in situ field remediation methods - university of illinois...

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04.2010 ELMİ ƏSƏRLƏR w PROCEEDINGS w НАУЧНЫЕ ТРУДЫ

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INTRODUCTIONArterial blockage in the petroleum industry is mostly

due to the deposition of heavy organic molecules from petroleum fluids. Heavy organic molecules such as asphaltenes, asphaltogenic acids, diamondoids and derivatives, mercaptans, organometallics, paraffin /wax and resins exist in crude oils (fig.1) in various quantities and forms [1, 2].

Such compounds could separate out of the crude oil solution due to various mechanisms and deposit, causing fouling in the oil reservoir, in the well, in the pipelines and in the oil production and processing facilities [1-6]. Solid particles suspended in the crude oil may stick to the walls of the conduits and reservoirs (fig.2). The toughness of the deposits has a lot to do whether there is asphaltene present in the crude oil even in minute quantities.

Asphaltene, which is a highly polar compound, generally act as a glue and mortar in hardening the deposits and, as a result, causing barrier to the flow of oil [7-14].

Depositions of the heavy organics present in crude oil happen due to various causes depending on their molecular nature. Mercaptans and organometallics depositions are due to dissociation, solubility effects, or attachment to surfaces. Diamondoids and paraffin/wax deposit and form solid crystals due, mostly, to lowering of temperature [15-17]. Resins are not known to deposit on their own, but they deposit together with asphaltenes [18]. The reasons for the asphaltenes and asphaltogenic acids deposition can be many factors including variations of temperature, pressure, pH, composition, flow regime, wall effect and electrokinetic phenomena. When several different heavy organic compounds are present in a

In this report the methodologies and analysis for in situ remediation of heavy organics in petroleum production, transportation and processing industries is presented. First the heavy organics which deposit from petroleum fluids are indentified and it is pointed out that the more difficult member of these compounds to deal with are asphaltenes. Six different in situ remediation methods are introduced which include: (i) production scheme alteration techniques; (ii) chemical treatment techniques; (iii) external force filed techniques; (iv) mechanical treatment techniques; (v) thermal treatment techniques; (vi) biological methods. Also eight steps that appear to be necessary and effective in prevention and moderating the severity of the deposition and remediation are introduced which include: (a) Predictive modeling and analysis; (b) dual completion of oil wells; (c) compatibility tests of injection fluids before applications; (d) consideration of the compositional gradient of heavy organics in reservoir in production scheme design; (e) application of mechanical removal technologies for deposits; (f) application of solvent for dissolution of deposits; (g) hot oil treatment of the in situ deposits; and (h) use of dispersant to stabilize the heavy organics, specially asphaltenes from deposition. Overall, a proper route to combat arterial blockage in the oil and gas industry is to consider a combination of prediction modeling, experimentation and remediation.

Keywords: asphaltene, organic deposits, oil treatment, steric colloidAdress: [email protected]

UDC 52.47.23

REMEDIATION OF ASPHALTENE AND OTHER HEAVY ORGANIC DEPOSITS IN OIL WELLS AND IN PIPELINES

G.Ali Mansoori

(university of Illinois)

Fig.1. Heavy organic molecules that deposit from petroleum fluids

Fig.2. Asphaltene molecules are highly sticky and they act as mortar which also cause other suspended particles stick to deposit cause fouling in petroleum

fluid arteries

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petroleum fluid their interactive effects must be also considered in order to understand the mechanisms of their collective deposition or lack of it. This is especially important when one of the interacting heavy organic compounds is asphaltene. For example a regular waxy crude containing minute amounts of asphaltene will behave differently at low temperatures (below the cloud point) compared with: (i) a clean waxy crude with no other heavy organics present in it; (ii) an asphaltenic crude containing some paraffin/wax or; (iii) a purely asphaltenic crude containing no paraffin/wax [19, 16].

Deposition of heavy organics in petroleum fluids may cause formation of suspended particles. In general, suspended particles in a crude oil fall into two classes: «basic sediment» and «filterable solids». Presence of suspended particles in petroleum fluids could have a severe economic impact on petroleum industry [5, 6]. Carried along in the oil, they may cause fouling, foaming, erosion, and/or corrosion. Depending on the case, coagulants (molecular weight < 10000) or flocculants (molecular weight > 10000), may provide an indirect aid in suspended particles removal (fig.3).

Coagulants are molecules with strong polar charge which act to disrupt charges on the surface of droplets of an opposite phase or suspended solid particles that would otherwise prevent it from coalescence. Flocculents, act to coalesce colloidal particles, because they attach to colloids and they increase their size beyond the Brownian law of suspension [20, 21].

The production and transportation of petroleum fluids will be severely affected by deposition of suspended particles (i.e. asphaltenes, diamondoids, paraffin/wax, sand, etc.) in production wells and/or transfer pipelines xx some of my older papers. In certain instances the amount of precipitation is rather high causing complete fouling of these conduits. Therefore, it is important to understand the behavior of suspended particles during petroleum flow conditions. We recently introduced an analytical

model for the prefouling behavior of suspended particles corresponding to petroleum fluids production conditions [5, 6]. We predicted the rate of particle deposition during various turbulent flow regimes. The turbulent boundary layer theory and the concepts of mass transfer were utilized to model and calculate the particle deposition rates on the walls of flowing conduits. The proposed model accounted for the eddy and Brownian diffusivities as well as for inertial effects. The analysis presented showed that rates of particle deposition during petroleum production on the walls of the flowing channel due solely to diffusion effects are negligible. It was also shown that deposition rates decrease with increasing particle size. However, when the process is momentum controlled (large particle sizes) higher deposition rates are expected.

