Sour Crude Oil Research Articles

Hydrocarbon-Mobility Steering for Optimum Placement of a Power Water Injector

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 164282, ’Hydrocarbon-Mobility Steering for Optimum Placement of a Power Water Injector Above Tar Mats - A Case Study From a Light-Oil Carbonate Reservoir in the Middle East,’ by Craig Saint and Thomas Glowig, Baker Hughes, and Ashis S.S. Swain, Nasser A. Al-Khaldi, Mohd. H. Al-Otaibi, Abdul Aziz Al Ghareeb, and Ahmad Bader Al Bader, Khafji Joint Operations, prepared for the 2013 SPE Middle East Oil and Gas Show and Exhibition, Manama, Bahrain, 10-13 March. The paper has not been peer reviewed. Tar mats are encountered in many Middle East carbonate reservoirs. In cases in which tar acts as a flow barrier between water and light oil, water injectors work most efficiently when placed horizontally immediately above the tar mat to maintain pressure support during production. As this strategy is pursued, a real-time tar-detection method is needed while drilling. The low mobility caused by tar can be detected with a formation-pressure- while-drilling (FPWD) tester, while a nuclear-magnetic-resonance (NMR) tool provides oil-viscosity estimation. Introduction The Ratawi limestone reservoir was discovered in 1963 in the offshore Neutral- Zone Concession area between Saudi Arabia and Kuwait. The production of light sour crude oil commenced in 1966. After an increase in gas/oil ratio and a sharp drop in reservoir pressure occurred, dump-water injection was started in 1975. Until recently, peripheral dump-water injection was used. Geologically, the reservoir is divided into three units, Units A, B, and C from top to base, respectively. Of these, Unit C is the main producing unit. The top of Unit C is considered as a possible sequence boundary/unconformity. Units A and B represent initial flooding over Unit C. The two units are composed of alternating porous limestone and less-porous or tight limestone, and show overall transgressive-system tract sequence. The heavy-oil zone was recognized above the oil/water contact. Additional drillstem tests and investigation of the separation between shallow and deep resistivity indicated fieldwide distribution of the heavy-oil zone. Wireline NMR and pressure data indicated presence of a tar/asphaltene zone in the heavy-oil zone. The operator’s strategy was to carry out peripheral water injection, placing the injectors above and as close as possible to the heavy-oil/tar zones, enabling better sweep and volumetric displacement of light oil toward potential producers. The reservoir characterization around the injector locations is critical for assessing carbonate heterogeneity, diagenetic uncertainty, asphaltene presence, and a transition zone of heavy-to-light oil. Assessment of risk-evaluating conventional- wirelinelog responses, seismic attributes, and nearby well dynamic information resulted in good prognosis of the area for deciding the entry point or landing point of the injectors and was crucial in well.placement. Offshore operations did not allow evaluation of the tar/asphaltene zone in each well because of higher operating costs from drilling a pilot hole. In recent wells, the placement was achieved on the basis of mobility steering as close as possible to the heavy-oil/tar zone.

Features and methods of heavy sour crude oil refining

The features and properties of distillate fractions and residue of heavy sour crude Orkhovitsk oil were examined and promising methods for their use were proposed in the paper. It was found that with increasing the temperature of fractions boiling, the content of sulfur compounds in them increases. The main regularities of the process of viscosity breaking of Orkhovitsk oil residue in the temperature range 410-450°С were studied. It was established that the process of viscosity breaking can not be considered as an independent and final stage of refining of Orkhovitsk oil residue. It was shown that the method of co-oxidation of Orkhovitsk oil residue and 11-13% masses of heavy pyrolysis resin at the temperature of 250°С, air supply 2.5h -1 during 6 hours allows obtaining the bitumen, which, by the main quality parameters, meets the requirements for road bitumen of the grade BND 60/90 according to DSTU 4044-2001. As a result of studying the basic regularities of modification of residual bitumen obtained from Orkhovitsk oil by the polymer latex Butonal NS 198, it was determined that inclusion of 2-3% masses of this modifier into bitumen, followed by mixing at 180°C for 2-6 h, allows obtaining the bitumen, which meets the requirements of the grade BND 60/90.

