A new quasi-steady method to measure gas permeability of weakly permeable porous media

Abstract

A new quasi-steady method for the determination of the apparent gas permeability of porous materials is presented in this paper along with the corresponding interpretative physical model derived from the unsteady flow equations. This method is mainly dedicated to the measurement of very low permeability of thin porous media, although thicker but more permeable samples may also be analyzed. The method relies on quasi-steady flow resulting from a (quasi) constant pressure maintained at the inlet face of the sample. Gas flow-rate, as low as 3 × 10(-10) m(3)/s, is determined from the record of pressure increase in a reservoir connected to the outlet face of the sample. An estimate of the characteristic time, t(c), to reach quasi-steady flow after imposing a constant pressure at the inlet is derived. It is validated by direct numerical simulations of the complete unsteady flow, clearly defining the required experimental duration for the method to apply. Experimental results obtained on rather permeable and thick rock samples are reported showing an excellent agreement of the measured permeability with that determined independently on the same sample whereas the experimental value of t(c) is also in very good agreement with the predicted one. The method is further employed on a composite material sheet allowing the identification of an apparent gas permeability of about 10(-23) m(2).

Isothermal Permeability of the Argillaceous Cobourg Limestone

“…These studies show that when the hydraulic pulse test results are corrected for the air fraction, they correspond closely to the results from steady state tests, which can provide the most accurate permeability estimates. Of related interest are recent studies by Jannot and Lasseux (2012) and Golfier et al (2015) that focus on the use of gas permeability tests for the estimation of permeability of respectively, weakly permeable media and vuggy sandstone, taking into consideration alternative laws for the pore fluid migration. This paper discusses the experimental procedures that have been developed for conducting both steady state and transient hydraulic pulse tests on cylindrical samples of the argillaceous Cobourg Limestone and presents results that indicate that cavity air fraction and axial stresses can influence the estimation of the permeability of the rock.…”

A new device to measure permeability evolution under pressure loading: Application to CFRP pipes

“…with k < 10 À15 m 2 , the flow rate is very small and practically impossible to measure, and therefore one usual measurand is pressure loss or gain. Thus, unsteady [27,28] and quasi-steady [23] methods have been developed to measure the permeability of such materials. For an overview of leak rate measurement methods, the reader may refer to [29].…”

“…Conventional permeability devices use a plate-specimen [13,[18][19][20][21][22][23] surrounded by two gas chambers. Crack growth and permeability measurement are often carried out separately [18,19,21].…”

Rigorous Modeling for Data Analysis towards Accurate Determination of Shale Gas-Permeability by Multiple-Repeated Pressure-Pulse Transmission Tests on Crushed Samples

“…The pressure at the upstream side of the confined core plug is increased above the initial pressure by a pressure step by connecting to an infinite volume constant pressure gas supply reservoir, and the downstream side pressure buildup is measured with time (Zoback and Byerlee, 1975, Metwally and Sondergeld, 2011. This technique attempts at distributing the net effective stress uniformly over the core length and accommodate evenly for the response of the whole core plug , Heller et al, 2013.…”

“…The basic definition of the net or effective confining (compressive) stress is the difference between the confining pressure C p and the sensitivity X of the porous material to the pore fluid pressure P p given as (Zoback and Byerlee, 1975, Walls and Nur, 1979, Zimmermann, 1983, Kümpel, 1991, Kwon et al, 2001:…”