Experimental Verification of the Petroelastic Model in the Laboratory – Fluid Substitution and Pressure Effects

Rasolofosaon, Patrick N.J.; Zinszner, B.

doi:10.2516/ogst/2011167

Cited by 14 publications

(17 citation statements)

References 33 publications

(35 reference statements)

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“…Contrary to the first break picking that leads to overestimated acoustic velocities, the computation of the phase velocity allows the minimization of heterogeneity effect. The measured phase velocities are more representative of the sample macroscopic behaviour and thus more consistent with the poromechanical approach leading to Gassmann's equation (Rasolofosaon and Zinszner 2012).…”

Section: A L T E R a T I O N I M P A C T O N T H E P E T R O A C O U supporting

confidence: 78%

Impact of chemical alteration on the poromechanical properties of carbonate rocks

Bemer

Nguyen

Dautriat

et al. 2016

Geophysical Prospecting

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A B S T R A C TThe technical and economic success of a CO 2 geological storage project requires the preservation of the site injectivity and integrity properties over its lifetime. Unlike conventional hydrocarbon gas injection, CO 2 injection may imply geochemical reactions between acidified pore fluids and target reservoir formations, leading to modifications of their poromechanical properties. To date, the chemical effects on the host rock mechanical behaviour are not satisfactorily taken into account in sitescale numerical models of CO 2 injection, mainly due to a lack of quantitative data. The present experimental work aims at characterizing the evolution of carbonate poromechanical properties induced by acid alteration. Unlike standard experimental approaches, the implemented alteration method induces a homogeneous dissolution pattern, which ensures reliable poromechanical measurements on altered samples. These well-controlled alteration conditions allow a proper interpretation of the test results through the macroscopic continuous approach of poromechanics. Petrophysical, geomechanical, and petroacoustic properties of outcrop carbonate samples have been measured for different levels of alteration to mimic long-term exposure to reactive brine. The obtained experimental data show clear trends of chemically induced mechanical weakening. Nuclear magnetic resonance measurements and microscanner imaging performed before and after alteration have provided complementary insights into the alteration effects at the microscopic scale.

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Section: A L T E R a T I O N I M P A C T O N T H E P E T R O A C O U supporting

confidence: 78%

Impact of chemical alteration on the poromechanical properties of carbonate rocks

Bemer

Nguyen

Dautriat

et al. 2016

Geophysical Prospecting

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“…Careful examination of both data sets shows that values of the bulk modulus of the solid‐filled rock at seismic and ultrasonic frequencies are very close, but the Ciz‐Shapiro predictions are different due to substantial difference between the seismic and ultrasonic drained moduli. We believe that the drained bulk modulus measured at low frequencies is more reliable, since it is the true drained modulus of a fluid‐saturated rock, whereas the ultrasonic modulus was measured on the dry rock, and hence could be altered by the drying process and depends on relative humidity (Rasolofosaon & Zinszner, ; Yurikov et al, ). Conversely, the shear moduli of the dry and drained rock are very close, but for solid‐filled rock the ultrasonic shear modulus is higher than low‐frequency modulus (by about 4 GPa).…”

Section: Resultsmentioning

confidence: 99%

A Seismic‐Frequency Laboratory Study of Solid Substitution in Bentheim Sandstone

et al. 2019

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Studying the effects of the solid pore fills on the elastic properties of rocks is of significant importance for a range of applications, such as, for example, monitoring of heavy oil reservoirs or modeling the transport properties of the rocks affected by salt precipitation or cementation. We present the results of the laboratory solid‐substitution experiments carried out on Bentheim sandstone at a seismic frequency of 2 Hz. The experiments were performed when the pore space of the tested sample was filled sequentially with solid (23°C) and liquid (40°C) octadecane. Previously, ultrasonic measurements on the same octadecane‐filled sandstone showed significant discrepancy from the predictions of Ciz‐Shapiro theory, which was explained by the effect of stiffening of compliant pores at the grain contacts. However, the present results show good agreement with the predictions of the Ciz‐Shapiro theory and suggest that the effect of stiffening of the compliant pores in presence of solid is negligible at low frequency.

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“…This is particularly true in Earth sciences, in the area of gas and oil recovery [Doornhof et al, 2006], groundwater management [Novakowski and Gillham, 1988], CO 2 sequestration [JafarGandomi and Curtis, 2011], and geothermal energy extraction [Jaya et al, 2008]. As the elastic properties of reservoir rocks are highly sensitive to the nature of the fluids saturating the pore space [Mavko et al, 2009;Rasolofosaon and Zinszner, 2012], remote seismic monitoring has been proposed as a tool to characterize fluid substitution processes in reservoirs [Rasolofosaon and Zinszner, 2004]. Successful laboratory studies were conducted by Wulff and Mjaaland [2002] looking at reflected seismic waves in a block of sandstone flooded by water and by [Stanchits et al, 2011] in fluid injection experiments with acoustic emissions recording and ultrasonic monitoring.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic monitoring of spontaneous imbibition experiments: Acoustic signature of fluid migration

et al. 2017

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Capillary rise experiments (spontaneous imbibition tests) were conducted in the laboratory with ultrasonic and X‐ray monitoring on the Sherwood sandstone and the Majella grainstone. The aim was to provide a direct comparison between the variation in seismic attributes (amplitude, velocity, spectral content, and energy) and the actual fluid distribution in the rock. Two pairs of ultrasonic P wave sensors located at different heights on a cylindrical rock specimen recorded every 5 s the waveforms when capillary forces make water rise up into the rock from the bottom in contact with a water tank. Simultaneously, computerized tomography scan images of a vertical cross section were also recorded. Two important results were found. (i) The amplitude of the first P wave arrival is impacted by the upward moving fluid front before the P wave velocity is, while the fluid front has not yet reached the sensors level. In contrast, the P wave velocity decreases when the fluid front reaches the Fresnel clearance zone. The spectral analysis of the waveforms shows that the peak frequency amplitude is continuously decreasing without noticeable frequency shift. (ii) A methodology based on the calculation of the analytical signal and instantaneous phase was designed to decompose each waveform into discrete wavelets associated with direct or reflected waves. The energy carried by the wavelets is very sensitive to the fluid substitution process: the coda wavelets related to reflections on the bottom end face of the specimen are impacted as soon as imbibition starts and can be used as a precursor for the arriving fluid.

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Experimental Verification of the Petroelastic Model in the Laboratory – Fluid Substitution and Pressure Effects

Cited by 14 publications

References 33 publications

Impact of chemical alteration on the poromechanical properties of carbonate rocks

Impact of chemical alteration on the poromechanical properties of carbonate rocks

A Seismic‐Frequency Laboratory Study of Solid Substitution in Bentheim Sandstone

Ultrasonic monitoring of spontaneous imbibition experiments: Acoustic signature of fluid migration

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