声速和衰减系数与含蜡原油特性的关系

当含蜡原油的温度低于蜡的析出温度后,蜡晶将不断析出并相互交联成网状结构,若网状结构达到一定强度,原油将失去流动而凝结。在该过程中不仅含蜡原油的流动特性发生变化,原油的声速和衰减系数也发生变化。本研究结果表明：含蜡原油的超速及衰减系数均随温度降低而增大;含蜡原油在凝结温度前后表现出不同的声速与温度的对应关系;含蜡原油在凝结后的声速的温度的关系同原油的含蜡量有关;含蜡原油的衰减系数在接近凝结温度时急剧     

帕尔曼发声器在原油防蜡降粘方面的应用

作为物理法采油技术的一种新应用，声波技术在原油防蜡降粘方向取得了有效的应用效果，文章论述了帕尔曼发声器在原油防蜡降粘方面的研究，从作用机理、实验研究、现场应用方面进行了详细的介绍。     

嗜蜡菌对含蜡原油除蜡降黏作用的影响

含蜡原油因其蜡组分的存在而导致原油在低温环境中黏度变大、流动性变差,而在管输的过程中,蜡晶的析出会降低管道的输送能力、甚至有堵塞管道的威胁。本文利用已发现的一株嗜蜡菌,利用其发酵液降解含蜡原油中的蜡组分,实验证明处理5天后的原油含蜡量降低、表观黏度下降,偏光显微镜观察油中蜡晶结构明显变小而分散。软件ImageJ对显微镜照片处理后测量得到:最大蜡晶粒径从609.1μm下降至72.1μm;平均费雷特径大小从79.1μm下降到50.3μm。     

复配菌对原油微观结构变化的研究

含蜡原油因其蜡组分的存在使其在开采和运输的过程中易使蜡晶析出,蜡晶析出堵塞管道,减小输送半径,严重时会发生凝管停运等事故,造成严重的经济损失.本文利用已发现的一株嗜蜡菌与产表面活性剂菌株进行复配,利用得到的复配菌发酵液按一定比例接种于含蜡原油中,实验表明作用7天后的原油含蜡量降低;利用ImageJ软件对偏光显微镜图片进行后处理发现蜡晶结构变小且密集;最后利用FBRM技术分析得原油中大粒径所占比例减少,小粒径所占比例增多.复配菌作为一种新方法、新思路,可以有效地降低含蜡原油在开采和运输过程中产生的危害,减少经济损失.     

复配菌优化培养及其在原油中的应用研究

微生物除蜡、降黏技术因高效、经济、无毒、无污染的优点,被广泛研究和采纳。本论文主要研究了嗜蜡菌SL-7以及用BH-12进行复配制成微生物菌剂SB7-12的除蜡、降黏研究。实验结果表明:优化后的复配菌SB7-12对原油具有降黏与除蜡双重功效,对原油中石蜡的降解率达83.3%,降黏率可达到43.3%。显微镜结果表明,微生物菌剂的加入使原油中微观蜡晶结构呈现出小而分散的特点,表观黏度降低,从而有利于提高原油流动性。     

超声波采油技术的原理及应用

文章介绍了超声波技术在油井增产，防蜡，防垢及除垢和对原油的降粘等方面的作用原理和作用效果，并说明了超声波采油的适用范围。     

一种线状纳米降凝剂与磁场协同对高含蜡原油的改性研究

本文研究了一种线状纳米降凝剂对高含蜡原油屈服应力的影响,采用偏光显微镜获得了加剂对原油中蜡晶形貌的影响。在此基础上引入磁场作用,分析了线状纳米降凝剂与磁场协同对屈服应力的影响。结果表明,相比传统乙烯/醋酸乙烯酯降凝剂,线状纳米降凝剂能够更明显的降低原油屈服应力。当施加本文所研究的恒定磁场时,磁场的引入削弱了线状纳米降凝剂对原油屈服应力的影响;而当施加本文所研究的交变磁场时,磁场能够起到增强线状纳米降凝剂对原油屈服应力的改善效果。     

