地面驱动单螺杆泵排出口压力计算

在采用节点系统分析方法优化设计地面驱动单螺杆泵采油系统所建立的模型中,需要求得螺杆泵吸入口和排出口压力,以便根据压差重新选择螺杆泵和设计抽油杆柱。在计算排出口压力计算过程中,考虑了由于抽油杆柱旋转引起杆管环空气液两相流摩阻的影响。以GLB40-42型螺杆泵为例,理论和计算数据分析表明,转速和抽油杆直径对流体流动摩阻压降有显著影响,从而为进一步优化设计螺杆泵和抽油杆柱提供了有力依据。     

地面驱动螺杆泵采油系统管道内流体摩阻分析

运用流体力学有关理论, 对地面驱动螺杆泵采油系统环空管道结构参数和螺杆泵转速对流体摩阻的影响进行了分析。分析结果表明, 当油管直径一定时, 过大的抽油杆直径会使抽油杆柱旋转所受的油液摩阻及油液流动摩阻增大; 泵的转速过高会使抽油杆柱旋转所受油液摩阻及油液流动摩阻增大。建议在满足抽油杆强度及其它条件下尽可能采用小直径抽油杆; 在满足泵排量、泵效及其它条件下尽量不要使泵转速过高。合理选择抽油杆直径和泵转速将显著降低地面驱动螺杆泵系统总的能量损失。     

倾斜管内高黏油水两相流的数值模拟

采用Fluent三维数值模拟方法研究了倾斜管内高黏油水乳化前后的流动状态,从流型与压降两方面总结了油水两相流的流动规律。实验结果表明,乳化前油水两相流的流型呈现油水交替、泡状流、水塞流、弹状流和环状流,而乳化后则以分层流、分散流、分层流且带有水包油为主。在一定倾角和入口流速下,管内压降随含水率的增加急剧减小;在一定入口流速和含水率下,管内压降随倾角增加逐渐减小。正交实验结果表明,入口流速对压降的影响最大,含水率次之,倾角的影响最小;最优组合为倾角20°、入口流速0.4 m/s、含水率40%。     

水平圆管油水两相变质量分层流压降计算

以往对水平圆管中复杂流体介质的流动规律研究的对象均是对水平圆管单相和气液两相变质量流动,关于存在壁面入流条件的水平圆管油水两相变质量流动的研究较少。为此对水平圆管油水两相变质量分层流动进行了微元分析,考虑壁面入流对其中油水两相变质量分层流动压降的影响,分别对油水两相应用连续性方程和动量守恒方程,得出了水平圆管油水两相变质量分层流动的基本模型和压降计算模型。通过模型求解揭示了在壁面入流条件下沿水平圆管的压降规律,并分析了壁面入流、圆管直径、油相黏度和含水率等主要参数对其中压降规律的影响。计算结果表明,当油相黏度较大时,随含水率的增加,沿水平圆管压降降低;而油相黏度较小时,随含水率的增加,沿水平圆管压降升高。     

大管径不同井斜油水两相流流型数值模拟

通过ICEM CFD建立倾角θ为±20°、±15°、±10°、±5°和0°(完全水平),内径为0.124m,长度为20m的井筒,利用FLUENT中的VOF多相流模型对大管径不同斜度井中的油水两相流进行数值模拟,得出不同油水混合速度、不同含水率和不同倾角时的流动变化规律;结合Trallero J L的流型分类方法,根据模拟得到的油水两相分布图划分了6种流型,并制作了以混合速度、倾角为坐标的流型图。倾角θ=0°(井筒水平)时,流型以分层流为主,随着混合速度的增加,其逐渐变为界面混杂的分层流;若含水率逐渐增大,流型将转变为油-油包水、油包水或水包油-水、水包油;倾角θ0°(井筒上倾)时,流型随流速的增大提前发生转变,并且水相出现回流,局部持水率变大;倾角θ0°(井筒下倾)时,水相在底部加速流动,局部持水率变小。计算结果与相关实验结果比较吻合。     

水平及倾斜圆管中油水两相分层流界面波对摩擦压降的影响

油水两相流在重力和界面张力共同作用下发生分层,由于剪切应力的作用,在管道流动中产生摩擦压降,油水两相分层流在流动参数改变时产生界面波,其对摩擦压降产生影响。实验研究水平和倾斜管道油水两相波状分层流界面波特性及其对摩擦压降的影响,并改进一维双流体模型预测摩擦压降。研究结果表明,管道倾角增加时,油水两相分层流界面波振幅增大,其对摩擦压降的影响也随之增强,改进的考虑界面波振幅的模型在不同管道倾角中的摩擦压降预测结果与实验数据吻合好。     

水平管内油气水三相流摩擦阻力的计算

在实验研究的基础上，通过流动机理的分析，建立了水平管内油气水三相分层流、间歇流和环状流摩擦压降的Lockhart—Martinelli经验关系式．分析了油水混合物含水率对水平管内油气水三相摩擦压降的影响，计算结果与实验结果符合良好。     

