Investigation on the unsteady-state two-phase fluid transport in the nano-pore system of natural tight porous media

Qiao, J.C.; Zeng, Jianhui; Jiang, Shu; Yang, Guangqing; Xiao, Fengchao; Feng, Song

doi:10.1016/j.jhydrol.2022.127516

Cited by 9 publications

(3 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In the unsteady-state method, water invasion is directly performed at a certain injection speed or injection pressure under the condition of satisfying the similarity criterion, and the gas production, cumulative liquid production, and pressure difference between the two ends of the rock core are measured at intervals [19]. However, in the unsteadystate method, a sufficiently high displacement speed or displacement pressure must be established to eliminate the end effect [20,21]. Compared with the steady-state method, the advantages of the unsteady-state method are that the measurement time is shorter, and the experimental intensity is lower [22].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Water-Invasion Gas Efficiency in the Kela-2 Gas Field Using Multiple Experiments

Han,

Xiong,

Jiang

et al. 2023

Energies

View full text Add to dashboard Cite

Although improving the recovery of water-invaded gas reservoirs has been extensively studied in the natural gas industry, the nature of the efficiency of water-invaded gas recovery remains uncertain. Low-field nuclear magnetic resonance (NMR) can be used to clearly identify changes in water saturation in the core during high-pressure water-invasion gas. Here, we provide four types of water-invasion gas experiments (spontaneous imbibition, atmospheric pressure, high-pressure approximate equilibrium, and depletion development water-invasion gas) to reveal the impact of the water-invasion gas efficiency on the recovery of water-invasion gas reservoirs. NMR suggested that imbibition mainly occurs in medium to large pores and that residual gas remains mainly in large pores. The amount of gas driven out from the large pores by imbibition was much greater than that driven out from the small pores. Our findings indicate that the initial gas saturation, contact surface, and permeability are the main factors controlling the residual gas saturation, suggesting that a reasonable initial water saturation should be established before the water-invasion gas experiments. Additionally, the water-invasion gas efficiency at high pressures can be more reliably obtained than that at normal pressures. After the high-pressure approximate equilibrium water invasion for gas displacement, a large amount of residual gas remains in the relatively larger pores of the core, with a residual gas saturation of 42%. In contrast to conventional experiments, the residual gas saturation and water displacement efficiency of the high-pressure approximate equilibrium water invasion for gas displacement did not exhibit a favorable linear relationship with the permeability. The residual gas saturation ranged from 34 to 43% (avg. 38%), while the water displacement efficiency ranged from 32 to 45% (avg. 40%) in the high-pressure approximate equilibrium water invasion for gas displacement. The residual gas saturation in the depletion development water-invasion gas experiment was 26–40% (average: 33%), with an efficiency ranging from 45 to 50% (average: 48%), indicating that the depletion development experiment is closer to the actual development process of gas reservoirs. Our findings provide novel insights into water-invasion gas efficiency, providing robust estimates of the recovery of water-invasion gas reservoirs.

show abstract

Section: Introductionmentioning

confidence: 99%

Investigation of the Water-Invasion Gas Efficiency in the Kela-2 Gas Field Using Multiple Experiments

Han,

Xiong,

Jiang

et al. 2023

Energies

View full text Add to dashboard Cite

show abstract

“…Pore-scale fluid flow experiment is an effective method to investigate the transport mechanisms and distribution characteristics of residual oil, including microfluidics [5][6][7][8], natural sandstone models [9][10][11][12][13], nuclear magnetic resonance [14][15][16], confocal laser [17][18][19], and CT scan [20][21][22]. Owing to the rapid development of CT technology, it has been widely used in EOR [23][24][25][26][27], carbon dioxide storage [28], environmental governance [29], water-rock interaction [30,31], reservoir modelling [32][33][34][35][36], hydraulic conductivity [37,38], and reservoir evaluation [39][40][41][42][43][44][45][46][47]. Due to the advantages of high resolution, nondestructive, and in situ, CT scan has become an effective method for investigating residual oil.…”

