Finding Suitable Acid for Acidizing of Low Permeable Sandstone Formation: A Research

Shafiq, Mian Umer; Shuker, Muhannad Talib

doi:10.2118/169641-ms

Cited by 9 publications

(5 citation statements)

References 3 publications

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“…Acidization has played a significant role in stimulating oil and gas recovery. , Matrix acidizing generally uses acid solutions, which creates or enlarges the flow channels of formation . The right type of acids or acid mixtures must be used to remove damage and improve the permeability of reserviors .…”

Section: Introductionmentioning

confidence: 99%

Study on Acidizing Effect of Cationic β-Cyclodextrin Inclusion Complex with Sandstone for Enhancing Oil Recovery

Zou

Qin

Yan

et al. 2014

Ind. Eng. Chem. Res.

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A novel supramolecular inclusion complex was prepared with cationic β-cyclodextrin and organic phosphoric acid. The inclusion action was investigated by UV−vis spectroscopy, and the cationic β-cyclodextrin inclusion complex was structurally evidenced by 1 H and 31 P NMR and FT-IR. With linear expansion tests, it was found that the novel inclusion complex possessed excellent clay stability. FT-IR, single-factor, and response surface method analyses showed that the inclusion complex acid system could not only retard acid−rock reaction but also intelligently regulate the acid−rock reaction rate to ensure a sufficient amount of acid to react with high-temperature oil-bearing sandstone reservoir in the progress of acid stimulation. On the basis of the core flood tests, an interaction mechanism was suggested that the inclusion complex acid system may open up for a new possibility to exhibit greater acidizing performance in high clay content, high-temperature, and low-permeability oil reservoirs, which contributes to improving core permeability and enhancing oil recovery.

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Section: Introductionmentioning

confidence: 99%

Study on Acidizing Effect of Cationic β-Cyclodextrin Inclusion Complex with Sandstone for Enhancing Oil Recovery

Zou

Qin

Yan

et al. 2014

Ind. Eng. Chem. Res.

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“…These products could potentially be iron(III) (Fe 3+ ) or iron(III) tetrachloro complex (FeCl 4− ), which were formed due to the reaction between iron ions and chloride ions which then resulted in the change in colour of the core samples into a yellowish brown colour. These colour changes were also observed by Shafiq and Shuker (2013), whereby the colour of the core samples changed to yellowish after saturating with acid. Core samples 1-14 were then saturated with emulsified acid which consequently caused the samples to change from yellowish grey to pale grey as shown in Fig.…”

Section: Colour Change Testmentioning

confidence: 53%

“…First, the volume of distilled water, acid and diesel is calculated using Eq. 1 (Shafiq and Shuker 2013) where V 2 is the total volume of the mixture which is set to be 150 ml for this study. M 1 given saturation of the acid by the supplier (In Liquid form).…”

Section: Synthesis Methodsmentioning

confidence: 99%

Application of emulsified acids on sandstone formation at elevated temperature conditions: an experimental study

