scholarly journals Compatibility evaluation of modified seawater for EOR in carbonate reservoirs through the introduction of polyphosphate compound

2019 ◽  
Vol 17 (2) ◽  
pp. 393-408 ◽  
Author(s):  
Bisweswar Ghosh ◽  
Liying Sun ◽  
Nithin Chacko Thomas
Keyword(s):  
Oil Recovery ◽  
Economic Benefits ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Core Flooding ◽  
Systematic Screening ◽  
Flood Water ◽  
Scaling Potential ◽  
Original Oil In Place ◽  
New Formulation

Abstract Waterflood-assisted oil recovery with sulfate-spiked seawater would cause incompatibility scaling in carbonate reservoirs and reduce economic benefits. This research investigated the benefits of polyphosphate compounds in reducing scaling potential as well as its effect on oil recovery when mixed in high sulfate flood water. Severity of scaling potential of sulfate-spiked water in a carbonate reservoir environment was measured, followed by systematic screening of a polyphosphate compound, which successfully inhibited the sulfate scale precipitation at concentration as low as 100 ppm. The new formulation (seawater with four times sulfate and phosphate, SW4SP) was evaluated and compared with benchmark formulation (modified seawater with four times sulfate, SW4S). Contact angle, ζ-potential and drainage studies show that SW4SP changed the rock wettability from oil wet to water wet to a larger degree compared to SW4S. Improved recovery efficiency of SW4SP was confirmed through a set of core flooding studies in the tertiary and quaternary flood modes. Whereas SW4S recovered 7.7% of original oil in place (OOIP), SW4SP recovered about 8% of OOIP in the tertiary mode under approximately identical flow conditions. Flooding with SW4SP in the quaternary mode following a tertiary flood with SW4S on the same core resulted in 1.7% additional oil recovery, showing improved efficiency of the new flood water formulation.

Saturated carbon dioxide nanofluids enhanced oil recovery in carbonate reservoir cores using nuclear magnetic resonance

2021 ◽  
Author(s):  
Yongsheng Tan ◽  
Qi Li ◽  
Liang Xu ◽  
Xiaoyan Zhang ◽  
Tao Yu
Keyword(s):  
Carbon Dioxide ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Residual Oil ◽  
Core Flooding ◽  
Nuclear Magnetic

<p>The wettability, fingering effect and strong heterogeneity of carbonate reservoirs lead to low oil recovery. However, carbon dioxide (CO<sub>2</sub>) displacement is an effective method to improve oil recovery for carbonate reservoirs. Saturated CO<sub>2</sub> nanofluids combines the advantages of CO<sub>2</sub> and nanofluids, which can change the reservoir wettability and improve the sweep area to achieve the purpose of enhanced oil recovery (EOR), so it is a promising technique in petroleum industry. In this study, comparative experiments of CO<sub>2</sub> flooding and saturated CO<sub>2</sub> nanofluids flooding were carried out in carbonate reservoir cores. The nuclear magnetic resonance (NMR) instrument was used to clarify oil distribution during core flooding processes. For the CO<sub>2</sub> displacement experiment, the results show that viscous fingering and channeling are obvious during CO<sub>2</sub> flooding, the oil is mainly produced from the big pores, and the residual oil is trapped in the small pores. For the saturated CO<sub>2</sub> nanofluids displacement experiment, the results show that saturated CO<sub>2</sub> nanofluids inhibit CO<sub>2</sub> channeling and fingering, the oil is produced from the big pores and small pores, the residual oil is still trapped in the small pores, but the NMR signal intensity of the residual oil is significantly reduced. The final oil recovery of saturated CO<sub>2</sub> nanofluids displacement is higher than that of CO<sub>2</sub> displacement. This study provides a significant reference for EOR in carbonate reservoirs. Meanwhile, it promotes the application of nanofluids in energy exploitation and CO<sub>2</sub> utilization.</p>

Effect of pressure variation on polymer flooding

2021 ◽  
Author(s):  
Ahmad Ali Manzoor
Keyword(s):  
Polymer Solution ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Constant Pressure ◽  
Maximum Pressure ◽  
Core Flooding ◽  
Sweep Efficiency ◽  
Black Oil Model ◽  
Original Oil In Place

