Based on the physical and chemical properties of investigated samples and considering the excellent oil recovery coefficient it is decided to expand the industrial application of catalysts in the given reservoir. The project is scheduled on the fourth quarter of 2021.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

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