Recent Development and Remaining Challenges of Iron Sulfide Scale Mitigation in Sour Gas Wells

Chen, Tao; Wang, Qiwei; Chang, Frank; Aljeaban, Norah

doi:10.2523/iptc-19315-ms

Cited by 10 publications

(8 citation statements)

References 21 publications

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“…In addition to that formulation, new copolymer chemistry containing the acrylamide, phosphonic acid, and sulfonic acid acrylic units has successfully prevented FeS formation when injected as 0.75 ppm active polymer . Importantly, it is suggested that inhibitors based on dispersion mechanism are more convenient to be employed for FeS inhibition cases in typical sour gas wells rather than nucleation and crystal-growth-based inhibitors …”

Section: Field Case Studiesmentioning

confidence: 99%

“…Another nonchemical corrosion prevention technique is the antiscalants coating with stable materials withstanding the harsh downhole conditions in sour gas wells. 70 The antiscalants are adsorbed onto the fluid boundary layer, thus eliminating the scales deposition onto the metal surfaces. Several types of protective coatings are applied on the inner surfaces of oil and gas transmission pipelines.…”

Section: Iron Sulfide Scale Inhibition and Controlmentioning

confidence: 99%

“…50 Importantly, it is suggested that inhibitors based on dispersion mechanism are more convenient to be employed for FeS inhibition cases in typical sour gas wells rather than nucleation and crystal-growth-based inhibitors. 70 A gas well located in Fairfield, Texas, had a severe buildup of iron sulfide in a sour gas well where the temperature was 149 °C. Foam-based iron sulfide inhibitors were successfully developed and field trials showed that these foam inhibitors held the iron sulfide suspended and prevented its deposition while H 2 S was kept in the gaseous phase.…”

Section: Field Case Studiesmentioning

confidence: 99%

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Review of Iron Sulfide Scale Removal and Inhibition in Oil and Gas Wells: Current Status and Perspectives

et al. 2021

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Iron sulfide scale is one of the main types of inorganic scales that block oil and gas wells. Iron sulfide has polymorph crystallinity structures, which complicate its dissolving and inhibition. Hydrochloric acid (HCl) is used conventionally to remove iron sulfide scale; however, toxic hydrogen sulfide (H 2 S) is released. Consequently, tubular corrosion and formation damage are accelerated. This review highlights the major role of understanding iron sulfide chemistry in developing chemicals for removing or inhibiting the different iron sulfide polymorphs. Furthermore, the physical features of iron sulfide types and the optimum conditions for their formation in terms of depth, temperature, pressure, and well types are explored. The article also emphasizes the mechanisms and introduces the new green formulations used to dissolve and inhibit iron sulfide. Moreover, recent theoretical work on molecular simulation efforts proved to be significant in identifying potential dissolvers and inhibitors and insightful on the reaction mechanisms. Furthermore, the field practice in removing this type of scale is illustrated with field case studies to present the obstacles facing the efficient implementation of the lab-scale techniques. Finally, the environmental impact and economic assessment are reviewed to identify the most efficient chemicals.

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Section: Field Case Studiesmentioning

confidence: 99%

Section: Iron Sulfide Scale Inhibition and Controlmentioning

confidence: 99%

Section: Field Case Studiesmentioning

confidence: 99%

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Review of Iron Sulfide Scale Removal and Inhibition in Oil and Gas Wells: Current Status and Perspectives

et al. 2021

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“…However, it was found that there was a limited effect on the dissolution rate by increasing volume ratio of the dissolver with the scale mass and increasing agitation under the test conditions [39]. Recent studies were performed to find an effective chemical solution for removing the precipitated iron sulfide scales, and improving the scale dissolution [40][41][42].…”

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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“… 1 It is reported that scales can deposit in many forms and in different locations in the well; for example, iron sulfide can deposit near the wellbore region, downhole, and topside tubes of the well, in addition to the sides of the reservoir. 2 Different wells may have scales that are different in composition, severity, and depth. For example, at around 2 km on the downhole tubing, the scale starts to be noticeable, and the severity increases with the depth.…”

Section: Introductionmentioning

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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Recent Development and Remaining Challenges of Iron Sulfide Scale Mitigation in Sour Gas Wells

Cited by 10 publications

References 21 publications

Review of Iron Sulfide Scale Removal and Inhibition in Oil and Gas Wells: Current Status and Perspectives

Review of Iron Sulfide Scale Removal and Inhibition in Oil and Gas Wells: Current Status and Perspectives

New Environmentally Friendly Acid System for Iron Sulfide Scale Removal

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

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