Oxidative Desulfurization of Crude Oil Incorporating Sulfone Decomposition by Alkaline Earth Metal Oxides

This work explores a novel approach to desulfurization of whole crude oil where thiophenic sulfur compounds are oxidized to sulfones followed by sulfone decomposition into sulfur-free hydrocarbons. The objective of this work is to study the effect of alkaline earth metal oxides on decomposition of sulfones in oxidized crude oil. About 73% of the sulfones in a preoxidized, medium sour crude oil was decomposed over CaO at 360 °C. SO2 was detected by TPD–MS and also measured by a quantitative method when the spent CaO sorbent was thermally treated in an inert atmosphere with sweep gas. No prominent decomposition of sulfur compounds was observed when untreated crude oil (not oxidized) was treated over CaO at 360 °C. This study demonstrates the feasibility of decomposing sulfones in oxidized crude oil over CaO-based materials.

Heavy Crude Oil Upgrading: Jazmin Crude

The Jazmin crude oil is located at the heart of Middle Magdalena in Colombia. It is heavy and sour crude oil with 43 wt.% of vacuum bottoms. It cannot be processed at the conventional refinery without being mixed with other lighter crudes, and should be upgraded to produce synthetic crude with higher concentration of distillates and lower acidity and carbon content. In this paper eight upgrading alternatives are presented. The alternatives include the processing of the crude, reduced crude and vacuum bottoms of the Jazmin crude oil using the following technologies: Distillation, solvent deasphalting, visbreaking, Delayed Coking, and Hydrotreating. The experiments were conducted at pilot scale, and there were used standard analysis techniques such as ASTM. In this study it was found that Jazmine crude oil and its heavy components produce high distillate yields when they were processed with thermal conversion processes. In addition those processes reduce the products acidity. Within the analyzed scheme the one corresponding to the visbreaking of the crude oil and the Delayed Coking of the vacuum bottoms from the visbreaking is perhaps the most attractive, giving 5.9 wt.% of gas, 78.2 wt.% of distillates and 15.9 wt.% of coke.

Modernization of oil refineries as the basis for the development of the Russian oil refining industry in the period of 2010–2020

Ways of developing and modernizing Russian oil refineries are considered on the basis of an analysis of the presentations of Russian and foreign companies at the 10th Russian and CIS Refining Technology Conference (RRTC) held by Euro Petroleum Consultants in Moscow on September 23–24, 2010. It is shown that the main trends in the development of the Russian oil refining industry with the purpose of overcoming the current economic crisis are the rational use of production facilities, the modernization of existing plants to increase the depth of processing and the profitability of production, satisfying the growing demand for motor fuels (especially diesel) and improving their quality to meet the parameters of eurostandards, increasing the conversion of the processing of oil at oil refineries, reducing the consumption of energy, and improving the process control and optimization systems at existing plants to increase their efficiency and minimize the environmental risks in operating plants. The development of hydrogenation processes that allow the synthesis of high-quality products from cheap sour crude oil or the qualified preparation of raw materials for the process of catalytic cracking must now become the main direction of oil refining in Russia and CIS countries. Oil residue processing technologies (e.g., hydrogenation processes, catalytic cracking, new and improved catalysts for hydrocracking, catalytic cracking, hydrotreatment of heavy oil residues; and hydrogen synthesis technologies) are discussed.

Rising Crude Oil Prices: The Link to Environmental Regulations

Crude oil is not a homogenous commodity. Light sweet crude oils produce a high percentage of products desired by consumers after distillation. Other crude oils (heavy, sour, or high-sulfur crude) must be heavily processed to obtain needed products. The failure to understand the differences between desirable light crudes and heavy sour crude oils can lead to bad forecasts of market behavior. Using a stylized model of the market, I show that tightening environmental regulations in the absence of adequate refining capacity to process heavy sour crude puts upward pressure on crude prices and explains the 2008 price increase. The upward pressure is exacerbated by the monopolist practices of heavy sour crude producers, who set price differentials to maximize income. This model also can be used to analyze the impact of the supplies lost from Libya in 2011.