Considering that the major barrier in a profitable deposition-free oil production scheme is the presence of asphaltenes in the crude the in situ remediation methods of asphaltenes in the petroleum fluids is discussed in the following sections.

In Situ Field Remediation Methods

In petroleum production initially it is necessary to take any number of steps necessary to prevent the fouling problems. Heavy organics deposition could be eliminated by modification of the production practices, rather than by chemical, mechanical, thermal or other external means. This may reduce the cost of production operation appreciably. This may be achieved by the optimum design of the oil production and transportation systems based on proper laboratory tests and implication of deposition prediction models [22-25].

Heavy organic deposits re- sulting from the presence of asphaltenes in crude oils are quite hard to deal with. Asphaltenes may be destabilized in any area of the oil production and processing facilities from as far back as the near wellbore area to as far down the system as in the petroleum refinery (fig.4,5).

Asphaltenes, in addition to their highly sticky characteristics which attach to solid surfaces, change their wettability [26], they could also act as nucleation sites for paraffin/wax and diamondoids crystallization which are often found within the same deposits.

Heavy organics deposition due to asphaltene flocculation could be controlled through the better knowledge of the mechanisms that cause their deposition in the first place [9, 27]. Processes can be altered to minimize the deposition and chemicals can be used

Fig.3. The role of coagulants and flocculants in deposition of a suspended particles

Fig.4. Locations (circled in green) where heavy organics deposition could occur most likely in the petroleum fluids production and transportation systems

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[28] to possibly control the deposition when process alterations are not effective. Heavy organics depositions and their remediation in petroleum fluid systems may be controlled using various techniques which include the following six categories: production scheme alterations, chemical treatment methods, external force fields exertion, mechanical treatment methods, thermal treatment techniques and biological methods [3, 4]. In what follows we briefly present the various categories of treatment methods.

I. Production scheme alterations techniques: They are used to control asphaltene and other heavy organics deposition and they include: (i) reduction of shear (fig.6); (ii) elimination of incompatible materials from asphaltenic crude oil streams (fig.7); (iii) minimization of pressure-drops in the production facility (fig.8); and, (iv) minimization of mixing of lean feed stock liquids into asphaltenic crude streams (fig.7), (v) neutralization of electrostatic forces (fig.9).

II. Chemical treatment techniques: They include: Addition of dispersants, antifoulants, coagulants,

flocculants and polar co-solvents which may be used to control asphaltene deposition in its various stages.

II.1. Dispersants work by surrounding the asphaltene molecules forming steric colloids, similar to the natural resin materials (fig.10).

II.2. To inhibit the attachment and growth of deposits on surfaces and walls they can be coated with antifoulant chemical compounds (fig.11, 12). Teflon (fig.11) which

Fig.5. Locations where heavy organics deposition could most likely occur in the petroleum refining/processing systems [14]

Fig.6. Pipe flow with Shear

Fig.7. Incompatible miscible fluids flow and separation of heavy ends in the form of colloids, flocs and

attachment to the walls of conduits

Fig.8. Minimization of pressure-drops in the petroleum production facility causing separation of phases from a miscible phase to oil, gas and heavy organics phase

Fig.9. Lack of neutralization of electrostatic forces may cause break up of asphaltene steric colloids, release

of sticky asphaltene particles and attachment to walls causing fouling in petroleum fluid flow lines


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is polytetrafluoroethylene (C2F4)n is one well-known antifoulant material used for coating surfaces to prevent organic and inorganic materials from attachment to surfaces [29].

Organotin compounds particularly tributyltin oxide (fig.12), are very effective as antifoulants and have been the antifoulant of choice for many years in marine, agricultural, wood and plastics industries. The effectiveness of TBTO is a result of the fact that it gradually leaches from the hull killing the fouling

organisms in the surrounding area. However, it is found to cause health and environmental problems [30].

II.3. Coagulants, which are mostly polymers, have a role similar to resins which form steric colloids and then flocculation of colloids in the form of flocs and precipitation (fig.13, 14).

II.4. Polar co-solvents (such as aromatic hydrocarbons) could re-dissolve the asphaltene deposits and need to have a high level polarity (aromaticity) to be effective (fig.15, 16).

When the concentration of polar solvents exceeds a certain level then asphaltene micelles will be formed

[31-34]:Organic material deposited into the production

installations of petroleum crude may cause operational problems. One may initially try to dissolve such deposits by various means like steam wash, diesel oil wash and heavy aromatics wash, etc. One may also consider using

a system of specifically designed additives to stimulate the wells. Such additives are best to be a mixture of an inhibitor of asphaltene precipitation, an asphaltene dispersant and an antifoaming agent [35].

