Performance evaluation of microemulsion acid for integrated acid fracturing in Middle Eastern carbonate reservoirs

WANG, Yunjin; ZHOU, Fujian; SU, Hang; LI, Yuan; YU, Fuwei; DONG, Rencheng; WANG, Qing; LI, Junjian

doi:10.1016/s1876-3804(23)60458-6

Cited by 13 publications

(7 citation statements)

References 27 publications

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“…Moreover, even after heating for 4 h at 150 and 180 °C, the viscosity retention remains above 63%, underscoring the commendable thermal stability of the coagulant. The elevated viscosity retention postheating and subsequent decrease in temperature suggest that the high temperature induces molecular chain extension, and upon temperature reduction, the molecular structure of the coagulant regains its original form, leading to an increase in the viscosity of the coagulating acid system . Considering the microcapsule structure of GLE-3, wherein N -isopropylacrylamide participates in forming the microcapsule shell, the gradual increase in temperature results in partial degradation of the polymer coagulant dissolved and released in the coagulating acid.…”

Section: Results and Analysismentioning

confidence: 99%

“…The elevated viscosity retention postheating and subsequent decrease in temperature suggest that the high temperature induces molecular chain extension, and upon temperature reduction, the molecular structure of the coagulant regains its original form, leading to an increase in the viscosity of the coagulating acid system. 28 Considering the microcapsule structure of GLE-3, wherein N -isopropylacrylamide participates in forming the microcapsule shell, the gradual increase in temperature results in partial degradation of the polymer coagulant dissolved and released in the coagulating acid. Simultaneously, the polymer encapsulated within the microcapsule is gradually released, preventing a rapid decline in the viscosity of the coagulating acid and maintaining a relatively high viscosity retention.…”

Section: Results and Analysismentioning

confidence: 99%

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Synthesis and Characterization of a Temperature-Sensitive Microcapsule Gelling Agent for High-Temperature Acid Release

Liu,

Zhou,

Wan

et al. 2024

ACS Omega

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Deep, high-temperature carbonate reservoirs, represented by the Chuanzhong-Gaomo Block and the Penglai Gas Field, have become important supports for increased storage and production in Sichuan Basin. However, acidization in hightemperature to ultrahigh-temperature reservoirs faces several technical challenges, such as fast acid-rock reaction rates, limited acid corrosion distances, and high risks of tubular corrosion. In this study, a novel high-temperature-resistant microencapsulated gelling agent GLE-3 was prepared using N-isopropylacrylamide (NIPAM) as the wall material, acrylamide (AM), 2-acrylamido-2methylpropanesulfonic acid (AMPS), and N-vinylcaprolactam (NVCL) as the core materials, and N,N′-methylenebis(acrylamide) (MBA) as the cross-linking agent through inverse emulsion polymerization. GLE-3 was structurally characterized using infrared spectroscopy, transmission electron microscopy, and particle size analysis, and its properties were evaluated. The results showed that GLE-3 exhibited uniform particle size distribution ranging from 10 to 100 μm. Under high-temperature conditions of 180 °C and a shear rate of 170 s −1 , the viscosity of the gel acid solution remained above 27.8 mPa•s, with a viscosity retention rate of 63.76%. Compared to GLE-1 (uncapsulated), GLE-3 demonstrated improved thermal stability and shear stability after microencapsulation. After 60 min of shearing at 180 °C and shear rate of 170 s −1 , the viscosity retention rate was 88.99%. Furthermore, under 180 °C conditions, GLE-3 exhibited good high-temperature slow-release performance compared to GLE-1, which unencapsulated with the same raw materials. By increasing the viscosity of the gel acid, delaying the acid-rock reaction rate, and providing high-temperature slow-release effects, the high-temperature resistance of the acid system was enhanced, ultimately achieving deep acidization in hightemperature reservoirs.

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Section: Results and Analysismentioning

confidence: 99%

Section: Results and Analysismentioning

confidence: 99%

Synthesis and Characterization of a Temperature-Sensitive Microcapsule Gelling Agent for High-Temperature Acid Release

Liu,

Zhou,

Wan

et al. 2024

ACS Omega

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“…After simulated iron scale damage, the core is put into a beaker, and the mass ratio of asphalt to heptane solution is 1:1. The specific damage process can refer to Wang‘s research [ 5 ]. The damaged core is placed into the core holder of the high-temperature and high-pressure driving device for acidizing ( Figure 14 ).…”

Section: Study On Plugging Removal Performance Of Microemulsion Acidmentioning

confidence: 99%

“…Microemulsion acid comprises three parts: acid phase, oil phase and surfactant. Most scholars believe that according to the continuous phase and dispersed phase classification, microemulsion can also be similarly divided into the following three categories: acid-in-oil type, acid-in-oil type and double-continuous type [ 5 ]. The structure of microemulsion acid and emulsified acid is very similar.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

