Experimental Investigation of Hybrid Techniques for Enhancing Alaska North Slope Viscous Oil Recovery

2021 ◽  
Author(s):  
Yaoze Cheng ◽  
Yin Zhang ◽  
Abhijit Dandekar
Keyword(s):  
Oil Recovery ◽  
Pressure Gauge ◽  
Measurement Range ◽  
Differential Pressure ◽  
Viscosity Reduction ◽  
North Slope ◽  
Oil Viscosity ◽  
Polymer Injection ◽  
Hybrid Techniques ◽  
Viscous Oil

Abstract Alaska North Slope (ANS) contains vast viscous oil resources that have not been developed effectively due to the lack of efficient Enhanced Oil Recovery (EOR) techniques. This study investigates the EOR performance of three new hybrid EOR techniques: HSW-LSW-LSP flooding, solvent-alternating-LSW flooding, and solvent-alternating-LSP flooding. Additionally, pressure-volume-temperature (PVT) tests have been conducted to investigate the oil swelling and viscosity reduction effects of the proposed solvent. It has been found that the oil recovery of HSW flooding was 43.42%, while the tested HSW-LSW-LSP flooding, solvent-alternating-LSW flooding, and solvent-alternating-LSP flooding could improve the oil recovery to 74.17%, 79.73%, and 85.87%, respectively. All three proposed hybrid EOR techniques can significantly enhance the viscous oil recovery since they were all designed to both improve the microscopic and macroscopic sweep efficiencies. In particular, the PVT test results confirmed that the proposed solvent in this study could effectively swell the viscous oil over 30% and significantly reduce the viscous oil viscosity by about 97%. However, the initially designed solvent-alternating-LSP flooding displacement experiment had to be terminated after the first slug of polymer injection due to the extremely high differential pressure, which was over the measurement range of the pressure gauge. Thus, the actually tested displacement process in this study was solvent-LSP flooding. The extremely high differential pressure was found to result from the polymer deposit and blockage at the outlet. Although the proposed solvent-alternating-LSP flooding may produce the highest oil recovery, it cannot be applied in the field until the issue of polymer precipitation is understood and solved. The study has practical guidance to the selection of proper EOR techniques to enhance viscous oil recovery on ANS.

An Experimental Study of Improving Viscous Oil Recovery by Using Hybrid Enhanced Oil Recovery Techniques: A Case Study of Alaska North Slope Reservoir

SPE Journal ◽  
2021 ◽  
pp. 1-20
Author(s):  
Yaoze Cheng ◽  
Yin Zhang ◽  
Abhijit Dandekar ◽  
Jiawei Li
Keyword(s):  
Oil Recovery ◽  
Oil Reservoirs ◽  
Viscosity Reduction ◽  
Displacement Efficiency ◽  
Natural Sand ◽  
Ζ Potential ◽  
Low Salinity ◽  
Viscous Oil ◽  
Reservoir Conditions ◽  
Salinity Water