III. External force field techniques: They include: (i) electrostatic force field; (ii) electrodynamic force field; and (iii) magnetic field; (iv) ultrasound techniques;

Fig.10. Steric colloids of asphaltene (asphaltene floc core) and resins (red aromatic head with black paraffin tails)

Fig.11. A non-bio antifoulant: Teflon=polytetrafluoroethylene

Fig. 12. A bio-antifoulant: Tributyltin oxide – An organotin

Fig.13. Flocculation of asphaltene due to increase in paraffin (nonpolar) content of petroleum [25, 32, 1]

Fig.14. Steric-colloid formation of asphaltene flocs (random aggregates) in the presence of excess amounts

of resins and paraffin hydrocarbons [25, 32, 1]

Fig.15. Aromatic hydrocarbons that could re-dissolve asphaltene deposits

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Fig.16. Asphaltene miclellization in the presence of excess amounts of aromatic hydrocarbons [31-33]

Fig.17. Pipeline pigs [www.pipingguide.net/2007/11/pipeline-pigging.html]

(v) microwave techniques. All these techniques are presently applicable for petroleum/laboratory operations and mostly for small scales.

IV. Mechanical treatment techniques: They include: (i) manual stripping, pigging, mechanical vibrations, etc.

Mechanical/manual stripping is probably the oldest method known for the removal of heavy hydrocarbon deposits. It is done by mechanically scraping the tubing. Pigging technology is well established, but it is most suitable for foams, waxy crude arteries and wax deposit removal (fig.17).

Pigging technology success for asphaltenic crude arteries is questionable. Soluble or insoluble pigs are injected into the oil arteries. The pigs would remove a portion of the deposit buildup as they travel through the lines. Although this method may be effective for cleaning the tubing and lines, it is not effective in removing the heavy organic deposits at the formation. There have been some advances in smart pigs which may take advantage of remote visualization, control, local heating, etc. Mechanical removal of deposits may be a cumbersome operation. In addition, the disposal of the deposits sometimes causes difficulties.

V. Thermal treatment techniques: They include: (i) in situ combustion (fig.18); (ii) steam injection (fig.19); (iii) hot water injection (fig.20); (iv) hot gas injection (fig.21); (v) hot chemicals injection; (vi) microwave technique of heating which is volumetric, sample-based (not the whole region), and center of sample heated the most versus the regular heating which heats the surface; (vii) use of exothermic chemical reactions.

Removal of deposits by hot fluid is performed by circulating it into the well, conduits, or by injection into the formation to open up plugged areas. This method works by melting the organic deposits. Therefore, it is important to insure that the melted organics are not re-deposited in another part of the formation. This happens when the hot fluid introduced to the formation becomes saturated with melted paraffins, and when the formation temperature is lower than the cloud point of

Fig.18. In situ combustion

Fig.19. Steam injection [fossil.energy.gov]

Fig.20. Hot water injection [afcee.af.mil]


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the hot fluid. under these circumstances precipitation will occur and consequently cause permeability reduction and damage to the formation.

VI. Biological methods: These may include in situ application of (i) anaerobic bacteria; (ii) aerobic bacteria; (iii) other microorganisms including fungus, etc. Such bio-processes that may reduce asphaltenes into lighter molecules is named biodegradation. Biodegredation mechanism of asphaltenes is perhaps the least known reaction mechanism for the biodegradation of a petroleum fraction. It appears that asphaltenic compounds are relatively inert to microorganisms attack, since they consist of complex structures of sheets of aromatic and alicyclic ring structures with very short alkyl side chains [36].

Various types of microorganisms that are capable of oxidizing asphaltenic compounds are widespread in nature. However, they need to be identified, isolated and grown in the lab to make them capable of biodegradation of large amounts of asphaltenic deposits. Biodegradation, if made practical, is an important

mechanism for removing these non-volatile components. It is a relatively slow process and may require months to years for microorganisms to degrade a significant amount of asphaltenes. During such biodegradation, the proper species of bacteria, fungi, etc. would metabolize asphaltenes as a source of carbon and energy. under aerobic conditions, asphaltene would decompose step by step into water, carbon dioxide, nitrogen oxides, and sulfur oxides.

DISCUSSION AND RECOMMENDATIONSThe steps that appear to be necessary and effective

in prevention, moderating the severity of the deposition and remediation are the following:

(A). PREDICTIVE MODELLING AND ANALYSIS - Resolution of the heavy organic deposition problem calls for detailed analyses of heavy organic containing oils from the microscopic standpoint and development of molecular models which could describe the behavior of heavy organics in hydrocarbon mixtures [37-41]. From the available laboratory, field, and refinery data it is proven that the heavy organics which exist in petroleum generally consist of very many particles having molecular weights ranging from a few

hundred to several hundred thousands. As a result distribution-function curves are used to report their molecular weight distribution [42-44]. Some of the heavy organics present in the oil deposit due to phase transitions from liquid to solid state. However, this is not generally the case for asphaltene particles. The high affinity of asphaltene particles to association with one another, their tendency to adsorb resins, and their extensively wide range of size distribution suggest that asphaltenes are partly dissolved and partly in colloidal state (in suspension) in oil peptized (or stabilized) primarily by resin molecules that are adsorbed on asphaltene surface [38].

Fig.21. In situ hot gas injection [sanleonenergy.com]

Fig.22. Static (PX) heavy organics deposition envelope (HODE) of a crude oil mixed with a miscible injectant (MI) at 60 oF but at various proportions and pressures.

