Utilization of Grid partitioning based Fuzzy inference system approach as a novel method to estimate solubility of hydrocarbons in carbon dioxide

Recently due to increasing demand for energy and declination of oil reservoir the researchers have been encouraged to investigate the enhancement of oil recovery (EOR) approaches. One of popular and wide applicable processes in EOR is carbon dioxide injection which is attractive for researchers and industries due to environmentally aspects, good efficiency in displacement and low cost. The carbon dioxide injection causes the hydrocarbons extracted from crude oil so the solubility of hydrocarbon in carbon dioxide which is one of the critical parameters affects this phenomenon becomes interesting topic for researchers. In the present work Grid partitioning based Fuzzy inference system approach as a new method for prediction of solubility of hydrocarbons in carbon dioxide as function of temperature, pressure and carbon number of alkane was applied. To show the accuracy of the model the coefficients of determination were determined as 0.9902 and 0.9584 for training and testing phases respectively.     

Applying Fuzzy c-means approach as a novel method for prediction of interfacial tension between carbon dioxide and hydrocarbons

The worldwide demand for energy increases and also the price of crude oil increases so these reasons have been caused the searchers have motivated to investigate enhanced of oil recovery (EOR) processes. The carbon dioxide injection is recognized as one of the favorable approaches of EOR because of high displacement efficiency, environmentally aspects and lower cost. The Interfacial tension between crude oil and carbon dioxide is known as one of the critical factors which affect the performance of injection. The main objective of the present investigation is development of Fuzzy c-means (FCM) approach as novel method to estimate interfacial tension between carbon dioxide and hydrocarbons as function of pressure, temperature, liquid and gas densities and molecular weight of alkane. The performance of predicting model was evaluated statistically and graphically and the results confirmed the ability of the model to predict interfacial tension between carbon dioxide and hydrocarbons.     

改进密度模型计算溶质在超临界CO_2中的溶解度

基于平衡常数k和超临界CO2密度ρ1的曲线关系,提出了一个改进的溶解度模型用于计算溶质在超临界CO2中的溶解度,该模型强化了温度对k的影响。改进的溶解度模型计算了18种溶质在超临界CO2中的溶解度,并与常用的Chrastil,Adachi-Lu,del Valle-Aguilera,Sparks模型进行了对比。计算结果表明,改进模型精度最高,其绝对平均偏差(AAD)的平均值为5.81%,而Chrastil,Adachi-Lu,del Valle-Aguilera,Sparks模型的AAD平均值分别为10.66%,7.38%,9.91%,7.00%。该模型为溶质在超临界CO2中的溶解度计算提供了一种新的方法。     

磷酸三丁酯在超临界二氧化碳中的溶解度

采用超临界萃取装置测定了热力学温度为303.15,313.15,323.15 K,压力为8.5～25.0 MPa条件下磷酸三丁酯(TBP)在超临界二氧化碳中的溶解度,并根据溶剂化缔合理论、相平衡规则及高压对溶剂化平衡的影响建立了溶解度的数学模型。结果表明,所建立模型的TBP溶解度预测值与实验值吻合良好。用Chrastil模型关联实验值发现,用模型计算的精度远高于Chrastil模型关联的结果。     

超临界CO_2萃取啤酒花溶解度研究

研究了啤酒花在超临界ＣＯ２中的平衡溶解度随介质温度和压力的变化规律，以及溶解特性。选择适宜的模型，用实验数据对模型进行验算，结果令人满意     

Utilization of LSSVM algorithm for estimating synthetic natural gas density

In the gas engineering the accurate calculation for pipeline and gas reservoirs requires great accuracy in estimation of gas properties. The gas density is one of major properties which are dependent to pressure, temperature and composition of gas. In this work, the Least squares support vector machine (LSSVM) algorithm was utilized as novel predictive tool to predict natural gas density as function of temperature, pressure and molecular weight of gas. A total number of 1240 experimental densities were gathered from the literature for training and validation of LSSVM algorithm. The statistical indexes, Root mean square error (RMSE), coefficient of determination (R²) and average absolute relative deviation (AARD) were determined for total dataset as 0.033466, 1 and 0.0025686 respectively. The graphical comparisons and calculated indexes showed that LSSVM can be considered as a powerful and accurate tool for prediction of gas density.     

