黑油高压物性参数模拟方法及应用

高压物性参数是评价储层流体性质、计算储量、开发设计、预测油田动态及三次采油不可缺少的资料.根据工程热力学原理,建立了适用于油藏烃类气-液-固三相相平衡的热力学方程,模拟计算黑油高压物性参数,并确定了气、液、固各相逸度的计算方法.胶质和沥青质是复杂的混合物,其化学结构和物理化学性质目前尚不完全明了,其物性参数在一定范围内变化.通过改进原油特征化方法,根据胜利油区原油所含胶质和沥青质的综合实验数据,选取了其物性参数及临界性质参数.利用井流物组成模拟计算黑油油藏流体的泡点压力、气油比、地层原油密度和体积系数等参数.模拟计算的高压物性参数与实验数据的相对误差均小于5%,符合程度较高.     

胶质对沥青质沉积影响研究进展

沥青质沉积会降低油藏润湿率,造成输油管道堵塞,严重影响原油开采。原油中的胶质对沥青质沉积有重要影响。其作用效果与胶质浓度、胶质分子结构及极性有关。本文从胶质的结构与性质,胶质对沥青质沉积的抑制作用和促进作用等方面介绍胶质对沥青质沉积影响的研究进展。     

黄河口凹陷原油物性特征及其影响因素

通过对黄河口凹陷不同层位的原油物性特征进行统计,结果表明:原油物性不仅受原油族组成的影响,而且也受成熟度、埋藏深度、保存条件和组分重力分异作用的影响.原油相对密度的影响因素较多,主要包括饱和烃、芳香烃、胶质含量、沥青质和含蜡量等;而原油黏度主要受饱和烃、芳香烃、胶质含量的影响,沥青质和含蜡量对其影响不大.分析认为,影响...     

温度对油砂沥青相渗规律影响研究

针对目前油砂沥青等超稠油油藏热采过程中相渗规律研究较少的现状,通过非稳态热水驱实验,利用ＪＢＮ 方法计算油水相对渗透率,探究温度对油砂沥青相渗规律的影响。研究表明：对于含油砂沥青储层而言,油相相对渗透率较大,水相相对渗透率很小,油水相对渗流能力极不平衡;随温度升高,束缚水饱和度增大,残余油饱和度减小,油水相对渗透率都增大,两相共渗区间扩大;超高的原油黏度和胶质沥青质含量是造成油砂沥青相渗规律有别于稀油的主要原因;高黏油相对水相的阻碍作用使水相相对渗透率远小于油相相对渗透率;温度升高,原油黏度减小,胶质沥青质解吸,进而影响油水分布、润湿性及水相黏性指进程度,引起渗流规律的变化。     

原油组分的性质与结构对其粘度的影响

粘度是流体的重要物理性质之一, 其数值的准确与否对制定油气田开发政策以及选用化工分离技术都具有重要意义。考察了现有粘度模型对原油粘度的计算精度, 发现其预测误差都较大。在此基础上, 提出利用四组分实验的数据将原油阳性组分分割成饱和烃、芳烃、胶质、沥青质等4 个假组分进行原油特征化的方法, 以更准确地描述原油阳性组分中不同性质与结构对原油粘度的影响。     

原油沥青质沉积和吸附引起储层损害的机理及损害程度评价

原油沥青质沉积对储层孔喉的堵塞和沥青质吸附引起的油藏岩石润湿性改变是造成储层损害、导致油井产能下降的重要机理之一。首先,从热力学平衡和溶解度两个方面论述了原油沥青质发生絮凝和沉积的机理,并采用粘度法测定了沥青质絮凝初始点;然后利用岩心流动实验方法,定量评价了沥青质沉积对储层岩石渗透率的影响;并采用经改进的自吸速率法,研究了原油沥青质吸附所引起的润湿性改变及其对产能的影响。实验结果表明,储层岩心油相渗透率下降的程度与沥青质沉积量、储层岩心的原始渗透率、沉积颗粒粒径以及原油流速等因素有关。原油沥青质在油藏岩石上的吸附所引起的润湿性改变是导致储层油相渗透率降低,从而造成储层损害的一个重要原因。     