In this figure L stands for liquid phase, L-V is the liquid-vapor two-phase region, L-S is the liquid-solid two-phase region, and L-V-S is the liquid-vapor-solid

three-phase region

Figure 23. Dynamic (QX) heavy organics deposition envelope (HODE) of a crude oil mixed with a miscible injectant (MI) at 60 oF but at various proportions and

pressures. In this figure Q=Uavg1.75d0.75/k, where Uavg (m/s)

stands for crude average velocity in a cylindrical conduit, d (m) is the conduit diameter and k (ohm-1/m)

is the crude electrical conductivity. The area above each curve represents the deposition region and under the

curve is the flow region with no deposition

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As a result, a realistic molecular model for the interaction of asphaltene and oil should take into account both the solubility in oil of one segment and suspension characteristic (due to resins) of another segment of the molecular weight distribution curve of asphaltene [38, 23, 24, 1, 2].

Initially laboratory work may be necessary to quantify and characterize the various families of heavy organics present in a crude and in general shed light on the reasons for such depositions [45-47]. Laboratory work joined with statistical mechanical plus kinetics modeling may result in the construction of heavy organics deposition envelop (HODE) such as the graph shown in figures 22 and 23 which would indicate the ranges of temperature and pressure where the crude oil deposits out heavy organic compounds at various temperatures, pressures, compositions/blending, electrokinetic effects, and flow

conditions [41].(B). Dual Completion - It is reported [48] that the use

of standard well completion techniques when heavy organics deposition is likely has often resulted in costly workovers for deposit removal in those wells. To combat the heavy organics deposit formation the completing wells with a dual completion is necessary (fig.24).

This is with the purpose of: i) using the inner tubing strings for solvent or dispersant injection or circulation, ii) access for lowering production testing devices. Sometimes an inner tubing string is used for production to meet production quotas when the main string is shut-in for maintenance or heavy organics cleaning.

(C). COMPATIBILITY TESTS - It is suggested that all well stimulation, injection and enhanced oil recovery fluids should be tested for static and dynamic compatibility with the reservoir fluids prior to operations,

Fig.24. A well with a dual completion

Fig.25. Phase envelops defining the composition regions of the heavy organics separation at a given

temperature and pressure

Figure 26. Compositional gradient scheme

Figure 27. Wirelining


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especially where asphaltenic crudes are present [49]. It is possible to perform certain experimental measurements to produce rather simple phase envelops like figure 25 through which one can define the composition regions of the heavy organics separation at certain temperature and pressures.

Such experimental compatibility tests may be costly if one needs to study all the possible regions of composition and pressure. However, static and dynamic compatibility modeling using the advanced statistical and fluid dynamic techniques can be quite efficient and economical

for shedding light on the problem by constructing heavy organics deposition envelopes (HODE) as shown by figures 22 and 23.

(D). composition gradient - It is generally understood that there is a composition gradient of heavy organics in petroleum reservoirs with deeper zones having higher fractions of the heavy organics (fig.26). The decision to produce first the top zone of the reservoir, which is generally less prone to heavy organics deposition, is always preferred. Actually most of the producing wells must be completed dual commingled. Production surveys would show from which zone most of the oil was being produced.

( E ) . M E C H A N I C A L R E M O V A L T E C H N I Q u E S - In certain circumstances mechanical removal techniques, especially wirelining may be effective means of combating the heavy organics problems [49]. An economical study may indicate whether mechanical removal methods of cleaning is preferred over cleaning by using solvents. For example at the Hassi Messaoud field, Algeria, necessitated frequent tubing scrapings and washings to maintain production [50, 51]. Cutting the deposits from the tubing by wireline method was too time-consuming and some times impractical, so a program of washing the tubing with a solvent was established.

(F). Solvent treatment - Solvent treatment of the oil is considered to be beneficial in some cases because it dilutes the crude oil and reduces the tendency of the heavy organics to precipitate. Solvent treatments may not be very successful largely because the solvents which can be used are limited to aromatic solvents (fig.15). Xylene is generally

the most common solvent selected to be used in well stimulations, workovers, and heavy organics inhibition and cleaning. In some cases xylene injection through the non-producing string (inner tubings shown in fig.24) actually may help to minimize the heavy organic deposition problem. In oil fields with frequent need for aromatic wash it may be necessary to design an aromatic solvent with stronger wash power and better economy for the particular deposit in mind [52].

Laboratory tests (fig.28) may be necessary to blend an appropriate aromatic solvent and/or dispersant for a

Crude oAPI

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t%

Asp

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esin

Canada, Atabasca 8.3 14.0 15.0 1.07

Venezuela, Boscan 10.2 29.4 17.2 0.58

Canada, Cold Lake 10.2 25.0 13.0 0.52

Mexico, Panucon 11.7 26.0 12.5 0.48

uSA, MS, Baxterville 16.0 8.9 17.2 1.93

Russia, Kaluga 16.7 20.0 0.5 0.025

uSA, TX, Hould 19.7 12.0 0.5 0.04Brazil, Campos,

Atabasca 19.7 21.55 2.8 0.13

uSA, CA, Huntington Beach 26.2 19.0 4.0 0.21

Canada, Alberta 29.0 8.5 5.3 0.62

India, Mangala crude 29.28 20-30 <0.50 <0.02

uSA, LA, Brookhaven 30.6 4.6 1.65 0.36

Russia, Balachany 31.7 6.0 0.5 0.08

Russia, Bibi-Eibat 32.1 9.0 0.3 0.03

Russia, Dossor 32.6 2.5 0.0 0.00

Russia, Surachany 35.0 4.0 0.0 0.00

uSA, TX, Mexia 36.0 5.0 1.3 0.26

Iraq, Kirkuk 36.1 15.5 1.3 0.08

Azeri BTC 36.1 0.03

Mexico, Tecoaminocan 36.7 8.8 1.5 0.17

Mexico, Isthmus 37.8 8.1 1.3 0.16

uSA, OK, Ok. City 38.0 5.0 0.1 0.02

uSA, OK, Tonkawa 40.8 2.5 0.2 0.08

France, Lagrave 43.0 7.5 4.0 0.53

uSA, LA, Rodessa 43.8 3.5 0.0 0.00

uSA, PA 44.3 1.5 0.0 0.00Algeria,

Hassi Messaoud 45.0 3.3 0.15 0.05

uSA, OK, Davenport 46.3 1.3 0 0

TableThe oAPI gravity, resin wt %, asphaltene wt % and asphaltene to resin ratio of

