It is well-known that colloid and interface science and petroleum production are inextricably linked. Whether in the reservoir, with its porous structure, or during recovery, crude oil is intimately ...associated with rock surfaces and with water, often in the form of emulsions. This situation leads to highly complex systems, comprising multiple colloids and interfaces, which require to be optimized if oil is to be recovered efficiently, both in terms of economic cost and with due concern for the environment. This book contains a compilation of contemporary research topics which illustrate various aspects of the importance of colloids and interfaces in crude oil recovery through modifying conditions between the rock, crude oil, and water in the reservoir, in order to achieve improved oil recovery. The specific topics covered relate both to conventional oils, in which waterflooding is the most common secondary and tertiary means of recovery, and to non-conventional heavy oil and natural bitumen, which require thermal recovery methods, owing to their high viscosity.
• The responses of stock prices differ depending on the net position of a country. • The responses of stock prices differ depending on the cause of oil price change. • The explanatory power of oil ...shocks relies on the importance of oil to the economy. • The effects of oil price uncertainty are stronger for oil-exporting countries. • Increases in oil price improve the market comovement of oil-exporting countries.
While the relationship between oil prices and stock markets is of great interest to economists, previous studies do not differentiate oil-exporting countries from oil-importing countries when they investigate the effects of oil price shocks on stock market returns. In this paper, we address this limitation using a structural VAR analysis. Our main findings can be summarized as follows: First, the magnitude, duration, and even direction of response by stock market in a country to oil price shocks highly depend on whether the country is a net importer or exporter in the world oil market, and whether changes in oil price are driven by supply or aggregate demand. Second, the relative contribution of each type of oil price shocks depends on the level of importance of oil to national economy, as well as the net position in oil market and the driving forces of oil price changes. Third, the effects of aggregate demand uncertainty on stock markets in oil-exporting countries are much stronger and more persistent than in oil-importing countries. Finally, positive aggregate and precautionary demand shocks are shown to result in a higher degree of co-movement among the stock markets in oil-exporting countries, but not among those in oil-importing countries.
An 8-week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, fatty acid composition, rate-limiting enzyme activities and gene expression related to ...lipid metabolism in large yellow croaker (Larmichthys crocea). Five iso-nitrogenous and iso-lipidic experimental diets were formulated to contain different lipid sources, such as fish oil (FO), soybean oil (SO), linseed oil (LO), rapeseed oil (RO) and peanut oil (PO), respectively. Triplicate groups of 50 fish (initial weight 13.77±0.07g) were stocked in 15 floating net cages (1.5m×1.5m×2.0m). Fish fed the diets containing RO and LO had lower weight gain and specific growth rates than those fed the FO, SO and PO diets. Survival, feed efficiency, protein efficiency ratio, hepatosomatic index, viscerasomatic index and condition factor were not significantly affected by different dietary lipid sources. Fish fed the diet containing FO had higher lipid content in whole body compared with the other groups, whereas fish fed the SO diet had the lowest muscle lipid content. Fatty acid profiles of muscle and liver reflected the fatty acid composition of the diets. Plasma glucose, triglyceride, and the enzymatic activity of aspartate aminotransferase and alanine aminotransferase were significantly influenced by different dietary lipid sources, while total protein, cholesterol, superoxide dismutase or malondialdehyde in plasma were not affected by the different dietary lipid sources. Fish fed the LO diet had lower adipose triglyceride lipase and fatty acid synthase activities in liver than those fed the diets containing FO and RO, while the LO diet resulted in the highest hepatic carnitine palmitoultransferase-1 activity. Hepatic gene relative expression of adipose triglyceride lipase and carnitine palmitoyltransferase-1 in fish fed PO diet was significantly higher than all other groups, whereas fish fed the SO and LO diets had lower relative expression levels of lipoprotein lipase than the other groups. The highest relative expression levels of fatty acid synthase and acyl-CoA diacylglycerol acyltransferase-2 were observed in the FO group, while the highest relative expression of glucose 6-phosphate dehydrogenase occurred in fish fed the FO and RO diets. In summary, based on the growth performance, FO and SO appear to be suitable lipid sources for large yellow croaker, with the findings of this study also providing a molecular insight into the role of lipid metabolic mechanism in response to different dietary lipid sources.
Individual vegetable oils have a characteristic fatty acids (FA) composition and unique phytonutrient profiles, enabling formulation of oil blends that may have health-promoting effects.
