Heavy oil sorption and recovery by using carbon fiber felts

On fibrous carbon materials, including activated carbon fibers, sorption capacity for heavy oils, less viscous A-grade and more viscous C-grade, was determined. Sorption capacity depended strongly on their bulk density; the correlation was the same as that found previously on exfoliated graphite and carbonized fir fibers. On carbon fiber felts, excellent recycling performance was observed, though sorption capacity was not so high as on exfoliated graphite and carbonized fir fibers. By filtration under suction, about 90% of sorbed A-grade heavy oil could be recovered and no decrease in sorption capacity was detected even after eight cycles. By washing with solvents, n-hexane for A- and C-grade oils and A-grade oil for C-grade oil, almost 100% recovery with no marked reduction in sorption capacity was found for each cycle. For the felts of PAN-based carbon fibers, rather severe operations for oil recovery, centrifugation and squeezing with twisting, could be applied without pronounced decreases in sorption capacity and recovery ratio.     

SAGD采油污水乳化特性及其破乳-絮凝试验研究

为了解决国内某油田SAGD采油污水油水分离的难题,对SAGD采油污水的水质特性和乳化特性进行研究,针对该污水开发并筛选出最优的高效破乳剂,考察了投加量对污水破乳效果的影响,并进行破乳-絮凝复配试验。试验结果表明:该油田SAGD采油污水的油、悬浮物、硫、Fe2+含量均较高,乳化程度严重且具有极强的乳化稳定性,油水分离困难;当破乳温度为65℃、停留时间为2 h时,投加500 mg/L无机药剂2#时除油率为87.7%,在破乳后的水样中投加2.5 mg/L的PAM6#,油可降至27.0 mg/L,悬浮物降至9.8 mg/L,处理后水样达到该油田回注水的水质标准。     

利用采油速度确定油藏采收率

水驱油藏进入高含水开发期以后,常规的水驱曲线对采收率的标定会出现很多问题。本文从渗流力学和物质平衡原理角度出发,推导出处于产量递减期间的油藏采油速度与采出程度之间的关系,发现存在线性特征。利用该关系可以对油藏动态和经济采收率进行标定,并给出了其适用条件。在此基础上利用孤东七区西Ng63 4的生产数据进行了实例验证。     

Extraction of palm oil using propane,ethanol and its mixtures as compressed solvent

This work is aimed to investigate the extraction of palm oil using pressurized ethanol and propane as solvents. The effects of temperature (293⿿333 K), pressure (from 10 to 20 MPa), solvent flow rate (from 1 to 5 mL/min), and composition of the solvent mixture were evaluated on the oil extraction yield, and chemical profile of the extracted oils. The experiments were conducted in a 100 mL extractor coupled to a HPLC pump for ethanol and a syringe pump for the propane displacement. Global yields up to 75 wt% were obtained in the experiments. The kinetic profiles of the extractions were described by the Sovová⿿s model, which presented good agreement with the experimental observations. The palm oils extracted with distinct solvents were characterized regarding its density and viscosity in a temperature range from 293 to 343 K, its chemical profile determined by GC/MS, and carotenoid content.     

Enhanced oil recovery using lignosulfonates

The effects of lignosulfonates on the recovery of oil from porous media were investigated using unconsolidated Ottawa sand saturated with Fuel Oil No. 4. Displacement tests were conducted for both secondary and tertiary strategies. At 1 Pore Volume injection the additional secondary recovery, relative to that obtained with water-flooding, varied between 1.3% and 8.5% for 1% and 10% lignosulfonate solutions respectively. The additional tertiary recovery for previously waterflooded sand was found to be 4.5% for 2 Pore Volumes injection of 1% lignosulfonate solution, and showed no increase with increasing concentration. Based on this preliminary work, lignosulfonate solutions would appear to be worthy of further attention in enhanced oil recovery studies.     

