Molecular and electronic structure elucidation of Fe<sup>2+</sup>/Fe<sup>3+</sup> complexed chelators used in iron sulphide scale removal in oil and gas wells

Onawole, Abdulmujeeb T.; Hussein, Ibnelwaleed A.; Sultan, Abdullah S.; Abdel‐Azeim, Safwat; Mahmoud, Mohamed; Saad, Mohammed A.

doi:10.1002/cjce.23463

Cited by 30 publications

(34 citation statements)

References 51 publications

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“… 24 Also, dissolvers that have low pH will increase the tubular corrosion and therefore damage the facilities’ integrity. 25 , 26 Recent research studies 27 − 30 are directed to provide chemical dissolvers with high pH to sustain the well downhole and surface equipment, processing units, and facilities; also, this will save the corrosion inhibitor and intensifier cost that is commonly added to the treatment operations for low pH dissolvers. 31 , 32 Ahmed et al 28 added tetrakis hydroxymethyl phosphonium salts (THPS) to ethylenediaminetetraacetic acid (EDTA) to formulate a slightly alkaline chemical solution with about pH value of 8.…”

Section: Scale Removalmentioning

confidence: 99%

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

et al. 2021

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Removal of oil field scales commonly requires low pH acid, which may cause many issues under downhole conditions. Because of the deposition of different scale types and the economic effect, there is a need to develop a remedial descaling fluid that can be effectively used to remove different types of scales at a different position in the well. This paper provides a new scale dissolver that is noncorrosive and has high scale dissolution performance for composite scales. This study shows a series of comprehensive experimental lab tests as scale characterization, equilibrium brine compositional analysis, fluid compatibility and stability, solubility test, precipitation tendency for the dissolved solids, corrosion test, and core flooding. The scale samples contain magnetite, kaolinite, calcium carbonate, and sulfate scales. The results showed that the dissolution rate was higher than 74% for composite field scale samples after 6 h at 70 °C, while the new dissolver completely dissolved the two samples at 100 °C after 5 h. The new dissolver outperformed the common commercial dissolver used in the oil and gas industry. The new dissolver has a pH of 9 and showed safe use regarding the precipitation of dissolved solids that can be produced during the scale treatment and a low corrosion rate of 0.063 kg/m 2 at 6.9 MPa and 100 °C for 6 h. Also, the new dissolver was tested through core flooding for Indiana limestone and showed core permeability enhancement; the treatment with the new dissolver enhanced the core permeability from an initial value of 0.67 milliDarcy (mD) to record 1.29 mD.

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Section: Scale Removalmentioning

confidence: 99%

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

et al. 2021

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“…This level of theory and basis set have been used in previous studies and known to give reliable results. 11 , 44 All calculations were done in implicit solvent using the polarizable continuum model self-consistent reaction field. 45 There were no imaginary frequencies, ensuring that the molecules had reached a true minimum.…”

Section: Computational Detailsmentioning

confidence: 99%

Density-Functional Theory Investigation of Barite Scale Inhibition Using Phosphonate and Carboxyl-Based Inhibitors

et al. 2020

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Scale deposition is a critical issue in oil and gas exploration and production processes, causing significant blocking in tubing and consequently flow assurance and economic losses. Most studies addressing the scale formation have been limited on the experimental impact of different variables on scale formation. In this work, the inhibition of barite scale deposition was investigated by employing molecular simulations for three different scale inhibitors, namely, polyaspartic acid (PASP), nitrilotrimethylenephosphonate (NTMP), and dimethylenetriaminepenta(methylene-phosphonic acid) (DETPMP). Geometrical analyses were used to explore the performances of the inhibitors and visualize the outcomes. quantitative structure activity relationship parameters were also used to predict the activity of the inhibitors in the system. The order of the inhibitors is in agreement with the experiments with the following values for binding energies: −1.06, −0.17, and −2.33 eV for PASP, NTMP, and DETPMP, respectively. The results of this study indicated that the inhibition strength of the three inhibitors on barite scale formation can be sequenced as DETPMP > PASP > NTMP. Moreover, the ecological toxicity (eco-tox) properties were predicted, and the environmental impact of the different inhibitors was assessed. All inhibitors showed comparable eco-tox properties and predicted to be soluble in water. Molecular simulations proved to be an effective tool in the prediction of the performance and toxicity of barite scale inhibitors.