The primary ...objective of this study was to investigate effects of 2 oil blends made with refined rice bran, flaxseed, and sesame oils, with distinct monounsaturated to saturated FA, polyunsaturated to saturated FA, and omega-3 (n–3) to omega-6 FA ratios and different phytonutrient concentrations on blood lipid profile, compared with refined olive oil as a control. The secondary outcomes were other markers of cardiometabolic health.
A parallel-design, randomized controlled trial compared consumption of 30 g of allocated intervention oil per day for a period of 8 wk. The study recruited 143 borderline hypercholesterolemic (LDL cholesterol: 3.06–4.51 mmol/L) Chinese volunteers between 50 and 70 y old and with a BMI (kg/m2) ≤27.5. All outcomes were measured every 2 wk, and the time × treatment interactions and the main effects of treatment and time were analyzed using an intention-to-treat approach.
Compared with baseline (week 0), there were significant reductions during the post-intervention time points in serum total cholesterol (-3.47%;P < 0.0001), LDL cholesterol (-4.16%;P < 0.0001), triglycerides (-10.3%;P < 0.0001), apoB (-3.93%;P < 0.0001), total to HDL-cholesterol (-3.44%;P < 0.0001) and apoB to apoA1 (-3.99%;P < 0.0001) ratios, systolic and diastolic blood pressures (-3.32% and -3.16%, respectively; bothP < 0.0001), and serum glucose (-1.51%;P < 0.05) and a small but significant increase in body weight (+0.7%;P < 0.001) for all 3 intervention oils but no effects of intervention on HDL-cholesterol or apoA1 concentration. No significant effects of treatment or time × treatment interactions were found.
Using blended vegetable oils that are extensively consumed in Asia, this study found that specific oil blends can improve blood lipid profile and other cardiometabolic parameters, to a similar extent as refined olive oil, in Chinese adults with borderline hypercholesterolemia. This trial is registered at www.clinicaltrials.gov as NCT03964857.
Presently alpha-linolenic acid (ALA) is the most widely used vegetarian LC3PUFA, but only marginal amounts are converted into eicosapentaenoic (EPA) and docosahexaenoic acid (DHA); both of which are ...strongly related to human health. Currently, fish oils represent the most prominent dietary sources of EPA and DHA; however, these are unsuitable for vegetarians. Alternative sources include flaxseed, echium, walnut, and algal oil but their conversion to EPA and DHA must be considered. The present systematic review sets out to collate information from intervention studies examining the bioavailability of alternative vegetarian long chain omega-3 (n-3) polyunsaturated fatty acids (LC3PUFA) sources. Ten key papers published over the last 10 years were identified with seven intervention studies reporting that ALA from nut and seed oils was not converted to DHA at all. Three studies showed that ingestion of micro-algae oil led to significant increases in blood erythrocyte and plasma DHA. Further work is now needed to identify optimal doses of alternative vegetarian LC3PUFAs and how these can be integrated within daily diets. The potential role of algal oils appears to be particularly promising and an area in which further research is warranted.
•A comprehensive literature review was conducted on CO2-EOR in tight oil reservoirs.•Specialized technologies are needed in the exploitation of China’s tight reservoirs.•The effect of CO2 diffusion ...is relatively exaggerated in experimental results.•CO2-crude oil interaction in nanopores may lead to an oil recovery increment.•CO2-water-minerals interaction influences the geomechanical properties of rock.
Primary oil recovery remains less than 10% in tight oil reservoirs, even after expensive multistage horizontal well hydraulic fracturing stimulation. Substantial experiments and simulation works have been performed to investigate CO2 enhanced oil recovery (CO2-EOR) potential in tight reservoirs; however, some results conflict with each other. The objectives of this paper are to fully understand the CO2-EOR mechanisms and to figure out the difference between tight oil exploitation in North America and China through a comprehensive literature review. It is shown that compared with Bakken and Eagle Ford formation, China’s tight oil reservoirs feature higher mud content and oil viscosity while they have a lower brittleness index of rock and formation pressure coefficient, leading to confined stimulated reservoir volume and further limited CO2-oil contact. The effect of CO2 molecular diffusion is relatively exaggerated in experimental results, which can be attributed to the dual restrictions of exposure time and oil-CO2 area in field scale. Numerical simulation works show that the shifted phase properties in nanopores lead to an oil recovery increment. The development of nano-scale chips withholding high pressure/temperature may advance the experimental study on the nanopore confinement effect. CO2-fluid-rock minerals interaction might be more complex due to the large specific surface area of nanopores in tight formations. The geomechanics coupling effect cannot be ignored when examining the CO2-EOR performance in tight reservoirs. And a comprehensive simulation study coupling with technical and economic feasibility is highly recommended before running a field test of CO2-EOR.
