共查询到20条相似文献,搜索用时 31 毫秒
1.
In this paper, an experimental technique was developed to study the interfacial interactions between crude oil and CO2 under reservoir conditions. By using the axisymmetric drop shape analysis (ADSA) for the pendant drop case, this new technique makes it possible to measure the interfacial tensions (IFTs) between crude oil and solvents, such as CO2, at high pressures and elevated temperatures. The major component of this experimental setup is a see-through windowed high-pressure cell. In this study, the IFT of the crude-oil-CO2 system was measured as a function of pressure at two fixed temperatures. It was found that, due to mutual interfacial interactions between crude oil and CO2, their dynamic IFT gradually reduces to a constant value, i.e., the equilibrium IFT. The major interfacial interactions observed in this study include light-ends extraction and initial turbulent mixing. At T = 58°C, the equilibrium IFT reaches 1-2 dyne/cm when P ≥ 13.362 MPa, and only partial miscibility is achieved even up to P = 28.310 MPa. Thus, this experimental study shows that only partial miscibility can be obtained in most CO2 flooding reservoirs. In addition, it is expected that the observed light-ends extraction and initial turbulent mixing phenomena may have significant effects on ultimate oil recovery and long-term CO2 sequestration. 相似文献
2.
In this study, the interfacial tension (IFT) of crude oil-carbon dioxide mixtures was measured to determine the minimum miscibility pressure. CO2 flooding with sand packs, long cores, and heterogeneous cores was conducted to investigate the oil recovery and storage efficiency. The experiment results show that the interfacial tension decreases linearly with increasing pressure at two different pressure ranges. Under immiscible condition, the oil recovery and storage efficiency are increased by 30.1% and 52.4% when the injection pressure is increased from 13 to 22 MPa, and improved by 16.3% and 22.04% when the permeability is decreased from 270 to 10 mD, respectively. Under miscible condition, increase of injection pressure can only lead to much slower increase of oil recovery and storage efficiency, and permeability almost has no influence on oil recovery and storage efficiency. The oil recovery and storage efficiency can be remarkably reduced by heterogeneity. Water alternating CO2 injection can improve the oil recovery and storage efficiency by 35.5% and 13.55%, respectively, compared with continuous injection. 相似文献
3.
《Egyptian Journal of Petroleum》2022,31(2):51-58
The phenomenon of oil swelling at the oil-carbonated water (CW) system could be an important mechanism during the water alternating gas (WAG) injection process. Nevertheless, the study of the main mechanisms during water flooding (WF) is a complex topic that has not been well revealed so far, especially for asphaltenic crude oil (ACO) systems. Hence, the main goal of this experimental work is to determine the influence of carbon dioxide (CO2) within the water phase in the interfacial tension (IFT) between water and crude oil for an extensive range of pressures between 400 psi and 2000 psi (i.e. 2.76–13.79 MPa), under two temperatures of 313.15 and 323.15 K (i.e. 40 and 50 °C) by axisymmetric drop shape analysis (ADSA) method. The experimental results demonstrate that the water/ CW and crude oil IFTs decline with time. The value of dynamic IFT (DIFT) between CW and crude oil decreased about 6 mN/m in comparison with the oil–water DIFT. As a result of the CO2 solubility, the crude oil droplet swells with increasing pressure. When the temperature rises, the effects of increasing entropy phenomena and decline of liquids density is dominant compared to the solubility of CO2. Thus, the volume of oil droplet increases with temperature, unexpectedly. In addition, as thetemperature increases the water/CW-Oil IFT is slightly reduced over a wide range of pressure evaluated. Nevertheless, there is a slight increase as the pressure increases for the water–oil system. According to the predicted results, interfacial tension of the CW-oil system declines with increasing pressure until the solubility of CO2 is reached to a maximum value and then approximately remains changeless. 相似文献
4.
