Application of Miscible Ethane Foam for Gas EOR Conformance in Low-Permeability Heterogeneous Harsh Environments

SPE Journal ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 1871-1883
Author(s):  
Mohamad Salman ◽  
Konstantinos Kostarelos ◽  
Pushpesh Sharma ◽  
Jae Ho Lee
Keyword(s):  
Oil Recovery ◽  
High Salinity ◽  
Total Dissolved Solids ◽  
Harsh Environments ◽  
Low Permeability ◽  
Type I ◽  
Fracture Networks ◽  
Operational Conditions ◽  
Minimum Miscibility Pressure ◽  
Carbon Dioxide Co2

Summary Unconventional plays pose a challenging set of operational conditions, including high temperature, high salinity, low permeability, and fracture networks. Aggressive development of these plays and the low primary recovery factors present an opportunity for using enhanced oil recovery (EOR) methods. This work presents a laboratory investigation of miscible ethane (C2H6) foam for gas EOR conformance in low-permeability, heterogeneous, harsh environments [<15 md, 136,000 ppm total dissolved solids (TDS) with divalent ions, 165°F]. The use of C2H6 as an alternative to carbon dioxide (CO2) offers several operational and availability strengths, which might expand gas EOR applications to depleted or shallower wells. Coupling gas conformance also helps improve displacement efficiencies and maximize overall recovery. Minimum miscibility pressure (MMP) displacement tests were performed for dead crude oil from the Wolfcamp Spraberry Trend area using C2H6 and CO2. Aqueous stability, salinity scan, and static foam tests were performed to identify a formulation. Subsequent foam quality and coreflood displacement tests in heterogeneous carbonate outcrop cores were conducted to compare the recovery efficiencies of three processes: gravity-unstable, miscible C2H6 foam; gravity-stable, miscible C2H6; and gravity-unstable, miscible C2H6 processes. Slimtube tests comparing C2H6 to CO2 resulted in a lower MMP value for C2H6. We identified a stable surfactant blend capable of Type I microemulsion and persistent foams in the presence of oil. Corefloods conducted with gravity-unstable miscible C2H6 foam, gravity-stable miscible C2H6, and gravity-unstable miscible C2H6 recovered 98.4, 61.9, and 42.6% oil originally in place, respectively. Our work shows that miscible C2H6 injection processes achieved significant recoveries even under gravity-unstable conditions. The addition of foam provides better conformance control, enhancing overall recovery at the laboratory scale, showing promise for field applications.

scholarly journals Low-tension gas process in high-salinity and low-permeability reservoirs

2020 ◽  
Vol 17 (5) ◽  
pp. 1329-1344
Author(s):  
Alolika Das ◽  
Nhut Nguyen ◽  
Quoc P. Nguyen
Keyword(s):  
Oil Recovery ◽  
High Salinity ◽  
Oxidative Degradation ◽  
Qualitative Assessment ◽  
Low Permeability ◽  
Displacement Efficiency ◽  
Fractional Flow ◽  
Hydrocarbon Gases ◽  
Low Tension ◽  
Low Permeability Reservoirs

Abstract Polymer-based EOR methods in low-permeability reservoirs face injectivity issues and increased fracturing due to near wellbore plugging, as well as high-pressure gradients in these reservoirs. Polymer may cause pore blockage and undergo shear degradation and even oxidative degradation at high temperatures in the presence of very hard brine. Low-tension gas (LTG) flooding has the potential to be applied successfully for low-permeability carbonate reservoirs even in the presence of high formation brine salinity. In LTG flooding, the interfacial tension between oil and water is reduced to ultra-low values (10−3 dyne/cm) by injecting an optimized surfactant formulation to maximize mobilization of residual oil post-waterflood. Gas (nitrogen, hydrocarbon gases or CO2) is co-injected along with the surfactant slug to generate in situ foam which reduces the mobility ratio between the displaced (oil) and displacing phases, thus improving the displacement efficiency of the oil. In this work, the mechanism governing LTG flooding in low-permeability, high-salinity reservoirs was studied at a microscopic level using microemulsion properties and on a macroscopic scale by laboratory-scale coreflooding experiments. The main injection parameters studied were injected slug salinity and the interrelation between surfactant concentration and injected foam quality, and how they influence oil mobilization and displacement efficiency. Qualitative assessment of the results was performed by studying oil recovery, oil fractional flow, oil bank breakthrough and effluent salinity and pressure drop characteristics.