Monitoring of the Chemical Species in a Liquid-Phase Claus Reaction

Although the Claus-reaction-based processes are widely used in industry to recover sulfur from sour gas or crude oil, the precise mechanism of this reaction remains unclear and controversial. The aim of this study was to determine the chemical species of the Claus reaction in an organic liquid phase [using polyethylene glycol 400 (PEG) as solvent] at 125−130 °C. A combined UV−vis and Raman spectroscopic approach is developed to monitor the sulfur speciation. In addition, ab initio molecular-modeling techniques lead to an exhaustive mapping of the Raman spectral properties of molecules. Several intermediate sulfur-containing species have also been identified, as a function of experimental conditions. These analytical results are required as preliminary data to describe the chemistry of the Claus reaction in the organic liquid phase. These data are helpful to improve the kinetic model for the subdew point Claus tail gas treatment, used in the refining and natural gas treatment industries.

Latest developments in sulfuric acid catalysts

This paper presents a review of current routes to utilize sulfur and sulfuric acid. Sulfur is a by-product from sour gas and crude oil processing and the precursor of sulfuric acid. As an oversupply is projected for the near-term future, it is prudent to investigate new sulfur applications and market domains that may facilitate a balancing of supply and demand. This consideration is especially relevant for the UAE, and the Middle East in general, due to the requirement to develop sulfur-rich sour gas resources to meet increasing energy needs. The goal of this review is to understand current sulfur oversupply, not as a problem, but as an opportunity to develop more sustainable technologies. Current routes are reviewed, and possible new applications and their potential as a sulfur sink and a sustainable alternative to existing technologies are discussed. Although sulfur is currently in oversupply, less than 5% positive balance according to Harrisson (2016), it must be noted that it is also a critical component in fertilizer production, having a direct impact on the food supply for the world’s growing population. Should the world find itself in a sulfur shortage in the future (which could be possible in the long-term (beyond 2030) as a result of growth in renewable energies, shale gas/oil proliferation and population growth), this would be a much greater problem than the current slight oversupply situation, thus making it important to consider sulfur recoverability as a key factor for any sulfur sink technologies explored.

Corrosion pyrophoric deposits as promoters of self-ignition of storage tanks with sour crude oil

The causes of the formation and the conditions for self-ignition of pyrophoric deposits in the vapor zone of tanks during the storage of sour crude oil were considered. It was demonstrated that creation of an oxygen-free atmosphere inside oil storage tanks seems to be the most promising approach to prevention of self-ignition and corrosion. This approach was effected in practice by supplying oil tanks with nitrogen from a membrane gas separator.

Hydrogen Effect on Fatigue Strength of Structural Materials

In this paper hydrogen effect on fatigue strength of structural materials related to the internal hydrogen embrittlement and hydrogen environment embrittlement is reviewed. The emphasis is focused upon the hydrogen assisted corrosion fatigue behavior of structural materials in aggressive gas and sour crude oil environments. The proposed mechanism of hydrogen effect on fatigue crack propagation behavior of structural materials is briefly summarized. Finally recommended researches in hydrogen effect on fatigue strength of structural materials are touched on briefly.

Oxidation of sulfides in petroleum diesel fraction with hydrogen peroxide catalyzed by molybdenum compounds

The catalytic properties of molybdenum compounds in the oxidation of sulfides from the diesel fraction of sour crude oil with hydrogen peroxide were studied. Comparative data on the performance of molybdenum complexes in the oxidation of diesel sulfides are reported. The activity of the catalysts was compared in terms of the degree and selectivity of conversion of sulfides into sulfoxides. The highest catalytic activity was shown by molybdenum bis-sulfoxide peroxo complexes.

Hydrogen Effect on Fatigue Strength of Structural Steels

In this paper hydrogen effect on fatigue strength of structural steels is mainly reviewed on the basis of the author's experimental results. The emphasis is focused upon the hydrogen related corrosion fatigue crack propagation behavior of the ship structural steels and their welded joints in sour crude oil environment. It can be concluded that the environment enhancement of the fatigue crack propagation rate in sour crude oil is dependent of hydrogen evolved by reaction of H2S and H2O in the sour crude oil with structural steels.

The determination of water in crude oil and transformer oil reference materials.

