Flow Assurance Issues and Control with Naphthenic Oils

Brocart, Benjamin; Hurtevent, Christian

doi:10.1080/01932690802316827

Cited by 24 publications

(33 citation statements)

References 2 publications

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“…It was thus obvious that, if having TPA, divalent ions in the water, and an high enough pH was necessary for risking to have a deposit, these conditions were not enough for this risk to be realized : an inhibitive mechanism was happening to prevent the formation of deposits. Coming from our various studies of acidic crude oils, described latter on, our hypothesis was that other naphthenic acids from the crude oil were able to prevent the formation of the deposit, as illustrated in [18] and schematically in Figure 1. It is very similar to what can be found in the crosslinking of thermoset networks for example.…”

Section: Risk Assessment Of Calcium Naphthenate Depositsmentioning

confidence: 97%

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Risk Assessment of Calcium Naphtenates and Separation Mechanisms of Acidic Crude Oil

et al. 2012

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For over a decade, being able to accurately predict the risk of calcium naphthenate deposition has been one of the goals of production chemistry studies for development of new fields. In order to fulfill this challenge, many studies have been performed both within the company and through collaborations in JIPs. These studies have also shown specific behaviours of acidic crude oil / water separation depending on processing conditions. They have also permitted the improved detection and quantification of tetraprotic acids that are one of the main building blocks of these deposits. In this work, we will show how these findings have been incorporated into a workflow used to quantify naphthenate deposition risk. In particular, we will try to illustrate how the "other" naphthenic acids of the crude oil can behave as an efficient natural inhibitor of the deposits, and why, even if tetraprotic acids are detected in quite a large number of oils, only a limited number of fields have faced large scale issues related to calcium naphthenate deposits, due either to "good" process design or good fortune. "Simple" physicochemistry tests turn out to be very powerful tools in order to assess the macroscopic behavior of the naphthenic acids, and their influence on the risk analysis. IntroductionWith the growth of petroleum products consumption, oil companies have to face not only the production of more difficult oils but they also have to develop fields in more and more difficult places (deep off shore, artic, …). There is a great need for flow assurance studies to be as accurate as possible both from a project perspective, in order not to over design for CAPEX concerns, as well as from an operational perspective, to be able to cope with scale issues. These studies should ensure efficient and reliable operation of the installations. When the developments are made on floating units, such as FPSO, the volume and the weight for surface installations have to be limited. As an example, optimizing the footprint of separators while keeping a good efficiency is a much greater need for FPSO than for traditional inland developments. This is also the case with additives as all the logistics involved are more difficult to organize: for example, in the case of acidic oils, limiting the use of acetic acid, to maintain low pH, is desirable both for logisitic and safety issues.

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Section: Risk Assessment Of Calcium Naphthenate Depositsmentioning

confidence: 97%

“…Proposed mechanism for calcium naphthenates scales formation (a) or inhibition (b) from[18] LC-UV calibration spectra and curve for the "pure" TPA recovered from field deposit LC…”

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confidence: 99%

Risk Assessment of Calcium Naphtenates and Separation Mechanisms of Acidic Crude Oil

et al. 2012

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“…Asphaltenes might also complex ARN in bulk oil, reducing the number of tetraacids available at the interface for complexation with calcium (Subramanian et al 2017). Brocart and Hurtevent (2008) demonstrated that low molecular weight monoacids are inhibitive to the formation of CaN by the ARN acids via inactivation of polymerization sites on the tetraacid. This occurs through monoacid-tetraacid associations at the interface where the divalent calcium ion complexes a monoacid on one arm and an ARN acid on the other.…”

Section: Effect Of Asphaltenes On Calcium Naphthenate Formationmentioning

confidence: 99%

Oilfield metal naphthenate formation and mitigation measures: a review

Eke

Victor-Oji

Akaranta

2019

J Petrol Explor Prod Technol

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Process facilities for the separation of hydrocarbons from produced water in the oilfield are critical to flow assurance, product quality and environmental compliance. The formation of metal naphthenates, which are emulsion stabilizers and equipment foulers, is deleterious to performance and integrity of these processes and facilities. Manual removal of deposits of these organic salts formed at the oil-water interface during separation processes is difficult and expensive; hence, the best operational option is inhibition. The conventional method for the inhibition of metal naphthenates, which relies on suppressing the deprotonation of naphthenic acids by common ion effect, is no longer tenable because it exacerbates internal corrosion problems in topside facilities. Current industry focus is on the development of effective surface active agents for inhibition of naphthenates. There are a plethora of chemical compounds with naphthenate inhibition potential such as sulphonates, phosphate esters, aminated phosphonates and sulphosuccinates, but compatibility issues make the choice of inhibitor a complicated process. In this paper, the drivers and mechanism of oilfield metal naphthenate formation are reviewed. Surfactants for oilfield metal naphthenate inhibition and the mechanisms of inhibition are highlighted with a view to process optimization.

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“…Recently, based on previous works and analyses by Vindstad et al, Brocart et al, , and Sjöblom et al, − Simon et al have proposed the following calcium deposition mechanism. Initially, due to the depressurization of crude oil during oil production, carbon dioxide is released and, as a result, the pH of the produced water is increased.…”

Section: Introductionmentioning

confidence: 99%

Screening of Inhibition of Calcium Naphthenate Deposition in Crude Oil

et al. 2021

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One of the initial steps in calcium naphthenate deposition is the reaction between ARN and Ca 2+ leading to the formation of an interfacial gel. After growing, this gel will form calcium naphthenate deposits that are a threat for irregularities in crude oil production and processing. It has been previously shown that crude oil components such as asphaltenes and naphthenic acids can weaken and inhibit the formation of the interfacial gel. Based on this observation, the inhibition efficiency of four crude oils is compared. The variations of interfacial tension (IFT) and interfacial dilational modulus E′ of ARN solution (concentration = 10 μM) in contact with Ca 2+ -containing aqueous solution (pH = 8) with varying crude oil concentration allow us to define a parameter characterizing the interfacial gel inhibition efficiency of crude oils to compare the systems with each other. The determined inhibition efficiency order of crude oils is not directly related to the total asphaltene and naphthenic acid contents in the crude oils and, therefore, cannot be directly predicted by performing simple chemical analysis of the oils. By selectively removing asphaltenes and/or naphthenic acids, it was found that naphthenic acids are the most prevalent inhibitors followed by asphaltenes in the tested crude oils. Other compounds present in crude oil also have a weak inhibition activity on the ARN/Ca 2+ interfacial gel. Finally, bottle tests were performed to upscale the results obtained at the interfacial scale. Bottle tests were performed at an ARN concentration 10 times higher than that used for IFT and interfacial rheology measurements. The tests indicate the presence of a soft solid material formed by the reaction between ARN and Ca 2+ even in the presence of the crude oil that was found to have the highest interfacial gel inhibition efficiency. This apparent contradiction is not understood at the moment, and hence, a better understanding of the ARN/ Ca 2+ system is required to extrapolate the results obtained at the interface to bigger scales.

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Flow Assurance Issues and Control with Naphthenic Oils

Cited by 24 publications

References 2 publications

Risk Assessment of Calcium Naphtenates and Separation Mechanisms of Acidic Crude Oil

Risk Assessment of Calcium Naphtenates and Separation Mechanisms of Acidic Crude Oil

Oilfield metal naphthenate formation and mitigation measures: a review

Screening of Inhibition of Calcium Naphthenate Deposition in Crude Oil

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