Rheological modeling and drag reduction studies of Indian heavy crude oil in presence of novel surfactant

Viscosity and rheology modeling of heavy crude oil were studied at different shear rate and temperature with and without naturally extracted surfactant Mahua. Drag reduction analysis was done in 2”-ID, 2.5 m horizontal pipeline at different temperatures and flow rates. Viscosity was reduced by 60.4% after addition of 1000 ppm Mahua at 50°C. Modeling analysis showed that crude oil-surfactant samples followed Power law model with high regression coefficients. Maximum drag reduction of 94.8% occurred after adding 2000 ppm Mahua to 85% heavy oil+15% water at 40°C and at a flow rate of 50 LPM.     

Comparative Studies on Synthetic and Naturally Extracted Surfactant for Improving Rheology of Heavy Crude Oil

Effect of surfactants on rheological properties of heavy crude oil obtained from Mehsana Asset, Gujarat, India, were studied. Studies on effectiveness towards flow behavior were made using a surfactant extracted from a tropical Indian plant Madhuca longifolia (Mahua) and nonionic surfactant Brij-30 considering various contributing parameters such as temperature, concentration, and shear rate. Tests were performed at controlled shear rate. At 25°C, 2000 ppm Mahua and Brij-30 addition reduced viscosity of crude oil by 48% and 52%, respectively. Complex and viscous modulus of crude oil decreased significantly due to addition of both the surfactants. FTIR studies of crude-surfactant mixture showed remarkable decrease in concentration of viscosity enhancing groups such as alkanes, alcoholic, and acidic groups indicating the effectiveness of both the surfactants. Naturally extracted surfactant may be used as flow improver for transporting heavy crude oil.     

Experimental investigation of the yield stress measurements for xanthan solutions and crude oil-xanthan emulsions

Yield stress measurements of xanthan aqueous solutions and crude oil-xanthan emulsions were investigated experimentally. The yield stress study was carried out for wide range of crude oil (0–75% by volume) and xanthan gum (0–10⁴ ppm) concentrations. Two types of xanthan polymers of Sigma and Kelzan were used for the current study. Aqueous solutions with higher xanthan concentration displayed higher cycles of shear rate-shear stress rheograms. Both aqueous solutions of Sigma and Kelzan showed similar behavior for concentration of ≤1000 ppm, however, Sigma solutions of higher concentrations reported slightly higher flow behavior than Kelzan. Similar rheogram behaviors are found for both Sigma and Kelzan emulsions up to concentration of 5,000 ppm. However, for 10,000 ppm, a slight higher profile for Sigma emulsions was reported.     

The Performance of Toluene and Naphtha as Viscosity and Drag Reducing Solvents for the Pipeline Transportation of Heavy Crude Oil

Heavy crude oil shows high viscosity combined with low mobility, which affects the efficient transportation through pipelines. Drag has long been identified as the main reason for the loss of energy in pipeline fluid transmission and other similar transportation channels. The main contributor to this drag is the viscosity as well as friction against pipe walls, which will result in more pumping power consumption. Various methods such as heating, upgrading, dilution, core annular flow, and emulsification in water have been used for their transportation. The influence of toluene and naphtha as a viscosity and drag reducing solvent on flow of Iraqi crude oil in pipelines was investigated in the present work. The effect of additive type, concentration, pipe diameter, solution flow rate, and heating on the percentage of drag reduction (%Dr) and percentage flow increase (%FI) were the variables of study. The maximum drag reduction was observed to be 40.48% and 34.32% using heavy oil flowing in pipeline diameter of 0.0508 m I.D. at 27°C containing 10 wt% naphtha and toluene, respectively. Also, the dimensional analysis is used for grouping the significant quantities into dimension less group to reduce the number of variables.     

Selection of Conditions for Shipment of Crude Oils in Pipelines

As the first studies showed, the new Uzbekistan crude oils are viscous. Using crude oil from the Mingbulak field, we found that its high viscosity (22.38 mm²/sec at 50°C) is primarily due to the high content of wax (up to 8.56 wt. %), silicone resins (up to 15.65 wt. %), and asphaltenes (6.8 wt. %) [1, 2]. Shipment of such crude in a pipeline requires high power consumption.     