various crude oils from around the world [various sources]

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given oil field from the points of view of effectiveness, economy, and environmental concerns. Then special formulas may be blended to achieve the goal of preventing or cleaning the heavy organics deposits which can be used by the field engineers.

[G). HOT OIL TREATMENT - Circulation with hot oil may be used to avoid or reduce the heavy organics deposition problem. A combination of solvent treatment and reverse and normal circulation with hot oil have been tried in the past in some oil wells with mixed results [49, 3, 4].

(H). DISPERSANT uSE - Injection of dispersants or antifoulants may be effective in certain crude oils where the ratio of resin to asphaltene is not high enough to prevent asphaltene flocculation and as a result heavy organics deposition. One thing which appears to have universal acceptance is that resins in the crude act as the peptizing agents of the asphaltene particles. It is generally a good practice to analyze a crude oil for its asphaltene and resin content and ratio. In Table 1 such data for a number of crude oils are reported versus their API gravity. Crude oils with higher asphaltene to resin ratios are more prone to heavy organics deposition. Of course there are exception to this rule mostly due to the possibility or presence of high amounts of aromatics in the crude, variations in the molecular structures of asphaltenes and resins, and the polydispersivity effects. For example, Boscan crude, which is second from the top of the list in Table 1, has had no deposition problem, while Tecoaminocan crude, which is close to the bottom of the list, is a crude oil with frequent deposition problems. Actually in Boscan crude, in addition to having a low asphaltene/resin ratio of 0.58 it has also a low saturates/aromatics ratio of 0.71.

High amounts of resins and aromaticity helps the asphaltene in this crude to stay in the solution and/or

suspended without deposition. Considering such severe exceptions to the rule one should not consider this ratio to be the only factor in evaluating the deposition potential of a crude oil. Other factors including the nature of hydrocarbons in the crude, the polydispersivities and polarities of asphaltene and resin, the presence of such compounds as paraffin /wax, organometallics and diamondoids, the nature of conduit, hydrodynamics and electrokinetics have also roles in the deposition. In order to quantify all these factors one has to use a comprehensive predictive model in which all these effects are incorporated [41].

ConclusionsInsofar as finding a rigorous universal solution to the

heavy organics deposition problem is concerned there is still a long way to go. Asphaltene flocculation can be controlled through better knowledge of the mechanisms that cause its flocculation in the first place. Processes can be changed to minimize the asphaltene flocculation and chemical applications can be used effectively to control depositions when process changes are not cost effective.

Since heavy organics deposition takes place during primary, secondary, and tertiary oil recovery, injection of peptizing agents (i.e.: resins) in proper amounts and places may prevent, or at least control, the heavy organics deposition problem. Furthermore, experiments could be performed (i.e.: of the coreflood type) where peptizing agents are injected to study their effect on inhibition of heavy organics deposition or permeability reductions. However, use of such additives to crude oil is economically quite prohibitive.

One interesting question posed by previous researchers [53, 50] is why there was asphaltic bitumen deposited at the bottom of the well considering that no phase change or any substantial temperature or pressure changes had taken place. The conclusion was that the question could only be answered after considerable light was thrown upon the nature of the asphaltic bitumen prior to its separation from the crude oil in the well. There were a few efforts to try to determine the size and nature of asphaltene particles while they still are in the original oil [53, 54].

Establishing the state of the asphaltene particles in the original crude oil seems to be a basic building block in the scientific quest to find a solution to many irreversible heavy organics deposition problems. Experimental and theoretical modeling work towards this end has been performed [55, 9], but more is needed. More experiments need to be done to duplicate Witherspoon et al.s’ ultracentrifuge work for different oils and possibly utilize other contemporary experimental techniques to establish the state of asphaltenes in crude oils. Meanwhile, it appears that any modeling effort that describes the phase behavior of asphaltenes in oil should take into account the lack of positive information on the structure of asphaltenes in the original oil and their molecular characteristics. This has been the philosophy followed in modeling activity [56, 38, 23, 12] proposed for predicting the deposition behavior of heavy organics in petroleum fluids.

Acknowledgements: The author appreciated the contributions of Dr. J.H.P. Sanchez in the initial stage of this research. This research was supported in part by PEMEX, IMP and Petrobras.