Shafiq

Chong

Mahmud

et al. 2018

J Petrol Explor Prod Technol

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Emulsified acid has attracted considerable attention of the oil and gas industry due to its delayed nature that allows deeper penetration of acid into the formation which essentially facilitate further enhancing the well productivity, and at the same time minimizes the corrosion issues. However, emulsified acid has only been extensively studied and applied on carbonate formations. Considering more than half of the reservoirs worldwide are sandstone reservoirs, studying the effects of emulsified acid on sandstone under high-temperature conditions would unlock the potential of emulsified acid and help generate more value for the oil and gas industry by improving the well productivity from sandstone reservoirs. To ensure the applicability of the emulsified acid on the real sandstone reservoir, which usually has a temperature higher than ambient conditions, the stability of emulsified acids is investigated under 300 °F. Then, the stable emulsified acid samples are developed and their impact on the properties of Berea sandstone core samples, including porosity, pore-size distribution, permeability and wettability, are investigated. The core samples have undergone pre-flush (10% HCl:5% CH 3 COOH) before the main flush (emulsified acid). The emulsified acids are prepared using hydrofluoric acid, hydrochloric acid, phosphoric acid, cationic surfactant and chelating agent. Fourteen core samples are saturated with different emulsified acids under vacuum conditions for 3 days to ensure maximum saturation. The porosity, permeability and wettability of each core sample are measured before and after the reaction with acid. Nuclear magnetic resonance analysis has been applied to evaluate the change in pore size distribution. This study has demonstrated that the emulsified acids are capable of improving the porosity and permeability of Berea sandstone core sample. The pore size distribution has also been affected by the application of emulsified acid, where more large pores have been evolved to the core samples due to the reaction of acids with the sandstone which ultimately helps in improving the productivity of hydrocarbons. This indicates less precipitation of the secondary reaction products resulting better enhancement in sandstone flow properties. These results demonstrate the potential of emulsified acid during sandstone acidizing as emulsified acid significantly improved the sandstone properties which can essentially enhance the well productivity.

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“…The research group in recent years led by Shafiq et al presented multiple experimentations using various acid combinations (Shafiq et al 2013b(Shafiq et al , 2014Shafiq and Shuker 2013;Shafiq et al 2015;Shafiq and Ben Mahmud 2016). The acid combinations tested by the authors included a mixture of orthophosphoric (H 3 PO 4 ) acid and HF; fluoroboric (HBF 4 ) acid and HCOOH; and HCOOH and HF.…”

Section: Retarded Acids and Organic Acidsmentioning

confidence: 99%

A preliminary screening and characterization of suitable acids for sandstone matrix acidizing technique: a comprehensive review

Leong

Mahmud

2018

J Petrol Explor Prod Technol

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Matrix acidizing is a broadly developed technique in sandstone stimulation to improve the permeability and porosity of a bottom-hole well. The most popular acid used is mud acid (HF-HCl). It is a mixture of hydrofluoric acid and hydrochloric acid. However, one of the conventional problems in sandstone acidizing is that mud acid faces significant issues at high temperature such as rapid rate of reaction, resulting in early acid consumption. This downside has given a negative impact to sandstone acidizing as it will result in not only permeability reduction, but can even extend to acid treatment failure. So, the aim of this study is to provide a preliminary screening and comparison of different acids based on the literature to optimize the acid selection, and targeting various temperatures of sandstone environment. This paper has comprehensively reviewed the experimental works using different acids to understand the chemical reactions and transport properties of acid in sandstone environment. The results obtained indicated that fluoroboric acid (HBF 4) could be useful in enhancing the sandstone acidizing process, although more studies are still required to consolidate this conclusion. HBF 4 is well known as a low damaging acid for sandstone acidizing due to its slow hydrolytic reaction to produce HF. This would allow deeper penetration of the acid into the sandstone formation at a slower rate, resulting in higher porosity and permeability enhancement. Nevertheless, little is known about the effective temperature working range for a successful treatment. Considering the pros and cons of different acids, particularly those which are associated with HF and HBF 4 , it is recommended to perform a comprehensive analysis to determine the optimum temperature range and effective working window for sandstone acidizing before treatment operation. Prior to sandstone acid stimulation, it is essential to predict the feasibility of acid selected by integrating the effects of temperature, acid concentration and injection rate. Therefore, this manuscript has thrown light into the research significance of further studies.

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Finding Suitable Acid for Acidizing of Low Permeable Sandstone Formation: A Research

Cited by 9 publications

References 3 publications

Study on Acidizing Effect of Cationic β-Cyclodextrin Inclusion Complex with Sandstone for Enhancing Oil Recovery

Study on Acidizing Effect of Cationic β-Cyclodextrin Inclusion Complex with Sandstone for Enhancing Oil Recovery

Application of emulsified acids on sandstone formation at elevated temperature conditions: an experimental study

A preliminary screening and characterization of suitable acids for sandstone matrix acidizing technique: a comprehensive review

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