A New Emulsified Acid to Stimulate Deep Wells In Carbonate Reservoirs: Coreflood and Acid Reaction Studies

Sayed, Mohammed; Nasr‐El‐Din, Hisham A.; Zhang, Lei; Zhou, Jianqin; Holt, Stuart Peter

doi:10.2118/151062-ms

Cited by 19 publications

(6 citation statements)

References 34 publications

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“…The most commonly used ratio for the two phases is a 70:30 acid to oil ratio. 161 Diesel emulsified acid (DEA) is common as it gains viscosity while shearing and can divert itself to low permeability formation sections. Nevertheless, it usually requires a long mixing time and could result in high-pressure losses during injection.…”

Section: Application Of Nps In Emulsion-based Stimulationmentioning

confidence: 99%

Application of Nanoparticles in Stimulation: A Review

et al. 2022

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Oil well stimulation treatments have been employed to improve the productivity index, either by imposing a negative skin effect through hydraulic fracturing or by reducing a positive skin effect using matrix acidizing. The commonly used stimulation fluids are polymer-based, viscoelastic surfactant-based, emulsion (oil)-based, and foam-based. The stability and performance efficiency of the stimulation fluids under harsh conditions of high temperature and high pressures have remained a critical factor. Thus, in recent times, the incorporation of nanoparticles (NPs) as additives in the fluid formulation has received significant attention. NPs have been reported as rheology modifiers, cross-linking agents, gel breakers, leakoff control additives, foam stabilizers, proppant surface modifiers, and emulsion stabilizers in different types of stimulation fluids. In this review, we discuss the application of nanoparticles in different types of stimulation fluids. The different roles of nanoparticles are highlighted. Factors affecting the performance of nanoparticles in stimulation fluids are also covered. Although laboratory experiments have shown the exceptional performance of nanoparticles, the field application of different nanoparticles in stimulation fluids is still limited.

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Section: Application Of Nps In Emulsion-based Stimulationmentioning

confidence: 99%

Application of Nanoparticles in Stimulation: A Review

et al. 2022

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“…and Chan, 2004 ), and the fracturing fluid technique has received considerable attention. Subsequently, other fracturing fluid techniques were greatly developed, for example, hydraulic fracturing fluids ( Zhang et al, 2018a ; Zhou et al, 2019 ), oil-based fracturing fluid ( Zhang et al, 2018b ), emulsified fracturing fluid ( Buijse and van Domelen, 2000 ; Sayed et al, 2012 ; Zakaria and Nasr-EI-Din, 2015 ), foam fracturing fluid ( Sayed and Al-Muntasheri, 2016 ; Dehdari et al, 2020 ; Qu et al, 2020 ), thickening fracturing fluid ( Liu and Li, 2016 ; Cai et al, 2018 ), alcohol-based hydraulic fracturing ( Marrugo-Hernandez et al, 2018 ), and surfactant fracturing fluid ( Zhang et al, 2018c ; Lu et al, 2019 ; Mejia et al, 2019 ; Tangirala and Sheng, 2019 ; Zhang et al, 2019 ). Although hydraulic fracturing fluid has been widely used, it still represents the poor stability to shear resistance and serious filtration loss.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Characterization of Surfactant for Retarding Acid–Rock Reaction Rate in Acid Fracturing

2021

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Acid fracturing is an effective method to develop ultra-low permeability reservoirs. However, the fast reaction rate reduces the effect of the acid fracturing and increases the near-well collapse risk. Therefore, it is necessary to retard the acid–rock reaction rate. In this work, we synthesized an acid-resistant Gemini zwitterionic viscoelastic surfactant (named VES-c), which has good performances such as temperature resistance, salt resistance, and shear resistance. Besides, a low concentration of VES-c increases the viscosity of the acid solution. The CO2 drainage method was used to measure the reaction rate between the dibasic acid and dolomite/broken core. We find that the dibasic acid containing 0.3% VES-c retards the dolomite reaction rate of 3.22 times compared with only dibasic acid. Furthermore, the dibasic acid containing 0.3% VES-c exhibits uniform distribution and is not easy to adhere to the solid surface. The VES-c also is favorable to reduce the formation of amorphous calcium carbonate. Retarding the rate of acid–rock reaction and enhancing the acidification are mainly attributed to VES-c's salt-tolerance, anti-adsorption, and the property of increasing the viscosity of the solution. Hopefully, this kind of surfactant retarding reaction rate is applied to other acid–rock reactions.