Wang

Zhou

Zou³

et al. 2023

Molecules

Self Cite

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Matrix acidification is one of the most effective stimulations to dissolve scales and remove damage in carbonate reservoirs. However, existing acid systems are difficult to dissolve organic and inorganic scales simultaneously, and complex multi-stage alternative injection often introduces new precipitation and damages the reservoir. Here, based on the retardation ability of emulsified acid and the stable structure of microemulsion, an oil-phase solvent was preferably selected, and the surfactant and cosurfactant were optimized to prepare an acid-in-oil type microemulsion acid capable of dissolving both organic and inorganic scales and high solubilizing for hydrochloric acid. Based on the rotating disc experiment, scale dissolution experiment and acid driving experiment, the acid-rock reaction kinetics, scale dissolution ability and acidizing and plugging removal performance of microemulsion acid in a carbonate reservoir were systematically studied and compared. The results show that Solvesso 150 (aromatic solvent) has the advantages of low toxicity, high flash point and high-scale dissolving ability. At NP−4: OP−10: A (cosurfactant) = 3:3:4, the microemulsion acid system has the strongest ability to solubilize hydrochloric acid and can solve the problem of low H+ concentration. The particle size of microemulsion acid is smaller compared to emulsified acid. At 60 °C, the mass transfer coefficient of microemulsion acid is 3.2 × 10−8 cm2/s, which is one order of magnitude less than that of emulsified acid. Microemulsion acid shows good solubility performance in dissolving organic and inorganic scales, and the comprehensive solubility of mixed scales can reach 98.28%. The stronger scale solubilization ability and lower acid-rock reaction rate enable microemulsion acid to form a thin and straight main wormhole, thus enhancing the acidizing and plugging removal effect. This study can solve the problem of poor hydrochloric acid solubilization ability of microemulsion acid to a certain extent, which provides theoretical and data support for the research and development of microemulsion acid and the efficient plugging removal technology for carbonate reservoirs.

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“…Morteza et al studied the microscopic mechanism of surfactant spontaneous imbibition oil displacement from nanometer scale by means of micro-nano CT and other technical means, and concluded that emulsification and wetting modification are the main mechanism of improving oil recovery in spontaneous imbibition process, while the influence of gravity is relatively small (Morteza et al, 2017;Anupong et al, 2022). Hatiboglu et al studied the influence of core size, solution salinity, temperature, crude oil viscosity, surfactant concentration and other related factors on spontaneous imbibition oil displacement efficiency through experiments, and found that crude oil viscosity, interfacial tension between surfactant solution and crude oil and wetting modification effect on rock have great influence on spontaneous imbibition oil displacement effect (Hatiboglu and Babadagli, 2004;Li, 2006;Peng et al, 2010;Li et al, 2011;Zhu et al, 2022;Wang et al, 2023). The above studies analyze the emulsification effect between the surfactant and the crude oil from the perspective of the interfacial tension between the surfactant and the crude oil, or determine whether the surfactant changes the direction and size of the capillary force by testing the wetting modification effect.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive analysis of influencing factors and mechanism of nano emulsion spontaneous imbibition oil displacement in tight sandstone reservoir

2023

Front. Energy Res.

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Tight sandstone reservoir has the characteristics of low porosity, low permeability and strong reservoir heterogeneity, which leads to a rapid decline in single well production after hydraulic fracturing. Adding nano emulsion to fracturing fluid can not only realize the dual function of fracturing and imbibition oil displacement, but also effectively prolong the stable production time of oil wells. In order to improve the understanding of the interaction between nano emulsion and reservoir, this paper based on the basic physical property test and analysis of nano emulsion, macroscopic and microscopic spontaneous imbibition oil displacement experiments, the mechanism of imbibition displacement of nano emulsion in tight sandstone reservoirs and the influence of related factors is clarified. The results show that: ①The particle size of the three types of nano emulsions ranges from 11 to 16 nm, and they can enter the nanopore throats deep in the reservoir, and can achieve good injectivity in tight reservoirs. The anionic AES nano emulsion is superior to cationic ADT and nonionic AEO-9 nano emulsion in terms of injectability, oil-water interfacial tension and wetting modification effect in tight sandstone cores, and the optimal concentration is 0.30 wt%. ②Spontaneous imbibition oil displacement experiments show that the nano emulsion concentration is not the higher the better. Since the nano emulsion adsorption on the solid surface reaches a dynamic equilibrium, the excessive nano emulsion cannot further change the wettability of the solid surface, and the lower oil-water interfacial tension has the opposite effect on the imbibition displacement. ③The migration and gathering of emulsified oil droplets in solution mainly included five processes: Saturated oil core/Nano-surfactant fluid emulsion reaction, Aqueous/Emulsified oil droplets, Emulsified oil droplet gathering phase, Demulsifying and emulsifying oil droplets, Oil phase after demulsification. The generation of remaining oil in porous media is due to the non-uniform wetting modification in different regions. This study further improves the understanding of the mechanism of spontaneous imbibition of nano emulsion in tight sandstone reservoirs.

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Performance evaluation of microemulsion acid for integrated acid fracturing in Middle Eastern carbonate reservoirs

Cited by 13 publications

References 27 publications

Synthesis and Characterization of a Temperature-Sensitive Microcapsule Gelling Agent for High-Temperature Acid Release

Synthesis and Characterization of a Temperature-Sensitive Microcapsule Gelling Agent for High-Temperature Acid Release

Preparation and Performance Study of Microemulsion Acid for Comprehensive Plugging Removal in Carbonate Reservoir

Comprehensive analysis of influencing factors and mechanism of nano emulsion spontaneous imbibition oil displacement in tight sandstone reservoir

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