Switchable Nonionic to Cationic Ethoxylated Amine Surfactants for CO2 Enhanced Oil Recovery in High-Temperature, High-Salinity Carbonate Reservoirs

SPE Journal ◽  
2013 ◽  
Vol 19 (02) ◽  
pp. 249-259 ◽  
Author(s):  
Yunshen Chen ◽  
Amro S. Elhag ◽  
Benjamin M. Poon ◽  
Leyu Cui ◽  
Kun Ma ◽  
...  
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Salinity ◽  
Capillary Tube ◽  
Mobility Control ◽  
Sweep Efficiency ◽  
Displacement Front ◽  
Flow Pathways ◽  
Co2 Flow ◽  
Carbon Dioxide Co2

Summary To improve sweep efficiency for carbon dioxide (CO2) enhanced oil recovery (EOR) up to 120°C in the presence of high-salinity brine (182 g/L NaCl), novel CO2/water (C/W) foams have been formed with surfactants composed of ethoxylated amine headgroups with cocoalkyl tails. These surfactants are switchable from the nonionic (unprotonated amine) state in dry CO2 to cationic (protonated amine) in the presence of an aqueous phase with a pH less than 6. The high hydrophilicity in the protonated cationic state was evident in the high cloudpoint temperature up to 120°C. The high cloud point facilitated the stabilization of lamellae between bubbles in CO2/water foams. In the nonionic form, the surfactant was soluble in CO2 at 120°C and 3,300 psia at a concentration of 0.2% (w/w). C/W foams were produced by injecting the surfactant into either the CO2 phase or the brine phase, which indicated good contact between phases for transport of surfactant to the interface. Solubility of the surfactant in CO2 and a favorable C/W partition coefficient are beneficial for transport of surfactant with CO2-flow pathways in the reservoir to minimize viscous fingering and gravity override. The ethoxylated cocoamine with two ethylene oxide (EO) groups was shown to stabilize C/W foams in a 30-darcy sandpack with NaCl concentrations up to 182 g/L at 120°C and 3,400 psia, and foam qualities from 50 to 95%. The foam produces an apparent viscosity of 6.2 cp in the sandpack and 6.3 cp in a 762-μm-inner-diameter capillary tube (downstream of the sandpack) in contrast with values well below 1 cp without surfactant present. Moreover, the cationic headgroup reduces the adsorption of ethoxylated alkyl amines on calcite, which is also positively charged in the presence of CO2 dissolved in brine. The surfactant partition coefficients (0 to 0.04) favored the water phase over the oil phase, which is beneficial for minimizing losses of surfactant to the oil phase for efficient surfactant usage. Furthermore, the surfactant was used to form C/W foams, without forming stable/viscous oil/water (O/W) emulsions. This selectivity is desirable for mobility control whereby CO2 will have low mobility in regions in which oil is not present and high contact with oil at the displacement front. In summary, the switchable ethoxylated alkyl amine surfactants provide both high cloudpoints in brine and high interfacial activities of ionic surfactants in water for foam generation, as well as significant solubilities in CO2 in the nonionic dry state for surfactant injection.

Lab Studies of MEOR Strains Optimization for High Salinity Reservoirs

2011 ◽  
Vol 343-344 ◽  
pp. 844-848
Author(s):  
Jing Chun Wu ◽  
Xiao Ming Lv ◽  
Zhi Jie Ou ◽  
Dai Yin Yin
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Produced Water ◽  
High Salinity ◽  
Low Permeability ◽  
Displacement Effect ◽  
Physical Experiments ◽  
Fermentation Liquor ◽  
Laboratory Results ◽  
Low Permeability Reservoirs

.Aiming at the high salinity at low-permeability reservoirs, a strain named S-4 that can yield a kind of bio-surfactants was screened from the produced water of oil wells in use of the Hemolysis of the bio-surfactants and its characteristics of making the color of blue gel plate change in its formation process. The laboratory results show that the surface tension of the strains fermentation liquor becomes less than 30mN/m after cultured by crude oil as the carbon source, and it would remain at the value of 31mN/m even if the concentration becomes a half; this bio-surfactant keeps stable when the salinity is in the range of 4000mg/L～50000mg/L; In physical experiments the strains can improve crude oil recovery ratio by 4% which shows a good oil displacement effect.