Section: Introductionmentioning

confidence: 99%

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Zhang

Lin

et al. 2022

Lithosphere

View full text Add to dashboard Cite

The wettability of mineral surfaces has significant impacts on transport mechanisms of two-phase flow, distribution characteristics of fluids, and the formation mechanisms of residual oil during water flooding. However, few studies have investigated such effects of mineral type and its surface wettability on rock properties in the literature. To unravel the dependence of hydrodynamics on wettability and minerals distribution, we designed a new experimental procedure that combined the multiphase flow experiments with a CT scan and QEMSCAN to obtain 3D digital models with multiple minerals and fluids. With the aid of QEMSCAN, six mineral components and two fluids in sandstones were segmented from the CT data based on the histogram threshold and watershed methods. Then, a mineral surface analysis algorithm was proposed to extract the mineral surface and classify its mineral categories. The in situ contact angle and pore occupancy were calculated to reveal the wettability variation of mineral surface and distribution characteristics of fluids. According to the shape features of the oil phase, the self-organizing map (SOM) method, one of the machine learning methods, was used to classify the residual oil into five types, namely, network, cluster, film, isolated, and droplet oil. The results indicate that each mineral’s contribution to the mineral surface is not proportional to its relative content. Feldspar, quartz, and clay are the main minerals in the studied sandstones and play a controlling role in the wettability variation. Different wettability samples show various characteristics of pore occupancy. The water flooding front of the weakly water-wet to intermediate-wet sample is uniform, and oil is effectively displaced in all pores with a long oil production period. The water-wet sample demonstrates severe fingering, with a high pore occupancy change rate in large pores and a short oil production period. The residual oil patterns gradually evolve from networks to clusters, isolated, and films due to the effects of snap-off and wettability inversion. This paper reveals the effects of wettability of mineral surface on the distribution characteristics and formation mechanisms of residual oil, which offers us an in-deep understanding of the impacts of wettability and minerals on multiphase flow and helps us make good schemes to improve oil recovery.

show abstract

“…For example, numerical Hele-Shaw investigations and experiments have been conducted to study the hydraulics of a well pumped with a variable discharge [9], fluid drainage through fractured media [10], fingered flow through sand [3], fluid-soil interaction [11], and the characteristics of the gas-injection barrier in two-dimensional porous media to understand the unexpected inflow mechanisms of groundwater in an unwanted area [12]. The majority of experiments that examine the effects of flow at the grain scale and any potential alterations of the characteristics of the soil-groundwater system are usually conducted in small size experiments at the mesoscale [7,[13][14][15][16]. Transient flow problems are usually conducted in a similar scale [5,8,17].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Effects of Porosity, Hydraulic Conductivity, Strength, and Flow Rate on Fluid Flow in Weakly Cemented Bio-Treated Sands

Konstantinou

Biscontin

2022

Hydrology

View full text Add to dashboard Cite

Fluid injection in a porous medium is the underlying mechanism for many applications in the fields of groundwater hydraulics, hydrology and hydrogeology, and geo-environmental engineering and in the oil and gas industry. Fluid flow experiments in porous media with a viscous fluid at varying injection rates were conducted in a modified Hele-Shaw setup. The granular media were three-dimensional bio-cemented sands of various grain sizes across various cementation levels, generating a matrix of various hydraulic conductivities, porosities, and strengths. The fluid injection experiments showed that a cavity-like fracture developed, which transitioned to crack-like fractures at higher cementation levels (hence, higher strength). As the flow rate increased, less infiltration was evident and higher breakdown pressure was observed, with propagation pressure reducing to zero. It was harder to induce an opening in cemented specimens with higher hydraulic conductivity and a larger pore network despite their lower strength due to excessive infiltration dominance, which inhibited the build-up of pressure required to generate a fracture. The results of this study suggest that, when designing fluid injection programs, the combined effects of hydraulic conductivity and strength need to be carefully considered.

show abstract

Investigation on the unsteady-state two-phase fluid transport in the nano-pore system of natural tight porous media

Cited by 9 publications

References 71 publications

Investigation of the Water-Invasion Gas Efficiency in the Kela-2 Gas Field Using Multiple Experiments

Investigation of the Water-Invasion Gas Efficiency in the Kela-2 Gas Field Using Multiple Experiments

Effects of Wettability and Minerals on Residual Oil Distributions Based on Digital Rock and Machine Learning

Experimental Investigation of the Effects of Porosity, Hydraulic Conductivity, Strength, and Flow Rate on Fluid Flow in Weakly Cemented Bio-Treated Sands

Contact Info

Product

Resources

About