预测石蜡沉积的热力学模型

溶解石蜡的原油在稳定状态下为真溶液,当热力学条件改变时,石蜡以结晶方式析出而沉积于孔隙介质表面或管壁,引起严重堵塞,给油田生产造成巨大危害。提出了预测石蜡从原油中沉积的热力学模型,根据正规溶液理论对固体混合物的非理想性进行了校正。该模型采用状态方程统一描述气相和液相,能够体现体系组成、压力、温度以及不同组分间相互作用的影响,使热力学模型能够更真实地反映多相相平衡规律;考虑了液相、固相的热容差对石蜡沉积的影响,能够确定石蜡从原油中开始析出的温度(或压力),以及随着温度的降低(或压力的改变)所沉积出的石蜡数量。用该模型预测的石蜡沉积起始温度与实验数据一致性较好。图2表2参6(邓春萍摘)     

张店油田储层注水影响因素探讨

张店油田在注水开发过程中，出现注水难和注不进去的现象，通过岩心试验评价不同毛管力，不同润湿性，不同温度下模拟注水以及注表面活性剂的岩心驱替试验，并结合张店油田储层有关特征，对影响张店油田注水驱油效果的因素做出分析评价。研究结果表明，毛细管力是影响注水的重要因素之一，随着样品水润湿性程度的增加，注水压力升高，驱油效率减小。注水温度越低高含蜡原油结蜡严重，影响注水。表面活性荆能降低油水界面张力，从而降低注入压力，提高原油采收率。     

高凝油渗流特性的实验研究

选择２块人造岩心和２块取自于沈北油田的天然岩心，分别在不同条件下饱和地层水，进行了油驱水实验，实验用油具有较高的含蜡量和凝固点；由实验观察可知，温度是决定高凝油渗流特性的决定性因素，当温度高于反常点时，原油呈牛顿流体，粘度在整个渗流过过程不变，反之则呈非牛顿流体，粘度对温度非常敏感，随温度降低，原油粘度升高，油相渗透率和驱油效率降低，在析蜡前后，变化尤为明显；高凝油的渗流特征还受压力梯度的影响，最     

高含蜡凝析气井石蜡沉积实验研究

国内外研究学者在石蜡沉积研究中对石蜡沉积机理及沉积模型模拟预测等方面进行了大量研究。为了研究某高含蜡气井的析蜡条件及预防措施,针对高含蜡凝析气井的脱气油,进行了石蜡沉积实验研究,发现在模拟研究井筒中油气多次接触过程中,脱气油的析蜡点和溶蜡点以及石蜡的沉积量随着接触次数的增加呈现先下降后上升的趋势。沉积点的测定研究能判断井筒是否结蜡,沉积量的测定研究能够预测井筒析蜡状况,以保证气井正常生产。研究表明该井在地层中不会出现石蜡沉积,同时,井口的温度应不低于42℃,井筒中也不会出现石蜡沉积。     

注水采收率的预测技术

交会图技术能够预测原油采收率，得到渗透率比率和分相流动曲线，此分相流动曲线能确定驱替效率。在埃及的Ｅｌ－Ｍｏｒｇａｎ Ｓｏｕｔｈ Ｋａｒｅｅｍ和Ｓｏｕｔｈ Ｂｅｌａｙｉｍ两个油藏中应用的例子，显示了这种方法是如何运用的。自１９８７年以来，两个油藏的含水率都大于５０％。这个交会图用于含水率超过５０％的油藏。它要求采收率和含水率之间是一个线性关系。     

微生物单井处理技术在徐家围子低渗透油田的应用

介绍了徐家围子低渗透油田微生物采油的现场试验。试验采用一组由产气的甲烷茵、分解石蜡的混合杆菌和产生物表面活性剂的芽孢杆菌组成的配伍菌,利用其综合作用解决低渗透油田水驱效果差,油井产量递减率偏高的生产问题。4口试验井已累积增油534.3t,有效期超过110d,投入产出比达到1:2.4以上。为高含蜡原油低渗透油田的增产提供了一条可行的方法。     

张店油田储层注水影响因素探讨

张店油田在注水开发过程中 ,出现注水难和注不进去的现象 ,通过岩心试验评价不同毛管力 ,不同润湿性 ,不同温度下模拟注水以及注表面活性剂的岩心驱替试验 ,并结合张店油田储层有关特征 ,对影响张店油田注水驱油效果的因素做出分析评价。研究结果表明 ,毛细管力是影响注水的重要因素之一 ,随着样品水润湿性程度的增加 ,注水压力升高 ,驱油效率减小。注水温度越低高含蜡原油结蜡严重 ,影响注水。表面活性剂能降低油水界面张力 ,从而降低注入压力 ,提高原油采收率。     

