New Insights into the Removal of Calcium Sulfate Scale

AlKhaldi, Mohammed; AlJuhani, Ahmad; Al-Mutairi, Saleh Haif; Gurmen, Mehmet Nihat

doi:10.2118/144158-ms

Cited by 25 publications

(13 citation statements)

References 10 publications

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“…5a), oil recovery and mining activities (e.g. Brusilovsky et al, 1992;Linnikov O.D., 2000;Ahmed et al, 2004;Mi and Elimelech, 2010;Al-khaldi et al, 2011;Olajire, 2015;Lu et al, 2012;Rosenberg et al, 2012). Anhydrite is the predominant scale-forming phase at higher temperatures >100 ºC, while gypsum scaling prevails at lower temperatures.…”

Section: Calcium Sulfate Phases In Engineered Environmentsmentioning

confidence: 99%

Calcium sulfate precipitation pathways in natural and engineered environments

2019

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The solution-mediated formation of calcium sulfate minerals, i.e. gypsum, anhydrite and bassanite, is a common process in both natural and engineered settings. It plays a key role in the global sulfur cycle and serves as an indicator of past environmental conditions on Earth and Mars. Products relying on the crystallization of these minerals have been employed since antiquity, and today they are an essential part of a wide array of industrial applications. Accordingly, the fundamental aspects of calcium sulfate mineralization have been the focus of intensive research during the past century. However, a recent flurry of studies addressing alternative, i.e. nonclassical, nucleation and growth mechanisms has spurred a revisit of the precipitation pathway of the most common phase, gypsum. The newly obtained data sketch a far more complex picture of the mineralization process than previously assumed. This has important consequences for the interpretation of calcium sulfate deposits, both from a geochemical and industrial point of view. In order to shed light on this issue, we discuss in this review both recent and long-standing observations of abiotic formation routes of calcium sulfate minerals as a function of the physicochemical solution properties. By integrating both the classical and non-classical perspectives on crystallization we put forward a unified model for calcium sulfate crystallization. Using this model, we (re)-evaluate the phase stability and transformations taking place in the CaSO 4-H 2 O system. Next, we look into the formation of calcium sulfate minerals occurring in close association with the biosphere. Employing the abiotic case scenario as a benchmarking tool, the possible influence and/or control exerted by biological activity (and its byproducts) on the precipitation pathway is critically reviewed. Finally, we point out the central issues that need to be resolved if we wish to fully understand and control the formation of calcium sulfate solids in natural and engineered environments.

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Section: Calcium Sulfate Phases In Engineered Environmentsmentioning

confidence: 99%

Calcium sulfate precipitation pathways in natural and engineered environments

2019

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“…CaSO4 is considered as a significant scale that transpired in the oil and gas industry. A study by Al-Khaldi et al confirms that CaSO4 may cause considerable change in injector and producer reservoirs [67]. Mahmoud et al demonstrated that the deposition of these scales in the reservoir could change the porosity and permeability of the reservoir [68].…”

Section: Calcium Sulfatementioning

confidence: 99%

“…BaSO 4 scales can be obtained from two primary sources in which one of them is the injection of seawater into the zone where the excess of Ba 2+ ion dominates the deposition of BaSO 4 scales. The deposition of scales proceeds due to the excess SO [67]. Mahmoud et al demonstrated that the deposition of these scales in the reservoir could change the porosity and permeability of the reservoir [68].…”