不饱和油藏存在气顶的可能性探讨

通过油藏流体物性实验及带气顶稠油油藏特征研究,明确了M油田的流体性质及油藏特征,从而建立稠油氧化带模式,确定该油藏为带气顶、底水的不饱和特稠油油藏。研究结果表明,在长期油水气相互作用的过程中,油藏边缘形成了类似壳体的氧化带,其中胶质、沥青质含量高,并具有封隔作用,使原油氧化产生的伴生气难以回溶到地层原油中,在一定的储盖条件下形成气顶。该研究成果打破常规流体分析的思路,明确了油藏流体特征,可为油藏开发策略提供重要的参考。     

CO2驱油过程中原油胶质对沥青质沉积的影响

沥青质沉积严重影响油田开发效果,为明确CO_2驱替过程中胶质对于沥青质沉积的影响,本文以不同胶质沥青质质量比的原油模拟液为研究对象,通过微观可视驱替实验,模拟CO_2驱替过程中沥青质沉积现象,确定其组分含量、物性、固相颗粒大小变化,分析胶质对沥青质稳定性的影响。研究结果表明:胶质以圆球状包裹沥青质,对沥青质起着稳定作用;当胶质沥青质质量比从1∶1升至6∶1时,沥青质沉积量、沉积潜力均先增大后减小,黏度则先减小后增大,胶质与沥青质质量比为2∶1时,黏度达到最低,沥青质沉积量、沉积潜力最大。沥青质沉积与胶质含量有关;沥青质胶质间存在一对作用力—吸附力与分散力,沥青质沉积量与这对力的作用效果相关。图16参25     

酸化淤渣的研究

本文研究了酸化淤渣的生成机理。研究认为,酸化淤渣含有许多不饱和物质,胶质和沥青质的含量同原油差别较大。酸化淤渣的生成是原油中胶质、沥青质析出的结果。在该过程中、胶质、沥青质会相互吸附和聚并,导致沥青质和苯不溶物的出现。根据研究脱沥青质原油和脱胶质沥青质原油的结果,认为胶质是酸化淤渣生成的主要来源。     

九4区齐古组稠油油藏开发中原油物性变化规律

克拉玛依油田九4区齐古组油藏的原油性质具有黏度高、酸值高、胶质含量高、含蜡量低、凝固点低、含硫量低、沥青质含量低、黏温敏感等特点。随着九1—九5区稠油油藏开发程度的不断加深,在不同开采阶段,油藏地下原油性质发生了较大程度的变化,如密度增大、凝固点升高、胶质和沥青质相对含量增大、完全脱气(溶解气油比降低)、黏度增大等等,这些都直接影响地下流体多相流动的渗流规律,从而最终影响稠油油藏的采出程度。     

A comprehensive experimental evaluation of asphaltene dispersants for injection under reservoir conditions

As the efficiency of dispersants with different origins is questionable for each typical oil sample, the present study provides a reproducible and reliable method for screening asphaltene dispersants for a typical asphaltenic crude oil. Four different asphaltene dispersants (polyisobutylene succinimide, polyisobutylene succinic ester, nonylphenol-formaldehyde resin modified by polyamines, and rapeseed oil amide) were prepared and their performance on two oils from an Iranian field under laboratory and reservoir conditions was studied. A thorough analysis including ash content and SARA tests was performed on the solid asphaltene particles to characterize the nature of deposits. Then a highly efficient carrier fluid, which is crucial when injecting dispersant into the wells, was selected from a variety of chemicals by comparing their solubility. In the next step, using an optical microscope, a viscometer, and a Turbiscan, the screening of dispersants under laboratory conditions was done on a mixture of dead oil and dispersant to evaluate the onset of asphaltene precipitation and its stability when titrating by a precipitant. Finally, two different mixtures of the efficient dispersants, live oil, and carrier fluid were used with the solid detection system (SDS) and the filtration method to examine their effects on the onset pressure of asphaltene precipitation and the asphaltene content of the crude oil under reservoir conditions. The results show that the combination of experimental methods used in this work could be consistently applied to screening asphaltene dispersants. Among the four different dispersants applied here, the dispersant based on nonylphenol-formaldehyde resin modified by polyamines showed the best performance on the available live oils. This chemical modified the onset pressure of asphaltene precipitation of light oil from 4300 psi to about 3600 psi and decreased the precipitated asphaltene of heavy oil by about 30 %.     