Figure 28. A laboratory model to test various solvents for heavy organics remediation [52]


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References 1. G.A.Mansoori. Phase behavior in petroleum fluids. //Petroleum Engineering – Downstream section

of Encyclopedia of Life Support Systems. uNESCO. uN. France: Paris. 2009(a). 2. G.A.Mansoori. A unified perspective on the phase behaviour of petroleum fluids //International

Journal of Oil, Gas and Coal Technology. -2009(b). –Vol.2(2). –P.141-167. 3. J.H.P.Sanchez, G.A.Mansoori. Modeling the behavior of asphaltene micelle in petroleum fluids

//Proceedings of the Second International Symposium on Colloid Chemistry in Oil Production (ISCOP '97). –Brazil: Rio de Janeiro. -1997. -Paper 12.

4. J.H.P.Sanchez, G.A.Mansoori. In Situ remediation of heavy organic deposits using aromatic solvents //Proceedings 5th Latin American and Caribbean Petroleum Engineering Conference and Exhibition. SPE. -1998(a.) -Paper 38966.

5. J.Escobedo, G.A.Mansoori. Prefouling Behavior of Suspended Particles in Petroleum Fluid Flow //Scientia, Transactions C: Chemistry and Chemical Engineering. -2010(a). –Vol. 17(1). –P.77-85.

6. J.Escobedo, G.A.Mansoori. Heavy-organic particle deposition from petroleum fluid flow in oil wells and pipelines //Petroleum Science. -2010(b). –Vol.7. –P.502-508.

7. G.A.Mansoori. Asphaltene Deposition: An Economic Challenge in Heavy Petroleum Crude utilization and Processing //OPEC Review. -1988. –P.103-113.

8. G.A.Mansoori. The occurance of asphaltene throughout production cycle //Proceedings of the 6th ADIPEC. TX: Richardson. SPE. -1994. –P.282-292.

9. G.A.Mansoori. Asphaltene, resin, and wax deposition from petroleum fluids //The Arabian Journal of Science and Engineering. -1996(a). –Vol.21(48). –P.707-723.

10. G.A.Mansoori. Arterial Blockage in the Petroleum and Natural Gas Industries (Causes &Effects, Economic Implications, & Preventive Measures) //Proceedings of Controlling hydrates, asphaltenes and wax conference. IBC uK Conferences, Ltd. London. Gilmoora House. -1996(b). -Paper No 2.

11. G.A.Mansoori. Asphaltene, resin, and wax deposition from petroleum fluids //The Arabian Journal of Science and Engineering. -1996(c). –Vol.21(48). –P.707-723.

12. G.A.Mansoori. Modeling of asphaltene and other heavy organics depositions //Journal of Petroleum Science and Engineering. -1997. –Vol.17. –P.101–111.

13. G.A.Mansoori. Cause and effect of deposition and fouling of heavy organics and other compounds in fuel and petrochemical processes //Ku International Journal of Science & Technology. Transaction B. -2002(a). –P.1-17.

14. G.A.Mansoori. Physicochemical basis of fouling prediction and prevention in the process industry //Journal of the Chinese Institute of Chemical Engineers. -2002(b). –Vol.33(1). –P.25-32.

15. A.N.Afanasyev, V.A.Matishev, Z.I.Syunyaev, V.V.Farafonov. Melting and Crystallization of Paraffins //Chemistry and Technology of Fuels and Oils. -1993. –Vol.29. –P.549-554

16. G.A.Mansoori, H.L.Barnes, G.M.Webster. Petroleum Waxes. //Chapter 19 in “Fuels and Lubricants Handbook”. ASTM Int'l, West Conshohocken, PA, 2003. –P.525-558.

17. G.A.Mansoori. Diamondoid Molecules //Advances in Chemical Physics. -2007. –Vol.136. –P.207-258.

18. J.P.Dickie, T.F.Yen. High resolution mass spectral examination of the resin fraction of petroleum asphaltenes //American Chemical Society (ACS) Division of Petroleum Chemistry. -1968. –Vol.13(2). –P.140-148.

19. S.Himran, A.Suwono, G.A.Mansoori. Characterization of alkanes and paraffin waxes for application as phase change energy storage medium //Energy Sources. -1994. –Vol.16. –P.117-128.

20. S.S.Schantz, P.L.Elliot. Economic implications of solids in crude and their ultimate fate in the refining process //National Petrochemical & Refiners Association Annual Meeting. uSA: Texas. San Antonio. -1994.

21. A.C.S.Ramos, L.Haraguchi, F.R.Notrispe etc. Interfacial and colloidal behavior of asphaltenes obtained from Brazilian crude oils //Journal of Petroleum Science and Engineering. -2001. –Vol.32(2-4). –P.201-216.

22. S.J.Park, T.K.Kwak, G.A.Mansoori. Statistical Mechanical Description of Supercritical Fluid Extraction and Retrograde Condensation //Intertaional Journal of Thermophysics. -1987. –No.8. –P.449-471.

23. S.J.Park, G.A.Mansoori. Aggregation and Deposition of Heavy Organics in Petroleum Crudes //International Journal of Energy Sources. -1988(a). –No.10. –P.109-125.

24. S.J.Park, G.A.Mansoori. Orgainc Deposition from Heavy Petroleum Crudes (A FRACTAL Aggregation Theory Approach) //Proceedings of the uNITAR/uNDP 4th International Conference on Heavy Crudes and Tar Sands. –Edmonton. –Alberta. -1988(b).

25. V.A.M.Branco, G.A.Mansoori, L.C.De Almeida Xavier etc. Asphaltene flocculation and collapse from petroleum fluids //Journal of Petroleum Science and Engineering. -2001. –Vol.32. –P.217-230.