Summary Shallow reservoirs on the Alaska North Slope (ANS), such as Ugnu and West Sak-Schrader Bluff, hold approximately 12 to 17 × 109 barrels of viscous oil. Because of the proximity of these reservoirs to the permafrost, feasible nonthermal enhanced oil recovery (EOR) methods are highly needed to exploit these oil resources. This study proposes three hybrid nonthermal EOR techniques, including high-salinity water (HSW) injection sequentially followed by low-salinity water (LSW) and low-salinity polymer (LSP) flooding (HSW-LSW-LSP), solvent-alternating-LSW flooding, and solvent-alternating-LSP flooding, to recover ANS viscous oils. The oil recovery performance of these hybrid EOR techniques has been evaluated by conducting coreflooding experiments. Additionally, constant composition expansion (CCE) tests, ζ potential determinations, and interfacial tension (IFT) measurements have been conducted to reveal the EOR mechanisms of the three proposed hybrid EOR techniques. Coreflooding experiments and IFT measurements have been conducted at reservoir conditions of 1,500 psi and 85°F, while CCE tests have been carried out at a reservoir temperature of 85°F. ζ potential determinations have been conducted at 14.7 psi and 77°F. The coreflooding experiment results have demonstrated that all of the three proposed hybrid EOR techniques could result in much better performance in reducing residual oil saturation than waterflooding and continuous solvent flooding in viscous oil reservoirs on ANS, implying better oil recovery potential. In particular, severe formation damage or blockage at the production end occurred when natural sand was used to prepare the sandpack column, indicating that the natural sand may have introduced some unknown constituents that may react with the injected solvent and polymer, resulting in a severe blocking issue. Our investigation on this is ongoing, and more detailed studies are being conducted in our laboratory. The CCE test results demonstrate that more solvent could be dissolved into the tested viscous oil with increasing pressure, simultaneously resulting in more oil swelling and viscosity reduction. At the desired reservoir conditions of 1,500 psi and 85°F, as much as 60 mol% of solvent could be dissolved into the ANS viscous oil, resulting in more than 31% oil swelling and 97% oil viscosity reduction. Thus, the obvious oil swelling and significant viscosity reduction resulting from solvent injection could lead to much better microscopic displacement efficiency during the solvent flooding. The ζ potential determination results illustrate that LSW resulted in more negative ζ potential than HSW on the interface between sand and water, indicating that lowering the salinity of injected brine could result in the sand surface being more water-wet, but adding polymer to the LSW could not further enhance the water wetness. The IFT measurement results show that the IFT between the tested ANS viscous oil and LSW is higher than that between the tested viscous oil and HSW, which conflicts with the commonly recognized IFT reduction effect by LSW flooding. Thus, the EOR theory of the LSW flooding in our proposed hybrid techniques may be attributed to low-salinity effects (LSEs) such as multi-ion exchange, expansion of electrical double layer, and salting-in effect, while water wetness enhancement may benefit the LSW flooding process to some extent. The LSP’s viscosity is much higher than the viscosities of LSW and solvent, so LSP injection could result in better mobility control in the tested viscous oil reservoirs, leading to improvement of macroscopic sweep efficiency. Combining these EOR theories, the proposed hybrid EOR techniques have the potential to significantly increase oil recovery in viscous oil reservoirs on ANS by maximizing the overall displacement efficiency.

Asphaltene Deposition Induced by Carbon Oxide and its Influence on Displacement Efficiency

2012 ◽  
Vol 594-597 ◽  
pp. 2451-2454
Author(s):  
Feng Lan Zhao ◽  
Ji Rui Hou ◽  
Shi Jun Huang
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Carbon Oxide ◽  
Viscosity Reduction ◽  
Core Flooding ◽  
Displacement Efficiency ◽  
Oil Composition ◽  
Oil Viscosity ◽  
Asphaltene Deposition ◽  
Total Oil

CO2is inclined to dissolve in crude oil in the reservoir condition and accordingly bring the changes in the crude oil composition, which will induce asphaltene deposition and following formation damage. In this paper, core flooding device is applied to study the effect of asphaltene deposition on flooding efficiency. From the flooding results, dissolution of CO2into oil leads to recovery increase because of crude oil viscosity reduction. But precipitated asphaltene particles may plug the pores and throats, which will make the flooding effects worse. Under the same experimental condition and with equivalent crude oil viscosity, the recovery of oil with higher proportion of precipitated asphaltene was relatively lower during the CO2flooding, so the asphltene precipitation would affect CO2displacement efficiSubscript textency and total oil recovery to some extent. Combination of static diffusion and dynamic oil flooding would provide basic parameters for further study of the CO2flooding mechanism and theoretical evidence for design of CO2flooding programs and forecasting of asphaltene deposition.