Investigation of non-Newtonian flow characterization and rheology of heavy crude oil

The heavy crude oil exhibits a non-Newtonian shear thinning behavior over the examined shear rate. The viscosity of the heavy crude oil decreases about 15.6% when the temperature increased from 30 to 60°C. Heavy crude oil was blended with the aqueous solution of surfactant and saline water in different volumetric proportions of NaCl, and Na₂CO₃ solution mixtures. The addition of 50% of the mixture to the heavy crude oil causes a strong reduction in the viscosity, about 67.5% at 60°C. The heavy crude oil fits the Power law model since it has the lowest average absolute percent error of 0.0291. The flow behavior index of the heavy crude oil reaches a value of 0.9305 at a temperature of 30°C and it increases to 0.9373 when the temperature raises 60°C, while the consistence coefficient decreases from 2.8811 to 2.3558.     

Effect of pour point depressant on wax deposition and drag reduction in horizontal pipelines

A newly synthesized pour point depressant (PPD) was used to decrease the wax deposition thickness and drag force during a waxy crude oil flow in two horizontal pipes of length 2.5 m each and inner diameters 1 inch and 2 inches. The flow rates of 80–120 LPM were used. 1,000-ppm PPD reduced the thickness of wax deposited by 31% and 72% at 120 LPM and 30°C in 1-inch and 2-inch pipes, respectively. There was about 15% drag reduction in both the pipes at 30°C and 120-LPM flow rate after adding 1,000-ppm PPD.     

Effect of reaction temperature and hydrogen donor on the Ni0@graphene-catalyzed viscosity reduction of extra heavy crude oil

Ni⁰@graphene nanocomposites were prepared via a solvothermal method and used as the catalysts for the viscosity reduction of extra heavy crude oil. Higher graphene content in Ni⁰@graphene nanocomposite has an adverse effect on its catalytic activity. The addition of tetralin and higher reaction temperature can obviously promote the catalytic activity. The catalyst accompanied by hydrogen donor can attain a viscosity reduction rate of 84.3% after the catalytic reaction under 280°C for 24 h and reduce the viscosity of crude oil from 174,219 to 27,352 mPa s (measured at 50°C).     

Improvement of heavy oil recovery and role of nanoparticles of clay in the surfactant flooding process

Increasing demand and dwindling supply of crude oil have spurred efforts toward enhancing heavy oil recovery. Recently, applications of nanoparticles (NPs) for heavy oil recovery have been reported. In this study, the use of clay NPs is investigated for enhanced oil recovery. Surfactant solutions and newly developed nanosurfactant solutions with 1600–2000 ppm SDS were tested. The crude oil had a viscosity of 1320 mPa.sec at test conditions. In this study, the role of NPs in the adsorption of surfactant onto solid surfaces of reservoir core is studied. The core flooding experiments showed high potential of using nanoclay for enhancing heavy oil recovery, where 52% of surfactant flooded heavy oil was recovered after injecting the NPs solvent. Moreover, nanoclay has generally better performance in enhancing the oil recovery at surfactant solution, near CMC conditions. The nanoclay surfactant solutions improved oil recovery. The nanoclay, however, showed improved performance in comparison with clay.     

Flow Enhancement of Medium-Viscosity Crude Oil

Abstract

This study investigated the different alternatives to enhance the flowability of crude oil with medium viscosity. These alternatives include the addition of water into crude oil to form water-in-oil emulsion, the addition of light petroleum product, the addition of flow improver, and a preheating technique. Temperature range of 10–50°C, water concentration range of 0–50% by volume, flow improver concentration range of 0–5000 ppm, and kerosene concentration range of 0–50% by volume were investigated in the flowability enhancement study of crude oil with medium viscosity. The flowability enhancement in terms of viscosity reduction was investigated using RheoStress RS100 from Haake. A cone–plate sensor was used with a cone angle of °4, cone diameter of 35 mm, and 0.137-mm gap at the cone tip. The addition of kerosene to crude oil improves the flowability much better than any other investigated technique.     

Experimental investigation of the rheological behavior of algerian crude oils from the quagmires

In this work, the rheological behavior for three types of crude oil coming from different quagmires namely Amassak, Tamendjelt and Tin Fouye of the TFT sector (Tin Fouye Tabankort/South Algeria) has been experimentally investigated. A controlled stress rheometer (AR 2000, TA Instrument) was used throughout this investigation. The experimental measurements in terms of flow and dynamic tests were carried out at different temperatures during the shear rate over the range of 0–700?s^?1 and frequency range of 0.1–10?rad/s. The obtained results show that the viscosity and shear stress of the crude oils decreases about 53.30%, 58.80%, and 59% respectively, when the temperature increased from 10 to 20?°C. The yield stress required to flow of crude oils also decreased to 37.06%, 89.78%, and 77.53% respectively. The dynamic analysis of the crude oils by identifying of the storage modulus (G′) and the loss modulus (G″) has indicated that the rheological properties of crude oils were significantly temperature-dependent.     

