A Black Oil Simulator that Includes the Impact of Capillary Pressure on Phase Behavior in Nano-Porous Unconventional Reservoirs

2016 ◽  
Author(s):  
Chet Ozgen ◽  
Tugce Calisgan ◽  
Tuba Firincioglu ◽  
Erdal Ozkan
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Unconventional Reservoirs ◽  
Black Oil ◽  
The Impact

Capillary pressure effect on phase behavior of CO2/hydrocarbons in unconventional reservoirs

Fuel ◽  
2017 ◽  
Vol 197 ◽  
pp. 575-582 ◽  
Author(s):  
Yuan Zhang ◽  
Hamid R. Lashgari ◽  
Yuan Di ◽  
Kamy Sepehrnoori
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Pressure Effect ◽  
Unconventional Reservoirs

Minimum Miscibility Pressure of Gas Injection in Unconventional Reservoirs

2021 ◽  
Author(s):  
Gang Yang
Keyword(s):  
Phase Behavior ◽  
Gas Injection ◽  
Fluid Phase ◽  
Unconventional Reservoirs ◽  
Unconventional Reservoir ◽  
Minimum Miscibility Pressure ◽  
Confined Fluid ◽  
Miscible Gas Injection ◽  
Fluid Characterization ◽  
The Impact

Abstract Unconvnetional reservoirs are predominantly consisted of nanoscale pores. The strong confinement effect within nanopores imposes significant deviations to the confined fluid phase behavior. Minimum miscibility pressure (MMP) in unconventional reservoirs, as a parameter highly related to the phase behavior of confined fluids, is inevitably affected by the nanoscale confinement. The objective of this work is to investigate the impact of nanoscale confinement on MMP of unconventional reservoir fluids and to recognize a reliable theoretical approach to determine the MMP values in unconventional reservoirs. A modified Peng-Robinson equation of state (PR EOS) applicable for confined fluid characterization is applied to perform the EOS simulation of the vanishing interfacial tension (VIT) experiments. The MMP of a binary mixture at bulk and 50 nm are obtained via the VIT simulation. Meanwhile, the multiple mixing cell (MMC) algorithm coupled with the modified PR EOS is applied to compute the MMP for the same binary system. Comparison of the calculated results to the experimental values recognize that the MMC approach has higher accuracy in determining the MMP of confined fluid systems. Moreover, this approach is then applied to predict the MMP values of both Bakken and Eagle Ford oil at different pore sizes with various injected gases. Results demonstrate that the nanoscale confinement causes drastic suppression to the MMP of unconventional reservoir fluids and the suppression rate increases with decreasing pore size. The drastic suppression of MMP is highly favorable for the miscible gas injection EOR in unconventional reservoirs.

Effect of Capillary Pressure on Phase Behavior in Tight Rocks and Shales

2013 ◽  
Vol 16 (03) ◽  
pp. 281-289 ◽  
Author(s):  
B.. Nojabaei ◽  
R.T.. T. Johns ◽  
L.. Chu
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Gas Flow ◽  
Dew Point ◽  
Bakken Formation ◽  
Equilibrium Equations ◽  
Two Phase ◽  
Small Pore ◽  
The Impact

Summary Phase behavior is important in the calculation of hydrocarbons in place and in the flow of phases through the rocks. Pore sizes can be on the order of nanometers for shale and tight-rock formations. Such small pores can affect the phase behavior of in-situ oil and gas because of increased capillary pressure. Not accounting for increased capillary pressure in small pores can lead to inaccurate estimates of ultimate recovery, and of saturation pressures. In this paper, capillary pressure is coupled with phase equilibrium equations, and the resulting system of nonlinear fugacity equations is solved to present a comprehensive examination of the effect of small pores on saturation pressures and fluid densities. Binary mixtures of methane with heavier hydrocarbons and a real reservoir fluid from the Bakken shale are considered. The results show that accounting for the impact of small pore throats on pressure/volume/temperature (PVT) properties explains the inconsistent gas/oil-ratio (GOR) behavior, high flowing bottomhole pressures, and low gas-flow rate observed in the tight Bakken formation. The small pores decrease bubble-point pressures and either decrease or increase dew-point pressures, depending on which part of the two-phase envelope is examined. Large capillary pressure also decreases the oil density in situ, which affects the oil formation volume factor and ultimate reserves calculations. A good history match for wells in the middle Bakken formation is obtained only after considering a suppressed bubblepoint pressure. The results show that the change in saturation pressures, fluid densities, and viscosities is highly dependent on the values of interfacial tension (IFT) (capillary pressure) used in the calculations.

The Effects of Protein Charge Patterning on Complex Coacervation

2021 ◽  
Author(s):  
Nicholas Zervoudis ◽  
Allie Obermeyer
Keyword(s):  
Phase Boundary ◽  
Phase Behavior ◽  
Predictive Models ◽  
Phase Portraits ◽  
Complex Coacervation ◽  
Protein Encapsulation ◽  
Protein Charge ◽  
Polypeptide Sequence ◽  
The Impact ◽  
Coacervate Phase

The complex coacervation of proteins with other macromolecules has applications in protein encapsulation and delivery and for determining the function of cellular coacervates. Theoretical or empirical predictions for protein coacervates would enable the design of these coacervates with tunable and predictable structure-function relationships; unfortunately, no such theories exist. To help establish predictive models, the impact of protein-specific parameters on complex coacervation were probed in this study. The complex coacervation of sequence-specific, polypeptide-tagged, GFP variants and a strong synthetic polyelectrolyte was used to evaluate the effects of protein charge patterning on phase behavior. Phase portraits for the protein coacervates demonstrated that charge patterning dictates the protein’s binodal phase boundary. Protein concentrations over 100 mg mL<sup>-1</sup> were achieved in the coacervate phase, with concentrations dependent on the polypeptide sequence. In addition to shifting the binodal phase boundary, polypeptide charge patterning provided entropic advantages over isotropically patterned proteins. Together, these results show that modest changes of only a few amino acids alter the coacervation thermodynamics and can be used to tune the phase behavior of polypeptides or proteins of interest.