Alkaline-surfactant-polymer (ASP) flooding has been proved to be an effective enhanced oil recovery (EOR) method. Reduction of interfacial tension (IFT) between crude oil and ASP solution is the main mechanism in ASP flooding. Evaluating IFT between crude oil and ASP solution is a key parameter for ASP flooding in laboratory experiments or field projects. In order to obtain good result of ASP flooding in the reservoir in Zahra field, the influence of the concentration of Na2CO3 on IFT between Zahra crude oil and ASP solution with three different surfactants, BHJC, SS-231, and SS-233, was researched. IFT was measured with surface tension meter SVT20N, Dataphysics Co. Germany, at 72°C. For the view of IFT result anionic surfactant BHJC is more suitable for the Zahra oil field. This research is helpful for practical application of ASP flooding in Zahra oil field. 相似文献
5.
Peng Lv 《Petroleum Science and Technology》2016,34(14):1279-1284
The interfacial tension (IFT) between alkali-surfactant-polymer (ASP) solution and crude oil is an important parameter for evaluating the feasibility of the ASP flooding for an oil field. The IFT between six series of ASP solution and crude oil from B oil field were measured at 65°C. Each series of ASP solution was composed of NaOH or Na2CO3, one of the three kinds of surfactants (S1, S2, and S3), and polymer FT60. The concentration of FT60 and surfactant were 1500 and 2000 mg/L, respectively. The research results show that the IFT between ASP solution and crude oil is ultra-low in the NaOH-FT60-S2 series and NaOH-FT60-S3 series and the best concentration of NaOH is 4000 mg/L and 8000 mg/L, respectively. NaOH-FT60-S2 series is more suitable for B oil field. The IFT between ASP solution and crude oil is ultra-low in the Na2CO3-FT60-S2 series and the best concentration of Na2CO3 is 4000 mg/L. 相似文献
6.
针对CO_2-EOR原油组分对混相能力影响的问题,应用界面张力消失法设计了不同碳数烃组分、不同族烃组分、不同含量烃组分混合模拟油与CO_2的最小混相压力实验,分析不同族烃组分与CO_2最小混相压力的变化规律,探寻原油中影响CO_2驱最小混相压力的关键组分。研究表明:原油中不同组分与CO_2的最小混相压力不同,相同碳数烃组分最小混相压力依次为:烷烃、环烷烃、芳香烃;同族烃的碳数越小,最小混相压力越小;相同碳数烃类的混合组分模拟油的最小混相压力小于单一烃组分的最小混相压力;原油中低碳数烷烃含量增加,最小混相压力降低,高碳数芳香烃含量增加,最小混相压力升高。该研究结果为多种类型油藏实施CO_2驱提高采收率提供了数据材料及理论支撑。 相似文献
7.
利用常规方法测量超低渗透油藏CO2-原油最小混相压力时,存在测量周期长、工作量大等问题,且不能直接观察到CO2与原油的混相状态。为了确定杏河超低渗透油藏CO2-原油的最小混相压力,采用界面张力法对杏河油藏CO2和原油进行室内实验。结果表明:随着平衡压力的升高,原油中溶解CO2的量增多, CO2-原油之间界面张力的变化可分为2个阶段,且均呈逐渐减小的线性关系;当平衡压力从4 MPa增大到28 MPa时, CO2-原油之间的界面张力由17.72 mN/m降到1.56 mN/m。界面张力法测得杏河油藏最小混相压力值为22.5 MPa,略大于细管实验测得的最小混相压力值22.3 MPa,由于二者数值相差仅0.9%,表明界面张力法测量超低渗透油藏最小混相压力具有较好的准确性。通过上述研究,确定了杏河油藏最小混相压力,为杏河油藏注CO2增产开发方案的制定提供了理论支持,但是由于最小混相压力高于油藏目前压力(17.5 MPa),在目前油藏条件下CO2与原油不能实现混相。 相似文献
8.