Extraction of rice brain oil using supercritical carbon dioxide and propane

Extraction of rice bran lipids was performed using supercritical carbon dioxide (SC−CO₂) and liquid propane. To provide a basis for extraction efficiency, accelerated solvent extraction with hexane was performed at 100°C and 10.34 MPa. Extraction pressure was varied for propane and SC−CO₂ extractions. Also, the role of temperature in SC−CO₂ extraction efficiency was investigated at 45,65, and 85°C. For the SC−CO₂ experiments, extraction efficiencies were proportional to pressure and inversely proportional to temperature, and the maximal yield of oil achieved using SC−CO₂ was 0.222±0.013 kg of oil extracted per kg of rice bran for conditions of 45°C and 35 MPa. The maximal yield achieved with propane was 0.224±0.016 kg of oil per kg of rice bran at 0.76 MPa and ambient temperature. The maximum extraction efficiencies of both SC−CO₂ and propane were found to be significantly different from the hexane extraction baseline yield, which was 0.261±0.005 kg oil extracted per kg of rice bran. A simulated economic analysis was performed on the possibility of using SC−CO₂ and propane extraction technologies to remove oil from rice bran generated in Mississippi. Although the economic analysis was based on the maximal extraction efficiency for each technology, neither process resulted in a positive rate of return on investment.     

Extraction of pomegranate seed oil using subcritical propane and supercritical carbon dioxide

Extraction of oil from pomegranate seeds as a waste product of the juice industry using supercritical carbon dioxide and subcritical propane was studied in this work. The influence of the main operating conditions of extraction, namely, the temperature and pressure of extraction on the oil extraction yield and the correspondent fatty acid profile were analyzed and reported here. Soxhlet extraction with n-hexane was done for comparison with supercritical extraction resulting in a maximum yield of oil of 22.31 wt %. Supercritical carbon dioxide and subcritical propane extracted up to 58.53% (corresponding to maximum yield of 13.06 wt %) and 76.73% (corresponding to maximum yield of 17.12 wt %) of the total amount of pomegranate seed oil as measured using Soxhlet extraction, respectively. Results indicated that the subcritical propane is a suitable and selective solvent for the extraction of the pomegranate seed oil in function of smaller times and pressures employed compared to carbon dioxide extraction. The fatty acid composition of the extracted oil showed the presence of fatty acids of C₁₆, C₁₈, C₂₀, C₂₂, and C₂₄ carbon chains. Punicic (C_18.3) was the major fatty acids and comprise up to 70% of the total fatty acid content of the extracted oil among all samples. Finally, Lack??s plug flow model as developed by Sovova was applied to both extraction systems and a good agreement with the experimental results was obtained.     

Enhanced oil recovery using nanoparticle-stabilized oil/water emulsions

We experimentally investigated nanoparticle-stabilized emulsions for enhanced oil recovery (EOR) applications. The emulsions were injected into a silica bead column containing mineral oil, and the oil recovery was calculated using a mass-balance approach. The experiments were carried out as follows: 1) The emulsions were injected into a column with 100% water saturation to investigate the mobility of the water and emulsions, 2) Water flooding was then carried out at initial oil and water saturation, and the emulsion flooding was injected to calculate the enhancement in the oil recovery rate. The results indicate that the nanoparticle-stabilized emulsions increased the oil recovery rate by 11% after water flooding. The mechanism for this is attributed to a greater pressure difference across the porous medium, leading to oil remaining in the pores being produced via a piston effect. These results indicate that nanoparticle-stabilized emulsions may be effective EOR agents.     

Enhanced oil recovery using carboxylate surfactant systems

Oil displacement tests in water wet Berea sandstone cores containing residual crude oil flooded with water have shown that high tertiary oil recoveries can be obtained using the sodium salts of readily available carboxylic acids. Using a 10% pore volume surfactant slug containing 3.0% sodium isostearate and 3.0% isopentyl alcohol followed by a polyacrylamide mobility buffer resulted in a 92% tertiary oil recovery, which compares well with recoveries using petroleum solfonates. Oil recoveries were highly dependent on pH and added base. Aliphatic C18 carboxylates gave higher recoveries at lower pH using sodium bicarbonate as the added base (pH 8.5) rather than sodium hydroxide, sodium carbonate or sodium orthosilicate (pH 11–13). In contrast, aromatic carboxylates e.g., sodium p-(1-pentylnonyl)benzoate, gave higher recoveries at higher pH using sodium carbonate rather than sodium bicarbonate. Carboxylates with branched alkyl groups, e.g., isostearate, gave higher tertiary oil recoveries than unbranched carboxylates, e.g., oleate or stearate. Low cost tall oils and tall-oil fatty acids, when neutralized with base, gave oil recoveries of 60–80%. Carboxylates were found to give good oil recoveries even when significant amounts of calcium ion were present.     

