Stability and settling characteristics of solvent-diluted bitumen emulsions

When bitumen emulsions are diluted with aliphatic solvents at solvent-to-bitumen ratios above a certain value, water droplets, solids, and precipitated asphaltenes tend to form clusters that are much larger than the individual components. This work demonstrates that bitumen emulsions diluted with aliphatic solvent exhibit settling behavior distinctly different from that of bitumen emulsions diluted with aromatic solvent. The aliphatic system exhibits a zone settling mode with sharp interfaces. A characteristic interface appears as a discontinuity between the clean oil phase and the hindered settling zone. Laboratory techniques have been developed for measuring settling rates by tracking the interface positions with time. As an example, an experimentally observed settling curve was modeled by solving the conservation law hyperbolic equations.     

Multielement analysis of Nigerian bitumen by TXRF spectrometry and the physical constants characterization of its hydrocarbon component

The Total reflection X-ray fluorescence (TXRF) Spectrometry analytical technique was used for the elemental characterization of bitumen extracted from Nigerian Oil sands. Twelve elements—K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As and Pb were detected and their concentrations, the enrichment factors and correlation determined. Very high enrichment factors were obtained for V, Cr, Ni, Cu, Zn, As and Pb. This has implication for environmental degradation during exploration, refining, transportation and/or marketing of the bitumen. The correlation matrix result indicated that some of the trace elements detected have common sources or similar chemical properties. Samples of the extracted bitumen were also subjected to solvent deasphaltened using n-pentane to obtain maltene and asphaltene. Oil (Hydrocarbon) component was eluted from maltene using n-pentane in a glass chromatographic column, which has been packed with activated neutral alumina of grade Brock Mann 1, type 507 C. The physical characteristics (API gravity, refractive index, viscosity, surface tension and melting point) of the oil eluted from the bitumen were determined. The percentage oil composition (36.98%) was comparable to equivalent values obtained for oil from Athabasca (48.10%) and Venezuela (40.30%) oil sands indicating that Nigerian oil sand is a rich source of petrochemicals. The results of physical characteristics also show that oil could be useful for lubrication purpose.     

Tar mats and residual oil distribution in a giant oil field offshore Abu Dhabi

This paper describes how geochemical data (Rock Eval analysis, SARA composition) combined with wireline log interpretation allows for the recognition of the distribution and continuity of bitumens in a main reservoir of an offshore giant field in Abu Dhabi. The integration of new geochemical data with data and field information provided by the oil company ZADCO allows for the recognition of two types of bitumen rich levels in the main reservoir of the field: a) one corresponding to bitumen rich main reservoir intervals associated with high resistivity and high oil saturation, these intervals can be called “tar mats”, b) the other corresponding to low oil saturated intervals, and can be classified as “heavy residual oil”.In terms of lateral and vertical distribution, the tar mats are found at the crestal area of the Present-day structure and are located at the base of the reservoir unit above a tight limestone which plays a role of being a vertical permeability barrier. The tar mats seem to be independent of the Present-day OWC and are not related to biodegradation processes. The heavy residual oil is mainly located in the Northeast and the Southeast parts of the field and close to the OWC but it is also present all around the field except 1) in the west, in the area of the spill point and 2) in the Northwest area where direct contact between mobile oil and water is detected.Study of the structural evolution demonstrates that a tilting of the field began at Dammam age time (Eocene). The tilting of the structure led to a reduction of the structural closure in the West followed by the leakage of part of the originally trapped oil.Numerical modeling of such a geological scenario leads to a distribution of fluids (water, movable oil and residual oil) very close to the one observed at Present-day time in the field. This modeling allows a prediction of the extension and distribution of the residual heavy oil within the studied reservoir and can be used to better define an optimal production scheme. The effects of the residual heavy oils on the fluid circulation are difficult to evaluate, depending on the distribution of the bitumen in the pore network.     

Separation and characterization of foulant material in coker gas oils from Athabasca bitumen

Gas oil streams from the upgrading of oilsands bitumen contain toluene insoluble, gummy, solid foulants that cause process problems by plugging hydrotreater feed filters and catalyst beds. From a process optimization standpoint, it is of considerable interest to determine the exact origin and nature of this material in order to design remedial measures. We selected coker heavy gas oil (KHGO) from bitumen upgrading as the primary test material for this work but also include samples from other parts of the process.Typically, solids content of gas oils are determined by a filtration method. For the KHGO sample used here, this approach yielded a value of 45 ppm. We also compared solids content using ultra- and low-speed centrifugation techniques. With toluene as the diluent, both of these centrifugation methods gave virtually the same toluene insolubles (TI) value, i.e. 24 and 23 ppm, respectively. For paraffinic diluents the measured TI contents ranged from about 50 to 200 ppm. Our results demonstrate that KHGO may contain significant amounts of TI not measured by conventional filtration.Characterization of gas oil TI from different sampling points in the bitumen upgrading circuit showed that it is a nitrogen and oxygen rich organic material, associated with minor amounts of inorganic elements representative of ash-forming iron minerals and alumino-silicate clay. The most likely source for this intractable toluene insoluble fraction appears to be a low molecular weight pyrrollic species present in heavy gas oil. Such compounds are easily oxidized to produce insoluble polymers that can interact with inorganic minerals and metals, producing gummy material capable of blinding filters.     

