Modeling CO2 Injection Including Diffusion in a Fractured-Chalk Experiment with Initial Water Saturation

2012 ◽  
Author(s):  
Sayyed Ahmad Alavian ◽  
Curtis Hays Whitson
Keyword(s):  
Water Saturation ◽  
Co2 Injection ◽  
Initial Water

scholarly journals Investigation on Coal Skeleton Deformation in CO2 Injection Enhanced CH4 Drainage From Underground Coal Seam

2021 ◽  
Vol 9 ◽  
Author(s):  
Chaojun Fan ◽  
Lei Yang ◽  
Gang Wang ◽  
Qiming Huang ◽  
Xiang Fu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Coal Seam ◽  
Initial Temperature ◽  
Water Saturation ◽  
Early Stage ◽  
Gas Injection ◽  
Strain Curve ◽  
Co2 Injection ◽  
Initial Water ◽  
Gas Drainage

To reveal the evolution law of coal skeleton deformation during the process of CO2 flooding and displacing CH4 in coal seam, a fluid-solid coupling mathematical model of CO2 injection enhanced CH4 drainage was established based on Fick’s law, Darcy’s law, ideal gas state equation, and Langmuir equation. Meanwhile, numerical simulations were carried out by implementing the mathematical model in the COMSOL Multiphysics. Results show that the CH4 content of both regular gas drainage and CO2 enhanced gas drainage gradually decreases with time, and the decreasing rate is high between 10 and 60 days. Compared with regular gas drainage, the efficiency of CO2 enhanced gas drainage is more obvious with greater amount of CH4 extracted out. When coal seam gas is extracted for 10, 60, 120, and 180 days, CH4 content in coal seam is reduced by 5.2, 17.2, 23.6, and 26.7%, respectively. For regular gas drainage, the deformation of coal skeleton is dominated by the shrink of coal matrix induced by gas desorption, and the strain curve shows a continuous downward trend. For CO2 enhanced gas drainage, the strain curve of coal skeleton showed a decrease—rapid increase—slow increase trend. The evolution of permeability is opposite to the evolution of coal skeleton strain. Higher gas injection pressure will lead to a greater coal skeleton strain. The pumping pressure affects the deformation of coal skeleton slightly compared with that of initial water saturation and initial temperature. Greater initial water saturation leads to larger deformation of coal skeleton in the early stage. The strain value of coal skeleton gradually tends to be consistent as gas injection prolongs. Higher initial temperature leads to greater reduction in coal skeleton strain when the gas injection continues. Research achievements provide a basis for the field application of CO2 injection enhanced CH4 drainage in underground coal mines.

Effect of Initial Water Saturation on Bypassed Oil Recovery during CO2 Injection at Different Miscibility Conditions

2015 ◽  
Vol 29 (7) ◽  
pp. 4114-4121 ◽  
Author(s):  
Keyvan Kazemi ◽  
Behzad Rostami ◽  
Maryam Khosravi ◽  
Danial Zeinabady Bejestani
Keyword(s):  
Oil Recovery ◽  
Water Saturation ◽  
Co2 Injection ◽  
Initial Water ◽  
Bypassed Oil

Role of molecular diffusion in the recovery of water flood residual oil

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Oil Recovery ◽  
Water Saturation ◽  
Fractured Reservoirs ◽  
Naturally Fractured Reservoirs ◽  
Gravity Drainage ◽  
Co2 Injection ◽  
Initial Water ◽  
Water Imbibition ◽  
Naturally Fractured ◽  
Carbon Dioxide Co2

Traditionally, carbon dioxide (CO2) injection has been considered an inefficient method for enhancing oil recovery from naturally fractured reservoirs. Obviously, it would be useful to experimentally investigate the efficiency of waterflooding naturally fractured reservoirs followed by carbon dioxide (CO2) injection. This issue was investigated by performing water imbibition followed by CO2 gravity drainage experiments on artificially fractured cores at reservoir conditions. The experiments were designed to illustrate the actual process of waterflooding and CO2 gravity drainage in a naturally fractured reservoir in the Brass Area, Bayelsa. The results demonstrate that CO2 gravity drainage could significantly increase oil recovery after a waterflood. During the experiments, the effects of different parameters such as permeability, initial water saturation and injection scheme was also examined. It was found that the efficiency of the CO2 gravity drainage decrease as the rock permeability decreases and the initial water saturation increases. Cyclic CO2 injection helped to improve oil recovery during the CO2 gravity drainage process which alters the water imbibition. Oil samples produced in the experiment were analyzed using gas chromatography to determine the mechanism of CO2-improved oil production from tight matrix blocks. The results show that lighter components are extracted and produced early in the test. The results of these experiments validate the premises that CO2 could be used to recover oil from a tight and unconfined matrix efficiently.