Indoor Study of Viscosity Reducer for Thickened Oil of Huancai

2012 ◽  
Vol 268-270 ◽  
pp. 547-550
Author(s):  
Qing Wang Liu ◽  
Xin Wang ◽  
Zhen Zhong Fan ◽  
Jiao Wang ◽  
Rui Gao ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Heavy Oil ◽  
High Viscosity ◽  
Oil Field ◽  
Viscosity Reduction ◽  
Oil Viscosity ◽  
Low Viscosity ◽  
Viscosity Reducer ◽  
Oil Water

Liaohe oil field block 58 for Huancai, the efficiency of production of thickened oil is low, and the efficiency of displacement is worse, likely to cause other issues. Researching and developing an type of Heavy Oil Viscosity Reducer for exploiting. The high viscosity of W/O emulsion changed into low viscosity O/W emulsion to facilitate recovery, enhanced oil recovery. Through the experiment determine the viscosity properties of Heavy Oil Viscosity Reducer. The oil/water interfacial tension is lower than 0.0031mN•m-1, salt-resisting is good. The efficiency of viscosity reduction is higher than 90%, and also good at 180°C.

High-Pressure Data and Modeling Results for Phase Behavior and Asphaltene Onsets of Gulf of Mexico Oil Mixed With Nitrogen

2014 ◽  
Vol 17 (03) ◽  
pp. 384-395 ◽  
Author(s):  
Odd Steve Hustad ◽  
Na Jia ◽  
Karen Schou Pedersen ◽  
Afzal Memon ◽  
Sukit Leekumjorn
Keyword(s):  
High Pressure ◽  
Gulf Of Mexico ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Positive Impact ◽  
Viscosity Reduction ◽  
Fluid Composition ◽  
Viscosity Data ◽  
Oil Viscosity ◽  
Reservoir Fluid

Summary This paper presents fluid composition, high-pressure pressure/volume/temperature (PVT) measurements, and equation-of-state (EoS) modeling results for a recombined Tahiti oil, Gulf of Mexico (GoM), and for the oil mixed with nitrogen in various concentrations. The data include: Upper and lower asphaltene onset pressures and bubblepoint pressures for the reservoir fluid swelled with nitrogen. At the reservoir conditions of 94 MPa (13,634 psia) and 94°C (201.2°F), asphaltene precipitation is seen after the addition of 27 mol% of nitrogen. Viscosity data for the swelled fluids showing that the addition of nitrogen significantly reduces the oil viscosity. Slimtube runs indicating that the minimum miscibility pressure (MMP) of the oil with nitrogen is significantly higher than estimated from published correlations. The data were modeled with the volume-corrected Soave-Redlich-Kwong (SRK) EoS and the perturbed-chain statistical association fluid theory (PC-SAFT) EoS. Although both equations provide a good match of the PVT properties of the reservoir fluid, PC-SAFT is superior to the SRK EoS for simulating the upper asphaltene onset pressures and the liquid-phase compressibility of the reservoir fluid swelled with nitrogen. Nitrogen-gas flooding is expected to have a positive impact on oil recovery because of its favorable oil-viscosity-reduction and phase behavior effects.

Design on Flow Measurement Solution with Intelligent Efflux Coefficient Standard Throttling Gear

2013 ◽  
Vol 325-326 ◽  
pp. 783-786
Author(s):  
Quan Sheng Duan ◽  
Qing Zhao ◽  
Li Cui Wang
Keyword(s):  
Lower Limit ◽  
Flow Measurement ◽  
Measurement Accuracy ◽  
Intelligent System ◽  
Design Method ◽  
Pressure Gauge ◽  
Measurement Range ◽  
Differential Pressure ◽  
National Standards

t is an in-depth research on the span measurement range ratio that standard throttling gear measures the flow is too small, and proposes the design method of multi-efflux coefficient standard throttling gear. Expanding the lower limit of measurable flow according to the relevant national standards GB/T2624-2006. Solution divides the span measurement range into several segments, each piece span measurement range corresponds to a differential pressure gauge, and calculates corresponding efflux coefficient depending on the GB/T2624-2006 to get many outflow coefficients on the different span measurement sub-range section. Intelligent system chooses corresponding efflux coefficients based on different differential pressure, and ensures measurement accuracy at the same time of expanding the lower limit.