Chemical-based enhanced oil recovery (EOR) techniques utilize the injection of chemicals, such as solutions of polymers, alkali, and surfactants, into oil reservoirs for incremental recovery. The injection of a polymer increases the viscosity of the injected fluid and alters the water-to-oil mobility ratio which in turn improves the volumetric sweep efficiency. This research study aims to investigate strategies that would help intensify oil recovery with the polymer solution injection. For that purpose, we utilize a lab-scale, cylindrical heavy oil reservoir model. Furthermore, a dynamic mathematical black oil model is developed based on cylindrical physical model of homogeneous porous medium. The experiments are carried out by injecting classic and novel partially hydrolyzed polyacrylamide solutions (concentration: 0.1-0.5 wt %) with 1 wt % brine into the reservoir at pressures in the range, 1.03-3.44 MPa for enhanced oil recovery. The concentration of the polymer solution remains constant throughout the core flooding experiment and is varied for other subsequent experimental setup. Periodic pressure variations between 2.41 and 3.44 MPa during injection are found to increase the heavy oil recovery by 80% original-oil-in-place (OOIP). This improvement is approximately 100% more than that with constant pressure injection at the maximum pressure of 3.44 MPa. The experimental oil recoveries are in fair agreement with the model calculated oil production with a RMS% error in the range of 5-10% at a maximum constant pressure of 3.44 MPa.

Characteristics of a Geobacillus sp. as an Enhanced Oil Recovery Material

2012 ◽  
Vol 496 ◽  
pp. 542-545
Author(s):  
Xiang Ping Kong
Keyword(s):  
Crude Oil ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Sewage Treatment ◽  
Core Flooding ◽  
Treatment Technology ◽  
Promising Candidate ◽  
Different Types ◽  
Displacement Experiments ◽  
Original Oil In Place

The enhanced oil recovery characteristics of a Geobacillus sp. was investigated by shake flask experiments, blind-tube oil displacement experiments and core flooding tests. The strain exhibited good properties such as resisting high temperature, taking different types of crude oil as the sole carbon source, reducing the viscosity of crude oil, emulsifying and dispersing crude oil or liquid wax. The oil in the dead area could be effectively driven out by the strain, and the oil recovery of original oil in place had been increased by 12.9-15.9% after 5 treatments in 50 days by adopting air-assistant technique (air/liquid 10:1, v/v) due to the synergistic effect of the bacteria and their metabolites such as biogas and biosurfactants. The strain seems to be a promising candidate for microbial enhanced oil recovery and underground sewage treatment technology.

scholarly journals Oil recovery for fractured-vuggy carbonate reservoirs by cyclic water huff and puff: performance analysis and prediction

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Daigang Wang ◽  
Jingjing Sun
Keyword(s):  
Oil Recovery ◽  
History Matching ◽  
High Efficiency ◽  
Carbonate Reservoir ◽  
Carbonate Reservoirs ◽  
Production Performance ◽  
Quantitative Prediction ◽  
Attractive Alternative ◽  
Marquardt Algorithm ◽  
The Impact

Abstract Cyclic water huff and puff (CWHP) has proven to be an attractive alternative to improve oil production performance after depletion-drive recovery in fractured-vuggy carbonate reservoirs. However, due to the impact of strong heterogeneity, multiple types of fractured-vuggy medium, poor connectivity, complex flow behaviors and oil-water relationship, CWHP is merely suitable for specific types of natural fractured-vuggy medium, usually causing a great difference in actual oil-yielding effect. It remains a great challenge for accurate evaluation of CWHP adaptability and quantitative prediction of production performance in fractured-vuggy carbonate reservoir, which severely restricts the application of CWHP. For this study, we firstly enable the newly developed fuzzy grey relational analysis to quantify the adaptability of CWHP. With production history of several targeted producers, the accuracy of the proposed method is validated. Based on the traditional percolation theory and waterflood mechanisms in various types of fractured-vuggy medium, a quantitative prediction model for cyclic water cut fwp and increased recovery factor ΔR is presented. The CWHP production performance is discussed by using the Levenberg-Marquardt algorithm for history matching. With a better understanding of the fwp ~ ΔR curve characteristics in different types of fractured-vuggy medium, proper strategies or measures for potential-tapping remaining oil are provided. This methodology can also offer a good basis for engineers and geologists to develop other similar reservoirs with high efficiency.

