热处理温度对长庆原油蜡沉积特性的影响

通过Couette蜡沉积装置及DSC热分析探究了热处理温度对长庆原油蜡沉积特性的影响,发现随着热处理温度的升高,长庆原油蜡沉积速率减缓,蜡沉积层老化速率加快;经50 ℃和60 ℃热处理的长庆原油,蜡沉积层出现了分层现象,其表层为流动性较强的凝油状蜡沉积层,底层为结构较为致密的类固态蜡沉积层;经70 ℃热处理的长庆原油,蜡沉积层极薄且致密,无分层现象,其表面无凝油状蜡沉积层。采用沥青质分散程度分析、DSC热分析及蜡晶形貌显微观察探究了其影响机理,发现随着热处理温度的升高,长庆原油沥青质分散程度增大,从而使其析蜡点降低,蜡晶团聚性增强,原油低温流动性得以改善,进而对其蜡沉积特性产生了显著影响。     

长10原油析蜡特性分析及化学防蜡剂筛选

安塞油田高52井区开采长10层原油,井筒和集输系统易结蜡。实验原油含蜡13.184%,含胶质1.267%,含沥青质0.029%(丙酮/苯吸附法测定),凝点18℃。用DSC方法测定了原油样由～70℃降温至-20℃的比热曲线,求得该原油析蜡点为41℃,第一、第二析蜡峰温分别为34℃、18℃;取原油结晶热为230J/g,由比热曲线得到单位温降析蜡量曲线,求得41～-20℃区间的总析蜡量为14.26%,其中41～18℃析蜡量为3.62%,约占含蜡量的25%。认为只要有效控制41～21℃区间析蜡,该原油即可安全输送。用冷指法在油温差10℃条件下测定5种防蜡剂控制该原油结蜡的效果,加量为100mg/kg,其中EP-3/35(链节结构与石蜡分子相同的支链聚合物)和多效剂9M(含表面活性剂的复配防蜡剂)效果很好,防蜡率分别为60.0%和59.8%。图3表1参2     

管输温度对EVA型防蜡剂防蜡效果的影响

采用Couette蜡沉积实验装置研究了聚乙烯醋酸乙烯酯(EVA)型防蜡剂对长庆原油蜡沉积特性的影响,分析了不同管输温度条件下EVA型防蜡剂的防蜡效果。研究发现,与空白原油相比,加剂原油的蜡沉积速率大幅降低,同时蜡沉积物的老化速率升高。无论是在恒定油壁温差还是在恒定壁温条件下,EVA型防蜡剂的防蜡效率均随油温的升高而不断降低,EVA对蜡沉积物老化速率的提升幅度均随油温的升高而不断增大。通过分析EVA型防蜡剂对长庆原油流动特性、低温胶凝结构特性及微观蜡晶形貌的影响,阐明了EVA型防蜡剂对长庆原油蜡沉积特性的影响机理,并从蜡沉积物初始凝油层抗剪切强度及蜡分子扩散速率2个角度揭示了管输温度对EVA型防蜡剂防蜡效果的影响。     

顺北原油防蜡剂的研制及防蜡机理

为防止顺北原油管道集输中结蜡,根据顺北原油析出蜡的碳链分布设计合成了以甲基丙烯酸十八酯、醋酸乙烯酯、对苯二乙烯为单体的超支化聚合物防蜡剂,考察了合成条件对防蜡剂防蜡性能的影响,采用冷指法评价了该防蜡剂的防蜡效果并分析了该防蜡剂的防蜡机理。研究结果表明,顺北原油的含蜡量为6.57%,析蜡点为23℃,在环境温度下极易结蜡。优化得到防蜡剂最佳合成条件为:甲基丙烯酸十八酯和醋酸乙烯酯摩尔比为5∶1,对苯二乙烯加量为单体总质量的0.02%,引发剂加量为单体总量的0.7%,聚合温度70℃,聚合时间为6 h。当防蜡剂加量为500 mg/L时防蜡率达到70%以上,表现出良好的防蜡效果。当加入防蜡剂600 mg/L后,原油凝点降低8℃,析蜡点降低13.4℃,防蜡剂与石蜡形成了共晶,破坏了石蜡的晶体结构,抑制了石蜡的继续增长,从而达到防蜡的效果。图19表1参10     

濮阳原油蜡沉积特性实验

利用旋转式动态结蜡装置,对濮阳原油进行不同油温、不同温差、不同转速等条件下的蜡沉积实验。濮阳原油高含蜡量、双析蜡峰的特性使其蜡沉积规律具有较大的变化性,在管输濮阳原油的过程中要尤其注意输送温度,尽量避开原油的最大析蜡高峰区。其他条件不变时,随油温升高,蜡沉积速率与蜡晶溶解度系数的变化趋势相同;随油壁温差增大,蜡沉积速率逐渐增大;随转速增大,蜡沉积速率逐渐减小。     

延长油田高含蜡原油防蜡剂筛选

针对目前延长油田油井结蜡现状,筛选出了适用于延长油田原油的酯基防蜡剂,复配防蜡剂CH-1：CH-2=1：2,最佳加量为2 000 mg/L,其防蜡率满足实际需要.对延长原油的加剂前后原油的粘温性以及加剂前后原油的流变性的研究发现,该防蜡剂能使延长原油原有的粘度及剪切应力减小,利于原油的流动并达到防蜡目的.对加剂前后原油的显微结构分析发现,加入防蜡剂后含蜡油中的蜡晶消失,说明新型防蜡剂有抑制固相基团沉积的能力.     