Double alkyl chain copolymers as flow improvers for heavy oil

As flow improvers for heavy crude oil, two oil-soluble copolymers (DM-S-VA, DA-S-VA) were successfully synthesized and characterized by ¹H NMR and GPC. A rich alkyl chain and appropriate molecular weight of copolymer play fundamental role in viscosity reduction of heavy oil. Furthermore, synergistic effect of surfactants on polymers can promote the viscosity reduction, and the best formulation can increase the viscosity reduction rate to 78% to oil A. Comparing with the apparent viscosity of the different heavy oil mixing system in a wide shear rate range (0.1–200 s^?1), the results show good stability and viscosity reducing effect.     

Kinetics of (TBAF + CO2) semi-clathrate hydrate formation in the presence and absence of SDS

In this communication, the impacts of adding SDS (sodium dodecyl sulfate), TBAF (tetra-n-butylammonium fluoride) and the mixture of SDS + TBAF on the main kinetic parameters of CO₂ hydrate formation (induction time, the quantity and rate of gas uptake, and storage capacity) were investigated. The tests were performed under stirring conditions at T = 5 ℃ and P = 3.8 MPa in a 169 cm³ batch reactor. The results show that adding SDS with a concentration of 400 ppm, TBAF with a concentration of 1–5 wt%, and the mixture of SDS + TBAF, would increase the storage capacity of CO₂ hydrate and the quantity of gas uptake, and decrease the induction time of hydrate formation process. The addition of 5 wt% of TBAF and 400 ppm of SDS would increase the CO₂ hydrate storage capacity by 86.1% and 81.6%, respectively, compared to pure water. Investigation of the impact of SDS, TBAF and their mixture on the rate of gas uptake indicates that the mixture of SDS + TBAF does not have a significant effect on the rate of gas uptake during hydrate formation process.     

Effect of surfactants and their blend with silica nanoparticles on wax deposition in a Malaysian crude oil

The present study investigated the wax deposition tendencies of a light Malaysian crude oil(42.4° API), and the wax inhibiting potential of some surfactants and their blends with nanoparticles. With the knowledge that the majority of the wax inhibition research revolved around polymeric wax inhibitors, which cause environmental issues, we highlighted the potential of surfactants and their blend with SiO_2 nanoparticles as wax deposition inhibitors. Different surfactants including oil-based, silane-based, Gemini and bio-surfactants were considered as primary surfactants. The primary surfactants and their respective blends at a concentration of 400 ppm were screened as wax inhibitor candidates using cold finger apparatus. The screening results showed a significant influence on the paraffin inhibition efficiency on wax deposition by using 400 ppm of silane-based surfactant, which decreased the wax deposition up to 53.9% as compared to that of the untreated crude oil. The inhibition efficiency among the silane-based surfactant(highest) and bio-surfactant(lowest)revealed an appreciable difference up to 36.5%. Furthermore, the wax from the treated sample was found to deposit in a thin gel-like form, which adhered inadequately to the surface of the cold finger. A further investigation by blending the 400 ppm silane-based surfactant with a 400 ppm SiO_2 nanoparticle suspension in a load ratio of 3:1 found that the wax inhibition decreased up to 81% as compared to the scenario when they were not added. However, we have shown that the synergy between the silane-based surfactant and the nanoparticles is influenced by the concentration and load ratio of surfactant and nanoparticles, residence time, differential temperature and rotation rate.     

Improvement of rheological properties of Algeria crude oil by addition of extra-light crude oil and a surfactant agent

Abstract

Effect of surfactant and extra-light crude oil addition on the rheological behaviors of an Algeria crude oil in order to improving its flowability were studied at low temperature. These rheological properties include steady flow behavior, yield stress and viscoelastic behavior. An AR-2000 rheometer was employed in all of the rheological examination tests. Results show that Toluene and extra-light crude oil addition causes a strong reduction in viscosity, the yield stress and can effectively increase of crude oil transport capacity. The toluene addition gets its best flow capacity and lowest viscosity at 6%. The extra-light crude oil addition obtains its best flow capacity and lowest viscosity at 50%. The viscoelasticity character of the crude oil has indicate a significantly influence by the addition of Toluene and extra-light crude oil.     