含蜡原油石蜡沉积模拟方法研究

对从苏丹Unity油田现场取得有代表性的原油样品进行了原油组分分析和析蜡点测试。并针对油田的生产状况,利用与美国德士古石油公司合作建立的自动化高压石蜡沉积循环管道模拟系统,采用冷却实验步骤测试了苏丹原油从高于原油析蜡点温度到较低环境温度范围内在现场流速、油温和环境温度下的石蜡沉积速率,定量研究了流速和油温对石蜡沉积速率的影响,并采用分子扩散和剪切效应的总效应来描述石蜡沉积机理。利用临界蜡张力作为模拟放大因子,采用半经验的石蜡沉积数学模型,预测了Unity油田21井的生产井筒在现场生产条件下的石蜡沉积情况,模拟了不同产量和不同时间的蜡沉积剖面。结果表明,该油井在目前高产条件下,未发生石蜡沉积问题;在低产时,须考虑清蜡和防蜡措施。     

油水井近井带无机结垢动态预测数学模型

在油田注水开发过程中,由于温度、压力等外界环境条件的变化以及不相容水的混合,容易产生无机结垢,堵塞地层孔隙或裂缝,严重影响油田开采.文章在总结国内外无机结垢预测模型基础上,将经典溶液理论、离子互吸理论与多孔介质中非等温渗流以及流体传质等基本原理相结合,建立了更符合油田实际情况的油水井近井带无机结垢动态预测数学模型,并与以往模型预测结果相比较,结果基本可靠.在此基础上,对吉林新民油田某油井结垢情况作出了预测.结果表明,油井无机结垢类型主要是碳酸钙垢,结垢最严重区域为油井井底及近井带,与实际情况基本吻合.该预测模型具有实用意义,可以快速、准确地为现场增产措施提供理论依据.     

韦庄油田储层裂缝预测研究

低渗透油层裂缝的存在是制约W2、W8等开发及调整效果的关键，利用有限元数值模拟法，求出岩石的破裂率、裂缝密度、应变能、剩余强度等裂缝预测参数来预测裂缝的发育及分布规律。在此基础上分析裂缝特征对开发井网布局、压裂、水平井设计的影响，为合理开发韦庄油田具有现实意义。     

石油管线蜡沉积试验研究进展

含蜡原油在开采和管输过程中由于环境温度的降低会沉积在井壁和管壁上,减小了管道的有效流通截面,降低管道的输送能力,甚至会造成管道堵塞事故。综述了国内外学者对于石油管线蜡沉积的试验研究进展,分析了不同蜡沉积装置的工作原理、特点和适用范围,并提出了一些研究建议。     

地层坍塌压力预测技术在钟市地区的应用

地层坍塌压力剖面的准确确定,对于井眼稳定和安全钻井至关重要,本文建立了地层坍塌压力的计算模型,并利用江汉油田钟市地区的测井资料连续地计算了该地区的地层坍塌压力,与已钻井井径扩大率的对比分析表明,计算模型正确,能应用于江汉油田钟市地区的实际钻井中。     

Laser Based Detection of Paraffin in Crude Oil Samples: Numerical and Experimental Study

A laser spectroscope was used to detect paraffin in paraffin contaminated oil samples. After passing through the oil sample, the laser light was detected by using a semi-conductor photodiode, which in turn converts the light signal into electric voltage. The samples studied have paraffin concentrations ranging from 20-60% wt and a thickness of 1-10 mm. The results showed a good agreement with Beer Lambert's Law for the attenuation of light. A 1-D mathematical model based on energy balance and describing the process of laser radiation attenuation within the oil sample was developed and numerically solved. The model was used to predict the net laser light and the amount of light absorbed per unit volume at any point within the oil sample. The results of the numerical model were found to be in correlation with those obtained from the experiments. The mathematical model presented was then used for different types of oil products to determine the local rate of absorption in an oil layer under different working conditions. Most of the factors affecting the light absorption were considered. The effects of the angle of incidence, bottom reflectivity, and layer depth are presented and discussed.     

