A comparison of rock physics models for fluid substitution in carbonate rocks

Misaghi, Ali; Negahban, Sajjad; Landrø, Martin; Javaherian, Abdolrahim

doi:10.1071/eg09035

Cited by 30 publications

(16 citation statements)

References 25 publications

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“…; Misaghi et al . ). In accordance with Gassmann's theory, fluid substitution increases the bulk modulus of a rock (Gassmann ), whereas the shear modulus remains constant (Berryman ).…”

Section: Introductionmentioning

confidence: 97%

Laboratory measurements of the effect of fluid saturation on elastic properties of carbonates at seismic frequencies

Mikhaltsevitch

Lebedev

Gurevich

2016

Geophysical Prospecting

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A significant portion of the world's hydrocarbon reserves are found in carbonate reservoirs, yet analysis of the petrophysical properties of these reservoirs is associated with a number of challenges. Some of these challenges stem from physical and chemical interactions between the carbonate rock matrix and pore fluids, which can affect elastic properties of the rock. Hence, the study of the pore fluid effects on the elastic properties of carbonates is important for understanding a change of the field performance properties of а carbonate reservoir caused by fluid movements during hydrocarbon extraction in producing fields. In this laboratory study, we investigate the applicability of Gassmann's model for predictions of the elastic moduli of water‐ and hydrocarbon‐saturated Savonnières limestone and the influence of partial water saturation on elastic and anelastic properties of the rock. We present the results of two sets of laboratory experiments on the Savonnières oolitic limestone where we: (i) evaluate the effect of full water and n‐decane saturation on elastic moduli and attenuation at seismic (0.1 Hz–120 Hz) and ultrasonic (0.5 MHz) frequencies; and (ii) quantify the dependence of elastic moduli and extensional attenuation on water saturation at two seismic frequencies of 1 Hz and 10 Hz. We demonstrate that the change in the bulk modulus of limestone fully saturated either with n‐decane or water is in agreement with Gassmann's fluid substitution theory, whereas the shear modulus is noticeably reduced. The measurements with partial saturation show that the bulk modulus decreases with increasing water saturation to a lesser extent than the Young's and shear moduli. Our results show that extensional attenuation in the samples with closed boundaries is insignificant under dry and fully saturated conditions but is influenced greatly by the liquid content when saturation is between 0 and 20% or 95% and 100%.

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“…; Misaghi et al . ). In accordance with Gassmann's theory, fluid substitution increases the bulk modulus of a rock (Gassmann ), whereas the shear modulus remains constant (Berryman ).…”

Section: Introductionmentioning

confidence: 97%

Laboratory measurements of the effect of fluid saturation on elastic properties of carbonates at seismic frequencies

Mikhaltsevitch

Lebedev

Gurevich

2016

Geophysical Prospecting

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“…Mineral composition and microstructure of carbonate rocks are the key factors that determine rock mechanical properties (Rhett and Lord 2001;Vanorio and Mavko 2011). In laboratory studies of the elastic properties of fluid-saturated carbonates conducted at ultrasonic frequencies, the applicability of Gassmann's relations to carbonate sedimentary rocks was questioned (Wang 1997; * E-mail: m.lebedev@curtin.edu.au Baechle et al 2005;Adam et al 2006;Sharma et al 2006;Vanorio, Scotallero and Mavko 2008;Misaghi et al 2010;Vialle and Vanorio 2011). Adam et al 2006 show that viscoelastic properties of fluid-saturated rocks measured at ultrasonic frequencies might differ significantly from the dynamic moduli at seismic frequencies for a small set of carbonate samples.…”

Section: Introductionmentioning

confidence: 99%

An experimental study of solid matrix weakening in water‐saturated Savonnières limestone

Lebedev

Wilson

Mikhaltsevitch

2014

Geophysical Prospecting

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A B S T R A C TPetrophysical properties of carbonate reservoirs are less predictable than that of siliciclastic reservoirs. One of the main reasons for this is the physical and chemical interactions of carbonate rocks with pore fluids. Such interactions can significantly change the elastic properties of the rock matrix and grains, making the applicability of Gassmann's fluid substitution procedure debatable. This study is an attempt to understand the mechanisms of fluid-rock interactions and the influence of these interactions on elastic parameters of carbonates. We performed precise indentation tests on Savonnières limestone at a microscale level under dry, distilled water, and n-Decane saturated conditions. Our experiments display softening of the rock matrix after water saturation. We have found that mainly the ooid cortices, peloid nuclei and prismatic intergranular cement are affected by water flooding. We also observed a shear modulus reduction in Savonnières limestone in an experiment performed at ultrasonic frequencies. One of the most important results obtained in our experimental study is that the Gassmann fluid substitution theory might not always be applicable to predict the elastic moduli of fluid-saturated limestones.

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“…Then, a difference was expected to get microporosity percent estimate. Therefore, the SC may be overestimating the spherical pore fractions, a similar problem described in Misaghi et al (2010).…”

Section: Resultsmentioning

confidence: 93%

“…Thus, bulk (K) and shear (µ) modulus and P-and S-wave velocities can be estimated by EEM models: KT (Kuster-Toksöz), SC (Selfconsistent) and DEM (Differential Effective Medium), see Mavko et al (2009);Misaghi et al (2010);and Berryman et al (2002). The pore aspect ratio is a textural parameter evaluated into the predominant dual pore system: (1) Interparticle or intercristaline porosity, a reference expected to oncolytic/oolitic grainstones; and a second expressive inclusion (2) Moldic, vuggy or spherical pore; or (3) Microporosity.…”

Section: Theory and Methodsmentioning

confidence: 99%

Dual pore system evaluation of Albian grainstone carbonates from Brazil using effective elastic media theory models

Neto¹,

Misságia²,

Ceia³

et al. 2013

SEG Technical Program Expanded Abstracts 2013

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Carbonates represent a significant portion of the Brazil's deepwater oil production, whose importance has increased with recent discoveries in the post-salt and pre-salt oil deposits. Often carbonates are characterized by a heterogeneous pore system, displaying a complex pore structure with wide range of pore sizes and shapes. This work aims towards investigating grainstone carbonates (Albian-age) of the offshore Campos Basin, Brazil by laboratorial evaluation and rock physics modeling to predict interparticle aspect ratio and quantitative fractions of a dual pore system approach under ultrasonic and dry conditions. The goal is to estimate elastic moduli considering intergranular porosity expected in oncolytic/oolitic grainstones using Effective Elastic Media (EEM) theories -KT (Kuster-Toksöz), SC (Self-consistent) and DEM (Differential Effective Medium), and either a spherical inclusions or a microporosity dominated pore system. The results show that the KT and DEM give a best compatibility with the texture of the Albian grainstone carbonates. Interparticle aspect ratio estimation and a quantitative prediction of the inclusion effects helped us to understand the elastic properties of Albian carbonates.

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A comparison of rock physics models for fluid substitution in carbonate rocks

Cited by 30 publications

References 25 publications

Laboratory measurements of the effect of fluid saturation on elastic properties of carbonates at seismic frequencies

Laboratory measurements of the effect of fluid saturation on elastic properties of carbonates at seismic frequencies

An experimental study of solid matrix weakening in water‐saturated Savonnières limestone

Dual pore system evaluation of Albian grainstone carbonates from Brazil using effective elastic media theory models

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