Modeling of Coprecipitation of Resin and Asphaltene in Crude Oil by Association Equation of State

Abstract

Resin content is an effective parameter that has adverse effect on precipitation of asphaltene in crude oil. Fluctuations in temperature, pressure, or oil composition disturb the chemical equilibrium in a reservoir, which results in coprecipitation of resin and asphaltene. In this work, coprecipitation of resin and asphaltene has been modeled using an association equation of state (AEOS) in which asphaltene and resin are considered associate components of oil. According to association fluid theory, the total compressibility factor is assumed to be the sum of physical and chemical compressibility factors. Liquid–liquid and liquid–vapor equilibrium calculations are accomplished with the assumption that asphaltene and resin do not contribute in the vapor phase. Comparison of experimental asphaltene precipitation with that obtained from the model developed proves the acceptability of the proposed model.     

气液固三相相平衡热力学模型与计算方法

原油中含有大量的高分子有机固相物质，因此，要准确地描述油气体系相平衡，必须对气液固三相相平衡进行研究，在对高分子有机烃类沥青沉降机理有了一定的认识的基础上，提出了大的交互作用系数，可以描述沥青与原油中轻质不相容性的程度。根据对油气烃类混合物体系的一般性认识与提出的沥青组分特征化方法，导出了与之相应的有其自身特殊性的气液沥青三相相平衡物料平衡方程组，用考虑沥青沉降三相闪蒸数值算法，对沥青沉降进行有效的理化模拟计算，此外，结合实例分析，给出了沥青质参考逸度的计算，饱和压力和沉降量的拟合方法。     

Prediction of asphaltene precipitation from n-alkane diluted crude oil by using PC-SAFT equation of state

The precipitation tendency of heavy organics such as asphaltene has posed great challenges for petroleum industry, and thus study of asphaltene precipitation amount and formation conditions seems to be necessary. One of the most common approaches for prediction of asphaltene precipitation is using thermodynamic models. In this study a PC-SAFT equation of state (EOS) is used to predict asphaltene precipitation in two Iranian dead oil samples. Asphaltene content is obtained by filtration method of the oil samples diluted with specific concentrations of different normal alkanes. Also liquid-liquid equilibrium is used for characterization of oil sample into one heavy phase (asphaltene) and another light phase (saturates, aromatics, and resin). Calculations show that the developed model is highly sensitive to interaction parameter between oil fractions. Prediction results were improved due to using Chueh-Prausnitz equation. The results indicate good potential of PC-SAFT EOS in the prediction of asphaltene precipitation in crude oil samples diluted with different normal alkanes. The model error is <5% and the model precision is increased by reducing the number of normal alkane carbons.     

环烷酸对高沥青质含量稠油乳状液稳定性的影响

以高沥青质塔河稠油为研究对象,从中分离出沥青质,配制成模型油乳状液;从辽河、苏丹原油中分离出天然羧酸,考察原油中天然羧酸对塔河沥青质模型油乳状液稳定性的影响。 结果表明,天然羧酸可以起到类似于胶质的作用,通过对沥青质的分散作用,降低沥青质模型油乳状液的稳定性。 有机羧酸和烷基芳磺酸可以起到与天然羧酸类似的作用,而且烷基芳磺酸降低模型油乳状液稳定性的能力更强。     

Data-driven modeling for determination of asphaltene stability condition in oil system

Asphaltene precipitation is accounted as one of the most serious problems during oil production so that it can decrease the production of crude oil and cause the blockage of reservoir rock pores, etc. An accurate prediction of phase behaviour of asphaltene is therefore important in oil production industry. Accurate prediction of phase behaviour of asphaltene precipitation i.e. stability state of asphaltene precipitation in oilfields is greatly desirable. To this end, the applicability domains of the most important variables for the determination of the stability state of asphaltene precipitation viz. aromatic + resin and asphaltene + saturates have been specified by using decision tree (DT) algorithm. Next, adaptive neuro-fuzzy inference system (ANFIS) approach was implemented in order to determine the stability state of asphaltene precipitation using the efficient variables of aromatic + resin and asphaltene + saturates. The results obtained in the current study demonstrate that the models proposed in this study provide desirable results in estmating the stability state of asphaltene precipitation in oilfields.     