含蜡原油乳状液触变性研究

触变性是含蜡原油管道停输再启动压力计算和原油可泵性评价的重要基础资料,为了确定油水混输海底管道的停输再启动特性,必须掌握含蜡原油乳状液的触变性.本文在脱水含蜡原油触变性研究的基础上,对含蜡原油油包水乳状液的触变性进行了研究,发现含蜡原油乳状液的触变趋势与脱水原油类似;建立了一个描述含蜡原油乳状液在恒定剪切速率作用下剪切应力衰减这一触变行为的数学模型.用最小二乘法对本文和文献中的实验数据进行拟合,结果表明,该模型能够较准确地描述在恒定剪切速率作用下剪切应力衰减的触变行为,不仅适用于含蜡原油乳状液,对脱水含蜡原油和化学剂改性含蜡原油也适用,与其他触变模型相比,该模型具有参数较少、计算方便等优点.     

蜡晶对油水界面稳定性的耗散粒子动力学研究

随着油田的不断开发，石蜡结晶和油水乳化作用为含蜡原油的开采、运输和储存带来巨大挑战。本文采用耗散粒子动力学方法研究了石蜡相变结晶对油水界面稳定性的影响。首先，计算了石蜡分子的序参量，揭示了水分子和油分子均会促进石蜡分子形成有序的固态晶体结构。其次，发现随着蜡含量的增加，油–水界面的表面张力逐步提高，石蜡分子会提高油–水界面的稳定性。最后，得到油–水界、蜡–水界面，蜡–油界面表面张力随温度的变化关系(298～348 K)。结果表明，当温度低于308 K，油–水界面和蜡水界面都能维持其界面的稳定性。对于蜡–油界面，当温度高于308 K时，达到石蜡的析蜡温度，石蜡晶体逐步熔化，蜡–油之间的界面张力急剧减小，蜡油界面逐渐消失。     

流体动力式发声器在采油工业中的应用研究

流体动力式声波发生器是一种有着悠久历史的声处理发生器 ,具有成本低廉、结构简单、坚固耐用以及动力源方便等特点 .在采油工业中 ,利用这种声处理技术可以降低原油粘度 ,改善原油物性以及地层渗流条件 ,达到最终提高采收率的目的 .文章论述了几种具有实际应用效果的流体动力式声波发生器在采油工业中的应用研究进展 ,并从作用机理、实验研究、现场应用等方面进行了详细的介绍 .     

蜡油和洗油的HPLC法测定

采用HPLC法测定蜡油和洗油的含量,通过以蜡油和洗油混合液质量比所得拟合曲线计算混合液中蜡油与洗油的质量比值,为生产中快速准确测定蜡油和洗油的混合溶剂比提供一种可行的方法。     

Gravitational Instability of a Two-Component Viscous Plasma with Finite Conductivity Flowing Through a Porous Medium with Fir Corrections

The gravitational instability of a two component plasma is studied to include the simultaneous effects of collisions, gyroviscosity, finite conductivity, viscosity and porosity of the medium within the framework of two-fluid theory. From linearized equations of the system, using normal mode analysis, the dispersion relations for parallel and perpendicular directions to the magnetic field are derived and discussed. For longitudinal wave propagation it is found that the value of critical JEANS' wave number increases with increasing density and decreasing temperature of the neutral component. For transverse wave propagation the value of critical JEANS' wave number depends on gyroviscosity, ALFVÉN number, ratio of sonic speeds and densities of the two component and porosity of the medium. It is observed that the effect of magnetic field and porosity is suppressed by finite condutivity of the plasma and similarly the effect of gyroviscosity is removed by viscosity from JEANS' expression of instability. For both the directions instability is produced when the velocity perturbations are considered parallel to wave vector. The damping effect is produced due to collisional frequency, permeability of the porous medium and viscosity. The density of the neutral component and porosity of the medium tends to destabilize the system while an increased value of FLR corrections leads the system towards stabilization.     

Kinetics of sonic coagulation and precipatation of high disperse aerosols

An equation describing the kinetic process of sonic coagulation is presented which accounts for changes in particule concentration, resulting from changing conditions in the sonic field and dust gas flow. Also the effects of other parameters such as temperature, viscosity and density of the medium were analysed practically to ascertain the optimum and limiting conditions of the analytical equations. The results indicate the ideal economic and practicable operating frequency of the sonic coagulation process.     