试析地面驱动螺杆泵采油技术优化

地面驱动螺杆泵是由地面电动机带动驱动头,经减速带动光杆和抽油杆柱旋转,驱动螺杆泵转子旋转抽油的一种抽油泵。本文着重就其优化技术进行了分析与探讨。     

螺杆泵采油工艺的合理应用

经过多年的开发研究 ,螺杆泵形成了有油管和无油管两种采油工艺。螺杆泵采油工艺相关技术参数的确定 ,包括地面驱动装置与泵型的匹配 ;抽油杆的选择 ;螺杆泵系统的优化设计 ;驱动装置的密封 ;防断脱抽油杆 ;空心转子螺杆泵采油技术等。螺杆泵配套技术的应用 ,在解决抽油杆断脱、驱动装置漏油等方面取得了实质性突破 ;在聚合物驱和三元复合驱中的应用均见到良好效果 ,可以作为目前克服抽油杆、油管偏磨的一项替代技术。今后在泵材料开发、泵结构的优化设计、自动控制及工况测试和潜油螺杆泵研制等方面的技术有待完善。     

垂直同心环空管内上升油水流动实验

以水和机械油为工质对垂直同心环空管内上升油水两相流动进行了研究，根据实验得到了油水两相流动的流型分布。在实验的基础上，通过一定的理论分析得到了各种流型的转换准则，对油水流动的持油率，压降的预测及相转变点的压降特性也进行了一定的研究，这些研究结果对环形管道油井的参数预测（如含水率，压降等）有一定的参考价值。     

垂直上升管内油水乳状液流动特性的研究

在石油、化学工业中,经常会遇到油水两种互不相溶的液体共同流动的情况.由于油水乳状液的广泛存在,以及采出液含水率的不断提高,导致油气集输过程中输液量的大幅度增加,给油气集输工艺和设备带来了新的困难.文中对垂直上升管内油包水型(W/O)和水包油型(O/W)油水乳状液的流动特性进行了实验研究.实验参数范围:含水率εw=0.0～1.0;压力p=0.1～0.6MPa;流量Q=0.14～1.7kg/s;温度T=10～45℃.实验结果分析得出了一个新的油水乳状液表观粘度的表达式,此表达式优于文献中别的预测模型,其计算值和实验结果吻合良好;同时得出一个新的油水乳状液发生相转变的判别式,分析了在相转变点附近油水乳状液在垂直上升管内的流动状态以及发生相转变和流量、含水率的关系;提出了采用Re和摩擦阻力系数的关联式计算摩擦阻力的方法,得到判别油水乳状液为牛顿流体和非牛顿流体的方法.该研究结果对管道输送系统的设计有一定的参考价值.     

Modeling of flow of oil-in-water emulsions through porous media

Formation and flow of emulsions in porous media are common in all enhanced oil recovery techniques.In most cases,oil-in-water(O/W) emulsions are formed in porous media due to oil-water interaction.Even now,detailed flow mechanisms of emulsions through porous media are not well understood.In this study,variation of rate of flow of O/W emulsions with pressure drop was studied experimentally,and rheological parameters were calculated.The pressure drop increases with an increase in oil concentration in the O/W emulsion due to high viscosity.The effective viscosity of the emulsion was calculated from the derived model and expressed as a function of shear rate while flowing through porous media.Flow of O/W emulsions of different concentrations was evaluated in sand packs of different sand sizes.Emulsions were characterized by analyzing their stability,rheological properties,and temperature effects on rheological properties.     

基于原油物性定量分析的原油乳状液转相点预测模型

以流动状态下的原油乳化含水率来表征原油-水体系的乳化特性,通过实验研究了体系含水率对原油乳化含水率的影响。研究表明：当体系含水率较小时,原油能将水相全部乳化,形成稳定的W/O乳状液;而当体系含水率超过一定的临界值后,原油乳化含水率急剧减少,形成的是W/O/W多重乳状液;该临界体系含水率,即为原油乳状液从W/O型向W/O/W型转变的转相点。确定了5个典型参数来表征原油物性,分别是沥青质胶质含量、蜡含量、机械杂质含量、原油酸值、原油全烃平均碳数。通过回归分析,建立了原油乳状液转相点预测模型,预测结果的平均相对偏差为3.2%。     

Influence of surfactants used in surfactant-polymer flooding on the stability of Gudong crude oil emulsion

The influences of an anionic-nonionic composite surfactant and petroleum sulfonate, used in surfactant-polymer flooding in Shengli Gudong oilfield, East China, on the interfacial properties of Gudong crude model oil and synthetic formation water was studied by measuring interfacial tension, interfacial viscoelasticity and Zeta potential. The influence of the surfactants on the stability of Gudong water-in-oil (W/O) and oil-in-water (O/W) emulsions was evaluated by separating water from the W/O emulsion and residual oil in the aqueous phase of the O/W emulsion respectively. The results showed that the two kinds of surfactants, namely anionic-nonionic composite surfactant and petroleum sulfonate, are both able to decrease the interfacial tension between the oil phase and the aqueous phase and increase the surface potential of the oil droplets dispersed in the O/W emulsion, which can enhance the stability of the W/O and O/W crude oil emulsions. Compared with petroleum sulfonate, the anionic-nonionic composite surfactant is more interfacially active and able to enhance the strength of the interfacial film between oil and water, hence enhance the stability of the W/O and O/W emulsions more effectively.     