26. D.T.Kim, M.E.Boudh-Hir, G.A.Mansoori. The role of asphaltene in wettability reversal //Proceedings of the 1990 SPE Annual Convention. TX: Richardson. 1990. –P.120–137 -Paper 20700.

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27. A.Eliassi, H.Modaress, G.A.Mansoori. Study of asphaltene flocculation using particle counting method //Proceed. Filtech 2005 (International Conference & Exhibition for Filteration & Separation Tech), I. Germany: Weisbaden. 2005. –P.506-511.

28. J.K.Borchardt. Chemicals used in Oil-Field Operations //Oil-Field Chemistry. Edited by Borchardt JK and Yen TF, ACS Symposium Series 396. Washington, DC, 1989.

29. A.C.Funderburg. Making Teflon stick //American Heritage of Invention and Technology. -2000. –Vol.16(1). –P.10-21.

30. R.C.Poller. The chemistry of organotin compounds. London: Logos Pub, 1970. 31. S.Priyanto, G.A.Mansoori, A.Suwono. Asphaltene micellization and its measurement //Proceedings

of the 3rd. International symposium on advanced and aerospace science and technology in Indonesia (ISASTI, 98). –Jakarta. – 1998. –P.843-860.

32. S.Priyanto, G.A.Mansoori. A.Suwono. Structure & Properties of Micelles and Micelle Coacervates of Asphaltene Macromolecule //Nanotechnology Proceedings of 2001 AIChE Annual Meeting. -2001(a.)

33. S.Priyanto, G.A.Mansoori, A.Suwono. Measurement of property relationships of nano-structure micelles and coacervates of asphaltene in a pure solvent //Chemical Engineering Science. -2001(b). –Vol.56. –P.6933-6939.

34. J.H.P.Sanchez, G.A.Mansoori. Prediction of the Phase Behavior of Asphaltene Micelle/Aromatic Hydrocarbon Systems //Journal of Petroleum Science and Technology. -1998(b). –Vol.16(3/4). –P.377-394.

35. J.C.Chavez, A.Lory. Estudio sobre la depositacion de material organico en instalaciones de produccion del area marina de Campeche //Revista del Instituto Mexicano del Petroleo. -1991. –Vol.22. –P.55-67.

36. Z.X.Niu, S.H.Guo, F.M.Li etc. Bio-Degradation of Resin and Asphalt in Viscous-Oil Contaminated Soil by Actonomyces //Journal of Agro-Environment Science. -2005. –Vol.24(4). –P.771-774.

37. L.G.Chorn, G.A.Mansoori. Multicomponent Fractions Characterization: Principles and Theories //in: C7+ Fraction Characterization. Advances In Thermodynamics Vol:1. New York, NY: Taylor & Francis Press, 1989. –P.1-10.

38. S.Kawanaka, K.J.Leontaritis, S.J.Park, G.A.Mansoori. Thermodynamic and Colloidal Models of Asphaltene flocculation //in "Oil Field Chemistry". ACS Symposium Series 396. Chapter 24. ACS. DC: Washington, 1989.

39. S.Kawanaka, S.J.Park, G.A.Mansoori. Organic Deposition from Reservoir Fluids //SPE Reservoir Engineering Journal. -1991. –No.3. –P.185-192.

40. H.Manafi, G.A.Mansoori, S.Ghotbi. Phase behavior prediction of petroleum fluids with minimum characterization data //Journal of Petroleum Science and Engineering. -1999. –Vol.22. –P.67–93.

41. G.A.Mansoori. ASPHRAC: A comprehensive package of computer programs and database which calculates various properties of petroleum fluids containing heavy organics //www.uic.edu/~mansoori/ASPHRAC_html. -2010.

42. K.J.Leontaritis, G.A.Mansoori. Fast crude-oil heavy-component characterization using combination of ASTM, HPLC, and GPC methods //Journal of Petroleum Science and Engineering. -1989. –Vol.2(1). –P.1-12.

43. G.A.Mansoori, D.Vazquez, M.Shariaty-Niassar. Polydispersity of heavy organics in crude oils and their role in oil well fouling //Journal of Petroleum Science and Engineering. -2007. –Vol.58(3-4). –P.375-390.

44. D.Vasquez, G.A.Mansoori. Identification and measurement of petroleum precipitates //Journal of Petroleum Science and Engineering. -2000. –Vol.26(1–4). –P.49–56.

45. Y.F.Hu, S.Lib, N.Liub etc. Measurement and corresponding states modeling of asphaltene precipitation in Jilin reservoir oils //Journal of Petroleum Science and Engineering. -2004. –Vol.41. –P.169–182.

46. S.A.Mousavi-Dehghani, M.R.Riazi, M.Vafaie-Sefti, G.A.Mansoori. An analysis of methods for determination of onsets of asphaltene phase separations //Journal of Petroleum Science and Engineering. -2004. –Vol.42 (2-4). –P.145-156.

47. D.Vasquez, J.Escobedo, G.A.Mansoori. Characterization of crude oils from southern Mexican oilfields //Proceedings of the International Petroleum Technology Exhibition. Mexico: Mexico City. Placio de Los Deportes. -1998.

48. C.Von Albrecht, W.M.Salathiel, D.E.Nierode. Stimulation of asphaltic deep wells and shallow wells in Lake Maracaibo, Venezuela. Advances in Methods of Increasing Well Productivity and Injectivity //Journal of Canadian Petroleum Technology. -1977. –Oil Sands PD7(1). –P.55-62.