注CO_2驱油技术的室内评价方法及应用概况

注CO_2驱油作为一种有效提高采收率的方法,在油气田开采中已经占据越来越重要的地位。阐述了CO_2驱油机理、及其对应的驱油方式。其中比较系统的总结出了现行测定及评价注CO_2驱参数的各种室内试验方法并调研了CO_2驱油技术的国外概况和国内应用现状,提出在气源上,建议有关油田与工厂合作,合理的利用工业废气,开展CO_2捕集和驱油埋存先导性研究。     

Application of LSSVM algorithm as a novel tool for prediction of density of bitumen and heavy n-alkane mixture

The most of oil reservoirs in the world are heavy oil and bitumen reservoirs. Due to high viscosity and density of these types of reservoirs the production has problems so importance of enhanced oil recovery (EOR) processes for them is clear. The injection of solvents such as tetradecane is known as one of methods which improve oil recovery from bitumen reservoirs. In the present investigation, the Least squares support vector machine (LSSVM) algorithm was used to estimate density of Athabasca bitumen and heavy n-alkane mixture in term of temperature, pressure and weight percent of the solvent. The Root mean square error (RMSE), average absolute relative deviation (AARD) and the coefficient of determination (R²) for total dataset are determined 0.033466, 0.0025686 and 1 respectively. The predicted results indicate that the LSSVM algorithm has potential to be a predicting machine for the bitumen-heavy alkane mixture density prediction.     

Box—Behnken法研究二氧化碳驱油效果影响因素

温室气体CO2使全球气候变暖,对人类的生存和社会经济的发展构成了严重威胁。CO2地质处置的最有效方式就是注入油气田。国外很多油田已成功地进行大规模CO2驱并取得较好的效果,证明CO2驱是三次采油中最具潜力的提高采收率方法之一。针对这一问题,文中综合考虑各种影响因素,基于详细理论研究与分析,建立典型CO2驱油模型,开展数值计算,在单因素分析的基础上,引入综合反映CO2驱油效果的无因次参数,运用Box—Behnken试验设计,通过曲面反应法建立计算CO2驱油采收率的二项式计算模型,并对反应曲面结果进行分析,得出无因次参数对CO2驱油效果的影响顺序和交互影响的显著性。其研究成果对CO2驱油具有理论及现场指导意义。     

超临界二氧化碳增稠剂溶解性实验评价*

超临界二氧化碳(CO2)黏度不足0.1 mPa·s,在加砂压裂中携砂困难,需添加增稠剂增大其黏度.鉴于增稠剂在CO2中的溶解性与其增黏效果密切相关,对比研究了聚合物ZCJ-01、表面活性剂微乳液APRF-2和表面活性剂乳液SC-T-183种增稠剂在液态、超临界CO2和水中的溶解性,利用Chrastil半经验模型对溶解度...     

CO_2在碳酸氢钠水溶液中溶解度的研究

实验研究了ＣＯ２在不同温度、压力下在碳酸氢钠水溶液中的溶解度，并对所测定的溶解度数据用新建立的热力学模型进行了模型计算，并同改进的Ｐ－Ｔ方程进行了比较。结果表明新热力学模型的计算结果与实验数据吻合较好，尤其在压力较高时，该模型能给出优于改进的Ｐ－Ｔ方程的计算结果。     

稠油油藏注CO2提高采收率影响因素研究

与稀油注CO₂提高采收率机理不同,CO₂与稠油无法达到混相,因此影响其开发效果的主要因素差别很大,特别是在热化学复合采油过程中,注入的CO₂主要发挥隔热、降黏、增能的作用。为了进一步研究不同因素对稠油油藏注CO₂驱替效果的影响,在稠油样品物性分析的基础上,利用正交实验方法研究了原油黏度、温度、压力和渗透率对稠油油藏注CO₂提高采收率的影响。温度对采收率影响最大,其他因素由大到小依次为：渗透率、压力、油样类型。根据实验结论及认识,综合考虑地层温度、油藏渗透率等因素,在胜利油田开展了稠油油藏注CO₂吞吐提高采收率矿场试验。从矿场实际生产结果来看,油藏温度增加以及油藏渗透率提高,都有利于注CO₂吞吐开发,都能够有效提高油井产量。