scholarly journals Effect of pressure variation on polymer flooding

2021 ◽  
Author(s):  
Ahmad Ali Manzoor
Keyword(s):  
Polymer Solution ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Constant Pressure ◽  
Maximum Pressure ◽  
Core Flooding ◽  
Sweep Efficiency ◽  
Black Oil Model ◽  
Original Oil In Place

Chemical-based enhanced oil recovery (EOR) techniques utilize the injection of chemicals, such as solutions of polymers, alkali, and surfactants, into oil reservoirs for incremental recovery. The injection of a polymer increases the viscosity of the injected fluid and alters the water-to-oil mobility ratio which in turn improves the volumetric sweep efficiency. This research study aims to investigate strategies that would help intensify oil recovery with the polymer solution injection. For that purpose, we utilize a lab-scale, cylindrical heavy oil reservoir model. Furthermore, a dynamic mathematical black oil model is developed based on cylindrical physical model of homogeneous porous medium. The experiments are carried out by injecting classic and novel partially hydrolyzed polyacrylamide solutions (concentration: 0.1-0.5 wt %) with 1 wt % brine into the reservoir at pressures in the range, 1.03-3.44 MPa for enhanced oil recovery. The concentration of the polymer solution remains constant throughout the core flooding experiment and is varied for other subsequent experimental setup. Periodic pressure variations between 2.41 and 3.44 MPa during injection are found to increase the heavy oil recovery by 80% original-oil-in-place (OOIP). This improvement is approximately 100% more than that with constant pressure injection at the maximum pressure of 3.44 MPa. The experimental oil recoveries are in fair agreement with the model calculated oil production with a RMS% error in the range of 5-10% at a maximum constant pressure of 3.44 MPa.

Surfactant-Aided Low-Salinity Waterflooding for Low-Temperature Carbonate Reservoirs

SPE Journal ◽  
2021 ◽  
pp. 1-17
Author(s):  
Yue Shi ◽  
Chammi Miller ◽  
Kishore Mohanty
Keyword(s):  
Low Temperature ◽  
Oil Recovery ◽  
Anionic Surfactants ◽  
Surfactant Solution ◽  
Carbonate Reservoirs ◽  
Spontaneous Imbibition ◽  
Wettability Alteration ◽  
Low Salinity ◽  
Low Salinity Waterflooding ◽  
Original Oil In Place

Summary Carbonate reservoirs tend to be oil-wet/mixed-wet and heterogeneous because of mineralogy and diagenesis. The objective of this study is to improve oil recovery in low-temperature dolomite reservoirs using low-salinity and surfactant-aided spontaneous imbibition. The low-salinity brine composition was optimized using ζ-potential measurements, contact-angle (CA) experiments, and a novel wettability-alteration measure. Significant wettability alteration was observed on dolomite rocks at a salinity of 2,500 ppm. We evaluated 37 surfactants by performing CA, interfacial-tension (IFT), and spontaneous-imbibition experiments. Three (quaternary ammonium) cationic and one (sulfonate) anionic surfactants showed significant wettability alteration and produced 43–63% of original oil in place (OOIP) by spontaneous imbibition. At a low temperature (35°C), oil recovery by low-salinity effect is small compared with that by wettability-altering surfactants. Coreflood tests were performed with a selected low-salinity cationic surfactant solution. A novel coreflood was proposed that modeled heterogeneity and dynamic imbibition into low-permeability regions. The results of the “heterogeneous” coreflood were consistent with that of spontaneous-imbibition tests. These experiments demonstrated that a combination of low-salinity brine and surfactants can make originally oil-wet dolomite rocks more water-wet and improve oil recovery from regions bypassed by waterflood at a low temperature of 35°C.