49. R.N.Tuttle. High pour-point and asphaltic crude oils in condensates //Journal of Petroleum Technology. -1983. –No.6. –P.1192-1196.

50. K.J.Leontaritis, G.A.Mansoori. Asphaltene Deposition: A Survey of Field Experiences and Research Approaches //Journal of Petroleum Science and Engineering. -1988. –Vol.1. –P.229.

51. C.E.Haskett, M.Tartera. A practical solution to the problem of aspahltene deposits - Hassi Messaoud Field, Algeria //Journal of Petroleum Technology. -1965. –No.4. -P.387-391.

52. F.Garcia-Hernandez. Estudio sobre el control de la depositacion organica en pozos del area Cretacica Chiapas-Tabasco //Ing. Pet. -1989. –No.7. –P39.


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53. D.H.Katz, K.E.Beu. Nature of asphaltic substances //Industrial & Engineering Chemistry. -1945. –Vol.37. –P.195-200

54. P.A.Witherspoon. A study of the colloidal characteristics of petroleum using the ultracentrifuge //Journal of Physical Chemistry. -1957. –Vol.61. –P.1296-1302.

55. T.F.Yen. Structural differences between asphaltenes isolated from petroleum and from coal liquid //Advances in Chemistry Series 195. J.W.Bunger and N.C.Li, Editors. Chemistry of Asphaltenes, -1979. –P.39-52.

56. K.J.Leontaritis, G.A.Mansoori. Asphaltene flocculation during oil recovery and processing: a thermodynamic-colloidal model //Proceedings of the SPE Symposium on Oil Field Chemistry. TX: Richardson. -1987. -Paper 16258.

57. J.Escobedo, G.A.Mansoori. Solid Particle Deposition During Turbulent Flow Production Operations //Proceedings SPE Production Operation Symposium. OK: Oklahoma City. -1995. -Paper 29488.

Удаление асфальтенов и других тяжёлых органических отложений из нефтяных скважин и трубопроводов

Г.Али Мансури(Университет Иллинойса)

Реферат

В статье представлены методы и анализ удаления тяжёлых органических веществ в добыче, транспорте и переработке нефти. Прежде всего идентифицируются тяжёлые органические веще-ства, которые отлагаются из нефтяных жидкостей, и отмечается, что более сложными элементами этих соединений являются асфальтены. Представлены шесть различных групп методов локаль-ного удаления: (i) изменение схемы добычи; (ii) химическая обработка; (iii) воздействие внешних сил; (iv) механическая обработка; (v) термическая обработка; (vi) биологическая обработка. Также представлены восемь этапов, которые оказываются необходимыми и эффективными при предот-вращении, снижении интенсивности и удалении отложений: (a) прогнозное моделирование и анализ; (b) заканчивание нефтяных скважин в двух горизонтах; (c) испытания на совместимость закачиваемых жидкостей перед применением; (d) анализ состава тяжёлых органических веществ в пласте при разработке схемы добычи; (e) применение методов механического удаления отло-жений; (f) применение растворителей для удаления отложений; (g) обработка горячей нефтью; (h) использование дисперсантов для предотвращения отложений тяжёлых органических веществ, особенно асфальтенов. В целом, правильный путь борьбы - это анализ сочетания прогнозного моделирования, экспериментирования и удаления отложений.

Neft quyuları və kəmərlərində ağır üzvi çöküntü və asfaltenlərin təmizlənməsi

G.Ali Mansuri (İllinoys universiteti)

Xülasə

Məqalədə neftin çıxarılması, nəqli və emalı proseslərində ağır üzvi birləşmələrin təmizlənməsi üsullarının təhlili təqdim edilir. İlk olaraq neft məhsulundan çökən ağır üzvi birləşmələr müəyyən edilir və qeyd edilir ki, bu tərkiblərin ən mürəkkəb komponentləri asfaltenlərdir. Lokal təmizlənmənin altı müxtəlif üsullar qrupu təqdim olunur: (i) neftçıxarma sxeminin dəyişməsi; (ii) kimyəvi emal; (iii) xarici qüvvənin təsiri; (iv) mexaniki emal; (v) istilik emalı; (vi) bioloji emal. Həmçinin çöküntülərinin qarşısının alınması, intensivliyinin azaldılması və təmizlənməsində zəruri və səmərəli ola bilən səkkiz mərhələ təqdim edilir: (a) qabaqcadan proqnozlaşdırma və təhlil; (b) quyunun iki məhsuldar layda tamamlanması; (c) tətbiq etməzdən əvvəl vurulan mayelərin uyğunluq testi; (d) neftçıxarma sxeminin işlənməsində laydakı ağır üzvi birləşmələrin tərkibinin nəzərə alınması; (e) çöküntülərin mexaniki təmizlənmə üsullarının tədbiqi; (f) çöküntülərin həll olunması üçün həlledicilərinin tətbiq edilməsi; (g) isti neft emalı üsulları; (h) ağır üzvi birləşmələrin, xüsusilə asfalten çöküntülərinin qabağını almag üçün dispersantların istifadəsi. Ümumiyyətlə mübarizənin düzqün yolu - proqnozlaşdırılma modelləşdirilməsinin, eksperimentlərin və ləğv edilmə üsullarının birləşilməsinin təhlilindədir.

in situ field remediation methods - university of illinois...

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