油气水混输减阻理论与方法

基于新滩垦东 18油水采出液的乳化水含量及特性 ,分析油气水在混输过程中的流动状态。应用反相乳化降黏法和气 非牛顿流体流动规律 ,研究W /O型乳状液的降黏效果、油水混输减阻效果以及油气水混输减阻途径。结果表明 :①油气水在混输过程中容易形成呈非牛顿特性的W /O型乳状液 ,油气水混输问题可归结为气液两相流中的气 非牛顿流体流动问题 ,其水力计算可参照成熟的气液两相流动的相关处理方法 ;②采用适当的降黏剂 ,可以有效地降低W /O型乳状液的黏度和油水混输压降 ,降黏率可达到 99%以上 ,减阻率可高于 6 0 % ;③油气水混输减阻可通过采用适当的化学剂改变W /O型乳状液的内外相或阻止其形成实现 ,其关键在于降低W /O型乳状液的稠度系数和流性指数或油水界面张力。     

含有油水乳状液油气水三相分层流的水力学模型

在油气水的三相管内流动中,分层流同样也是一种常见流型。由于互不相溶的油水两相之间相互作用及分散程度的复杂性,所以油气水三相分层流比一般的气液两相分层流要复杂许多。使用一维三流体模型求解含有油水乳状液的分层流、即气体/(W/O型)乳状液/(W/O/W型)多重乳状液的三相分层流。通过模型的求解可以确定油气水分层流的相分率及其他相关参数和压降。     

流动改进剂降低含水原油转相点的实验研究

为了了解流动改进剂对大庆含水原油在集输管路中流动的影响,在具有长20 m水平工作段的管道流动实验装置上,在40℃测量了流动改进剂DODE加量分别为0、150、200和250mg/L、含水率分别为30%～90%的高含水原油不同流量下的流动参数,计算出剪切速率和表观黏度.在直径76和50 mm管道内,剪切速率691/s的表现黏度～含水率关系曲线均按先上升,达到最大值后又下降的规律变化,表观黏度最大值对应的含水率即转相点含水率,转相点含水率随剪切速率降低而减小,在同一剪切速率下随流动改进剂加量增大而减小,最后基本趋于稳定不变.不加剂含水原油的转相点含水率为50%～70%,加剂250 mg/L时的稳定值在35%～45%,即流动性改进剂可使W/O原油乳状液提前转相.将实验数据用S函数进行拟合,得到了可预测加入一定量流动改进剂的含水原油转相点含水率的方程.认为流动改进剂的作用是形成O/W乳状液或拟乳状液及在管壁形成亲水膜.图5参8.     

乳化稠油中多重乳滴的形成及对乳状液性质的影响

在新滩肯东451区块产出的平均含水58%的稠油(W/O乳状油)中以0.6 mg/g油的加量加入复配乳化剂HATJ72,在50℃搅拌2分钟转相形成的O/W乳状液,含大量复杂的多重乳滴,观测到了以水为最外相的七重乳滴.多重乳滴稳定性差,讨论了影响多重乳滴稳定性的因素:乳化剂及其加量;搅拌强度;温度;Ostwald熟化作用及形成原始乳滴时的油水比.由该区块净化稠油和含水7.2%的塔河稠油加水加乳化剂配制的O/W乳状液中乳滴结构比较简单,绝大多数为W/O/W型.与由肯东稠油加水加乳化剂配制的O/W乳状液相比,肯东含水(58%)稠油加乳化剂转相形成的含水相同(35%)的O/W乳状液,表观黏度较低且黏度较不稳定.简介了获得成功的肯东451站含水稠油乳化降黏集输试验.在含水58%的稠油中按0.6 mg/g油的加量加入乳化剂HATJ72和自由水,转相形成O/W乳状液,输送温度50℃,乳化液滴结构复杂,乳状液稳定性较差,输送至下游5公里处时,管道垂直方向上含水、油、水滴数量、黏度已有很大差异.液滴结构复杂、乳状液稳定性差,是自由水引起的,因此应控制掺水量.     

利用搅拌器测量油水混合体系的流变性

使用搅拌器测量油水乳状液的流变性 ,它的主要优点是在搅拌油水体系的同时测量乳状液的流变性 ,适用于测量现场乳状液的流变性 ,操作方便 ,并能消除测量W /O乳状液常发生的壁面滑移。由牛顿流体的搅拌功率准数与雷诺准数的关系可推出M =AμN ,利用机油在层流下标定力矩常数A ,根据Metzner假设 ,搅拌槽内的平均剪切速率与转速成正比 ,即γa=kSN ,据此采用含水率 40 %～ 6 0 %的W /O乳状液标定kS。这样由 μa=M /AN及γa=kSN可测得流体的流变性。经试验验证这种方法的测量误差小于 10 % ,满足工程技术要求     

