Iraqi Oil Fields Research Articles

Oil biomarkers, isotopes, and palynofacies are used for petroleum system type and migration pathway assessments of Iraqi oil fields

Analysis of δ13C aromatic and saturated hydrocarbons plus extracts from source-rock plots in graphical diagram as well as δ13C% and C28/C29 ratio of source-age sterane biomarkers of 300 scattered crude oil samples have enabled this study to assess groupings of hydrocarbons into families related to sedimentary basins in Iraq. Oil sources include Middle Jurassic strata of Sargelu Formation in the Zagros fold belt of North Iraq and eastern part of Mesan Governorate with Middle Jurassic as well as Upper Jurassic/Lower Cretaceous Chia Gara Formation in the North East based on a C28/C29 ratio of nearly 6 and 8, respectively. Mesopotamian Basin oil sources comprised mainly of Upper Jurassic/Lower Cretaceous Sulaiy Formation above the Upper Jurassic lower regional seal of the Gotnia Anhydrite except were thinned and faulted with a C28/C29 ratio that ranges between 5 and 9, which could cause mixing with Middle Jurassic Sargelu Formation oil. Middle Triassic oil in North West Iraq is recorded within Kurra Chine Formation with a C28/C29 ratio of 4, while Lower Palaeozoic oil sources are recorded in West Iraq. On the other hand, one formation may have multiple pay zones of Jurassic and Lower Cretaceous sources, such as Zubair and Yamama formations. The kerogens of the source rocks are confirmed by chemical analytical studies of pyrolysis and by microscopic studies of palynofacie types of the disseminated organic matters. PetroMod software basin modeling for hydrocarbon generation and palynomorphs for source-rock age assessments are discussed too. Oil accumulations in the reservoirs are assessed in this study using petrophysical properties to obtain hydrocarbon filling of the rocks and trapping dynamically mobile hydrocarbons in structural and stratigraphic traps in structural cross section and seismic sections. Petroleum system framework, interpreted in this study, could be used for hydrocarbon exploration and for mineral genesis of sulfur deposits through systematic studies and analysis in the proposed oil field especially when they are plotted on seismic section images for assessing the extent of source and reservoir rocks, and hence predicting hydrocarbon migration paths and finding new reservoirs and pay zones.

Synthesis of Local Demulsifiers and Evaluation in Iraqi Oil Fields

De-emulsifiers are one of the important industrial additives used commonly in petroleum industry in order to separate the salt water from crude oil in wet crude oil fields of south oil company (S.O.C) in Iraqi fields.
 In the present study, it has been prepared local demulsifies by synthesis Gemini surfactants bis (Quaternary ammonium salt). The local de-emulsifier was assessed in the laboratories of South Oil Company (S.O.C) Comparison with the results of commercial de-emulsifier (A), where the local material efficiency was higher than the important commercial (A) adopted in the S.O.C by bottle Test and later was produced (6) barrels of material prepared and evaluated in AL-SHAMIA Degassing station in Iraqi South Rumaila .
 Where, evaluated the local de-emulsifier in the fields and show the positive results, this describes the evaluation of field emulsifying the local material in this study with lost cost of preparation of a one barrel about 500$ in the time that the cost of one barrel of commercial de-emulsifier is 1000$.
 The assessment was in the conditions of commercial de-emulsifier, depending on the natural of Dehydrator and Desolater in addition of the effective Dose is 25ppm and by 100% separation efficiency in same fresh oil source.
 The efficiency of local de-emulsifier studied Varity of parameters like: Temperature and the time required to separation function of the Dose.
 The field evaluation conditions of local de-emulsifier were under control outside of the oils (fresh) of D2 (Desolater) of isolation units to examine all of the water and salt content of crude oil.

Undersaturated Oil Compressibility Prediction for Mishrif Reservoir in the Southern Iraqi Oil Fields Using Artificial Neural Network