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“…Buijse and van Domelen studied the effect of the injection rate, viscosity, and acid volume fraction on the emulsified acid pore volume to breakthrough in carbonate rocks. Sayed et al studied the performance of the emulsified acid in low and high permeability carbonate formations using coreflood experiments. It was found that the high permeability carbonate cores consumed more acid volume to breakthrough than did the low permeability cores.…”

Section: Introductionmentioning

confidence: 99%

Flow of Emulsified Acid in Carbonate Rocks

Zakaria

Nasr‐El‐Din

Ziauddin

2015

Ind. Eng. Chem. Res.

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We conducted tracer experiments on core samples from six different carbonates to study the flow of acid fluid through the porous media of carbonate rocks and correlate the carbonate pore classes to the acid response. Pore structures were characterized by section analysis, high pressure mercury injection tests, and nuclear magnetic resonance measurements; mineralogy was determined by X-ray diffraction. Tracer concentration profiles were analyzed to quantify the carbonate pore-scale heterogeneity. The heterogeneity is expressed using a parameter fthe available fraction of pore structure contributing to the flow. From the results, different characterization methods could be connected to the acid fluid flow through the porous media of carbonate rocks. It was also found that the response of the acid depends on the carbonate pore classes. Applications include the design of matrix acid treatments in carbonate rocks. ■ INTRODUCTIONThe goal of acid-stimulation treatments in carbonate reservoirs is to remove or bypass formation damage by creating highconductivity channels known as wormholes. To propagate deeper wormholes in the formation for better productivity enhancement, retarded acids should be used. Emulsified acids are one of the most widely used retarded-acid systems. HCl acid is commonly used as the internal phase of the emulsion. For the external phase, oil and diesel are the most commonly used hydrocarbons. The external hydrocarbon phase acts as a diffusion barrier to reduce the diffusion of the acid droplets to the surface of the rock, 1,2 which helps in the creation of deep wormholes. Several studies 3−5 examined the reaction of emulsified acid with carbonate. Navarrette et al. 4 indicated that the reaction rate of 28 wt % HCl emulsified acid with limestone was 8.5 times less than that of 28 wt % HCl with limestone. Al-Anazi et al. 6 studied the application of the emulsified acid in tight carbonate rocks using coreflood experiments, and the results showed that the emulsified acid can form deep wormholes in tight carbonate cores. Buijse and van Domelen 7 studied the effect of the injection rate, viscosity, and acid volume fraction on the emulsified acid pore volume to breakthrough in carbonate rocks. Sayed et al. 8 studied the performance of the emulsified acid in low and high permeability carbonate formations using coreflood experiments. It was found that the high permeability carbonate cores consumed more acid volume to breakthrough than did the low permeability cores. Also, an optimum injection rate was observed for the highpermeability cores whereas the acid pore volumes to breakthrough decreased with increases in the injection rate for lowpermeability formations.Hoefner and Fogler 9 studied the pore evolution during the flow and the reaction of the acid in porous media. The initiation of wormholes occurs when the live acid penetrates into pores present in carbonate rocks, and then, pore structure evolution occurs. The process is more efficient when only the large pores in the matrix lead to wormholes. 10 C...

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A New Emulsified Acid to Stimulate Deep Wells In Carbonate Reservoirs: Coreflood and Acid Reaction Studies

Cited by 19 publications

References 34 publications

Application of Nanoparticles in Stimulation: A Review

Application of Nanoparticles in Stimulation: A Review

Synthesis and Characterization of Surfactant for Retarding Acid–Rock Reaction Rate in Acid Fracturing

Flow of Emulsified Acid in Carbonate Rocks

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