Paraffin deposits

The techniques of paraffin removal and paraffin prevention have been reviewed [810]. In particular, inhibitors for paraffin deposits are copolymers of ethylene with vinylacetate [525-527,1597] or polymers from p-nonylphenyl methacrylate and p-dodecylphenyl methacrylate [773]. These materials lower the pour point of the oil. It has been shown that for oils which differ in the content of n-paraffins and asphalt-resinous substances, it is necessary to use blends of copolymers of different compositions and molecular weights to obtain optimal efficiency. Polyacrylamide and wastes from the production of glycerol with a concentration of 400 mg/liter of oil have also been claimed to be effective as paraffin inhibitors [536]. 

Effect of Flow Improver Additives on Paraffin Deposition... 

S. D. Dzhanakhmedova, E. I. Pryanikov, S. A. Sulejmanova, K. K. Mamedov, E. G. Dubrovina, N. M. Indyukov, and A. B. Sulejmanov. Composition for preventing asphaltene-resin-paraffin deposits—contains waste from production of synthetic glycerine, in mixture with polyacrylamide. Patent SU 1761772-A, 1992. 

A. G. Sharov, R. A. Terteryan, L. I. Burova, and L. A. Shulgaitser. Effect of a copolymer inhibitor of paraffin deposits on oils of various fields. Neft Khoz, (9) 55-58, September 1989. 

Mannich bases are present as auxiliaries and additives throughout the whole working process of the petroleum industry, from crude oil extraction up to the final products. Indeed, they are used as oleophilizers in drilling fluids- or in the treatment of cmde oil, such as desalting and prevention of paraffin deposits. Mannich bases and derivatives are, moreover, employed as antifoulants - in heat exchangers as well... 

Emulsions stabilized by paraffin are usually restricted to light crude oils in oil-field production. If paraffin deposition that restricts production is occurring upstream of an oil-treating facility, it may be feasible to apply a paraffin crystal modifier to the crude oil to prevent paraffin deposition and to eliminate paraffin as an emulsifying agent. A paraffin crystal modifier must enter an oil system at a temperature greater than the cloud point of the crude oil and upstream of the problem area. 

Paraffin deposition has also been reported in the retinal fundi, the liver, and the spleen, in addition to the lungs (111). 

There is abundant field evidence for the existence of SP cells over petroleum reservoirs. Indeed this evidence itself was used to find petroleum reservoirs for almost 100 years before the cells were recognised. It includes gaseous and liquid hydrocarbon seeps, paraffin deposits, halo-type metal anomalies, iron and manganese deposition, carbonate cementation, hard-drilling areas, magnetic anomalies (associated with magnetite mineralisation) and elevated uranium concentrations (Tomkins, 1990). Chapters 5-7 of this volume and references provided therein document many of these features. 

Sometimes the more volatile oils will escape where the strata have been eroded, unless asphaltic or paraffinic deposits coat the faces of the strata, and act as seals. 

For solving this problem the analytical approximate method of integral correlations proposed by Goodman (1958) and improved by Volkov et al (1988) can be employed. This method was successfully used by Fomin et al (1994) for solving more complex problem of moving heat source within the borehole in application to melting of the paraffin deposition in the annulus. 

The rings tested at Ukrneft Co. have shown tight sealing of the tubing butts, are not subjected to paraffin deposition, reduce resistance to liquid flows and are operable in temperatures up to 100° C [148]. The rings of inhibited composites suppress crevice corrosion on pipe faces and prolong their life by 1.5-2 times. 

Puskas et al. extracted paraffinic deposits from oil wells and pipelines (47). This hydrophobic paraffin derivative had a high molar mass and melting point and contained polar end groups (carbonyls). This paraffinic derivative stabilized water-in-oil emulsions at concentrations of 1 to 2%. 

S Puskas, J Balazs, T Haraszti, L Turi, I Dekany. The influence of paraffinic deposits and their fractions on the stability of cmde oil emulsions. Petroleum abstracts 1st SPE Brazil Sect et al., Colloid Chemistry in Oil Production, Ash-phaltenes Wax Deposition International Symposium, Proceedings 230—235, Abstract no. 627, 639, Vol 36, no. 28, 1996. 

Primary alkylamines have been found to enhance the performance of compositions useful for dissolving alphaltene and paraffin deposits. In addition, primary alkylamines are useful for producing drilling fluids that are stable when acidic gases are present. 

V. F. Nezhevenko, V. M. Grigor ev, and V. I. Kudentsov, Use of Paint Coatings for Protecting Oil Equipment from Paraffin Deposits and Corrosion, Byull. Kuibyshev. Covnarkhoza, No. 7, Kuibyshev (1962), p. 28. 

Caldas, J. N. (1997), Estudo Experimental e Modelagem Termodinamica da Floculagao dos Asfaltenos, PhD Thesis, COPPE/UFRJ, Rio de Janeiro Calemma, V. Iwanski, R Nali, M. Scotti, R. Montanari, L. (1995). Structural Characterization of Asphaltenes of Different Origins. Energy Fuels, 9, 225-230 Carnahan, N. F., (1989). Paraffin Deposition in Petroleum Production - Journal of Petroleum Technology, v 41,1024 1025... 

Paraffin. Paraffin deposition is a function of reservoir or wellbore temperature. If the temperature is above the doud point (the point at which the paraffin present in the oil begins to deposit), deposition will not take place. However, a slight reduction in temperature can cause the paraffin to crystalhze (douding the oil) and deposit in perforations or in the wellbore. Such a temperature change may occur during any well operation in which fluid is introduced from the surface to the wellbore or formation. 

Paraffin deposition as a result of near-wellbore fluid temperature reduction... 

Like paraffin deposits, asphaltenes cannot be removed with acid treatment. Acid can cause asphaltene deposition or, more specifically, sludge (as discussed in chapters 3 and 6). For all intents and purposes, sludge damage should be considered irreversible. Removal can be attempted with solvent solutions containing dispersant (surfactant). 

Uses Dispersant that penetrates, removes and prevents the redeposition of paraffin deposits, cleaning the production equipment of accumulations reduces the flow resistance of hydrocarbons in flowlines and pipelines under cold conditions Features Compatible with most other paraffin chemicals, additives and organic solvents typically used in the formulation of paraffin compds. 

Uses Corrosion, scale fonnation inhibitor used in oil well operations Features Synergistic ability to disperse, degrade and prevent paraffin deposition ... 

Uses Cone, dispersant for removing paraffin deposits, water wetting soiids, and iron suifides demuisifier intermediate emuisifier in emuision breaker formulations paraffin dispersant for downhole, flow line, free-water knockout, or tank bottom applic. 

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