Section: Barium Sulfatementioning

confidence: 99%

A Review of Green Scale Inhibitors: Process, Types, Mechanism and Properties

Mazumder

2020

Coatings

103

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In the present time, more often, it has been seen that scaling has grown as widely and caused problems in the oilfield industry. Scaling is the deposition of various salts of inorganic/organic materials due to the supersaturation of salt-water mixtures. Many works have been proposed by researchers using different methods to solve the problem, of which scale inhibition is one of them. The scale inhibitors, particularly for antiscaling, have derived from natural and synthetic polymers. Among different polymers, inorganic and organic compounds (polyphosphates, carboxylic acid, ethylenediaminetetraacetic acid (EDTA), etc.) can effectively manage the oilfield scales of which many are toxic and expansive. Scale inhibitors of alkaline earth metal carbonate and sulfates and transition metal sulfide are commonly used in oilfield applications. Scale inhibition of metallic surfaces is an essential activity in technical, environmental, economic, and safety purposes. Scale inhibitors containing phosphorus appear to have significant achievements in the inhibition process despite its toxicity. However, phosphorus-based inhibitors can serve as supplements prompting eutrification difficulties. Besides these increasing environmental concerns, green scale inhibitors are renewable, biodegradable, and ecologically acceptable that has been used to prevent, control, and retard the formation of scale. Considering the facts, this review article summarized the concept of scale, various green scale inhibitors, types, mechanisms, comparative performance, significance, and future aspects of green scale inhibitors, which will shed light and be helpful for the professionals working in the oil and gas industries.

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“…For Cr-13 alloys, a 0.5 vol% of corrosion inhibitor was added, and a corrosion rate of 0.04 lbm/ft 2 was obtained. The acceptable limit of the corrosion that is in the range of 0.02 to 0.05 lbm/ft 2 was set by the operator and service companies to protect the coiled tubing, well tubulars, and the formation from the iron-scale precipitation (Al-Mutairi et al 2005;Kalfayan 2008). In wells with corrosive gases, tubular consisting of low-carbon steel, Cr-based steel, or corrosion-resistant Cr-Ni alloys can be effectively protected by a combination of GLDA with a minimal amount of corrosion inhibitor.…”

Section: Introductionmentioning

confidence: 99%

Stimulation of Seawater Injectors by GLDA (Glutamic-Di Acetic Acid)

Mahmoud

Abdelgawad

Elkatatny

et al. 2016

SPE Drilling &Amp; Completion

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Seawater is injected to maintain the reservoir pressure that supports the oil production from carbonate and sandstone reservoirs. In certain regions, the seawater contains more than 4,000 ppm sulfate, and the formation contains more than 19,000 ppm calcium; this will cause calcium sulfate precipitation at the reservoir conditions. The precipitate at the reservoir conditions will be anhydrite, and it will cause formation damage that will reduce the well injectivity. Stimulation treatments are required to recover the well injectivity; this requires stopping water injection to perform the stimulation treatments, and also it requires flowing back the well after stimulation treatment.In this study, we are proposing a new method that we can use to stimulate water injectors without stopping the water injection. The new method includes adding a chelating agent to the injected seawater at the wellhead at 15 wt% concentration. The fluid will be injected at the surface with the seawater with a specific dose to achieve the required concentration. Several solubility and coreflooding tests were performed with actual carbonate cores and GLDA (glutamic-di acetic acid) chelating agent at different temperatures. The chemical injection does not need coiled tubing and can be injected at the surface with the seawater. The chelating agents will sequester all calcium in solution and will prevent the calcium sulfate precipitation. GLDA chelating agent will be used with seawater, with no need to use treated or fresh water. Also, flowing back the well is not required because the fate of GLDA in the aquifer is soluble.Solubility tests up to 250 F at high pressure showed that the GLDA is stable with seawater. Coreflood experiments and computed-tomography scans showed the ability of GLDA in the creation of dominant wormholes through 6-and 1.5-in. carbonate cores at 212 and 150 F, respectively. GLDA chelating agent can be used to stimulate seawater injectors without additives because this chemical is stable and mild with the well tubulars. Previous corrosion studies on GLDA showed that its corrosion rate is in the allowable range without adding corrosion inhibitors.

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New Insights into the Removal of Calcium Sulfate Scale

Cited by 25 publications

References 10 publications

Calcium sulfate precipitation pathways in natural and engineered environments

Calcium sulfate precipitation pathways in natural and engineered environments

A Review of Green Scale Inhibitors: Process, Types, Mechanism and Properties

Stimulation of Seawater Injectors by GLDA (Glutamic-Di Acetic Acid)

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