pH-Insensitive Polymeric Particles for Enhanced Oil Recovery in Reservoirs With Fractures

SPE Journal ◽  
2017 ◽  
Vol 23 (01) ◽  
pp. 34-47 ◽  
Author(s):  
Krishna Panthi ◽  
Kishore K. Mohanty
Keyword(s):  
Oil Recovery ◽  
High Salinity ◽  
Divalent Cations ◽  
Sweep Efficiency ◽  
Flow Capacity ◽  
Polymeric Particles ◽  
The Matrix ◽  
Polymeric Particle ◽  
Carbon Dioxide Co2 ◽  
Brine Injection

Summary Many carbonate reservoirs have natural fractures that reduce the sweep efficiency of displacement processes. The goal of this study is to improve oil recovery by reducing fluid bypassing caused by fractures, especially in carbon dioxide (CO2) floods. The pH-insensitive polymeric particles (PIPPs) synthesized in this study can plug fractures in reservoir rocks and divert fluid flow into the rock matrix. PIPPs swell in brine similar to polymeric particle gels (PPGs) published in literature; the swelling is a function of brine salinity. A PIPP expands many times (≈35 times) in deionized (DI) water, but swells only approximately 3 times in very-high-salinity (20 wt% NaCl) brine. The swelling of the particles is independent of pH in the range of 2 to 12. The swelling process is reversible with salinity. In water without divalent cations, these particles are stable at 80°C for at least a month. Coreflood results show that these small particles can be transported through fractures during high-salinity-brine injection and reduce the flow capacity of the fractures during low-salinity-brine injection. Subsequently, the injection fluid (brine, toluene, or CO2) is diverted into the matrix, and recovers oil from previously unswept matrix. PIPP injection increases waterflood recovery in cores with full fractures and half fractures connected to the inlet. PIPP placement also increases oil recovery for tertiary miscible/CO2 floods.

ASSESSMENT OF OIL WELL PRODUCTIVITY IN LOW-PERMEABILITY RESERVOIRS IN THE FIELDS OF EASTERN SIBERIA

2017 ◽  
pp. 30-36
Author(s):  
R. V. Urvantsev ◽  
S. E. Cheban
Keyword(s):  
Oil Recovery ◽  
Large Scale ◽  
Oil And Gas ◽  
Oil Extraction ◽  
Low Permeability ◽  
Oil Well ◽  
Eastern Siberia ◽  
Development Costs ◽  
Traditional Fields ◽  
Low Permeability Reservoirs

The 21st century witnessed the development of the oil extraction industry in Russia due to the intensifica- tion of its production at the existing traditional fields of Western Siberia, the Volga region and other oil-extracting regions, and due discovering new oil and gas provinces. At that time the path to the development of fields in Eastern Siberia was already paved. The large-scale discoveries of a number of fields made here in the 70s-80s of the 20th century are only being developed now. The process of development itself is rather slow in view of a number of reasons. Create a problem of high cost value of oil extraction in the region. One of the major tasks is obtaining the maximum oil recovery factor while reducing the development costs. The carbonate layer lying within the Katangsky suite is low-permeability, and its inventories are categorised as hard to recover. Now, the object is at a stage of trial development,which foregrounds researches on selecting the effective methods of oil extraction.

scholarly journals The Effect of Carbonyl and Hydroxyl Compounds on Swelling Factor, Interfacial Tension, and Viscosity in CO2 Injection: A Case Study on Aromatic Oils

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 94
Author(s):  
Asep Kurnia Permadi ◽  
Egi Adrian Pratama ◽  
Andri Luthfi Lukman Hakim ◽  
Doddy Abdassah
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Viscosity Reduction ◽  
Co2 Injection ◽  
Minimum Miscibility Pressure ◽  
Lower Viscosity ◽  
Hydroxyl Compounds ◽  
Swelling Factor