Coefficient of Isothermal oil compressibility is required in transient fluid flow problems, extension of fluid properties from values at the bubble point pressure to higher pressures of interest and in material balance calculations [1, 2]. Coefficient of Isothermal oil compressibility is a measure of the fractional change in volume as pressure is changed at constant temperature [3]. Coefficients of isothermal oil compressibility are usually obtained from reservoir fluid analysis. Reservoir fluid analysis is an expensive and time consuming operation that is not always available when the volumetric properties of reservoir fluids are needed. For this reason correlations have been developed and are being developed for predicting fluid properties including the coefficient of isothermal oil compressibility.
 This paper presents an application of Artificial Neural Network (ANN) methods for estimation of isothermal oil compressibility for the Mishrif reservoir oils among of commonly available field data, according to the fact that this method is useful when relationships of parameters are too complicated. The method is proposed as a more effective prognostic tool than are currently available procedures.
 In this study, back propagation (BPN) network was used to develop an ANN model to predict isothermal oil compressibility. A three layer feed-forward network has been selected which has the best correlation coefficient in testing the models. The new model of undersaturated oil compressibility in which the first layer consists of five neurons representing the input values of pressure above bubble point, solution gas oil ratio at bubble point, oil gravity API, reservoir temperature and gas specific gravity. The second (hidden) layer contains 12 neurons, and the third layer contains one neuron representing the output values of undersaturated oil compressibility. It was found that the new model estimate undersaturated oil compressibility for Mishrif reservoir crudes in the southern Iraqi oil fields much better than the published ones. The present model predicts undersaturated oil compressibility with an average absolute relative error of 3.86% for the testing data set.

Risk Analysis Application to the Petroleum Field Development , A Southern Iraqi Oil Field - case study.

The development process of oil and gas fields is one of the most important technical and engineering challenges facing the oil companies operating in all areas of the oil sector during the production life of these fields, because of the variables and complexities associated with the development embodied in the analysis process of decision-making rational choices in the development stage of producing oil fields. In this research approved the application of risk analysis as a decision-making in the implementation of the development project of the oilfield under study, which is located in southern Iraq, as well as determine the effect of inaccuracy of some variables in this analysis, which was quantified in two parts, the first of which was related to risk analysis in the event of current situation of the field in terms of productivity, while the second one related to the proposed development method, where it underwent the cases mentioned in this part of the risk analysis, except in cases where production runs up to the water cut in producing wells up to 80% were excluded from the analysis. Results of this analysis for both parts were compared with the amount of accumulated production that were calculated previously for the same cases mentioned in previously Part II, which provided under the developmental study of the mentioned field in 2007 for one of the produced formation in the primary reservoir of the field. The comparison results reflect the importance and eligibility implications of the used tools as promising and supported in their decision-making in right way of engineering studies submitted for the development of oil fields. As well as the results indicate the importance of adopting risk analysis is a good guide to evaluate the methodology and scalability performance of oil fields and the completion of operations associated with them.

Age assessments and palynofacies of the Jurassic oil source rocks succession of North Iraq

Palynomorps of mainly dinoflagellate cysts are used in this study to assess age of Middle Jurassic (Bajocian–Bathonian) Sargelu, Upper Jurassic (Upper Callovian–Lower Oxfordian) Naokelekan, Upper Jurassic (Kimeridgian and Oxfordian) Gotnia and Barsarine, and Upper Jurassic–Lower Cretaceous (Beriassian–Tithonian) Chia Gara source rock Formations. Materials used for this palynological study are 85 core and cutting samples of five oil exploratory wells of Bj-1, Tk-3, Aj-8, K-109 and Tq-1 of selected North Iraqi oil fields. Palynofacies assessments are performed for this studied succession by ternary kerogen plots of the phytoclast, amorphous organic matters and palynomorphs. Accordingly, Chia Gara and Sargelu Formations are both deposited in distal suboxic to anoxic basin and can be correlated with kerogens classified microscopically as Type A and Type B, which comprised principally brazinophyte algae, dinoflagellate cysts, spores, pollen, foraminifera test linings and phytoclasts that could indicate affect of upwelling current. These deposits contain up to 18 wt% total organic matters that are capable to generate hydrocarbons within mature stage of thermal alteration index (TAI) range in Stalplin’s scale of 2.7–3.0 for the Chia Gara Formation and 2.9–3.1 for the Sargelu Formation.

An Optimum Bits Selection for a Southern Iraqi Oil Field Located in Basra Region by Depending a New Algorithm