The Percolation of Liquid Through a Compliant Seal—An Experimental and Theoretical Study

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Sorin-Cristian Vlădescu ◽  
Carmine Putignano ◽  
Nigel Marx ◽  
Tomas Keppens ◽  
Tom Reddyhoff ◽  
...  
Keyword(s):  
Surface Energy ◽  
Capillary Pressure ◽  
Contact Pressure ◽  
Roughness Length ◽  
Theoretical Study ◽  
Theoretical Explanation ◽  
Channel Section ◽  
Hydrophilic Surfaces ◽  
New Apparatus ◽  
The Impact

New apparatus is described to simulate a compliant seal interface, allowing the percolation of liquid to be viewed by a fluorescence microscope. A model, based on the boundary element (BE) methodology, is used to provide a theoretical explanation of the observed behavior. The impact of contact pressure, roughness, and surface energy on percolation rates are characterized. For hydrophilic surfaces, percolation will always occur provided a sufficient number of roughness length scales are considered. However, for hydrophobic surfaces, the inlet pressure must overcome the capillary pressure exerted at the minimum channel section before flow can occur.

Thermodynamic Analysis of Phase Behavior at High Capillary Pressure

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 1977-1990 ◽  
Author(s):  
Mohsen Rezaveisi ◽  
Kamy Sepehrnoori ◽  
Gary A. Pope ◽  
Russell T. Johns
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Thermodynamic Analysis ◽  
Phase Stability ◽  
Tangent Plane ◽  
General Purpose ◽  
Distance Method ◽  
Capillary Equilibrium ◽  
Production Behavior ◽  
Reservoir Simulator

Summary High capillary pressure has a significant effect on the phase behavior of fluid mixtures. The capillary pressure is high in unconventional reservoirs because of the small pores in the rock, so understanding the effect of capillary pressure on phase behavior is necessary for reliable modeling of unconventional shale-gas and tight-oil reservoirs. As the main finding of this paper, first we show that the tangent-plane-distance method cannot be used to determine phase stability and present a rigorous thermodynamic analysis of the problem of phase stability with capillary pressure. Second, we demonstrate that there is a maximum capillary pressure (Pcmax) where calculation of capillary equilibrium using bulk-phase thermodynamics is possible and derive the necessary equations to obtain this maximum capillary pressure. We also briefly discuss the implementation of the capillary equilibrium in a general-purpose compositional reservoir simulator. Two simulation case studies for synthetic gas condensate reservoirs were performed to illustrate the influence of capillary pressure on production behavior for the fluids studied.

QEMSCAN-Assisted Interpretation of Imbibition Capillary Pressure for Multiporosity Carbonate Rocks

SPE Journal ◽  
2020 ◽  
pp. 1-17
Author(s):  
Aymen Alramadhan ◽  
Yildiray Cinar
Keyword(s):  
Capillary Pressure ◽  
Numerical Models ◽  
Rock Composition ◽  
Rock Samples ◽  
Rock Types ◽  
Centrifuge Tests ◽  
Medium Permeability ◽  
Mercury Injection Capillary Pressure ◽  
The Impact ◽  
Selection Of

Summary In this paper, we present an experimental study that explores the potential links between the imbibition capillary pressure Pci and the pore systems and/or mineralogy for carbonate reservoirs undergoing waterflood. A systematic workflow has been formulated to ensure the data quality ofPci, minimize uncertainty in derivingPci from centrifuge tests, and analyze the data considering the pore-size distribution from mercury injection capillary pressure (MICP) and mineralogy from Quantitative Evaluation of Minerals by Scanning Electron Microscopy (QEMSCAN). The workflow starts with assessing the centrifuge production data for gravity-capillary equilibrium at each speed. Then, the quality-checked data are used to generate six differentPci curves using analytical and numerical models. The resulting curves provide a measure of the variability in solutions for various rock types and assist in the selection of the most-representativePci curve. Finally, the representative Pci curves of all rock samples are analyzed together with the MICP and QEMSCAN data to examine the change in Pci curves as a result of changes in the number and character of rock types, pore systems, dominant pore-throat radii, and mineralogy. Findings from this study shed light on the impact of mineralogy and pore systems on Pci. From the mineralogy perspective, the presence of dolomite, microporous calcite, or rutile and anatase (TiO2) within the rock composition is found to affect the Pci of the carbonate samples used in this study. The rock samples with these minerals should be separated from other bimodal samples before attempting to obtain a correlation between Pci and pore systems. The data analysis further reveals that some bimodal samples of medium permeability yield a better waterflood imbibition efficiency than those of the high-permeability samples. This observation is attributed to a better communication between the micropore and macropore systems, and a closer proximity of the peak radii of the micro- and macropore systems of the medium-permeability samples.

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