Enhanced Oil Recovery in Gasflooded Carbonate Reservoirs by Wettability-Altering Surfactants

SPE Journal ◽  
2014 ◽  
Vol 20 (01) ◽  
pp. 60-69 ◽  
Author(s):  
Leizheng Wang ◽  
Kishore Mohanty
Keyword(s):  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Surfactant Solution ◽  
Carbonate Reservoir ◽  
Wettability Alteration ◽  
Foam Formation ◽  
Recovery Technique ◽  
Flow Functions ◽  
Original Oil In Place ◽  
Water Gas

Summary Gas-aided gravity drainage is a common oil-recovery technique in anticline-shaped oil reservoirs. If the permeability is low and the reservoir is oil-wet, the remaining oil saturation can be quite high. The goal of this work is to mobilize a part of this oil by surfactant injection. An anionic-surfactant formulation was developed to alter wettability and lower interfacial tension (IFT) for a gasflooded, carbonate reservoir. Different coreflood strategies, including gas/water/surfactant/water (GWSW), gas/surfactant/gas (GSG), gas/surfactant/water (GSW), and gas/surfactant/water/gas (GSWG) floods, were investigated. GSG, GWSW, and GSWG corefloods conducted in limestone cores recovered an additional 40–50% of the original oil in place (OOIP) because of the injection of surfactant. GSW corefloods conducted in a vuggy dolomite recovered less: an approximately 20%-of-OOIP incremental recovery. Numerical simulation was used to match GSG and GSW corefloods and estimate multiphase-flow functions. A 2D conceptual simulation model using these functions was built for an anticline reservoir for gas and surfactant-solution injection. GSG flooding using wettability-altering surfactant exhibited high oil recovery at the field scale. IFT reduction, wettability alteration, and foam formation contributed to enhanced oil recovery (EOR).

scholarly journals Enhancing Oil Recovery with Hydrophilic Polymer-Coated Silica Nanoparticles

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5720
Author(s):  
Alberto Bila ◽  
Ole Torsæter
Keyword(s):  
Oil Recovery ◽  
Spontaneous Imbibition ◽  
Rock Surface ◽  
Core Flooding ◽  
Ambient Conditions ◽  
Interfacial Chemistry ◽  
Sweep Efficiency ◽  
Dynamic Interactions ◽  
Tertiary Oil Recovery ◽  
Original Oil In Place

Nanoparticles (NPs) have been proposed for enhanced oil recovery (EOR). The research has demonstrated marvelous effort to realize the mechanisms of nanoparticles EOR. Nevertheless, gaps still exist in terms of understanding the nanoparticles-driven interactions occurring at fluids and fluid–rock interfaces. Surface-active polymers or other surface additive materials (e.g., surfactants) have shown to be effective in aiding the dispersion stability of NPs, stabilizing emulsions, and reducing the trapping or retention of NPs in porous media. These pre-requisites, together with the interfacial chemistry between the NPs and the reservoir and its constituents, can result in an improved sweep efficiency. This paper investigates four types of polymer-coated silica NPs for the recovery of oil from water-wet Berea sandstones. A series of flooding experiments was carried out with NPs dispersed at 0.1 wt.% in seawater in secondary and tertiary oil recovery modes at ambient conditions. The dynamic interactions of fluids, fluid–rock, and the transport behavior of injected fluid in the presence of NPs were, respectively, studied by interfacial tension (IFT), spontaneous imbibition tests, and a differential pressure analysis. Core flooding results showed an increase in oil recovery up to 14.8% with secondary nanofluid injection compared to 39.7% of the original oil in place (OOIP) from the conventional waterflood. In tertiary mode, nanofluids increased oil recovery up to 9.2% of the OOIP. It was found that no single mechanism could account for the EOR effect with the application of nanoparticles. Instead, the mobilization of oil seemed to occur through a combination of reduced oil/water IFT, change in the rock surface roughness and wettability, and microscopic flow diversion due to clogging of the pores.

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