Even drill bits cost are about 3-5% of the total drilling budget, but bits performance affects as much as 60% of the drilling cost[1] that would explain the necessity of continuous studying and developing this tool to improve drilling performance. Unfortunately, most of Iraqi oil fields managed by states companies does not give the proper attention for bits optimization issues, that would cause insufficient bits used to drill a certain formation due to the absence of a serious dealing with formation hardness and other bit selection criteria while designing, or making bits purchases contracts, or they would satisfy by a minimum rates of penetration.
 Unfortunately, the bit selection issue is matched the optimum selection for the drilling parameters issue, it is a matter of tri and error [2].
 In this study, a southern Iraqi oil field located in Basra region have been selected to optimize the bits used to drill its wells.
 Summarizations of bits selection methods have been reviewed, advantages and disadvantages of possibility to applicant those methods in Basra regions have been introduced. A proper algorithm for selecting bits in Iraq was also presented. An economic evaluation for a different bit type's strategies used to drill holes of Mishrif wells in Basra oil fields region also discussed.
 This study improve that using bits holding the IADC code 425, M322 PDC bit with 6th blades and 16mm cutter size and M323 PDC bit with 5th blades and 6mm cutter size are the optimum selection to drill the surface, intermediate, and production holes consequently.
 This study is applicable to all Iraqi oil fields and especially for Basra region oil fields due to its large analogous on the lithology column and the drilling problems may combined the drilling operations among the different oil fields in this area.

Use of flocculated magnetic separation technology to treat Iraqi oilfield co-produced water for injection purpose

Bench-scale simulation of flocculated magnetic separation (FMS) technology was performed using a jar-tester to treat produced water from four Iraqi oilfields. The results revealed that effluent water with low oil content and suspended solid can be achieved. Settling time for FMS is several times less than that of conventional process. These features make FMS, followed by a polishing oil removal step, such as nutshell filters, attractive to treat Iraqi produced water for injection purpose.

Duplex Inhibition of CO2 Corrosion in Iraqi Oilfield

Duplex Inhibition of CO2 Corrosion in Iraqi Oilfield

NUMERICAL SIMULATION OF A NATURALLY FRACTURED RESERVOIR.

This research is concerned with the development of a numerical model for stratified normally fractured reservoirs. Three dimensional three phase flow black oil simulation model is adopted. The dual porosity-dual permeability model is used. The IMPES (Implicit Pressure Explicit Saturation) method is used to solve the difference equations. The Tertiary trap in K oil field (an Iraqi oil field) was simulated by the numerical model. The trap consists of six layers having different properties. Equally spaced Cartesian grids were used to divide each layer into 1600 cells in the x-y plane with the thickness as the dimension of each grid block in z direction. Applying the two IMPES pressure equations to each grid of the simulated domain resulting in a block seven diagonal coefficient matrix.

Crystallography: The Long-Term Price of Oil

Management It seems only the proverbial blink of an eye since the principal determinants of the price of crude oil on world markets were the tax-paid cost of the Burgan field in Kuwait and the producing allocations decided by the Texas Railroad Commission. Crude oil was in such abundant supply 50 years ago that British Petroleum, then half-owner of the Kuwait concession, and the world's largest oil producer by far, sold more than half a million BOPD of its share of production to its partner, Gulf Oil, at the overlift price, one-eighth way between the accounting cost of production (then about USD 0.80/bbl) and the posted price of USD 1.75. Gulf Oil turned around and resold most of its Kuwait overlift oil at a larger profit, and nobody seemed to care. The world was awash in oil. On the domestic front, supply was so abundant that Texas oil wells were permitted to pump for only 97 days in 1958. Suffice it to say that we no longer exist in a world of oversupply. West Texas Intermediate (WTI) futures on Nymex briefly crossed the USD 100/bbl threshold in late 2007. Alberta has become the new Kuwait, and the Texas Railroad Commission figuratively relocated from Austin to Vienna and became OPEC. Like the Seven Sisters before them, OPEC has attempted to control the price of oil on world markets, with Saudi Arabia shouldering the role of market regulator. While the majors showed impressive solidarity in their dealings with foreign governments, the supply fundamentals were not in their favor. The nationalization of IPC's holdings in Iraq, for example, was precipitated by the refusal of the majors to develop new Iraqi oil fields when there was already too much oil on the market. So what has happened to trigger the more than seventy-fold increase in the price of oil since the 1960s, when the arm's-length price of Kuwait crude was around USD 1.35/bbl, and what lessons may we glean from this history as we peer intently into the crystal ball of price predictions? The Lessons of History As Winston Churchill famously remarked, "Those that fail to learn from history are doomed to repeat it." Three principal forces have been at play over the past 50 years, and we would be remiss in ignoring them.Population and economic growth, which powered world consumption of refined products to grow from 21.3 to 84.4 million BOPD between 1960 and 2006.Cumulative oil production since 1960, which, notwithstanding published recoverable-reserves estimates to the contrary, exceeded reserves additions.The remarkable adaptability of consumers to higher prices, abetted by frequently undisciplined or short-sighted government policies that encourage inefficient use of transportation fuels.