非生物(无机)成因油气基础科学问题

为了更好地了解原油、沥青的成因,对克拉玛依油田沥青、塔里木盆地干酪根和沥青、辽河油田下第三系干酪根和沥青A以及原油进行了Pb、Sr、N d同位素研究,结果表明:准噶尔、塔里木和辽河3个盆地的沥青及原油的Pb同位素均显示出了壳-幔相互作用的特征,也均表现出不同于干酪根Pb同位素组成的特征(干酪根的Pb同位素组成明显表现出壳源的特征);克拉玛依沥青的Rb-Sr等时线年龄及初始Sr比值(87Sr/86Sr)I(即IO)与达尔布特断裂带附近金矿的成矿年龄和IO相一致,表明沥青与金矿的金均来自相同的深部源区。指出在准噶尔盆地通过深部地震测深所获得的中地壳低速层存在的信息支持了这样一个假说,油气可能为非生物(无机)成因。     

紫外光老化对沥青化学族组成和物理性能的影响

在较高温度下对两种基质沥青（AH-70、AH-90）进行了紫外光氧老化，研究了紫外光对两种沥青化学族组成和物理性能的影响。结果表明：在紫外光的连续辐照下，两种沥青的饱和分、芳香分和沥青质含量的变化趋势基本相同，即饱和分含量变化很小，芳香分含量明显降低，沥青质含量显著增大，而两种沥青的胶质含量变化有明显差异：AH-70的胶质含量先略微增大后又减小最后基本不变；AH-90的胶质含量先稍微增大而后持续减少，总减少量明显比AH-70多。沥青族组分的变化直接影响其物理性能，在老化过程中，沥青的软化点、针入度和延度的变化与沥青的族组成的变化表现出良好的对应关系。     

Enhancement of the thermal design of bitumen emulsion tanks by Scale Analysis,CFD models and experimental tests

The present paper applies Scale Analysis, numerical simulations and experimental tests to enhance the thermal design of a commercial mobile bitumen emulsion tank for road pavement. The objective is the reduction of diesel oil consumption with the lowest increment in heating time. The complexity of heat transfer in the system lies on the highly three dimensional behaviour of the fluid flow and the large disparity between characteristic length scales to be considered. Besides, the main heat transfer mechanism depends on the location. In spite of these difficulties, the proposed design achieves a reduction of 40% in diesel oil consumption with only a 28% increase in heating time.     

Effect of temperature on bitumen conversion in a supercritical water flow

This article deals with a study of bitumen conversion (the gross-formula CH_1.47N_0.01S_0.007) in a supercritical water (SCW) flow continuously supplied at the bottom of the vertically located tubular reactor. At the first stage, bitumen was continuously supplied from the top of the reactor into a counter-current SCW flow (400 °C, 30 MPa) for 60 min. At the second stage (after ceasing the supply of bitumen into the reactor), SCW was pumped through the layer of bitumen residue at uniform (2.5 °C/min) temperature increase from 400 to 700 °C at 30 MPa. The amount and composition of the liquid and volatile conversion products were measured. It is revealed that during bitumen supply into the reactor and subsequent pumping of SCW through the layer of bitumen residue in the temperature increasing mode from 400 to 500 °C, the yields of liquid conversion products are equal to 26.9 and 45.4%, respectively, relative to the weight of bitumen supplied into the reactor. Oils are the major components of these liquid products. Participation of H₂O molecules in redox reactions became evident due to the formation of CO and CO₂ even at 400 °C. A significant increase in the yields of H₂, CH₄, and CO₂ are detected at T > 600 °C. Based on the sulfur balance, it can be stated that the degree of bitumen desulfurization at 400–700 °C due to sulphur removal in form of H₂S accounts for 21.6 wt.% A solid carbonaceous bitumen residue, obtained after SCW conversion, is characterized by high specific surface (224 m²/g).     

利用测井资料研究和评价生油岩

本文首先介绍生油岩及其定性、定量评价指标，然后介绍用测井资料研究生油岩的依据及其地球物理特征，最后利用回归分析得到氯仿沥青“Ａ”、有机碳ＴＯＣ、吸附烃面积Ｓ１＋热解烃Ｓ２及二氧化碳面积Ｓ３与自然伽玛ＧＲ、电阻率Ｒｔ的相关关系。     

Clay minerals in nonaqueous extraction of bitumen from Alberta oil sands: Part 1. Nonaqueous extraction procedure

A non-aqueous bitumen extraction process was studied where only toluene and heptane, with no water additions, were used to extract bitumen from two Alberta oil sands ore samples. One sample had a high bitumen (13.5 wt.%) and low fines (5.3 wt.% < 45 μm) contents, while the other sample had an intermediate bitumen (10.5 wt.%) and high fines (23.3 wt.%) contents. Bitumen recovery and product quality were measured under different process conditions such as the ratio of toluene to heptane and settling time. The Dean Stark procedure was used to determine the solids, bitumen and water contents of the extraction products. In addition, the water content was determined by the Karl Fischer titration method. High bitumen recovery was obtained for both oil sands ore samples although the high fines ore sample was more sensitive to the extraction conditions, especially the toluene to heptane ratio. A product with high purity, containing more than 99.5 wt.% bitumen on a solvent-free basis, was produced at room temperature under the optimum extraction conditions tested. The optimum settling time to achieve a pure product was less than 10 min, based on solids and water contents in the supernatant.