槐糖脂用于含油砂质土壤处理及石油资源回收

模拟了以生物型表面活性剂槐糖脂配制水溶液和微乳液对原油污染土壤进行处理并回收原油的实验,通过对比证明槐糖脂微乳液对含油土壤的原油脱除效果优于其水溶液,分析了槐糖脂、NaCl、丙三醇的添加量对原油脱除效果的影响,并筛选出3种微乳液配方。将原始原油、土壤与3种配方微乳液回收的原油、土壤进行理化性质对比发现：回收土壤的pH略高且大致呈中性,黏粒体积分数减少,zeta电位无明显变化,微乳液处理对土壤的理化性质影响较小;回收原油中饱和分含量升高,芳香分、胶质和沥青质含量降低,灰分含量增加,密度增大,黏度降低,表明回收原油具备一定的经济使用价值。将3种配方微乳液进行温度和循环利用实验以检验原油脱除效果的稳定性,结果表明：随着温度的升高,微乳液对含油土壤的原油脱除率先升高后趋于稳定,微乳液循环使用5次,对含油土壤的原油脱出率仍在60%以上,其中配方槐糖脂10%、丙三醇3.5%、NaCl 2.5%、柴油19.2%的微乳液处理含油土壤的稳定性最好。     

Phase behavior of sunflower oil and soybean oil in propane and sulphur hexafluoride

Phase equilibria of sunflower and soybean oils in propane and sulphur hexafluoride (SF₆) have been investigated. The phase behavior of sunflower oil-propane and soybean oil-propane systems has been studied using high-pressure variable-volume cell. For both systems, the transition of the two-phase system to one-phase system was observed visually at 25 °C and 40 °C and at different system compositions generally in the range of 0.2-0.7 weight fraction of propane.Furthermore, high-pressure vapor-liquid phase equilibrium data (P-T-x-y) for the sunflower oil-SF₆ and soybean oil-SF₆ systems have been measured at temperatures of 25 °C and 40 °C and pressures from 10 bar to 500 bar using a static-analytic method. For the above mentioned systems with SF₆ the tree phase region was observed at pressures near the phase transition of SF₆ from vapor to liquid phase. Additionally, phase inversion for both investigated systems was recorded, as well.     

化学驱提高辽河油田原油采收率研究

针对辽河油田区块的油藏条件,在室内进行了无碱二元驱和弱碱三元驱提高原油采收率的研究。对3种表面活性剂SL-YD、HL-1、BH进行了筛选,优选出了对该地层原油具有最佳降低界面张力效果的表面活性剂SLYD和HL-1;然后与聚合物PAM复配,组成二元体系,最佳配方为0.16%PAM+0.20%SL-YD;最后筛选得出了弱碱三元体系0.16%PAM+0.15%SL-YD+0.30%Na2CO3。室内实验表明,无碱二元体系和弱碱三元体系可以使油水界面张力降到10-3mN/m以下,可以大幅度提高原油的采收率,增幅超过10%。     

Investigating the effect of nano-silica on efficiency of the foam in enhanced oil recovery

Due to the vast production of crude oil and consequent pressure drops through the reservoirs, secondary and tertiary oil recovery processes are highly necessary to recover the trapped oil. Among the different tertiary oil recovery processes, foam injection is one of the most newly proposed methods. In this regard, in the current investigation, foam solution is prepared using formation brine, C₁₉TAB surfactant and air concomitant with nano-silica (SiO₂) as foam stabilizer and mobility controller. The measurements revealed that using the surfactant-nano SiO₂ foam solution not only leads to formation of stable foam, but also can reduce the interfacial tension mostly considered as an effective parameter for higher oil recovery. Finally, the results demonstrate that there is a good chance of reducing the mobility ratio from 1.12 for formation brine and reservoir oil to 0.845 for foam solution prepared by nanoparticles.     