The measurement of the amount of water in oils is of significant economic importance to the industrial community, particularly to the electric power and crude oil industries. The amount of water in transformer oils is critical to their normal function and the amount of water in crude oils affects the cost of the crude oil at the well head, the pipeline, and the refinery. Water in oil Certified Reference Materials (CRM) are essential for the accurate calibration of instruments that are used by these industries. Three NIST Standard Reference Materials (SRMs) have been prepared for this purpose. The water in these oils has been measured by both coulometric and volumetric Karl Fischer methods. The compounds (such as sulfur compounds) that interfere with the Karl Fischer reaction (interfering substances) and inflate the values for water by also reacting with iodine have been measured coulometrically. The measured water content of Reference Material (RM) 8506a Transformer Oil is 12.1+/-1.9 mg kg(-1) (plus an additional 6.2+/-0.9 mg kg(-1) of interfering substances). The measured water content of SRM 2722 Sweet Crude Oil, is 99+/-6 mg kg(-1) (plus an additional 5+/-2 mg kg(-1) of interfering substances). The measured water content of SRM 2721 Sour Crude Oil, is 134+/-18 mg kg(-1) plus an additional 807+/-43 mg kg(-1) of interfering substances. Interlaboratory studies conducted with these oil samples (using SRM 2890, water saturated 1-octanol, as a calibrant) are reported. Some of the possible sources of bias in these measurements were identified, These include: improperly calibrated instruments, inability to measure the calibrant accurately, Karl Fischer reagent selection, and volatilization of the interfering substances in SRM 2721.

A coulometric method for determining substances that interfere with the measurement of water in oils and other chemicals by the Karl Fischer method.

In order to fulfill a need to measure water in crude oils containing materials that interfere with the measurement of water by the Karl Fischer method, by reacting with iodine or iodide, a coulometric method has been developed and validated using 0.1 mol L(-1) Sodium thiosulfate as a calibrant. These interfering substances were measured in water-mass-equivalents, which were expressed as the mass of water that reacts with an equal mass of iodine in the Karl Fischer method. The SO(2)-free reagent that has been modified reacts quantitatively with sodium thiosulfate, cysteine and ascorbic acid but does not react with vinyl acetate. The level of interfering substances was measured in five transformer oils (including Reference Materials RM 8506 and RM 8507), a high and a low sulfur crude oil (Standard Reference Materials SRM 2721 and SRM 2722 respectively), a white oil, a high-vacuum oil and a high-viscosity base-stock oil. One oil contained less than 10 mg kg(-1) (water-mass-equivalents of interfering substances in oil) and two oils (RM 8507 and Drakeol 35) contained no measurable amount of interfering material (<0.2 mg kg(-1)). SRM 2271, a sour crude oil contained 834 mg kg(-1) (standard deviation (SD)=25 mg kg(-1)) (water-mass-equivalents of interfering substances in oil). Approximately 20% of this material was volatile and an additional 20% appeared to undergo some degradation (possibly oxidation) once the oil was exposed to air. These results indicate that this is a general method for measuring substances in oils that react with iodine and that it is capable of measuring in a variety of oils, using commercial instrumentation, interfering substances that inflate water measurements.

Analysis of Refinery Hydrogen Distribution Systems

Increasingly strict environmental and product-quality regulations, the shrinking market for high-sulfur fuels, and the price benefit of processing heavier and more sour crude oils has pushed oil refiners to increase their hydrocracking and hydrotreating capacities. The resulting increase in hydrogen consumption and limited or even decreased generation are creating tight hydrogen balances in many refineries throughout the world. The efficient use of hydrogen is a necessity, with refineries facing eroded margins due to constrained refinery operations or the need for significant investments in hydrogen generation and purification. This paper addresses the problem of refinery hydrogen distribution. A systematic method for the analysis of hydrogen distribution systems based on the concept of hydrogen surplus is proposed. This method sets targets for the minimum flow rate of fresh hydrogen required by the refinery before any system design. The analysis method is used to provide quantitative insights and to iden...

Removal of Selenocyanate in Water by Precipitation: Characterization of Copper−Selenium Precipitate by X-ray Diffraction, Infrared, and X-ray Absorption Spectroscopy

During refining of sour crude oils produced from reservoirs containing seleniferous marine shales, selenium is concentrated into process waters and wastewaters. Selenium, present in the waters as selenocyanate, must be removed to meet regulatory discharge limits. Treatment of wastewaters with copper(II) salts effectively precipitates selenium. An objective of the present study was to determine whether selenium was precipitated as elemental Se or immobilized in the form of cyanate complexes or any other form that remains to be identified. The precipitate had a Se/(Se+S) mole ratio of 0.09. The incorporation of selenium in the copper thiocyanate lattice was proven by X-ray diffraction. The presence of native selenium was disallowed by Se K-edge X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy. Selenium was shown by EXAFS to be present as selenide and surrounded by one nearest C atom and three next-nearest Cu atoms. This local environment is typic...