A Study on Creep Behavior of Gelled Daqing Crude Oil

Abstract

Gelled waxy crude oils have complex rheological properties. Experimental research and mechanical analogy were performed for the creep behavior of Daqing crude oil. The experienced stages in creep process were partitioned based on the changes of strain and strain rate with the increasing loading time. When the loading stress was lower than the yield stress, there existed three stages; namely, instant elastic deformation, decelerated creep, and constant rate creep. When the applied stress was higher than the yield stress, accelerated creep occurred after the above three stages. By applying mechanical analogy, the elastic element, viscous element, plastic element, and accelerated creep element were employed to reflect the interior strain mechanism of crude oil under creep condition. A creep equation was proposed by incorporation with the analysis on the creep experiment. Based on the creep equation, nonlinear regression was conducted by using the creep experiment data of Daqing crude oil at different temperatures of 28°C, 29°C, 30°C, and 31°C, respectively. The average correlation coefficient was 0.9907. Substituting the calculated equation parameters into the creep equation, the creep behavior under other shear stresses can be predicted at the same temperatures. The average relative deviation is 8.29%. The change of strain of crude oil before yielding can be accurately described by the creep equation.     

复杂压力系统地层压力预测方法在文东油田的应用

建立了复杂压力系统地层压力预测方法的数学模型 ,并利用文东油田文 13块已钻井的测井资料、采油注水井的地质资料 ,预测了 4口调整井的孔隙压力、坍塌压力、破裂压力 ,并据此推荐了实钻时所采用的钻井液密度 ,取得了良好的施工效果     

Prediction of Wax Deposition in an Insulation Crude Oil Pipeline

This study establishes an insulation crude oil pipeline wax deposition experimental device and describes the experimental method for insulation crude oil pipeline wax deposition. The experimental program is based on the operational plan of Tieling–Huludao insulation crude oil pipeline. The data are analyzed according to the effect of varying oil temperature, insulation thickness, and flow on wax deposition. Using SPSS software, a Daqing crude oil wax deposition rate model is derived from the linear regression. The use of the wax deposition rate model forecasts the wax deposition of the Tieling–Huludao insulation crude oil pipeline during different seasons.     

电加热开采稠油油藏影响因素研究

根据电加热油藏的机理,建立了电加热过程中电流场、渗流场、温度场的数学模型。利用有限差分法对该模型进行了求解．并对无因次电导率、电极位置和电极半径对原油采收率的影响进行了模拟试验研究。研究结果表明,无因次电导率和电极位置对采收率影响较大,而电极半径的影响较小。     

An Experimental Study on Wax Deposition of Water in Waxy Crude Oil Emulsions

Abstract

The key factors affecting wax deposition of water-in-oil emulsion were studied experimentally using a cold finger device. Wax deposition characteristics of emulsions were obtained. The results showed that the wax deposition profile of emulsions as a function of temperature parameters was similar to that of single oil. However, the effect of the extent of water cut on wax deposition was obviously different at different temperatures. Furthermore, the relative mass of deposit was proposed and found independent of water cut, from which wax deposition rate at different water cuts could be predicted and the predicted values were in good agreement with experimental data.     

The Effect of Tube Orientation and Pour Point Depressant on Paraffin Wax Deposition

Abstract

A flow loop was used to study wax deposition in the laboratory. Data are presented to demonstrate that the tube orientation and pour point depressants have significant effects on the paraffin wax deposition for oil from the Octh Louie, a Cretaceous formation in the Manderson Field, Wyoming. Changing the tube orientation from horizontal to vertical reduced the amount of wax deposited by 28% for a tube wall (T_wall) temperature of 42°F. The circulating oil temperature (T_bulk) was held constant at 76 ± 3°F. The amount of wax deposited was found to be a linear function of the driving force (T_bulk – T_wall) and the wax appearance temperature (WAT) was estimated by extrapolating this linear relationship to a point of zero wax deposition. The WAT thus obtained (94.5°F) varied considerably with the cloud point (62°F) obtained using the ASTM D2500 method. Change in viscosity with time has also been investigated. Addition of a specific pour point depressant (PPD) at a concentration of 5 mL/gallon reduced wax deposition by 52%; concentrations of 10 mL/gallon of oil reduced the wax by 61%. Changing the flow regime from laminar to turbulent also had a significant effect, reducing the wax deposition by up to 42%. Gas chromatography–mass spectrometry (GC-MS), gas chromatography–flame ionization detection (GC-FID) analyses and other relevant property data pertaining to the oil are also presented.     

青西油田地层压力预测技术的研究与应用

地层压力预测对提高钻井速度、保护油层、合理设计井身结构和钻井液密度有着重要的意义。通过对完成井岩心和测井资料的分析处理，建立了青西油田地层压力预测数学模型，十多口井的现场应用表明，该模型压力预测结果误差小于10％；完井试油发现，储层污染明显减小，产量与邻井相比大幅度提高，取得了较好的经济效益。同时，也为青西油田提高钻井速度、缩短钻井周期、提高勘探开发效益奠定了坚实的基础。