Optimization strategies and impact of low oil price on long term SAGD projects

Steam assisted gravity drainage (SAGD) has been known as a commercially proven high ultimate recovery process for bitumen and heavy crudes. It is an energy intensive process, which is economical when oil price is above certain value. When the oil price goes below the economic threshold of project, steam injection can be decreased or completely stopped for a certain period of time, and can resume thereafter when the condition alters. The objective of this study is to provide comprehensive information about the effect of steam injection interruptions on thermal project performance. An optimization strategy for the SAGD process, in cases where steam injection interruption occurs, is discussed using actual reservoir models of different geological formations. An economical model is used to evaluate operating strategy effect on the net present value (NPV) of the project. The parameters, like shut-in period, initial steam injection period, etc, are optimized for Athabasca type oil sand reservoirs. The results show several key mechanisms exist in the life cycle of the SAGD process that must be included to reflect the field scale behaviour; otherwise, the mechanistic simplicity of the models could lead to directional and semi-quantitative conclusions. Among the mechanisms, temperature effect on basic petrophysical properties of reservoir rocks was found to have an important role in the oil recovery, and considerably impacts the results of optimization. When the steam injection is interrupted, an optimum shut-in period can be determined to maximize the oil recovery. The optimum length of steam injection interruption depends on the initial steam injection period.     

Yield,nitrogen recovery efficiency and quality of vegetables grown with organic waste-derived fertilisers

More sustainable production of high-quality, nutritious food is of worldwide interest. Increasing nutrient recycling into food systems is a step in this direction. The objective of the present study was to determine nitrogen (N) fertiliser effects of four waste-derived and organic materials in a cropping sequence of broccoli, potato and lettuce grown at two latitudes (58° and 67°N) in Norway during 3 years. Effects of anaerobically digested food waste (AD), shrimp shell (SS), algae meal (AM) and sheep manure (SM) at different N application rates (80 and 170 kg N ha^?1 for broccoli, and 80 and 60 kg N ha^?1 for potato and lettuce, respectively) and residual effects were tested on crop yield, N uptake, N recovery efficiency (NRE), N balance, N content in produce, mineral N in soil, product quality parameters and content of nitrate in lettuce. Mineral fertiliser (MF) served as control. Effects on yield, N uptake, NRE, N balance and product quality parameters could to a great extent be explained by estimated potentially plant-available N, which ranked in the order of AD > SS > SM > AM. Results for crops fertilised with AD and SS were not significantly different from MF at the same N application rate, while AM, in agreement with its negative effect on N mineralisation, gave negative or near-neutral effects compared to the control. No residual effect was detected after the year of application. The results showed that knowledge about N dynamics of relevant organic waste-derived fertilisers is necessary to decide on the timing and rate of application.     

利用微生物提高高含水期稠油油藏采收率研究

NB油田原油粘度大,边底水较发育,无水采油期短,含水率上升较快。根据油藏特点,通过室内物理模拟实验,研究了微生物提高稠油油藏高含水期采收率的能力。结果表明,微生物体系能够有效的提高采收率,当含水率达到98%时,注入0.3 PV微生物C体系,采收率增幅为3.78%;当增加注入量为0.6 PV时,采收率增幅显著提高,为14.4%。微生物在油藏环境下能很好的繁殖生长,并通过代谢产物改变原油性质,使油水界面张力下降了31.48%,原油粘度下降了26.35%。     

Oil recovery from oil in water emulsions using a flotation column

A flotation column was used to recover oil from oil in water emulsions. The feed oil concentrations investigated were relatively high, in the range of 0.25 to 8 percent by volume. Previous studies using conventional flotation cells dealt with very dilute systems where the oil concentration was less than 0.1 percent by volume. The oil recovery was found to decrease with an increase in the feed oil concentration. The addition of wash water to the froth zone of the column had little effect on the oil recovery. The oil recovery decreased with increasing feed flow rate and surfactant concentration. The effect of increasing the gas flow rate was to initially increase the oil recovery. The oil recovery data were analyzed using a kinetic model. The order of the flotation kinetics was found to be 0.6. The gas hold-up behaviour of the recovery and the froth zones of the flotation column is found to correlate well with the drift-flux model.