An experimental study on electrical effect on asphaltene deposition

Asphaltene generally existed in colloidal form in cruds and will precipitate in non-equilibrium conditions. Asphaltene instability may take place in the reservoir leading to permeability damage and contributing to flow restriction issues. It may also occur in production strings and surface facilities causing pipe blockage. Any change in oil composition or pressure and temperature at any stage of production will destabilize crude oil producing asphaltene precipitation. In this paper, the stability of target crude oil under the influence of a direct current and contacting with polar fluid, water, is investigated. The amount of the asphaltene deposit and its electrical charge at various operating conditions are investigated. The fact that deposits form on the anode surface proves that asphaltene particles possess a positive charge. The amounts of asphaltenes precipitation were increased considerably by increasing water as polar component.     

A novel test method for evaluate asphaltene inhibitor efficiency on reservoir rock

Asphaltene deposits can reduce the productivity of the reservoir as well as foul piping and surface equipment. Current chemical and mechanical methods for treating deposition are only partially effective partly because the deposition process is poorly understood. The most commonly way to asphaltene precipitation reduction is applying an asphaltene inhibitor. In order to investigate the extent of formation damage by asphaltenes in crude oil this work has used electro kinetic technique to study the adsorption of asphaltenes in rock pores. Most researchers investigate the kinetics of adsorption by monitoring changes in the concentration of asphaltene or polymer in a dispersion of adsorbent particles or capillaries. This study is a coherent approach to measure amount of asphaltene adsorption on rock surface and survey effect of asphaltene inhibitors on precipitation reduction in porous media.     

Test Methods for Determining Asphaltene Stability in Crude Oils

Abstract

The high cost of remediating asphaltene deposition in crude oil production and processing has necessitated the development of test methods for determining the stability of asphaltenes in crude oils. In the current work, the stability of asphaltenes in crude oils of varying API gravity is predicted using the Oliensis Spot Test, the Colloidal Instability Index, the Asphaltene–Resin ratio, and a solvent titration method with NIR solids detection. The test methods are described in detail and experimental data from them presented. The experimental stability data were validated via correlation with field deposition data. The effectiveness of the various tests as predictors of the stability of asphaltenes in oils is discussed. The Colloidal Instability Index and the solvent titration method were found to predict a crude oil's propensity towards asphaltene precipitation better than both the Asphaltene–Resin ratio and the Oliensis Spot Test. For oils with low asphaltene content where most stability tests fail, live oil depressurization is proposed as the test for predicting the stability of asphaltenes.     

Synthesis,characterization and evaluation of a novel asphaltene inhibitor to control organic solid deposition in petroleum formation

This research work deals with synthesis of N-phenylamino hexanol tetramer to be used as an asphaltene inhibitor for crude oil in pores of reservoir. The synthesized additive was characterized using FTIR and Proton NMR spectroscopy, which confirms the formation of tetramer. Asphaltene deposition in the pores of sandstone core is studied by flooding the virgin and additive beneficiated crude oil indicating less deposition in beneficiated crude oil. Wettability alteration studies showed less contact angle hysteresis for virgin crude oil compared to the synthesized inhibitor beneficiated crude oil, which also aids to the lesser deposition of solid in the later one.     

EFFECT OF ASPHALTENE AND RESINS ON THE STABILITY OF WATER-IN-WAXY OIL EMULSIONS

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil. Asphaltene and resins separated from a crude oil were used to stabilize the water-in-oil emulsions. Synthetic formation water was utilized as the aqueous phase of the emulsion. The emulsion stability increased with increasing the concentration of asphaltene with a subsequent decrease in the average particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they form very stable emulsions. Dynamic viscosity and pour point measurements provided evidence for resins-paraffin waxes interactions. Asphaltene in the form of solid aggregates form suitable nuclei for the wax crystallites to build over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interface which was proved by the ability of asphaltene to reduce oil/water interfacial tension. Consequently, nucleation of the wax crystallites by asphaltene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.     

