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

2012 ◽  
Author(s):  
Bahareh Nojabaei ◽  
Russell T. Johns ◽  
Lifu Chu
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Fluid Density ◽  
Tight Rocks

Study on Phase Behavior of CO2/Hydrocarbons in Shale Reservoirs Considering Sieving Effect and Capillary Pressure

2021 ◽  
Author(s):  
Yapeng Tian ◽  
Binshan Ju ◽  
Xudong Wang ◽  
Hongya Wang ◽  
Jie Hu ◽  
...  
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Shale Reservoirs ◽  
Sieving Effect

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.

A compositional numerical study in hydraulic fractured tight reservoir: Considering capillary pressure in phase behavior calculation

2021 ◽  
Vol 196 ◽  
pp. 108071
Author(s):  
Yuhua Ma ◽  
Shuoliang Wang ◽  
Zhihong Kang ◽  
Libin Zhao
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Numerical Study ◽  
Tight Reservoir

Uncertainty Quantification and Reduction in Capillary Pressure and In-Place Volume Measurements on Tight Rocks

2017 ◽  
Author(s):  
Shreerang S. Chhatre ◽  
Hemant Sahoo ◽  
Keili Vidal ◽  
Robert Longoria ◽  
Prateek Patel
Keyword(s):  
Uncertainty Quantification ◽  
Capillary Pressure ◽  
Volume Measurements ◽  
Tight Rocks

Compositional Simulation of Discrete Fractures Incorporating the Effect of Capillary Pressure on Phase Behavior

2016 ◽  
Author(s):  
Nithiwat Siripatrachai ◽  
Turgay Ertekin ◽  
Russell Johns
Keyword(s):  
Phase Behavior ◽  
Capillary Pressure ◽  
Compositional Simulation ◽  
Discrete Fractures

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

scholarly journals Nanopore Confinement Effect on the Phase Behavior of CO2/Hydrocarbons in Tight Oil Reservoirs considering Capillary Pressure, Fluid-Wall Interaction, and Molecule Adsorption

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Zhixue Zheng ◽  
Yuan Di ◽  
Yu-Shu Wu
Keyword(s):  
Phase Behavior ◽  
Pore Size ◽  
Capillary Pressure ◽  
Confinement Effect ◽  
Oil Reservoirs ◽  
Co2 Injection ◽  
Tight Oil ◽  
Tight Reservoirs ◽  
Tight Oil Reservoirs ◽  
Nanopore Confinement

The pore sizes in tight reservoirs are nanopores, where the phase behavior deviates significantly from that of bulk fluids in conventional reservoirs. The phase behavior for fluids in tight reservoirs is essential for a better understanding of the mechanics of fluid flow. A novel methodology is proposed to investigate the phase behavior of carbon dioxide (CO2)/hydrocarbons systems considering nanopore confinement. The phase equilibrium calculation is modified by coupling the Peng-Robinson equation of state (PR-EOS) with capillary pressure, fluid-wall interaction, and molecule adsorption. The proposed model has been validated with CMG-Winprop and experimental results with bulk and confined fluids. Subsequently, one case study for the Bakken tight oil reservoir was performed, and the results show that the reduction in the nanopore size causes noticeable difference in the phase envelope and the bubble point pressure is depressed due to nanopore confinement, which is conductive to enhance oil recovery with a higher possibility of achieving miscibility in miscible gas injection. As the pore size decreases, the interfacial tension (IFT) decreases whereas the capillary pressure increases obviously. Finally, the recovery mechanisms for CO2 injection are investigated in terms of minimum miscibility pressure (MMP), solution gas-oil ratio, oil volume expansion, viscosity reduction, extraction of lighter hydrocarbons, and molecular diffusion. Results indicate that nanopore confinement effect contributes to decrease MMP, which suppresses to 650 psi (65.9% smaller) as the pore size decreases to 2 nm, resulting in the suppression of the resistance of fluid transport. With the nanopore confinement effect, the CO2 solution gas-oil ratio and the oil formation volume factor of the oil increase with the decrease of pore size. In turn, the oil viscosity reduces as the pore size decreases. It indicates that considering the nanopore confinement effect, the amount of gas dissolved into crude oil increases, which will lead to the increase of the oil volume expansion and the decrease of the viscosity of crude oil. Besides, considering nanopore confinement effect seems to have a slightly reduced effect on extraction of lighter hydrocarbons. On the contrary, it causes an increase in the CO2 diffusion coefficient for liquid phase. Generally, the nanopore confinement appears to have a positive effect on the recovery mechanisms for CO2 injection in tight oil reservoirs. The developed novel model could provide a better understanding of confinement effect on the phase behavior of nanoscale porous media in tight reservoirs. The findings of this study can also help for better understanding of a flow mechanism of tight oil reservoirs especially in the case of CO2 injection for enhancing oil recovery.

Effect of Pore-Size Distribution on Phase Transition of Hydrocarbon Mixtures in Nanoporous Media

SPE Journal ◽  
2016 ◽  
Vol 21 (06) ◽  
pp. 1981-1995 ◽  
Author(s):  
Lei Wang ◽  
Xiaolong Yin ◽  
Keith B. Neeves ◽  
Erdal Ozkan
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Pore Size Distribution ◽  
Phase Behavior ◽  
Pore Size ◽  
Capillary Pressure ◽  
Size Distribution ◽  
Hydrocarbon Mixtures ◽  
Nanoporous Media ◽  
Light Oil

Summary Pore sizes of many shale-oil and tight gas reservoirs are in the range of nanometers. In these pores, capillary pressure and surface forces can make the phase behavior of hydrocarbon mixtures different from that characterized in pressure/volume/temperature (PVT) cells. Many existing phase-behavior models use a single pore size to describe the effect of confinement on phase behavior. To follow up with our earlier theoretical studies and experimental observations, this research investigates the effect of pore-size distribution. By use of a vapor/liquid equilibrium model that considers the effect of capillary pressure, we present a procedure to simulate the sequence of phase changes in a porous medium caused by a pore-size distribution. This procedure is used to simulate depressurizations of a light oil and a retrograde gas confined inside nanoporous media, the pore-size distributions of which are characteristic of tight reservoirs. The fluid compositions are representative of typical reservoir fluids. Predictions of the model show that phase transition in nanoporous medium with pore-size distribution is not described by a single phase boundary. The initial phase change in the large pores alters the composition of the remaining fluid, and, in turn, suppresses the next phase change. For the two cases studied, models with and without capillary pressure gave similar predictions. For light oil, capillary pressure still noticeably increased the level of supersaturation, and the critical gas saturation had a strong influence on the properties of produced fluids. For retrograde gas, the effect of capillary pressure was insignificant because of the low interfacial tension (IFT). Despite the choice of fluids, calculations indicate that the smallest pores are probably always occupied by hydrocarbon liquid during depressurization.

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