重新回收温室气体CO2注入地层原油进行混相驱油是实现CO2封存和利用的主要途径之一,但其最小混相压力(MMP)被认为是该技术的一个关键参数。采用悬滴法测定了CO2和4种不同地层原油之间的界面张力,并直观地确定了4种不同地层原油注CO2驱油的MMP分别为:24.12MPa、24.81MPa、26.87 MPa和31.69 MPa。同时,采用多项式外延法确定各自的MMP,对比发现外延法确定的MMP误差均在3.0%以内,且MMP越高,误差越小。该实验表明,采用界面消失技术确定MMP具有操作简单、耗时少、成本低、准确度高等特点。 相似文献
9.
Ping Guo Yisheng Hu Jishun Qin Shi Li Songjie Jiao Fu Chen 《Petroleum Science and Technology》2017,35(4):345-350
In some low-permeable reservoirs, the miscibility pressure is far higher than the formation pressure, which makes it not feasible to have a CO2 miscible displacement. In this study, an oil-soluble surfactant, CAE, was designed and synthesized to reduce interfacial tension (IFT) and CO2-oil minimum miscible pressure (MMP), making it possible to release miscible displacement increasing oil recover. Experiment results showed that oil soluble surfactant can be dissolved in supercritical CO2 but not soluble in water. It is also found that the CAE preslug displacement has the higher displacement efficiency than displacement with the CAE dissolved in CO2. Based on a series of CAE preslug displacement experiments with varying CAE concentrations, the optimal injection concentration of CAE is 0.2%. Moreover the MMP determined under the CAE concentration of 0.2% is 6.1 MPa lower than that of pure CO2 displacement. It reduces the MMP more than liquid gas preslug displacement (3.2 MPa) when the same volume of liquid gas is used with the CAE used in CAE preslug displacement test. 相似文献
10.
用界面张力法测定CO2与原油的最小混相压力 总被引:1,自引:0,他引:1
采用悬滴法,测定了在模拟地层温度为356.5K、压力为8.54~23.43MPa时的CO2与原油间的界面张力.实验发现,CO2与原油间的界面张力随压力的增加近似呈线性下降趋势.对该数据进行了线性回归,并用外推法计算出当界面张力为零时的最小混相压力为24.17MPa,与实验观测达到一次接触混相状态时的压力(23.43MPa)相比,相对误差为3.16%.采用界面张力确定CO2与原油间的最小混相压力,既可通过直接观测接触混相状态确定,也可利用所测界面张力数据进行估算,操作简单易行,且耗时少. 相似文献
11.
Abstract The injection of alkali and alkali/polymer solutions is a well-known enhanced oil recovery technique. This article demonstrates how wood ash can be used as a source of low cost alkali instead of synthetic alkali that is also environmentally friendly. From the experimental studies, it is found that the pH value of 6% wood ash extracted solution is very close to the pH value of 0.5% synthetic NaOH or of 0.75% Na2SiO3 solution. A preliminary microscopic study of oil/oil droplets interaction in natural alkaline solution was carried out in order to understand the oil/water interface changes with time and its effect on oil/oil droplet coalescence. Also, interfacial tension (IFT) was measured for both synthetic and natural alkaline solutions. The IFT values in the presence of acidic crude oil show comparable results. 相似文献
12.
针对X底水油藏油井注水后综合含水上升过快的问题,利用HB70/300型高压物性分析仪开展了该区块原油相态特征实验、注气相态特征实验,并运用细管法开展了注CO2最小混相压力实验。对比分析了CO2和N2两种性质气体注入前后原油的相态特征变化,确定了该区块原油注CO2最小混相压力,为X油藏注气提高采收率可行性提出依据。实验结果表明,X油藏原始地层压力为46.01 MPa,原油饱和压力为11.06 MPa,注N2后饱和压力上升迅速,在原始地层条件下难以实现混相,表现出典型的非混相特征;注CO2后饱和压力上升较平缓,细管法测得的最小混相压力为28.03 MPa,说明利用CO2可实现CO2的混相驱替,而且最终的驱替效果比较理想。说明该油藏可开展注CO2混相驱,为进一步的开发方案调整提供了依据和合理的建议。 相似文献
13.