基于高速摄像与多参数结合的油水两相流流型实验分析

通过在垂直小管径多相流实验装置上的实验,利用高速摄像机拍摄了油/水两相流多种流动状态下的高速摄像图片,对不同流量及不同含水率下拍摄的图片进行了流型划分。在垂直小管径实验装置上进行了差压传感器及阻抗传感器在油水两相流中的实验。差压传感器在油/水两相流中的实验结果体现了油/水两相流流型的变化规律,差压值出现波峰的含水率范围可确定为流型转换的过渡区域;阻抗含水率传感器在油/水两相流中的含水率测量下限可确定水为连续相范围。通过高速摄像与差压传感器及阻抗传感器相结合,综合分析得到了垂直小管径油水两相流流型图。     

油水乳状液W/O型转相为O/W型的矿场验证

油水乳状液不稳定的表现之一是转相。注水开发的油田,油井含水上升,乳状液中水(或油)的内相体积增大。当含水上升到一定程度即内相体积增大到一定数值时,油水乳状液将发生转相,即由 W/O 或O/W 型转为 O/W 或 W/O 型。同时,由于转相,使游离水增多,回压降低,管线沿程的流动阻力减小,这对原油的不加热输送,减少油田老区改造的投资以及减少脱水破乳剂的用量,都是很有利的。     

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%。     

胜利油田金17块稠油-水乳化特性及其对乳化驱油的影响

胜利油田金17块稠油油藏采用水驱后采出液乳化严重，地层流动能力降低，导致开发效果变差。通过乳化状态分析、黏度和流变性测试、油水界面张力测试等研究稠油和水的乳化特性，分析乳化稠油的流动特性；通过对油田常用的乳化驱油剂与W/O型乳状液再乳化形成乳状液的乳化状态、粒径、黏度和黏弹性分析，对乳化稠油再乳化特性进行了研究；分析乳化稠油再乳化机理，并对乳化驱油研究提供了思路。结果表明：乳化严重影响稠油乳状液的黏度，在油藏温度（60℃）条件下，含水率为60%的W/O型乳状液，其黏度、黏性模量和油水界面张力分别是脱水稠油的11.9倍、13.49倍和2.49倍。当含水率高于40%时，非牛顿特性变强、黏度开始呈指数式增大、黏性模量增大显著、油水界面张力迅速增大，严重制约了其在孔隙介质中的流动性。当乳化稠油与乳化驱油剂再乳化时，形成W/O/W型多重乳状液。乳状液的粒径、黏度和黏弹性随着W/O型乳状液中初始含水率的升高而增大。当初始含水率为60%时，乳化驱油剂LPA,HPF和SDS与W/O型乳状液再乳化后形成乳状液的粒径分别为91.3,40.6和27.5μm。相比于它们与脱水稠油形成的乳状液，粒径分别增大7....     

油包水乳状液电导率与电破乳研究

通过水滴在电场中所受偶极力的表达式,讨论了W/O乳状液的电破乳机理及介电常数、电导率.借助乳化剂Span80,由50号白油、52号基础油、胜利孤岛原油和蒸馏水制备了含水10%、20%、30%的W/O乳状液,测定了乳状液30℃时的介电常数和黏度.在板电极长宽(cm)8×15、板间距2 cm的电破乳实验装置上,测定了实验W/O乳状液的油水分离效率与板间电压(2～9 kV)、电场作用时间(30、60、120 s)、沉降时间(5～20 s,30℃)的关系,结果如下.在相同实验条件下,含水10%的白油、基础油、孤岛原油乳状液的黏度、电导率和油水分离效率均依次增大;含水30%的白油乳状液在电场中被击穿;白油、基础油乳状液的分离效率随含水率增大而下降,随板问电压增大而上升;含水丰20%的基础油乳状液的分离效率随电场作用时间和沉降时间的延长而上升.讨论了所得结果.图5表1参5.     

地面驱动螺杆泵泵送油水乳化液时的摩阻研究

对地面驱动螺杆泵泵送油水乳化液时的摩阻特性进行了全面的研究。通过测量摩擦压降研究了油包水与水包油乳化液之间的相转变现象,分析了不同含水率下抽油杆转速对油包水乳化液及水包油乳化液流动摩擦压降的影响。实验和分析表明,当含水率为0.41~0.43时,水包油乳化液将向油包水乳化液转换;抽油杆的旋转效应在水包油乳化液时对摩擦压降的影响要大于油包水乳化液。通过实验数据处理,获得了不同流型下抽油杆旋转时环型管道内幂律型油水乳化液流动摩擦阻力的实验关系式。这些研究结果对地面驱动螺杆泵的设计及应用有一定参考价值。     

