scholarly journals Klinkenberg effect for gas permeability and its comparison to water permeability for porous sedimentary rocks

2006 ◽  
Vol 3 (4) ◽  
pp. 1315-1338 ◽  
Author(s):  
W. Tanikawa ◽  
T. Shimamoto
Keyword(s):  
Pore Pressure ◽  
Water Permeability ◽  
Gas Flow ◽  
Gas Permeability ◽  
Slip Flow ◽  
Sedimentary Rocks ◽  
Water Film ◽  
Klinkenberg Effect ◽  
Two Phase ◽  
Order Of Magnitude

Abstract. The difference between gas and water permeabilities is significant not only for solving gas-water two-phase flow problems, but also for quick measurements of permeability using gas as pore fluid. We have measured intrinsic permeability of sedimentary rocks from the Western Foothills of Taiwan, using nitrogen gas and distilled water as pore fluids, during several effective-pressure cycling tests at room temperature. The observed difference in gas and water permeabilities has been analyzed in view of the Klinkenberg effect. This effect is due to slip flow of gas at pore walls which enhances gas flow when pore sizes are very small. Experimental results show (1) that gas permeability is larger than water permeability by several times to one order of magnitude, (2) that gas permeability increases with increasing pore pressure, and (3) that water permeability slightly increases with increasing pore-pressure gradient across the specimen. The results (1) and (2) can be explained by Klinkenberg effect quantitatively with an empirical power law for Klinkenberg constant. Thus water permeability can be estimated from gas permeability. The Klinkenberg effect is important when permeability is lower than 10−18 m2 and at low differential pore pressures, and its correction is essential for estimating water permeability from the measurement of gas permeability. A simple Bingham-flow model of pore water can explain the overall trend of the result (3) above. More sophisticated models with a pore-size distribution and with realistic rheology of water film is needed to account for the observed deviation from Darcy's law.

scholarly journals NMR Analysis Method of Gas Flow Pattern in the Process of Shale Gas Depletion Development

Geofluids ◽  
2022 ◽  
Vol 2022 ◽  
pp. 1-7
Author(s):  
Rui Shen ◽  
Zhiming Hu ◽  
Xianggang Duan ◽  
Wei Sun ◽  
Wei Xiong ◽  
...  
Keyword(s):  
Flow Pattern ◽  
Pore Pressure ◽  
Shale Gas ◽  
Gas Flow ◽  
Continuous Medium ◽  
Slip Flow ◽  
Flow Patterns ◽  
Transitional Flow ◽  
Analysis Method ◽  
Adsorbed Gas

Shale gas reservoirs have pores of various sizes, in which gas flows in different patterns. The coexistence of multiple gas flow patterns is common. In order to quantitatively characterize the flow pattern in the process of shale gas depletion development, a physical simulation experiment of shale gas depletion development was designed, and a high-pressure on-line NMR analysis method of gas flow pattern in this process was proposed. The signal amplitudes of methane in pores of various sizes at different pressure levels were calculated according to the conversion relationship between the NMR T 2 relaxation time and pore radius, and then, the flow patterns of methane in pores of various sizes under different pore pressure conditions were analyzed as per the flow pattern determination criteria. It is found that there are three flow patterns in the process of shale gas depletion development, i.e., continuous medium flow, slip flow, and transitional flow, which account for 73.5%, 25.8%, and 0.7% of total gas flow, respectively. When the pore pressure is high, the continuous medium flow is dominant. With the gas production in shale reservoir, the pore pressure decreases, the Knudsen number increases, and the pore size range of slip flow zone and transitional flow zone expands. When the reservoir pressure is higher than the critical desorption pressure, the adsorbed gas is not desorbed intensively, and the produced gas is mainly free gas. When the reservoir pressure is lower than the critical desorption pressure, the adsorbed gas is gradually desorbed, and the proportion of desorbed gas in the produced gas gradually increases.

scholarly journals Absolute linear instability in laminar and turbulent gas–liquid two-layer channel flow

2013 ◽  
Vol 714 ◽  
pp. 58-94 ◽  
Author(s):  
Lennon Ó Náraigh ◽  
Peter D. M. Spelt ◽  
Stephen J. Shaw
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Stability Boundary ◽  
Density Ratio ◽  
Bottom Layer ◽  
Linear Instability ◽  
Absolute Instability ◽  
Two Phase ◽  
Order Of Magnitude ◽  
Temporal Modes

AbstractWe study two-phase stratified flow where the bottom layer is a thin laminar liquid and the upper layer is a fully developed gas flow. The gas flow can be laminar or turbulent. To determine the boundary between convective and absolute instability, we use Orr–Sommerfeld stability theory, and a combination of linear modal analysis and ray analysis. For turbulent gas flow, and for the density ratio $r= 1000$, we find large regions of parameter space that produce absolute instability. These parameter regimes involve viscosity ratios of direct relevance to oil and gas flows. If, instead, the gas layer is laminar, absolute instability persists for the density ratio $r= 1000$, although the convective/absolute stability boundary occurs at a viscosity ratio that is an order of magnitude smaller than in the turbulent case. Two further unstable temporal modes exist in both the laminar and the turbulent cases, one of which can exclude absolute instability. We compare our results with an experimentally determined flow-regime map, and discuss the potential application of the present method to nonlinear analyses.