电导率与O/W乳状液的稳定性

 测定了不同油相体积分数的O/W乳状液电导率，考察了油相体积分数、乳化条件、温度对O/W乳状液电导率的影响，研究了O/W乳状液电导率与其浓相体积变化分数、吸光度的关系。结果表明，对于较稳定的O/W乳状液，油相体积分数对O/W乳状液电导率有明显的影响，油相体积分数越大，电导率越小；反之，电导率越大。乳化条件越苛刻，电导率越小。温度越高，电导率越大。O/W乳状液电导率随时间变化曲线的斜率可以表征在O/W乳状液的破坏过程中，油珠上浮、聚集、聚并、油相体积分数变化的程度以及乳状液的稳定性。     

Demulsification of dilute O/W emulsion by DC electric field

In this article, the effect of demulsification of dilute O/W emulsion in DC electric field and its mechanism are investigated. The results show that the demulsification process of dilute O/W emulsion is divided into three stages: water layer formation, re-emulsification with transverse diffusion and uplift-stabilization of O/W emulsion. There is a critical current in the electro-demulsification of dilute O/W emulsion. Some evidences confirm that O/W emulsion system with surfactant produces a surface tension gradient in the height direction during the stratification process. The critical current together with the surface tension gradient causes different demulsification processes and current variation for different emulsions.     

Friction factors for hydraulic calculations considering presence of cuttings and pipe rotation in horizontal/highly-inclined wellbores

Pressure loss calculations have a vital role for determining hydraulic horsepower requirements and to predict bottomhole treating pressure. One of the major concerns in developing hydraulic programs is to estimate the frictional pressure losses while cuttings are present in the annulus during pipe rotation. An experimental work has been carried out in a cuttings transport flow loop capable of operating at various inclinations. The pressure drop in the test section was recorded for variable flow rates, cuttings concentrations, pipe inclinations and rotation speeds. Existence of cuttings increase the pressure drop due to decrease in flow area inside the wellbore. As there are cuttings in the system, pipe rotation decreases the frictional pressure loss considerably in particular if the pipe is making an orbital motion in the eccentric annulus. Cuttings bed thickness defined as the ratio of cuttings bed area to the wellbore area is expressed in terms of dimensionless parameters obtained from dimensional analysis. Empirical expressions and charts for friction factor are proposed for low and high viscosity fluids in terms of combined Reynolds number and stationary cuttings bed thickness.     

钻柱偏心旋转对环空摩阻压降影响的数值模拟研究

准确预测钻柱偏心旋转工况下的环空摩阻压降是复杂结构井控压钻井的重要理论基础,但常规钻井液环空摩阻压降计算方法无法直接计算复杂结构井的环空摩阻压降。为此,应用数值模拟方法,分析了偏心度（0～67.42%）和钻柱转速(0～114.65 r/min)对典型环空（Ф127.0 mm钻杆和Ф215.9 mm井眼）中摩阻压降梯度的影响。分析结果表明：偏心度小于45.00%时,转速和偏心度对摩阻压降梯度影响较弱,摩阻压降梯度随转速增大略有降低,随偏心度增大而增大;偏心度大于45.00%时,低转速（<60 r/min）下摩阻压降梯度随偏心度增大而降低,高转速（≥60 r/min）下摩阻压降梯度随偏心度增大而略有增大。基于数值模拟结果,建立了偏心度分类的无因次偏心环空摩阻压降梯度预测模型,计算了南海某水平井Ф215.9 mm井段的ECD,并与PWD测试结果进行了对比,平均相对误差为0.45%,表明该模型具有较好的准确性。研究结果表明,无因次偏心旋转环空摩阻压降计算模型可以精细描述环空压力场和准确计算ECD,为控压钻井水力参数优化提供指导。     

稠油-水两相水平管流流型实验研究

以高粘度稠油和水为工质,将稠油和水先经搅拌罐混合,再由螺杆泵输送进入实验环道流程,在内径为25.4mm、长52m的水平钢质管道中,模拟了稠油油田现场情况。描述了实验流型,并命名了一种新的流型——Ew/o+D(Ew/o)/w间歇流流型,研究了稠油-水两相管流的压降及反相过程,重点探讨了混合流速对反相的影响。研究结果表明,随着混合流速的增大,反相有提前发生的趋势。在含水率为0.35-0.55时,混合流速的增大将直接引发反相。