A factor influencing the effectiveness of CO2 injection is miscibility. Besides the miscible injection, CO2 may also contribute to oil recovery improvement by immiscible injection through modifying several properties such as oil swelling, viscosity reduction, and the lowering of interfacial tension (IFT). Moreover, CO2 immiscible injection performance is also expected to be improved by adding some solvent. However, there are a lack of studies identifying the roles of solvent in assisting CO2 injection through observing those properties simultaneously. This paper explains the effects of CO2–carbonyl and CO2–hydroxyl compounds mixture injection on those properties, and also the minimum miscibility pressure (MMP) experimentally by using VIPS (refers to viscosity, interfacial tension, pressure–volume, and swelling) apparatus, which has a capability of measuring those properties simultaneously within a closed system. Higher swelling factor, lower viscosity, IFT and MMP are observed from a CO2–propanone/acetone mixture injection. The role of propanone and ethanol is more significant in Sample A1, which has higher molecular weight (MW) of C7+ and lower composition of C1–C4, than that in the other Sample A9. The solvents accelerate the ways in which CO2 dissolves and extracts oil, especially the extraction of the heavier component left in the swelling cell.

scholarly journals Investigation on the effect of active-polymers with different functional groups for EOR

e-Polymers ◽  
2020 ◽  
Vol 20 (1) ◽  
pp. 61-68
Author(s):  
Dong Zhang ◽  
Jian Guang Wei ◽  
Run Nan Zhou
Keyword(s):  
Functional Groups ◽  
Oil Recovery ◽  
Molecular Size ◽  
Type I ◽  
Cleaning Efficiency ◽  
Sweep Efficiency ◽  
Profile Control ◽  
Branched Chain ◽  
Swept Volume ◽  
Enhance Oil Recovery

AbstractActive-polymer attracted increasing interest as an enhancing oil recovery technology in oilfield development owing to the characteristics of polymer and surfactant. Different types of active functional groups, which grafted on the polymer branched chain, have different effects on the oil displacement performance of the active-polymers. In this article, the determination of molecular size and viscosity of active-polymers were characterized by Scatterer and Rheometer to detect the expanded swept volume ability. And the Leica microscope was used to evaluate the emulsifying property of the active-polymers, which confirmed the oil sweep efficiency. Results show that the Type I active-polymer have a greater molecular size and stronger viscosity, which is a profile control system for expanding the swept volume. The emulsification performance of Type III active-polymer is more stable, which is suitable for improving the oil cleaning efficiency. The results obtained in this paper reveal the application prospect of the active-polymer to enhance oil recovery in the development of oilfields.

scholarly journals Mechanism of active silica nanofluids based on interface-regulated effect during spontaneous imbibition

2021 ◽  
Author(s):  
Xu-Guang Song ◽  
Ming-Wei Zhao ◽  
Cai-Li Dai ◽  
Xin-Ke Wang ◽  
Wen-Jiao Lv
Keyword(s):  
Contact Angle ◽  
Interfacial Tension ◽  
Oil Recovery ◽  
Dynamic Contact Angle ◽  
Liquid Interface ◽  
Spontaneous Imbibition ◽  
Wettability Alteration ◽  
Low Permeability ◽  
Oil Water ◽  
Solid Liquid

AbstractThe ultra-low permeability reservoir is regarded as an important energy source for oil and gas resource development and is attracting more and more attention. In this work, the active silica nanofluids were prepared by modified active silica nanoparticles and surfactant BSSB-12. The dispersion stability tests showed that the hydraulic radius of nanofluids was 58.59 nm and the zeta potential was − 48.39 mV. The active nanofluids can simultaneously regulate liquid–liquid interface and solid–liquid interface. The nanofluids can reduce the oil/water interfacial tension (IFT) from 23.5 to 6.7 mN/m, and the oil/water/solid contact angle was altered from 42° to 145°. The spontaneous imbibition tests showed that the oil recovery of 0.1 wt% active nanofluids was 20.5% and 8.5% higher than that of 3 wt% NaCl solution and 0.1 wt% BSSB-12 solution. Finally, the effects of nanofluids on dynamic contact angle, dynamic interfacial tension and moduli were studied from the adsorption behavior of nanofluids at solid–liquid and liquid–liquid interface. The oil detaching and transporting are completed by synergistic effect of wettability alteration and interfacial tension reduction. The findings of this study can help in better understanding of active nanofluids for EOR in ultra-low permeability reservoirs.

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