Vaibhav Kedar 《Petroleum Science and Technology》2018,36(12):835-842
The effect of salts and different surfactants on the equilibrium as well as dynamic interfacial tension (DIFT) between crude oil and water was investigated. Three different types of surfactants with identical hydrophobic chain length C12: Sodium Lauryl Ether Sulphate (SLES), Dodecyl Trimethyl Ammonium Bromide (DTAB), Polyoxyethylene (23) lauryl ether (C12E23) were used in this study. SLES shows better synergism of salt and surfactant mixture amongst the surfactants studied. The order of synergism of salts with the surfactant observed was MgCl2>CaCl2> NaCl. The results obtained from partition coefficient study show that the addition of salts favours the partition of surfactants into the oil phase hence reduce IFT more effectively. DIFT results reveal that, salt accelerates the surfactant migration towards the interface, hence, reducing the t* value. 相似文献
14.
AbstractSulfate anion is well-known for being one of the most active agents to be injected into the oil reservoirs and being capable of not only altering the interfacial properties of crude oil but also enhancing the water solution properties in oil recovery. In the current study, the effects of temperature and pressure were studied on interfacial tension (IFT) as well as the adsorption behavior of two different solutions containing sulfate anion using experimental measurements and modeling approaches. Although it was expected that IFT values of the studied systems might decrease as temperature increased due to the improvement in the molecule mobility and solubility of crude oil in water, which consequently might lead to the reduction in its free energy, the reverse trend was observed. The measured dynamic IFT values and adsorption behavior revealed that surface excess concentration of natural surfactants (ГNS) can be considered as the most effective parameter on interpreting IFT behavior as a function of temperature. 相似文献
15.
Mohammad Madani Peyman Abbasi Ghasem Zargar Pezhman Abbasi 《Petroleum Science and Technology》2017,35(23):2179-2186
Development of reliable and accurate models to estimate carbon dioxide–brine interfacial tension (IFT) is necessary, since its experimental measurement is time-consuming and requires expensive experimental apparatus as well as complicated interpretation procedure. In the current study, feed forward artificial neural network is used for estimation of CO2–brine IFT based on data from published literature which consists of a number of carbon dioxide–brine interfacial tension data covering broad ranges of temperature, total salinity, mole fractions of impure components and pressure. Trial-and-error method is utilized to optimize the artificial neural network topology in order to enhance its capability of generalization. The results showed that there is good agreement between experimental values and modeling results. Comparison of the empirical correlations with the proposed model suggests that the current model can predict the CO2–brine IFT more accurately and robustly. 相似文献
16.
Abstract It is essential that precipitation of asphaltenes is recognized early in the planning stage of any CO2 enhanced oil recovery (EOR) project so that appropriate testing can be performed to evaluate whether there will be a negative impact on reservoir performance. This article presents detailed evaluations of slim tube data that were obtained during CO2 injection using a medium-gravity Iranian crude oil. A crude oil from Bangestan reservoir of Ahwaz oilfield containing 18.2% asphaltenes with ~31.5 °API gravity was flooded by purified CO2 (>96% CO2) in a slim tube apparatus under 2,700 psi at 110°C. We were going to determine the minimum miscibility pressure (MMP) of the sample oil under injection of CO2 flood, but when a CO2 slim tube test was performed for this oil at 2,700 psi, less than half of the saturated oil in the tube was recovered, which implied that the displacement process was immiscible. At this pressure, the asphaltene deposition in the slim tube apparatus was so severe that even a pressure gradient of 6,200 lb/in2 was not able to displace any fluid through the capillary tube. Therefore, we abandoned MMP determination with this sample and investigated the problem. Due to the high percentage of asphaltenes in the sample, using the slim tube MMP as an apparatus for determining minimum miscibility pressure of CO2 and sample oil can be misleading. 相似文献
17.