Viscous Oil Recovery by Polymer Injection; Impact of In-Situ Polymer Rheology on Water Front Stabilization

2018 ◽  
Author(s):  
Bartek Vik ◽  
Abduljelil Kedir ◽  
Vegard Kippe ◽  
Kristian Sandengen ◽  
Tormod Skauge ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Polymer Rheology ◽  
Polymer Injection ◽  
Viscous Oil ◽  
Water Front

Study on In Situ Carbon Dioxide-Generation Flooding

2012 ◽  
Vol 502 ◽  
pp. 179-183
Author(s):  
Hong Jing Zhang ◽  
Shuang Bo Dong ◽  
Zhe Kui Zheng
Keyword(s):  
Carbon Dioxide ◽  
Oil Recovery ◽  
Flow Direction ◽  
Physical Models ◽  
Viscosity Reduction ◽  
Oil Viscosity ◽  
Foamy Oil ◽  
Oil Displacement ◽  
Generation Technology

Aiming at the source and corrosiveness of carbon dioxide, the in-situ carbon dioxide generation technology to enhance oil recovery was proposed。This paper presents the in-situ carbon dioxide generation technology mechanism, the expansion, viscosity reduction; oil-displacement efficiency and foamy oil of this technology were experimentally evaluated by using microscopic models and physical models. The experimental results indicated that the in-situ carbon dioxide generation technology could be used to produce enough carbon dioxide and get good efficiencies of oil expansion, reduction of viscosity and enhancement of oil displacement. Under the conditions of 2010mPa•s in oil viscosity, 60°C and 10MPa, the volume of oil could be expanded by25%, and the viscosity of oil can reduced to 52.7% , and the CO2 can displacement，restraining viscous fingering and changing liquid flow direction and carrying the residual oil.

Applied Research of Heat Self-Generated CO2 Technology in Steam Huff and Puff

2014 ◽  
Vol 1010-1012 ◽  
pp. 1693-1698
Author(s):  
Yi Ding ◽  
Guo Wei Qin ◽  
Peng Liu ◽  
Zi Li Fan ◽  
Hong Wei Xiao ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Field Experiments ◽  
Reduction Rate ◽  
Viscosity Reduction ◽  
Oil Viscosity ◽  
Blowing Agent ◽  
Steam Flooding ◽  
Gas Flooding

Heat self-generated CO2 technique is proposed, which is focused on the problems of recovery difficulty, poor effect steam soaking and so on for heavy oil reservoirs. This technology is combining of steam flooding and gas flooding and so on. Its main mechanism is the application of steam heating blowing agent to generate a large volume of gases (including CO2, NH3, etc) in the formation. While some of these gases acting with the oil to reduce the oil viscosity, some form miscible flooding to reduce water interfacial tension, so as to achieve the purpose of enhancing oil recovery. An optimized selection of the heat blowing agents was performed. By comparison the difference before and after the reaction of blowing agent solution, the increase of alkaline is occurred after the reaction, and is helpful to reduce oil viscosity and lower interfacial tension, etc. Studies indicate that heat-generating CO2 flooding technology can get a maximum viscosity reduction rate of 76.7%, oil-water interfacial tension decreased by 54.77%, further improve oil recovery by 4.17% based on the steam drive, which shows a technical advantage toward conventional EOR method. The field experiments indicate that the technique can greatly improve the oil production, which will provide a powerful technical supporting for the efficient development of heavy oil.

NETTING OF VISCOUS OIL

1987 ◽  
Vol 1987 (1) ◽  
pp. 115-122
Author(s):  
Gerard A. L. Delvigne
Keyword(s):  
Oil Recovery ◽  
Pollution Control ◽  
Empirical Equation ◽  
Oil Pollution ◽  
Mesh Size ◽  
Oil Viscosity ◽  
Oil Leakage ◽  
Oil Slick ◽  
Viscous Oil ◽  
Laboratory Flume

ABSTRACT Nets are used in oil pollution control activities to separate the oil and water, or as a more easily manageable alternative to impermeable barriers. The threat of oil leakage through nets is inherent to their use. Tests were performed in a laboratory flume, resulting in an empirical equation relating the leaking rate through a net to the oil viscosity, relative net-water velocity, and mesh size. The influence of turbulence and waves was also examined. Indications are given for useful net applications for corralling an oil slick with an unmoored vertical floating net, protecting specific areas with vertical moored nets, and using trawl nets for oil recovery.

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