Palynofacies Analysis and Hydrocarbon Generation Potential of Dokan and Gulneri Formations (Upper Cretaceous) from selected wells in Northern Iraqi Oil Fields

Sixty five cutting samples from Dokan and Gulneri Formations in three subsurface sections from Khabbaz, Jambour and Taq-Taq oil fields at Northern Iraq have been selected to be studied optically and analytically from Palynofacies points of view. Four palynofacies types have been determined depending on the ratio of the existed palynomorphs, phytoclasts, amorphous and opaque organic materials. The suggested paleoenvironment of deposition for Dokan and Gulneri Formations is seems to be deposited in proximal to distal shelf environment and that depending on the ratio of the palynomorphs, amorphous and phytoclasts to each other. The optical examination of the organic matter revealed the slightly mature to mature condition of the organic matter (TAI between 3 and +3). The GC analysis also supported such a maturity condition as the Pr/Ph ratio for the studied sections was greater than 1 while the Carbon Preference Index (CPI) less than 1. TOC values of different depths have been determined and types of amorphous organic matter from their ability to hydrocarbon potential also pointed out optically. By connecting between maturity stage, quality and quantity of the organic matters in the Formations of Dokan and Gulneri in the studied sections a number of oil and condensate-wet gas zones have been detected at certain depths of each section.

Natural Enemy, Natural Ally: Toward an Environmental History of War (review)

Reviewed by: Natural Enemy, Natural Ally: Toward an Environmental History of War Robert G. Angevine (bio) Natural Enemy, Natural Ally: Toward an Environmental History of War. Edited by Richard P. Tucker and Edmund Russell. Corvallis: Oregon State University Press, 2004. Pp. vii+280. $29.95. Reports indicating that the U.S. military accelerated its attack on Iraq in 2003 in order to prevent the destruction of Iraqi oilfields and avert ecological disaster suggest that sensitivity to the possible environmental impact of war is now widespread. Yet the editors of Natural Enemy, Natural Ally note that there have been few systematic academic efforts to explore the historical relationship between war and the environment. Indeed, the lack of scholarly study nearly stymied their attempts to produce a book on this topic. After eight years of work, however, they have drawn together a collection of interesting case studies that provides a useful introduction. Richard Tucker and Edmund Russell's primary purpose is "to argue for the importance of understanding war as a major and distinctive force in environmental change, as well as the environment as a force in shaping warfare" (p. 2). The majority of the nine case studies focus on how war has altered the natural environment. A few, such as Roger Levine's discussion of [End Page 657] how different perceptions of the landscape affected the way Zulu and Xhosa speakers conducted war in nineteenth-century Africa, consider how the environment has influenced war. Tucker and Russell's second goal is to illustrate the current state of scholarship in the field. Tucker's historical survey of the impact of warfare on the natural world is intended to serve as a guide to the existing literature, but his melodramatic prose and antitechnology bias weaken its utility. For example, he describes how the superior weaponry of Western nations enabled them to overwhelm their "human prey" by the mid-nineteenth century, and he seems to believe that the principal product of technological advance is greater savagery and destruction (p. 25). The third objective of the book is to encourage further research, and both the high quality of the case studies and the current relevance of the topic should help achieve this goal. Although the editors stress the need for more geographic and temporal diversity in the future, their case studies already cover a wide range of periods and locales. Some of the most interesting address the impact of war on the relationships between government institutions seeking to regulate the environment and private companies. Tucker argues that the intensive demand for forest resources during the world wars greatly expanded public control over those resources in many of the combatant nations. Because the exigencies of war forced governmental forest services to work closely with private-sector timber firms, commercial priorities dominated postwar forest management. Similarly, coeditor Russell suggests that the world wars forged ties between chemical companies and the military that fostered the development of insecticides and chemical weapons, thereby increasing the ability of human beings to kill both insects and other humans on a large scale. Several contributors point out that war has not always had a detrimental effect on the natural world. William Tsutsui's insightful examination of the environmental history of wartime Japan reveals that the impact of war can be "uneven, contradictory, and often equivocal" (p. 210). Japanese mobilization for World War II intensified the cutting of old-growth forests and the hunting of seals, and wartime scarcity encouraged the "harvesting" of songbirds. Simultaneously, however, the destruction of Japan's fishing fleet had the effect of swelling fish-stocks, and energy resource shortages encouraged research in alternative fuels. Simo Laakkonen describes similar effects in Finland, where wartime demands paralyzed environmental policy but also protected forests, reduced the discharge of pollutants into the water, and increased use of local, renewable resources. Another case study tells how the central government's role in developing and preserving the environment in precolonial India depended on its ability to manage its relations with militarized families and prevent destructive local wars. Others reexamine the Battle of Gettysburg and the American Civil War through an environmental lens, recount efforts to stop the spread [End Page 658] of pests and...