Laboratory measurement and interpretation of nonlinear gas flow in shale

2015 ◽  
Vol 26 (06) ◽  
pp. 1550063 ◽  
Author(s):  
Yili Kang ◽  
Mingjun Chen ◽  
Xiangchen Li ◽  
Lijun You ◽  
Bin Yang
Keyword(s):  
Pore Pressure ◽  
Gas Flow ◽  
Gas Adsorption ◽  
Slip Flow ◽  
Transition Flow ◽  
Confining Stress ◽  
Slippage Effect ◽  
Longmaxi Shale ◽  
Close Relationship ◽  
Flow Mechanisms

Gas flow mechanisms in shale are urgent to clarify due to the complicated pore structure and low permeability. Core flow experiments were conducted under reservoir net confining stress with samples from the Longmaxi Shale to investigate the characteristics of nonlinear gas flow. Meanwhile, microstructure analyses and gas adsorption experiments are implemented. Experimental results indicate that non-Darcy flow in shale is remarkable and it has a close relationship with pore pressure. It is found that type of gas has a significant influence on permeability measurement and methane is chosen in this work to study the shale gas flow. Gas slippage effect and minimum threshold pressure gradient weaken with the increasing backpressure. It is demonstrated that gas flow regime would be either slip flow or transition flow with certain pore pressure and permeability. Experimental data computations and microstructure analyses confirm that hydraulic radius of flow tubes in shale are mostly less than 100 nm, indicating that there is no micron scale pore or throat which mainly contributes to flow. The results are significant for the study of gas flow in shale, and are beneficial for laboratory investigation of shale permeability.

Gas Flow Through Water-Saturated Shear Zones: Field and Laboratory Experiments and Their Interpretation

1997 ◽  
Vol 506 ◽  
Author(s):  
P. Marschall ◽  
J. Croisé ◽  
U. Fischer ◽  
R. Senger ◽  
E. Wyss
Keyword(s):  
Shear Zone ◽  
Gas Flow ◽  
Two Phase Flow ◽  
Gas Permeability ◽  
Numerical Models ◽  
Shear Zones ◽  
Parameter Estimates ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Processes

ABSTRACTGas threshold pressure tests and gas tracer tests have been performed at the Grimsel Test Site to study two-phase flow processes in a shear zone. In addition, capillary pressure and gas permeability measurements were carried out in the laboratory on drillcore samples. The laboratory investigations were complemented by assessing the pore structure of the shear zone material. The interpretation of the field tests with numerical models indicated that the structural and two-phase flow parameters to be determined are highly correlated with one another and, consequently, the parameter estimates can be rather uncertain. The joint interpretation of field and laboratory results, however, led to a more stringent description of the two-phase flow processes, expressed by a better overall fit of the test data and smaller uncertainty ranges of the estimated parameters. The results showed that the gas mobility in the shear zone was very high even at high water saturation and gas flow was limited to the narrow zones of brittle deformation along the shear zone.

Analytical and Experimental Investigations of Gas-Flow Regimes in Shales Considering the Influence of Mean Effective Stress

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 557-572 ◽  
Author(s):  
Alireza A. Moghadam ◽  
Rick Chalaturnyk
Keyword(s):  
Flow Regime ◽  
Effective Stress ◽  
Gas Flow ◽  
Gas Permeability ◽  
Slip Flow ◽  
Flow Regimes ◽  
Absolute Permeability ◽  
Apparent Permeability ◽  
Reservoir Conditions ◽  
Slip Flow Regime

Summary Flow conditions determine the flow regimes governing gas flow in porous media. Slip-flow regime commonly occurs in laboratory gas-permeability measurements, and one must consider the physics of that when finding the absolute permeability of a sample. Accurate permeability estimates are paramount for production forecasts, financial planning, and recovery estimation. Slip flow is present in low-permeability rocks, both in the laboratory environment and at reservoir conditions. Gas flow through the matrix lies under the slip-flow regime for the majority of low-permeability-reservoir production scenarios, and accurate prediction of pressure and production rate requires a good understanding of the flow regime. In this paper, an analytical study is conducted on the dominant flow regimes under typical shale-gas reservoir conditions. A flow-regime map is produced with respect to gas pressure and matrix permeability. Steady-state gas-permeability experiments are conducted on three shale samples. An analytical model is used to match the experimental results that could explain the order-of-magnitude difference between the permeabilities of gas and liquid in shales. Experimental results are combined with further tests available in the literature to inform a discussion of the model's parameters. The results improve the accuracy of gas-flow modeling and of absolute-permeability estimates from laboratory tests. Similar tests performed at various mean effective stresses investigate the influence of mean effective stress on flow regime and apparent permeability. The results indicate that flow regime is a function of mean effective stress, and that the apparent permeability of shale rocks is a function of both flow regime and mean effective stress.