高蜡原油清防蜡剂的研制与应用

以科新公司防蜡剂产品KS-30-01(主要成分为聚丙烯酸高碳醇酯)为基础,通过对主溶剂和表面活性剂进行筛选研制了一种高蜡原油用管道用清防蜡剂.实验结果表明,降黏率、防蜡率均随防蜡剂用量的增多而增加,且溶蜡速率随清蜡剂用量的增多而增加.d号清防蜡剂对乍得原油防蜡率可达45.4％,溶蜡速率0.0441 g/min,降黏率7...     

CRT—2聚合物防蜡剂的研制

CRT－2聚合物的分子中含有长的非极性支链和一定数量的极性原子和基团,是一种适用于高含蜡胶质原油特点的高分子型防蜡剂。对含蜡量为16．3％的中原油田原油,当加入100mg/l CRT－2防蜡剂时,其防蜡率高达79．24％,同时使含蜡原油从塑性流体转变成牛顿流体,提高了原油的流动性,是一种新型,高效的防蜡剂。     

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.     

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.     

延长管输原油的组分特征及其析蜡行为

为了研究延长原油不同组分的特征及其析蜡行为,利用柱色谱分离法、傅里叶红外光谱、紫外分光光度法（UV）、差示扫描量热法（DSC）和偏光显微分析等表征方法及手段,将采自延长油田的原油样品分离为13个组分(C1~C13),考察了各极性组分(C2~C13)对饱和烃组分(C1)结蜡行为的影响。结果表明,原油中含有可有效抑制蜡晶析出的组分。C1中分别加入其他不同极性组分(C2~C13)后,其结蜡行为与原油原始状态差异较大;在冷却结晶时,胶质、沥青质组分使C1的蜡晶颗粒数增多,尺寸相对减小,有效地减弱了蜡晶之间的联结强度,削弱了蜡晶缔合形成大块蜡晶聚集体的倾向。     

Experimental Investigations of the Mitigation of Paraffin Wax Deposition in Crude Oil Using Chemical Additives

Abstract

Wax deposition from crude oil is a very expensive problem for oil producers around the world. The objective of this study is to understand the characteristics of paraffin wax deposition and to test the effectiveness of solvents in the inhibition of the crystallization and subsequent precipitation of the paraffin wax and to test the most effective concentration of the solvent used. The oil used here is from the Dakota formation from the Fourteen Mile Field in the Big Horn Basin of Wyoming. Two paraffin inhibitors were tested for this crude oil on a horizontal flow system. The inhibitors are mixtures of solvents, pour point depressants, and wax crystal modifiers. These inhibitors were tested at different concentrations and temperatures and the deposition rates were obtained for each. One inhibitor especially designed for this crude oil was relatively successful, reducing the deposition by up to 59% depending on the temperature.     

An Evaluation of the Performance of Selected Wax Inhibitors on Paraffin Deposition of Nigerian Crude Oils

Paraffin deposition in oil production constitutes a critical and difficult to control problem, in terms of productivity and production operation costs, going from the reservoir to surface facilities. In Nigeria, operators spend millions of dollars each year to control the deposition of paraffin and to deal with other paraffin deposition related problems. Expenditures of this magnitude obviously have a significant impact on profits. The main purpose of this work is to assess the net effect of many commercial wax inhibitors on paraffin deposition from a wide range of waxy crude oil systems in Nigeria for the selection of an efficient additive. Deposition from a wide range of waxy crude oil systems from Nigerian oilfields were examined with and without chemical wax deposition inhibitors. The devices used to produce the deposits investigated were cold spot and dynamic flow wax deposition apparatus capable of producing field-like deposits with relatively small volumes of oil in minutes. Results show that most of the commercial wax inhibitors tested could decrease the deposition of wax, but none has the economical capability to solve the paraffin deposition problem for an extended period of time. One intriguing result was that the addition of xylene improved the performance of three wax inhibitors tested. It was also observed that there are subtle differences in inhibitor performance depending on deposition tendencies of crude oil.     

Artificial Neural Network's Prediction of Wax Deposition Potential of Nigerian Crude Oil for Pipeline Safety

Abstract

Paraffin wax deposition from crude oil along pipeline is a global problem, making preventive methods preferred to removal methods. In this work, a neural network model based on mathematical modeling technique using regression analysis as the statistical tool was developed to predict the wax deposition potential of 11 reservoirs in Nigeria. Using the viscosity-pressure-temperature data obtained from these fields to supervise the model, the model accurately predicted the present real-life situation in each field. Conclusively, the model could be used to predict wax deposition potential of any reservoir that is yet to be explored provided the temperature used during prediction is close to the actual reservoir temperature.     

Studies of Wax Deposition Onset in the Case of Indian Crude Oil

Abstract

Before taking any decision regarding strategies for prevention and remediation of wax deposition problems in the production tubing, pipeline, and process equipment, it is essential to identify the conditions of wax deposition and to predict wax deposition rates. In this article a study on the prediction of wax deposition, different factors affecting the deposition, and the practical applications of laboratory results obtained for characterization of the Indian crude oils have been presented. The waxy crude characterization study was performed on both stock tank crude oil and recombined integrated crude oil. The results of it exemplify the influence of composition, temperature, and pressure on the solid behavior of Indian paraffinic crudes.     

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。