流速对井筒降粘及地面油水混输管线降粘的影响

分析了油水流速对流动状态的影响，水平管线中随流速增加出现了6种流动状态；油井井筒中随流速提高到临界流速后出现了油水或水连续相流动，试验得出提高油水混合流体流速也可实现降粘开采输送，并将理论应用于地面油水输送管线及油井举升中取得明显效果。     

原油长输管道应用降凝剂研究

应用于输油管道的降凝剂,通过研究,在马惠宁输油管线进行了现场试验。结果表明:原油经过50ppm降凝剂处理,凝固点由16℃降至-2℃;5℃、11.5s^-1时粘度由1363mPa·s降至122.7mpa·s;反常点由24℃降至15℃;降凝剂处理原油与加热输送原油同期相比。油耗降低56%,电耗降低8%。处理温度、高速剪切、重复加热对改善原油低温流变性有一定的影响:原油理想的降凝剂处理温度应是最佳热处理温度;降凝剂的应用存在最佳始注入量,且遵循μ=μ₀+Ae^-Bq规律;应用降凝剂长时间低温输油时,不宜用局部加热和大排量冲刷方法处理管线;采用热共处理和降凝剂综合技术,可改善原油低温的流变性。实现管道常温输送,产生良好的经济和社会效益。     

A Comprehensive Evaluation of High Viscous Crude Oil from Shuguang No. 1 Zone of Liaohe Oil Field

Abstract

The high viscous crude oil from Shuguang No. 1 zone of Liaohe oil field has the characteristics of high density (ρ ₂₀ = 0.9977 g cm^?3), great viscosity (ν ₁₀₀ = 1223.9 mm² s^?1) and high pour point (48°C), which are similar to those of the residue distillation of general crude oils. It contains no gasoline distillation and the diesel oil fraction yield is just 7.19%. It is often used as fuels after emulsification. But this oil is so vicious that it cannot be atomized uniformly and burned fully. In order to make full use of it, this kind of high viscous crude oil has been evaluated comprehensively and the properties of its various distillations are analyzed respectively. The results indicate that this crude oil contains less wax, but more resins and asphaltene, which belongs to low-sulfur naphthene-base crude oils and it is the suitable material to produce high-quality paving asphalt. Based on its characteristics, the optimum processing scheme is put forward and the high-quality paving asphalt is produced by using the distillation higher than 350°C.     

The Viscosity Reduction of Heavy and Extra Heavy Crude Oils by a Pulsed Magnetic Field

Abstract

Ever increasing world energy demand requires the use of all hydrocarbon resources available, especially heavy and extra heavy crude oils, in the near future. However, transportation of these crudes is very difficult due to their high viscosity and low mobility. There are many different methods to reduce heavy crude oil viscosity. Some of these methods are heating, blending, water-in-oil emulsion formation, upgrading, and core annular flow, but each of these methods has several problems. The aim of this research is to investigate a new method to reduce viscosity for pipeline transportation. In this method, asphalt molecules, which are mainly responsible for high viscosity, are aggregated temporarily to micronized clusters while going through a pulsed electric field, causing a reduction of the viscosity. This method does not change the oil's temperature and is very suitable for underwater pipelines. Magnetic fields of 0.03 to 0.3 T were exerted on two kinds of heavy crude oils and viscosity reduction up to 7% was observed.     

Viscosity Reduction of Heavy and Extra Heavy Crude Oils by Pulsed Electric Field

Abstract

The ever-increasing world energy demand would require the use of all hydrocarbon resources available, especially heavy and extra-heavy crude oils in the near future. However, transportation of these crudes is very difficult due to their high viscosity and low mobility. There are many different methods to reduce heavy crude oil viscosity. Some of these methods are heating, blending, water-in-oil emulsion formation, upgrading, and core annular flow. But each of these methods has several problems. The aim of this research is to investigate a new method to reduce viscosity for pipeline transportation. In this method asphalt molecules, which are mainly responsible for high viscosity, are aggregated temporarily to micronized clusters while going through a pulsed electric field, causing a reduction of the viscosity. This method does not change the oil's temperature and is very suitable for underwater pipelines. The authors applied electric fields in the range of 0.5 to 1.8 KV/mm an Iranian heavy crude oil and viscosity reduction up to 7% was observed.