イラクの石油ポテンシャル―石油地質概要と南部の大規模未開発油田―

Geological Survey Department of Japan National Oil Corporation has been conducting in-house studies on petroleum geology and undeveloped giant fields of Iraq, and this paper gives an outline of the results of the studies. Iraqi oil fields have the following characteristics: i) Main reservoirs are the Cretaceous carbonate and sandstone rocks in southern oil fields and the Tertiary carbonate rocks in northern oil fields, ii) Typical structures are gentle anticline in southern oil fields and steep anticline with reverse fault in northern oil fields, iii) Oil fields have multiple reservoirs. In southern Iraq, there are many undeveloped giant fields including Majnoon, West Qurna and Bin Omar fields, which have reserves of more than 5 billion barrels. Main reservoirs of the fields are the early Cretaceous Yamama formation, Zubair formation, Nahr Umr formation and the late Cretaceous Mishrif formation. The area where each formation shows good reservoir properties are restricted and this can be explained by the difference of depositional environment of the formation in the area. Development costs of the undeveloped fields in southern Iraq are estimated to be from hundreds of millions of dollars to billions of dollars although unit costs($/bbl) for the development are fairly low. Difference in productive formations and/or operation environments(desert or swamp) affect the development costs.

Petroleum reserves and undiscovered resources in the total petroleum systems of Iraq: reserve growth and production implications

ABSTRACT Iraq is one of the world’s most petroleum-rich countries and, in the future, it could become one of the main producers. Iraq’s petroleum resources are estimated to be 184 billion barrels, which include oil and natural gas reserves, and undiscovered resources. With its proved (or remaining) reserves of 113 billion barrels of oil (BBO) as of January 2003, Iraq ranks second to Saudi Arabia with 259 BBO in the Middle East. Iraq’s proved reserves of 110 trillion cubic feet of gas (TCFG) rank tenth in the world. In addition to known reserves, the combined undiscovered hydrocarbon potential for the three Total Petroleum Systems (Paleozoic, Jurassic, and Cretaceous/Tertiary) in Iraq is estimated to range from 14 to 84 BBO (45 BBO at the mean), and 37 to 227 TCFG (120 TCFG at the mean). Additionally, of the 526 known prospective structures, some 370 remain undrilled. Petroleum migration models and associated geological and geochemical studies were used to constrain the undiscovered resource estimates of Iraq. Based on a criterion of recoverable reserves of between 1 and 5 BBO for a giant field, and more than 5 BBO for a super-giant, Iraq has 6 super-giant and 11 giant fields, accounting for 88% of its recoverable reserves, which include proved reserves and cumulative production. Of the 28 producing fields, 22 have recovery factors that range from 15 to 42% with an overall average of less than 30%. The recovery factor can be increased with water injection, improved and enhanced oil recovery methods (IOR and EOR) in various reservoirs, thus potentially increasing Iraq’s reserves by an additional 50 to 70 BBO. Reserve growth is a significant factor that has been observed, to some extent, in nearly all Iraqi oil fields. Historically, producing fields have shown an average growth of 1.6 fold (or 60%) in their recoverable reserves over a 20-year period (1981-2001). With periodic assessments of reservoirs, application of available technology, and an upgrading of facilities, increases in reserves are expected in the future.

The Rise of the Shadow Warriors

THE RECENT WAR in Iraq was, among other things, a powerful advertisement for the effectiveness of the United States' storied special operations forces. Americans are just now learning what role these commandos played in the conflict, but already it has emerged that, during the early days of the fighting, they managed to secure crucial airfields in western Iraq, protect the country's oil fields from saboteurs (fewer than lo Iraqi oil fields were ignited, compared to the more than 700 Kuwaiti fields that were set ablaze in 1991), and, most famously, rescue Private Jessica Lynch from an Iraqi hospital. Yet these achievements, although impressive, do not fully explain the unprecedented prominence currently enjoyed by special operations forces within the U.S. military. True, such troops may have been well suited to the kind of missions they were given in Iraq. But they also happen to fit precisely into the model of a leaner, more flexible military that Defense Secretary Donald Rumsfeld is fighting to create at the Pentagon. And Rumsfeld has made no secret of his plans to thrust special forces into the lead role in the war on terrorism, by using them for covert operations around the globe. The special forces' success in Iraq has also obscured a more ominous consequence of their newfound popularity: that expanding their role in the way Rumsfeld intends could be very dangerous for U.S. foreign policy. Thanks to the vagueness of U.S. law governing covert action,