Biodiesel is an alternative and renewable diesel fuel, can be produced from diverse kinds of vegetable oils. The biodiesel effects on engine performance and emissions vary as the source of oil ...changes. In this study, castor oil biodiesel (CAB), coconut oil biodiesel (COB) and waste cooking oil biodiesel (WCB) were produced by transesterfication approach and blended with conventional diesel fuel (CDF). The volumetric blending ratios of biodiesels with CDF were set at 5, 10, 20, and 30. Tests were carried out under different loads and speeds which simultaneously change. Change in engine performance and emission characteristics against speed or load were investigated on a turbocharged DI compression ignition engine. Viscosity, oxygen amount in fuel, length of hydrocarbon chain, cetane number, biodiesel amount in fuel, engine speed, load have been considered separately, for better consideration of the effects of each parameters, in this study they were considered and compared in similar laboratorial condition. Based on the main effects of load and engine speed on emissions and engine performance, it this study both of them were considered simultaneously. Totally, the experimental results indicated that the best performance and emission characteristics belong to WCB and COB blends respectively fueled in the diesel engine.
•Engine performance and emission characteristics were considered for biodiesels.•Engine speed and load concurrently vary.•Specific biodiesel–diesel blends aimed to improve fuel properties.•WCB, COB and CAB are the best biodiesels respectively.
Stearine fish oil (SFO) and palm oil (PO) have emerged as promising alternatives for the replacement of fish oil (FO) in aquafeeds. This study evaluated the replacement of FO with alternative oils in ...practical diets for Litopenaeus vannamei. In a clear brackish water study (14.1 g/L) utilizing shrimp (0.29 ± 0.02 g, initial weight), FO was replaced by SFO at inclusion ratios of 100:0, 75:25, 50:50, 25:75, and 0:100 (FO:SFO) and PO as 90% of FO. After 55 days, no significant differences (p < 0.05) in final weight, growth, or survival of shrimp were observed. A second trial (8 weeks) in low‐salinity water (2.1 g/L) with shrimp (0.92 ± 0.02 g, initial weight) evaluated diets with 100% FO, 100% SFO, 90% PO, 90% soybean oil (SO), or 90% flaxseed oil (FXO) as a replacement for FO and four commercially produced diets with 2% of FO, SO, PO, or FXO. One treatment received half rations of the commercial FO diet, and one treatment was based entirely on natural productivity. Results show that the fatty acid profiles of the tail muscle conformed to the lipids of the feed, and highly unsaturated fatty acids (HUFAs) were preserved. Following 8 weeks of culture, there were no significant differences in production performance.
In world practice, the role of reproduction of raw material base of oil production by implementing modern methods of oil recovery enhancement (thermal, gas, chemical, microbiological) on the basis of ...innovative techniques and technologies is rapidly growing and is becoming more important. It is concluded that at present, the priority of increasing oil reserves in world oil production is the development and industrial introduction of modern integrated methods of enhanced oil recovery, which can provide a synergistic effect in the development of new and developed oil fields. This article presents a review and comparative analysis of theoretical and practical methods of improving oil recovery of conventional and unconventional reservoirs. The paper examines in detail methods of improving oil recovery, taking into account the factors of enhanced oil recovery of oil reservoirs. Considered the main methods and technologies currently used to develop oil fields and recommendations for their effective use, taking into account the variety of external factors of oil production: the geological structure of the reservoir, its volume, and properties of oils. It is shown that there is no universal method of oil reservoir development, and it must be chosen after a thorough feasibility study among several proposed models. When describing the methods of enhanced oil recovery, special attention is also paid to the physical processes that occur as a result of applying the technology. In conclusion, the positive and negative characteristics of the presented methods included in EOR are presented, and recommendations that may influence the choice of practical solutions for engineers and oil producers are given. Conclusions are made that development systems, placement and choice of operating mode of wells essentially depend on the geological structure of the reservoir, its volume and properties of oils. An important role in this is the construction of a geological model of the production facility. The used hydrodynamic models of development are based on physical laws, about which oil producers sometimes don’t even suspect, and the authors of the models are not always able to convey it to the real producers. The authors consider it reasonable to make a logical generalizing conclusion that understanding processes occurring in the reservoir and taking appropriate measures for optimization and intensification of oil production will allow making oil production as effective as possible.
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