基于化学计量的渤海原油组分检测方法

原油中沥青质、胶质及蜡3种组分的含量是油田开发、生产与输送工艺设计及运行方案制定的重要基础数据,其传统标准检测方法一般存在周期长、精度低、溶剂有毒等问题,这将严重影响原油组分的检测效率、生产工艺与操作方案的合理性。为此,基于化学计量学原理,对300组渤海地区的原油样品进行实验,建立红外光谱与原油组分的多元校正模型,提出了通过检测原油红外光谱来预测原油组分的方法。通过多次重复性实验对比分析发现,该方法的平均相对误差、绝对误差及标准差分别为5.3%、5.1%、6.1%,重复性小于3%、再现性小于15%,优于标准检测方法,且该检测方法比标准方法耗时短、成本低、可靠性与检测效率高。     

南海原油胶质、沥青质结构表征及原油降黏研究

南海原油储量丰富,其开发利用具有重要的经济价值和战略意义。从南海原油中分离出胶质和正庚烷沥青质并对其进行表征,合成了含氮长链聚合物型降黏剂,同时考察了合成降黏剂对南海原油的降黏效果。结果表明：南海原油属高胶质、高沥青质原油,胶质和沥青质容易形成缔合结构是其黏度较高的主要原因;胶质和沥青质分子具有由烷基链连接起来的含有侧链的芳香片结构,且含有形成氢键的极性基团,胶质和沥青质的平均相对分子质量分别为760和1 129;构建的南海原油胶质和沥青质平均分子结构式参数与表征结果吻合;添加1 000 μg/g降黏剂的南海原油在15 ℃和40 ℃下的降黏率分别为44.2%和40.2%,屈服应力值从1 070 Pa降至563 Pa,降黏效果显著。     

Prediction of Asphaltene Precipitation during Pressure Depletion and CO2 Injection for Heavy Crude

Abstract

In this work, a thermodynamic approach is used for modeling the phase behavior of asphaltene precipitation. The precipitated asphaltene phase is represented by an improved solid model, and the oil and gas phases are modeled with an equation of state. The Peng-Robinson equation of state (PR-EOS) was used to perform flash calculations. Then, the onset point and the amount of precipitated asphaltene were predicted. A computer code based on the solid model was developed and used for predicting asphaltene precipitation data reported in the literature as well as the experimental data obtained from high-pressure, high-temperature asphaltene precipitation experiments performed on Sarvak reservoir crude, one of Iranian heavy oil reserves, under pressure depletion and CO₂ injection conditions. The model parameters, obtained from sensitivity analysis, were applied in the thermodynamic model. It has been found that the solid model results describe the experimental data reasonably well under pressure depletion conditions. Also, a significant improvement has been observed in predicting the asphaltene precipitation data under gas injection conditions. In particular, for the maximum value of asphaltene precipitation and for the trend of the curve after the peak point, good agreement was observed, which could not be found in the available literature.     

胜利原油活性组分对其与烷基苯磺酸盐溶液组成的体系油-水界面张力的影响

 采用柱色谱四组分分离方法(SARA)对胜利原油进行分离,依次得到沥青质、饱和分、芳香分和胶质;采用碱醇液法萃取胜利原油得到其酸性组分,测定了各原油活性组分模拟油与烷基苯磺酸盐配制的系列标准溶液组成体系的油-水界面张力。结果表明,原油的酸性组分在低质量分数时通过改变油相的等效烷烃碳数（EACN）影响体系的油-水界面张力;高质量分数时则与表面活性剂混合吸附,使得体系油-水界面张力大幅度升高。胶质对其模拟油-表面活性剂标准溶液体系的油-水界面张力的影响与酸性组分的规律一致;沥青质的界面活性弱于酸性组分,混合吸附能力较弱,高质量分数时使体系油-水界面张力小幅度升高;饱和分和芳香分只影响油相的性质。