In-depth understanding of interactions between crude oil and CO2 provides insight into the CO2-based enhanced oil recovery (EOR) process design and simulation. When CO2 contacts crude oil, the dissolution process takes place. This phenomenon results in the oil swelling, which depends on the temperature, pressure, and composition of the oil. The residual oil saturation in a CO2-based EOR process is inversely proportional to the oil swelling factor. Hence, it is important to estimate this influential parameter with high precision. The current study suggests the predictive model based on the least-squares support vector machine (LS-SVM) to calculate the CO2–oil swelling factor. A genetic algorithm is used to optimize hyperparameters (γ and σr2) of the LS-SVM model. This model showed a high coefficient of determination (R2 = 0.9953) and a low value for the mean-squared error (MSE = 0.0003) based on the available experimental data while estimating the CO2–oil swelling factor. It was found that LS-SVM is a straightforward and accurate method to determine the CO2–oil swelling factor with negligible uncertainty. This method can be incorporated in commercial reservoir simulators to include the effect of the CO2–oil swelling factor when adequate experimental data are not available. 相似文献
18.
During CO2 flooding, extraction of lighter hydrocarbons from crude oil makes the remaining oil hard to be recovered. In this work, we design a new experimental method to characterize the effect of CO2 extraction on crude oil. The experimental results show that, the volume of extracted hydrocarbons increases as system pressure increases. The hydrocarbons with wider carbon number can be extracted from crude oil at high pressures. Moreover, the wax precipitation and viscosity of the remaining oil increase with increasing pressure. This study is expected to provide the basic understanding of the mechanisms of CO2 flooding for enhanced oil recovery. 相似文献
19.
微-纳米受限空间原油-天然气的最小混相压力(MMP)对致密/页岩油储层注天然气提高采收率参数优化、方案设计及产能预测至关重要,但至今尚缺少获取该参数的可靠方法。针对这一关键问题,提出一种微-纳米受限空间原油-天然气界面张力(IFT)计算方法,通过原油-天然气相平衡计算得到Parachor模型参数从而计算出IFT,并基于界面张力消失法(VIT)预测MMP。该方法改进了气液平衡计算及Peng-Robinson状态方程,考虑了毛细管压力并修正了流体的临界压力和临界温度,简化了传统计算方法,并将气/液相压力考虑到平衡常数Ki的迭代公式中。通过设计8组不同组分天然气并以长庆油田原油和拟注入天然气为实例,分别计算了孔隙半径rp为5 000 nm、1 000 nm、500 nm、100 nm、10 nm时的IFT和MMP。计算结果表明,压力越高,IFT越小;在rp为100~5 000 nm时,原油-天然气体系的IFT和MMP基本不受rp的影响;当rp≤100 nm时,IFT和MMP显著降低,MMP最大降幅达38.76%,说明致密/页岩油储层注天然气提高采收率相比常规储层注天然气更容易混相。原油-天然气体系的MMP与C2—C4含量呈现负相关性,且rp越小,MMP递减速度越快,最大降幅达57.33%(rp=10 nm,C2—C4摩尔分数增至40%)。将计算结果与文献报道数据进行对比,进一步验证了模型的可靠性。 相似文献
20.
Mutual interactions between oil and gas are critical factors affecting the gas enhancing oil recovery (EOR) process. Focusing on CO2/oil and natural gas/oil systems, their interactions are researched and compared by extraction capacity and solubility measurement experiments. Core flood tests are also implemented to determine the effects of interactions on oil recovery. Results show that CO2 can extract more light oil from the original and its extraction efficiency can reach 59.3% at 46 MPa, whereas that of natural gas is only 7.3%. However, heavy components content and viscosity of the residual oil processed by CO2 increases significantly because of extraction, while natural gas does not affect the composition of the residual so remarkably. With increased pressure, solubility of CO2 and natural gas in a light oil present a linear growth trend with similar rate, but the former is greater than the latter by about 130m3/m3. Core flood tests show that, for the continuous gas injection in the secondary oil recovery process, recovery of CO2 flood is about 20% higher than that of natural gas due to the late breakthrough of CO2, as most of the crude oil is produced before breakthrough. 相似文献