Assessing the Gas Transport Mechanisms in the Swiss L/ILW Concept Using Numerical Modeling and Supporting Experimental Work

2010 ◽  
Author(s):  
Irina Gaus ◽  
Paul Marschall ◽  
Rainer Senger ◽  
John Ewing ◽  
Joerg Rueedi
Keyword(s):  
Host Rock ◽  
Gas Flow ◽  
Gas Transport ◽  
Gas Permeability ◽  
Low Permeability ◽  
Gas Migration ◽  
Transport Mechanisms ◽  
Transport Capacity ◽  
Two Phase ◽  
Tunnel System

In low/intermediate-level waste (L/ILW) repositories, anaerobic corrosion of metals and degradation of organic materials produce hydrogen, methane, and carbon dioxide. Gas accumulation and gas transport in a L/ILW repository is an important component in the safety assessment of proposed deep repositories in low-permeability formations. The dominant gas transport mechanisms are dependent on the gas overpressures as with increasing overpressure the gas transport capacity of the system increases. The dominant gas transport mechanisms occurring with increasing gas pressure within the anticipated pressure ranges are: diffusion of gas dissolved in pore water (1), two phase flow in the host rock and the excavation damaged zone (EDZ) whereby no deformation of the pore space occurs (2), gas migration within parts of the repository (if repository materials are appropriately chosen) (3) and pathway dilation (4). Under no circumstances the gas is expected to induce permanent fractures in the host rock. This paper focuses on the gas migration in parts of the repository whereby materials are chosen aimed at increasing the gas transport capacity of the backfilled underground structures without compromising the radionuclide retention capacity of the engineered barrier system (EBS). These materials with enhanced gas permeability and low water permeability can supplement the gas flow that is expected to occur through the EDZ and the host rock. The impact of the use of adapted backfill and sealing materials on the gas pressure build-up and the major gas paths were assessed using numerical two-phase flow models on the repository scale. Furthermore, both the gas and water fluxes as a function of time and gas generation rate can be evaluated by varying the physical properties of the materials and hence their transport capacity. Results showed that by introducing seals with higher gas permeability, the modelled gas flow is largely limited to the access tunnels and the excavation disturbed zone for the case of a very low permeability host rock. The bulk of the gas flows through the repository seal and the adjacent EDZ into the tunnel system. In addition to the demonstration of the gas flow in the seal and access tunnel system by numerical models, laboratory results confirm the high gas transport capacity of the sand/bentonite mixtures. In a next step a multi year demonstration scale experiment (GAST) at the Grimsel Test Site is envisioned.

Experimental Study of the Klinkenberg Effect on the Gas Permeability of Coal

2017 ◽  
Vol 10 ◽  
pp. 83-92 ◽  
Author(s):  
Renato Zagorščak ◽  
Hywel Rhys Thomas
Keyword(s):  
Effective Stress ◽  
Gas Flow ◽  
General Trend ◽  
Gas Permeability ◽  
Stress Conditions ◽  
Klinkenberg Effect ◽  
Intrinsic Values ◽  
Anthracite Coal ◽  
The Mean ◽  
Gas Pressures

This paper presents the results of an experimental investigation on gas flow and Klinkenberg effect in coal. An anthracite coal sample is subjected to a range of effective stress conditions in order to investigate a general trend of coal permeability reduction with an increase in effective stress. Based on the measured values of permeability at different mean gas pressures for constant effective stress conditions, intrinsic values of permeability in the range 0.2 – 1.5 mD and gas slip factors are determined using the Klinkenberg plot. Using measured gas permeability and calculated intrinsic permeability values, an assessment of the mean gas pressure required to minimize the Klinkenberg effect is conducted.

scholarly journals Measurement of Gas-permeability of Rocks Using an Oscillating Pore Pressure Method and a Gas Flow Method

2003 ◽  
Vol 119 (8) ◽  
pp. 514-518 ◽  
Author(s):  
Akito TSUTSUMI ◽  
Takehiro HIROSE ◽  
Kazuo MIZOGUCHI ◽  
Shinichiro UEHARA ◽  
Keiji SATO ◽  
...  
Keyword(s):  
Pore Pressure ◽  
Gas Flow ◽  
Gas Permeability ◽  
Flow Method ◽  
Pressure Method
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