固体微粒对油水体系的乳化稳定作用

采用静置（或离心）沉降法和乳滴稳定性测试法，研究了与钻井液、完井液有关的若干种固体微粒对油、水体系乳化稳定性的影响。研究结果表明，在一定条件下，钻井液中的某些固体微粒能完全或部分替代表面活性剂，对油、水体系起乳化稳定作用。一般情况下，亲油的固体微粒（如有机土）倾向于稳定Ｗ／Ｏ乳状液；亲水的固体微粒倾向于稳定Ｏ／Ｗ乳状液；接近中性润湿的固体微粒（如ＳＮ－１）对两类乳状液均具有一定的稳定作用。固体微粒     

Flow Characteristics of Crude Oil with High Water Fraction during Non-heating Gathering and Transportation

In order to ensure the safety of the non-heating gathering and transportation processes for high water fraction crude oil, the effect of temperature, water fraction, and flow rate on the flow characteristics of crude oil with high water fraction was studied in a flow experimental system of the X Oilfield. Four distinct flow patterns were identified by the photographic and local sampling techniques. Especially, three new flow patterns were found to occur below the pour point of crude oil, including EW/OW stratified flow with gel deposition, EW/OW intermittent flow with gel deposition, and water single-phase flow with gel deposition. Moreover, two characteristic temperatures, at which the change rate of pressure drop had changed obviously, were found during the change of pressure drop. The characteristic temperature of the first congestion of gel deposition in the pipeline was determined to be the safe temperature for the non-heating gathering and transportation of high water cut crude oil, while the pressure drop reached the peak at this temperature. An empirical formula for the safe temperature was established for oil-water flow with high water fraction/low fluid production rate. The results can serve as a guide for the safe operation of the non-heating gathering and transportation of crude oil in high water fraction oilfields.     

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。     

VISCOSITY OF WATER IN OIL EMULSIONS

Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted.

The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 10⁶, 5×10⁶ and 15×10⁶ erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used.

The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.     

特超稠油污水回掺降粘集输工艺

通过对河南古城油田BQ10区特超稠油乳状液的室内试验分析,指出该种乳状液的实际相突变点为68%左右,当相浓度Φ≥68%时,以W/O型为主的乳状液突变为以O/W型为主的乳状液.乳状液变型后,原油与管道内壁之间的摩擦以及原油之间的摩擦转变为水与管道内壁及水与水之间的摩擦,从而大幅度降低其粘度和摩阻损失;通过对古城BQ10区特超稠油区块单元内部污水回掺降粘集输的现场试验,证明与室内试验分析得出的结论相符合,说明区块单元污水回掺不同于常规的掺热水,也不同于掺联合站处理过的净化污水,它优于单井掺稀油.最后指出该工艺可有效地降低井站回压,方便生产管理,降低开采成本,提高采油效率和经济效益,具有低耗节能的优点.     

VISCOSITY OF WATER IN OIL EMULSIONS

ABSTRACT

Increase in water cut in oil fields generally calls for an increase in the capacity of transport pipelines. Proper design and operation of the latter requires good knowledge of the thermophysical properties of flow resistance of crude-oil water mixtures. An experimental program aimed at measurements of oil-water emulsion viscosity for water cuts prior to the inversion point was conducted.

The present work reports on measurements of Nimr crude oil-water mixtures viscosity for different water cuts and a typical range of temperatures representative of field conditions (20°-50°C). Three mixing intensities of 10⁶, 5×10⁶ and 15×10⁶ erg/cm-sec generated by a dynamic coalescer and directly relevant to field conditions were used.

The results suggest that the inversion point occurs around a value of water cut of 35%. Both Newtonian and non-Newtonian (pseudo-plastic) behaviour were observed, and the ASTM viscosity model is found to be applicable to the emulsions. The effect of the mixing intensity on the resulting emulsion viscosity was found to be important at low temperatures and decreased at high temperatures. The experimental data fitted the available correlations in the literature.     

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。     

Experimental investigation of the effects of various parameters on viscosity reduction of heavy crude by oil–water emulsion

The effects of water content, shear rate, temperature, and solid particle concentration on viscosity reduction(VR) caused by forming stable emulsions were investigated using Omani heavy crude oil. The viscosity of the crude oil was initially measured with respect to shear rates at different temperatures from 20 to 70 C. The crude oil exhibited a shear thinning behavior at all the temperatures. The strongest shear thinning was observed at 20 C. A non-ionic water soluble surfactant(Triton X-100) was used to form and stabilize crude oil emulsions. The emulsification process has significantly reduced the crude oil viscosity. The degree of VR was found to increase with an increase in water content and reach its maximum value at 50 % water content.The phase inversion from oil-in-water emulsion to water-inoil emulsion occurred at 30 % water content. The results indicated that the VR was inversely proportional to temperature and concentration of silica nanoparticles. For water-in-oil emulsions, VR increased with shear rate and eventually reached a plateau at a shear rate of around350 s-1. This was attributed to the thinning behavior of the continuous phase. The VR of oil-in-water emulsions remained almost constant as the shear rate increased due to the Newtonian behavior of water, the continuous phase.