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“…The understanding of the origin of iron, formation of the iron sulfides, and sulfidation processes for iron surfaces is very important for the chemical surface interactions and provides a key role for designing the removal of iron sulfide scale [43]. Recently, a work by Onawole et al [44] provided a new way for designing green chelating agents for the chemical removal of iron sulfide scale. Another recent study was performed to determine the optimum treatment time and pH control for the chelating agent as a chemical dissolution for the iron sulfide [45].…”

Section: Iron Sulfide Scale Removalmentioning

confidence: 99%

New Environmentally Friendly Acid System for Iron Sulfide Scale Removal

Gamal¹,

Abdelgawad²,

Elkatatny³

2019

Sustainability

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Iron sulfide scale is a common problem in the oil and gas industry. The precipitation of the iron sulfide scale on the well completion tools or inside surface flow lines restricts the flow of the produced fluids and might affect the integrity of the pipelines or the surface and subsurface tools. Failure of the downhole completions tools will not only reduce the production rates but it might require workover and remedial operations that will add extra cost. The main objective of this paper is to evaluate a new environmentally friendly acid system (NEFAS) for iron sulfide scale removal using an actual field sample. The scale sample collected from a natural gas well is dominated by pyrrhotite (55%) in addition to calcite (21%), pyrite (8%), and torilite (6%) with minor traces of hibbingite, siderite, geothite, akaganeite, and mackinawite. High-temperature solubility tests were performed by soaking 2 g of the scale field sample with 20 cm3 of the NEFAS under static condition at 125 °C for different time periods (2, 6, 12, 18, and 24 h). The solubility results were compared with commercial solutions for iron sulfide scale removal such as hydrochloric acid (15 wt.%), glutamic acid diacetic acid (GLDA, 20 wt.%), and high density converters (HDC-3) under the same conditions. The corrosion test was performed at 125 °C for the developed solution after mixing with 2 wt.% corrosion inhibitor (CI) and 2 wt.% corrosion intensifier (CIN). The results were compared with HCl (15 wt.%) under the same conditions. NEFAS consists of 75 wt.% biodegradable acid at pH of 0.04. NEFAS achieved 83 g/L solubility of iron sulfide scale after 6 h at 125 °C under static conditions. The solubility efficiency was very close to 15 wt.% HCl after 24 h where the solubility was 82 and 83 g/L for NEFAS and HCl, respectability. HDC-3 and GLDA (20 wt.%) achieved a lower scale solubility; 18 g/L and 65 g/L respectively, after 24 h. NEFAS achieved a corrosion rate of 0.211 kg/m2 after adding the CI and and CIN compared to 0.808 kg/m2 for HCl. The new environmentally friendly biodegradable acid system provides efficient performance for the scale removal without harming the environment and causing any side effects to the operation.

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Molecular and electronic structure elucidation of Fe²⁺/Fe³⁺ complexed chelators used in iron sulphide scale removal in oil and gas wells

Cited by 30 publications

References 51 publications

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

Density-Functional Theory Investigation of Barite Scale Inhibition Using Phosphonate and Carboxyl-Based Inhibitors

New Environmentally Friendly Acid System for Iron Sulfide Scale Removal

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Molecular and electronic structure elucidation of Fe2+/Fe3+ complexed chelators used in iron sulphide scale removal in oil and gas wells

Cited by 30 publications

References 51 publications

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

Development of a Unique Organic Acid Solution for Removing Composite Field Scales

Density-Functional Theory Investigation of Barite Scale Inhibition Using Phosphonate and Carboxyl-Based Inhibitors

New Environmentally Friendly Acid System for Iron Sulfide Scale Removal

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Molecular and electronic structure elucidation of Fe²⁺/Fe³⁺ complexed chelators used in iron sulphide scale removal in oil and gas wells