Diffusion of Methane and Ethane Through the Reservoir Cap Rock: Implications for the Timing and Duration of Catagenesis: Discussion

Leythaeuser, B. M. Krooss2 and D.

doi:10.1306/522b42c1-1727-11d7-8645000102c1865d

Cited by 5 publications

(2 citation statements)

References 30 publications

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“…In shale reservoirs with ultralow permeability and porosity, nanopore-throats with hydrophilic walls are normally filled with brine originating from high-salinity formation water or low-salinity hydraulic fracturing fluids, ,, leading to the critical pressure that impedes the transport of hydrocarbon. − The displacement pressure, also termed breakthrough pressure or critical pressure, which refers to the pressure required for driving nonwetting fluid to break through the capillary resistance of rock and form a continuous fluid flow, could be very high in the nanopore-throat channels. , Therefore, investigations of the displacement pressure are crucial for evaluating the sealing capacity of shale as caprocks and the migration of oil in tight reserviors. − Previous studies of the salinity effect ,, show that the capillary resistance is closely related to the water salinity. However, the hydrodynamical behaviors of fluids confined in nanopores are strongly influenced by fluid–pore wall interactions. − Nonequilibrium molecular dynamics (NEMD) simulations have been widely utilized and proven as a promising technique for the investigation of pressure-driven fluid transport through nanochannels. − …”

Section: Introductionmentioning

confidence: 99%

Molecular Insights into the Salinity Effects on Movability of Oil–Brine in Shale Nanopore-Throat Systems

Cheng,

Lu,

et al. 2023

Langmuir

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Low-salinity flooding has been well recognized as a promising strategy to increase shale oil recovery, but the underlying mechanism remains unclarified, especially for complex nanopore networks filled with oil–brine fluids. In this study, the pressure-driven flow of an oil–brine fluid with varying salinities in shale nanopore-throat channels was first investigated based on molecular dynamics simulations. The critical pressure driving oil to intrude into a nanothroat filled with brine of varying salinities was determined. Simulation results indicate that the salinity of brine exhibits great effects on the movability of oil, and low salinity favors the increase of oil movability. Further analysis of the interactions between fluid and pore walls as well as the displacement pressures reveals dual effects of brine salinity on oil transportation in a nanopore-throat. On the one hand, hydrated cations anchoring onto throat walls enlarge the effective flow width in the throat before the hydration complexes reach the maximum. On the other hand, the interfacial tension between oil and brine increases with the brine salinity, which increases the capillary resistance and leads to a higher displacement pressure. These findings highlight the effects of brine salinity on oil movability in a nanopore-throat, which will promote the understanding of oil accumulation and dissipation in petroleum systems, as well as help to develop enhanced oil recovery.

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Section: Introductionmentioning

confidence: 99%

Molecular Insights into the Salinity Effects on Movability of Oil–Brine in Shale Nanopore-Throat Systems

Cheng,

Lu,

et al. 2023

Langmuir

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“…Its low porosity and permeability play a very important role in the accumulation and preservation of hydrocarbons [2,3]. Currently, the sealing capacity of shale is mainly evaluated by high-pressure mercury intrusion, gas diffusion test, triaxial stress test and breakthrough pressure test [4][5][6], from the perspective of throat size, porosity, permeability, diffusion coefficient and gas breakthrough pressure [7][8][9][10]. Due to experimental limitations (such as high pressure, threshold time, relaxation time and pore size), however, these methods are deficient in some respects, for example, the destructive effects of high-pressure mercury intrusion on pore structure at the high-pressure stage and the dependence on threshold in CT scan identification [11].…”

Section: Introductionmentioning

confidence: 99%

A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance

Xiao

et al. 2022

Energies

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The porous and low-permeability characteristics of a shale gas reservoir determine its high gas storage efficiency, which is manifested in the extremely high breakthrough pressure of shale. Therefore, the accurate calculation of breakthrough pressure is of great significance to the study of shale gas preservation conditions. Based on a systematic analysis of a low-field NMR experiment on marine shales of the Longmaxi Formation in the Sichuan Basin, a shale gas breakthrough pressure determination technique different from conventional methods is proposed. The conventional methods have low calculation accuracy and are a tedious and time-consuming process, while low-field NMR technique is less time-consuming and of high accuracy. Firstly, the NMR T2 spectrum of shale core sample in different states is measured through low-field NMR experiment. The NMR T2 spectra of sample in water-saturated state and dry state are combined to model the mathematical relationship between shale gas breakthrough pressure and NMR T2 spectrum. It is found that the gas breakthrough pressure is power-exponentially related to the geometric mean of NMR T2 spectrum and positively related to the proportion of micropores. Accordingly, the shale gas breakthrough pressure is quickly and accurately calculated using continuous NMR logging data and then the sealing capacity of the shale caprocks is evaluated, providing basic parameters for analyzing unconventional hydrocarbon accumulation, preservation and migration. This technique has been successfully applied with actual data to evaluate the sealing capacity of shale caprock in a shale gas well in the Sichuan Basin. It can provide a good basis for the evaluation and characterization of shale oil and gas reservoirs.

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Relative permeability of tight hydrocarbon systems: An experimental study

Ghanizadeh

Song

Clarkson

et al. 2021

Fuel

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Diffusion of Methane and Ethane Through the Reservoir Cap Rock: Implications for the Timing and Duration of Catagenesis: Discussion

Cited by 5 publications

References 30 publications

Molecular Insights into the Salinity Effects on Movability of Oil–Brine in Shale Nanopore-Throat Systems

Molecular Insights into the Salinity Effects on Movability of Oil–Brine in Shale Nanopore-Throat Systems

A Technique to Determine the Breakthrough Pressure of Shale Gas Reservoir by Low-Field Nuclear Magnetic Resonance

Relative permeability of tight hydrocarbon systems: An experimental study

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