Changes in mutagenicity during crude oil degradation by fungi.

Two fungal strains, Cunninghamella elegans and Penicillium zonatum, that grow with crude oil as a sole carbon source were exposed to three crude oils that exhibit a range of mutagenic activity. At regular time intervals following fungal incubation with the various crude oils, extracts were tested for the presence of mutagenic activity using the spiral Salmonella assay. When the most mutagenic of the oils, Pennsylvania crude oil, was degraded by C. elegans or by P. zonatum, its mutagenicity was significantly reduced; corresponding uninoculated (weathered) controls of Pennsylvania crude remained mutagenic. West Texas Sour crude oil, a moderately mutagenic oil, exhibited little change in mutagenicity when incubated with either C. elegans or P. zonatum. Swanson River Field crude oil from Cook Inlet, Alaska is a slightly mutagenic oil that became more mutagenic when incubated with C. elegans; weathered controls of this oil showed little change in mutagenicity. Mycelial mat weights measured during growth on crude oils increased corresponding to the biodegradation of about 25% of the crude oil.

高硫化水素原油中における高張力鋼および軟鋼の疲労破面の定量解析

Corrosion fatigue crack propagation tests of HT50 (TMCP) and mild steel and corrosion fatigue life test of HT50 (TMCP) were conducted in sour crude oil containing 400ppm H2S. The detailed SEM observations were carried out on these fracture surfaces obtained. The crack propagation rate of these steels in the sour crude oil was accelerated in the stress intensity factor range, ΔK higher than about 16MPa√m. The ratio of acceleration of the crack propagation rate, da/dN in the sour crude oil in the ΔK of 30MPa√m was 7 for HT50 (TMCP) and mild steel.In the higher stress range of S-N curve for the round notched bar specimens of HT50 (TMCP), the influence of sour crude oil containing 400ppm H2S on the fatigue life was observed obviously. The fatigue life ratio decreased with decreasing the stress to unity at the lower axial stress.It was found that the crack propagated predominantly on the cleavage fracture surface in association with brittle striation in the accelerated crack propagation area of fracture surface in the sour crude oil.The striation spacing per cycle, S obtained from the measured striation spacing ΔS versus ΔK curve was well coincident with the da/dN-ΔK curve in the accelerated crack propagation area.It might be concluded that the environmental enhancement of the fatigue crack propagation rate in sour crude oil is dependent on hydrogen evolved by reaction between the structural steels and hydrogen sulfide in the sour crude oil.

サワー原油中における構造用鋼の腐食疲労強度

サワー原油中における構造用鋼の腐食疲労強度

Rheological studies of Ratawi vacuum residue at 366 K

Ratawi vacuum residue is a typical bottom-of-the-barrel fraction from an asphaltenic sour crude oil, and previous work indicates that Ratawi asphaltenes are typical petroleum asphaltenes. The rheology of Ratawi vacuum residue is analysed in this work by employing theories given by Pal and Rhodes, Eilers, Campbell and Forgacs, and Grimson and Barker to describe the rheology of concentrated suspensions of solid particles. The excellent and self-consistent description provided by these theories shows that Ratawi asphaltenes are a distinct species in vacuum residue. Information about the macrostructure of asphaltenes in their natural environment, the crude oil or residue, is also obtained. Ratawi asphaltenes are solvated spheres of different sizes in the vacuum residue. Their solvated volume is two to three times the dry volume at 366 K. Direct interparticle interactions between solvated asphaltenic particles are weak at 366 K. These forces are repulsive, and account for the stability of Ratawi vacuum residue with respect to asphaltene precipitation. A method of employing the Grimson-Barker theory suggests that the Ratawi asphaltenes are charged. The solvation effect arises because polar molecules in the non-asphaltenic fraction surround the particles and screen the charge.