An evaluation of enhanced oil recovery strategies for a heavy oil reservoir after cold production with sand

Cold heavy oil production with sand (CHOPS) is the process of choice for unconsolidated heavy oil reservoirs with relatively high gas content. The key challenge of CHOPS is that the recovery factor tends to be between 5% and 15%, implying that the majority of the oil remains in the ground after the process is rendered uneconomic. Continued cold production (without sands) is not productive for a post‐CHOPS reservoir because of the low oil saturation and depleted reservoir pressure in the wormhole regions. There is a need to develop viable recovery processes for post‐CHOPS reservoirs. Here, different follow‐up processes are examined for a post‐CHOPS heavy oil reservoir. In post‐CHOPS cold water flooding, severe water channeling is ineffective at displacing high viscosity heavy oil. Hot water flooding improves the sweep efficiency and produces more oil compared with cold water flooding. However, the swept region is limited to the domain between the neighboring wormhole networks, and the energy efficiency of the process is relatively poor. Compared with the hot water flooding case, steam flooding achieves higher oil production rates and lower water use. A cyclic steam stimulation strategy achieves the best performance regarding oil production rates and water usage. Based on our results, it is observed that thermally based techniques alone are not capable to recover the oil economically for post‐CHOPS reservoirs. However, it is suggested that techniques with combined use of thermal energy and solvent could potentially yield efficient oil recovery methods for these reservoirs. Copyright © 2015 John Wiley & Sons, Ltd.     

基于多维计数型布鲁姆过滤器的大流检测机制

高速网络环境中,实时、准确地提取大流量对于网络安全和网络管理具有重要意义。该文针对传统的流量测量方法受计算资源和存储资源的限制,提出了一种基于多维计数型布鲁姆过滤器(Multi-Dimensional Counting Bloom Fliter, MDCBF)的大流检测机制。它将1维的计数型布鲁姆过滤器(Counting Bloom Fliter, CBF)结构,扩展到支持多维业务流表示、查询和统计计数的MDCBF结构。基于Apriori原理,通过对MDCBF实施重正化,实现了用户自定义的大流检测。并能自适应地配置CBF参数,允许测量误差控制在预定义的范围内。基于计算机产生的模拟数据和实际互联网数据进行了仿真实验,结果显示：该方法既能获得较小的测量误差,又能获得较高的空间利用率。     

表面增强拉曼光谱技术在环境污染物检测中的应用

表面增强拉曼散射(SERS)光谱具有高灵敏性及高选择性,它已被用于科学研究及生产实践的多个领域。本文阐述了近几年来SERS技术在检测重金属离子、多环芳烃、微生物、农药等环境污染物中的发展状况,并分析了该技术在这些应用领域的优点与不足。最后,预测了SERS的发展趋势。     

SAGD双水平井随钻磁导向系统的研制及应用

针对实测信号微弱、频变、窄带的特点,设计出低噪声、窄通频带、高精度的数据采集滤波电路,有效地滤除了干扰和噪声,使系统探测精度达到±0.3m左右;根据磁感应强度数据的采集要求,制定了单组数据校验的通信协议,减少了干扰导致的个别数据传输错误对整体数据的影响。     

硫化技术在重金属固废综合利用方面的研究

重金属固废的综合利用价值较高,但是当前综合利用技术处于实验室水平较多,工业可行性较低;参考“硫化-浮选”工艺,重金属的硫化技术成为该工艺能否在固废综合利用方面应用的关键。本文在介绍了表面硫化技术、机械硫化技术、水热硫化技术、硫化沉淀技术和硫化焙烧技术及其在天然矿物方面应用的基础上,总结硫化技术在重金属固废(废渣、飞灰和污泥为主)综合利用方面的适用性和研究进展;进一步讨论五种硫化技术在重金属固废综合利用方面的优缺点,指出针对不同理化性质的固废应选择不同的硫化技术;最后得出硫化技术的发展方向为明确硫化物的晶体和表面性质等和可浮性之间的关系,明确硫化率的影响因素,掌握硫化物晶体结构和表面性质的调控技术。     

原子吸收光谱法测定 EMD 中 Co、Ni、Cu、Pb

论述了采用原子吸收光谱法测定ＥＭＤ中Ｃｏ、Ｎｉ、Ｃｕ、Ｐｂ的方法。对影响测定的因素进行了试验。试验结果表明：当ＥＭＤ中Ｍｎ（Ⅱ）含量不超过１５％时,用仪器的最佳工作条件测定。此法回收率为９９．７８％～１００．４５％之间,变异系数为０．２１％～０．７５％。     

Enhanced heavy oil recovery and performance by application of catalytic in-situ combustion

Combustion tube experiments were carried out under various conditions to investigate the performance of catalytic in-situ combustion for recovering heavy oil. Compared with baseline experiment, the catalytic combustion exhibited better performance. Fractional oxygen gas in effluent gases was reduced by 2.9%, while fractional carbon dioxide and carbon monoxide was increased by 1.0% and 0.6%, respectively. Oxygen utilization efficiency was increased by 2.1% and apparent H/C atom ratio was lowered by 0.9%. The combustion performance was obtained under optimum experimental condition of air injection rate of 2.9?mL/min, preheated temperature of 190?°C, and grain-size gradation 2.     

Evaluation of a new alkaline/microbe/polymer flooding system for enhancing heavy oil recovery

The new alkaline/microbe/polymer (AMP) flooding system was first constructed and evaluated for enhancing oil recovery. The system is composed of 0.3?wt% Na₂CO₃, 2?wt% microbial cultures and 0.2?wt% polymer. Compared with the conventional alkaline/surfactant/polymer (ASP) system, the AMP system exhibits identical displacement properties. Chromatography analysis reveals crude oil is not negatively affected by the microbes in AMP system. Further comparative core flooding experiments using the AMP and ASP systems demonstrate that the AMP system possesses greater potential for enhancing heavy oil recovery, which shows the characteristic of two-stage additional oil increment with total additional oil recovery of 17.11%–19.91%.     

The aquathermolysis of heavy oil from Riphean-Vendian complex with iron-based catalyst: FT-IR spectroscopy data

In this paper, we investigated the influence of steam treatment on structural group composition of resins and asphaltenes of heavy oil. The object of investigation was oil-saturated rocks from Riphean-Vendian complex. The extracted crude oil was determined as a high-viscous fluid. The resins and asphaltenes destructed in a small extent due to thermal treatment. The oil-soluble iron-based catalyst intensified the destructive processes. The content of sulfur compounds (-SO) in resins and asphaltenes drastically decreased due to reduction reaction of sulfoxide to sulfide and hydrogen sulfide. The results showed that catalytic aquathermolysis, even at low temperature ranges, promoted the cracking reaction of most macromolecular components and increased the content of light fractions of heavy oil. Consequently, it reduced its viscosity.     

Relations between asphaltene content,viscosity reduction rate of heavy oil and ultrasonic parameters

Ultrasonic treatment could decrease the viscosity of heavy oil and previous study on had focused on one heavy oil sample and involved less on the influence of asphaltene content. This study examined the effect of asphaltene content on viscosity reduction rate by ultrasonication. A comparison on samples with various asphaltene content and vibration parameter was made. The results showed that the optimal vibration frequency might decrease as the asphaltene content increased, whereas the optimal vibration intensity and the optimal treatment time were suggested to be enlarged. A semi-quantitative correlation was matched, which helped for numerical simulation about ultrasonic treatment.