What Happens to the Iraqi Oil?: Thoughts on Some Significant, Unexamined International Legal Questions Regarding Occupation of Oil Fields

Possible US and allied occupation of Iraqi oil fields following any military action against Saddam Hussein would raise a variety of interesting legal issues under the international law of belligerent occupation. With specific regard to Article 55 of the 1907 Hague Regulations on the Laws and Customs of War on Land, an occupant's treatment of state‐owned immovables, such as oil reserves, must accord with the rules of usufruct. In the essay that follows, the authors look at how the rules of usufruct affect three particular matters that have not previously received extensive consideration: (1) the latitude of an occupant to employ sophisticated producing technologies that increase the degree to which an oil field may be swept clean; (2) the permissibility of increasing the rate or volume at which oil is produced from a particular field; and, (3) the uses to which an occupant may put either the oil produced or the proceeds from sales of such. The authors suggest that a usufructuary is permitted to exercise a rather broad, though not unlimited, discretion in connection with selecting extraction technologies and rates of production. As for how the oil produced or the proceeds from such may be used, it is suggested that international law forbids any use that can be seen as being for the enrichment of the occupant.

Analyzing and Optimizing Bits Performance in Three Iraqi Oil-Fields

Analyzing and Optimizing Bits Performance in Three Iraqi Oil-Fields

Feasibility of Dynamic Acid Corrosion Control in Oil Well Tubing

Matrix acidizing operations are regarded as one of the most important and familiar operations in Iraqi oil wells. These operations are carried out in a routine way, injecting 15% hydrochloric acid with 1% ACI (the acid corrosion inhibitor used with HCl acid in southern Iraq) for stimulation of carbonate formation. Since oil production was started in Iraq, the acidizing jobs have been carried out using the above concentration. In spite of the experience in performing the acidizing jobs in the southern part of the Iraqi oil fields, it has been found that the above concentration of ACI is high for 15% HCl. An experimental study has been carried out to investigate the corrosion in oil well tubing, which is of great importance in well acidizing operations, to establish a successful acid corrosion control in oil well production tubing. The investigation was carried out on coupons of three types with two different concentrations of hydrochloric acid (15%, 28%). The investigation was extended to cover the effects of the following: (1) volume of acid (milliliters)/area of test coupon (square inches), VIA; (2) agitation of acid; (3) effective contact time; (4) concentration of ACI (acid corrosion inhibitor). Comparison of static and dynamic tests was covered in this work. It is found that as VIA increases, acid corrosion rate decreases for all values of ACI concentration to a certain limit, and also that increasing the effective contact time increases the rate of corrosion. The study proves the importance of dynamic conditions which depict real or actual field circumstances.

Alternative Flow-Pattern Maps Can Improve Pressure-Drop Calculations of the Aziz et al. Multiphase-Flow Correlation

Summary An improvement in pressure-drop calculations of the Aziz-Govier-Fogarasi multiphase-flow correlation is presented. This improvement was achieved after several combinations of different flow-pattern maps with the correlation were attempted. Field data taken from 15 flowing oil wells of an Iraqi oil field and the published data of Poettmann and Carpenter and Chierici et al. are used for testing the performance of the various combinations. The introduction of ± 15% uncertainty in the values of bubblepoint pressures and solution GOR's predicted by the Vasquez fluid-property correlation appears to have insignificant effects on pressure-drop calculations. The effects of changing the direction of pressure-drop calculations confirms the findings of the work of Gregory et al. Although all the attempted combinations show an improvement in pressure-drop calculations over the original correlation, the Duns-Ros flow-pattern-map combinations produce the best results. Its overall absolute average percent deviation for the Iraqi oilfield data set is 3.05%, compared with 7.23% for the original correlation. Also, the percent of calculated pressure-drop points deviating by more than ± 5% from the observed points is reduced from 52.5% for the original correlation to 17% for this combination.

Bromine as an indicator of oil migration in northern Iraqi oil fields

The Br content of oil varies systematically along the paths of oil migration in northern Iraqi oil fields, indicating that this element may be used as an indicator of oil movement. The variation in Br parallels that of V and Ni, and like these two elements it is concentrated in the asphaltene fraction of petroleum.