准噶尔盆地南缘井筒堵塞物中沥青质分子组成研究

采用傅里叶变换离子回旋共振质谱分析技术,分析了准噶尔盆地南缘高探1井原油及井筒堵塞物抽提物中沥青质化学组成及差异,探讨了沥青质的组成及结构与沥青质沉积关系,对于沥青质聚集理论研究具有重要意义.研究结果显示,高探1井原油及井筒堵塞物抽提物中沥青质分子主要为N1、N1 O1、O1、O2、O3和O4类化合物,但堵塞物抽提物中...     

EFFECT OF ASPHALTENE AND RESINS ON THE STABILITY OF WATER-IN-WAXY OIL EMULSIONS

ABSTRACT

Asphaltene, resins and paraffin waxes, their mutual interactions and their influence on the stability of water-in-oil emulsions have been studied. 20 wt % paraffin wax dissolved in decalin was used to model the waxy crude oil. Asphaltene and resins separated from a crude oil were used to stabilize the water-in-oil emulsions. Synthetic formation water was utilized as the aqueous phase of the emulsion. The emulsion stability increased with increasing the concentration of asphaltene with a subsequent decrease in the average particle size distribution of the emulsion. Resins alone are not capable of stabilizing the emulsion, however, in the presence of asphaltene they form very stable emulsions. Dynamic viscosity and pour point measurements provided evidence for resins-paraffin waxes interactions. Asphaltene in the form of solid aggregates form suitable nuclei for the wax crystallites to build over with a mechanism similar to that of paraffin wax crystal-modifiers. As asphaltene are polar in nature they are derived at the oil/water interface which was proved by the ability of asphaltene to reduce oil/water interfacial tension. Consequently, nucleation of the wax crystallites by asphaltene and resins at the interface will add to the thickness of the oil-water interfacial film and hence increase the stability of the emulsion.     

Comparison of the inhibitory capacity of vegetable oils,and their nonionic surfactants on Iran crude oil asphaltene precipitation using Quartz crystal microbalance

Asphaltene deposition is one of the main problems in some oil field production. Using the cheap chemical compounds to control asphaltene precipitation is one of the important tools in crude oil field development. Vegetable oil are natural chemical compounds which can be used as asphaltene stabilizer. In this work, the inhibitory capacity of the vegetable oils, their binary mixtures, and their binary mixtures with nonionic surfactants were studied by Quartz Crystal Microbalances. The results show that the turnip oil, binary mixtures of rosemary oil/sesame oil, sweet almond oil/camomile oil, and olive oil/tritoonX-100 are more efficient than other additives and the percentages of the inhibitory capacity are 87%, 89%, 90, and 90% respectively.     

沥青质伤害油藏数值模拟研究

沥青质伤害是造成油井产能下降的一个重要因素,是目前油田普遍存在的问题,及时判断伤害的原因及程度在油田生产中极其重要.从渗流力学和多元相平衡理论出发,分析了沥青质沉积影响因素及伤害机理.在考虑沥青质和岩石吸附过程以及储层伤害导致绝对渗透率减小的条件下,建立了沥青质溶解模型和沥青质沉积堵塞模型,较全面地反映了沥青质对储层的伤害机理.在黑油模型基础上,增加了考虑沥青质伤害的油藏数值模拟软件模块,可实现沥青质的聚结、沉积对储层伤害的油藏模拟计算.应用实际油藏数据设计单井概念模型,对沥青质沉积造成的储层伤害程度进行了模拟计算,随着油井生产时间增加及油井产量提高,沥青质沉积对储层的伤害增大.     

Parametric analysis of the effect of operation parameters on asphaltene deposition: An experimental study

Changing pressure, temperature, and composition cause instability in crude oil and create a problematic issue which is called asphaltene deposition. Asphaltene deposition causes problems in wettability alteration and flow assurance in different parts of petroleum industry so asphaltene deposition becomes a challenging issue in petroleum engineering. Hence, it is necessary to predict asphaltene deposition and investigate parameters which effect on asphaltene deposition. In this contribution, because of similarity between pore throat of reservoir rock and capillary tube, to investigate parameters such as asphaltene content, precipitant ratio, flow rate, and temperature effect on asphaltene deposition, a capillary setup was constructed and a model was developed to relate pressure drop along capillary tube to permeability reduction.