A Unified Parameter to Represent Reservoir Heterogeneity

2021 ◽  
Author(s):  
Nandana Ramabhadra Agastya
Keyword(s):  
Water Saturation ◽  
Pressure Ratio ◽  
Universal Method ◽  
Permeability Ratio ◽  
Initial Water ◽  
Vertical Permeability ◽  
Radar Chart ◽  
Horizontal Permeability ◽  
Water Cut ◽  
Thief Zone

Abstract We aim to find a universal method and/or parameter to quantify impact of overall heterogeneity on waterflood performance. For this purpose, we combined the Lorenz coefficient, horizontal permeability to vertical permeability ratio, and thief zone permeability to average permeability ratio, with a radar chart. The area of the radar chart serves as a single parameter to rank reservoirs according to heterogeneity, and correlates to waterflood performance. The parameters investigated are vertical and horizontal permeability. Average porosity, initial water saturation, and initial diagonal pressure ratio are kept constant. Computer based experiments are used over the course of this entire research. We conducted permeability studies that demonstrate the effects of thief zones and crossflow. After normalizing these parameters into a number between 0 and 1, we then plot them on a radar chart. A reservoir's overall degree of heterogeneity can be inferred using the radar chart area procedure discussed in this study. In general, our simulations illustrate that the larger the radar chart area, the more heterogenous the reservoir is, which in turn yields higher water cut trends and lower recovery factors. Computer simulations done during this study also show that the higher the Lorenz coefficient, the higher the probability of a thief zone to exist. Simulations done to study crossflow also show certain trends with respect to under tonguing and radar chart area.

scholarly journals Estimating reservoir permeability with borehole radar

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. H51-H60
Author(s):  
Feng Zhou ◽  
Iraklis Giannakis ◽  
Antonios Giannopoulos ◽  
Klaus Holliger ◽  
Evert Slob
Keyword(s):  
Water Saturation ◽  
Time Lapse ◽  
Drilling Mud ◽  
Invasion Depth ◽  
Initial Water ◽  
Oil Drilling ◽  
Reservoir Evaluation ◽  
Reservoir Permeability ◽  
Borehole Radar ◽  
Porosity And Permeability

In oil drilling, mud filtrate penetrates into porous formations and alters the compositions and properties of the pore fluids. This disturbs the logging signals and brings errors to reservoir evaluation. Drilling and logging engineers therefore deem mud invasion as undesired and attempt to eliminate its adverse effects. However, the mud-contaminated formation carries valuable information, notably with regard to its hydraulic properties. Typically, the invasion depth critically depends on the formation porosity and permeability. Therefore, if adequately characterized, mud invasion effects could be used for reservoir evaluation. To pursue this objective, we have applied borehole radar to measure mud invasion depth considering its high radial spatial resolution compared with conventional logging tools, which then allows us to estimate the reservoir permeability based on the acquired invasion depth. We investigate the feasibility of this strategy numerically through coupled electromagnetic and fluid modeling in an oil-bearing layer drilled using freshwater-based mud. Time-lapse logging is simulated to extract the signals reflected from the invasion front, and a dual-offset downhole antenna mode enables time-to-depth conversion to determine the invasion depth. Based on drilling, coring, and logging data, a quantitative interpretation chart is established, mapping the porosity, permeability, and initial water saturation into the invasion depth. The estimated permeability is in a good agreement with the actual formation permeability. Our results therefore suggest that borehole radar has significant potential to estimate permeability through mud invasion effects.

scholarly journals Magnetic Resonance Imaging of Methane Hydrate Formation and Dissociation in Sandstone with Dual Water Saturation

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3231
Author(s):  
Stian Almenningen ◽  
Per Fotland ◽  
Geir Ersland
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Methane Hydrate ◽  
Water Saturation ◽  
High Water ◽  
Growth Patterns ◽  
Resonance Imaging ◽  
Initial Water ◽  
Hydrate Dissociation ◽  
The Core

This paper reports formation and dissociation patterns of methane hydrate in sandstone. Magnetic resonance imaging spatially resolved hydrate growth patterns and liberation of water during dissociation. A stacked core set-up using Bentheim sandstone with dual water saturation was designed to investigate the effect of initial water saturation on hydrate phase transitions. The growth of methane hydrate (P = 8.3 MPa, T = 1–3 °C) was more prominent in high water saturation regions and resulted in a heterogeneous hydrate saturation controlled by the initial water distribution. The change in transverse relaxation time constant, T2, was spatially mapped during growth and showed different response depending on the initial water saturation. T2 decreased significantly during growth in high water saturation regions and remained unchanged during growth in low water saturation regions. Pressure depletion from one end of the core induced a hydrate dissociation front starting at the depletion side and moving through the core as production continued. The final saturation of water after hydrate dissociation was more uniform than the initial water saturation, demonstrating the significant redistribution of water that will take place during methane gas production from a hydrate reservoir.

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