A technique for evaluating the oil/heavy-oil viscosity changes under ultrasound in a simulated porous medium

Theoretically, Ultrasound method is an economical and environmentally friendly or “green” technology, which has been of interest for more than six decades for the purpose of enhancement of oil/heavy-oil production. However, in spite of many studies, questions about the effective mechanisms causing increase in oil recovery still existed. In addition, the majority of the mechanisms mentioned in the previous studies are theoretical or speculative. One of the changes that could be recognized in the fluid properties is viscosity reduction due to radiation of ultrasound waves. In this study, a technique was developed to investigate directly the effect of ultrasonic waves (different frequencies of 25, 40, 68 kHz and powers of 100, 250, 500 W) on viscosity changes of three types of oil (Paraffin oil, Synthetic oil, and Kerosene) and a Brine sample. The viscosity calculations in the smooth capillary tube were based on the mathematical models developed from the Poiseuille’s equation. The experiments were carried out for uncontrolled and controlled temperature conditions. It was observed that the viscosity of all the liquids was decreased under ultrasound in all the experiments. This reduction was more significant for uncontrolled temperature condition cases. However, the reduction in viscosity under ultrasound was higher for lighter liquids compare to heavier ones. Pressure difference was diminished by decreasing in the fluid viscosity in all the cases which increases fluid flow ability, which in turn aids to higher oil recovery in enhanced oil recovery (EOR) operations. Higher ultrasound power showed higher liquid viscosity reduction in all the cases. Higher ultrasound frequency revealed higher and lower viscosity reduction for uncontrolled and controlled temperature condition experiments, respectively. In other words, the reduction in viscosity was inversely proportional to increasing the frequency in temperature controlled experiments. It was concluded that cavitation, heat generation, and viscosity reduction are three of the promising mechanisms causing increase in oil recovery under ultrasound.     

Experimental investigation on the effect of ultrasonic waves on reducing asphaltene deposition and improving oil recovery under temperature control

A well-known complication in the oil reservoir during oil production is asphaltene deposition in and around the production wellbore. Deposition of asphaltene around the production wellbore may cause a significant pressure drop and in turn loss of efficiency in the production process. Various mechanical and chemical methods have been employed in order to reduce asphaltene formation or to eliminate the precipitate. A novel technique which presented a great potential for prevention or elimination of asphaltene is spreading out the high energy ultrasound wave within the oil reservoir. In this study, in a glass micro-model, asphaltene precipitation was first simulated in a transparent porous medium and its removal by application of high energy ultrasound wave was then investigated. To simulate asphaltene precipitation, the micro-model was first saturated with oil and then a normal-pentane was injected. This was followed by flooding the porous media with brine while propagating ultrasound waves (30 kHz and 100 W) to eliminate asphaltene precipitation. The experiment setup was equipped with a temperature controller. The results indicate a significant reduction in asphaltene precipitation in the oil reservoir may be achieved by application of ultrasound energy. Asphaltene particle deposition has been solved reversibly in the oil layer of porous medium and with the oil layering mechanism, the rate of oil production has been increased. In some spots, water/oil emulsion has been formed because of the ultrasonic vibration on the wall. Both the crude and synthetic oils were examined.     

Sound Absorption of Locally Resonant Sonic Materials

The acoustic properties of locally resonant sonic materials with viscosity are theoretically investigated by using the multiple-scattering approach. We find that the absorption of a two-layer slab dominates the wave attenuation in the resonant frequency region under the condition of moderate or high viscous level. The fundamental mechanism operating in local resonance for absorption is investigated for the viability by the mode translation in the scattering process of a single scatterer. Finally the absorption performance in a multi-layer system is discussed.     

A sonic crystal diode implementation with a triangular scatterer matrix

This paper investigates a nonreciprocal sound transmission effect provided by a triangular lattice two-dimensional sonic crystal made of rods in a triangular cross-section. This sonic crystal (SC) device works as a frequency selective acoustic diode operating at a frequency of 8950 Hz. The scatterer matrix of the sonic crystal diode prototype was composed of triangular shaped wood rods that break the symmetry of the spatial inversion and provide nonreciprocal wave transmission with a contrast rate of 89% in experiments. This acoustic diode device can provide a high contrast, narrow band, one-way sound transmission for acoustic wave control applications.