1. Heavy-Oil Reservoirs: Their Characterization and Production

Chopra, Satinder; Lines, Larry; Schmitt, Douglas R.; Batzle, Michael

doi:10.1190/1.9781560802235.ch1

Cited by 17 publications

(30 citation statements)

References 76 publications

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“…Behura et al (2007) did not measure the bulk moduli of the rock and oil. We assumed that the bulk modulus of the Uvalde heavy oil depends on frequency and temperature to a much lesser extent than the shear modulus (Chopra et al 2010), and thus, we use the constant value K f = 3GPa.…”

Section: T H E U V a L D E E X P E R I M E N Tmentioning

confidence: 99%

“…Estimating the impact of solid pore fill on effective elastic properties is important for a number of applications such as modelling the effects of salt precipitation (Baumann, Henninges, and De Lucia 2014) and predicting the effects of rock matrix dissolution and related problems (Vanorio, Nur, and Ebert 2011). Models that quantify the effect of a solid pore fill on elastic properties can also be extended to a viscoelastic pore fill; this can help understand the seismic response of rocks saturated with heavy oil or bitumen subjected to changes in temperature and pressure (Chopra et al 2010). * E-mail: Stanislav.glubokovskikh@curtin.edu.au In an analogy to the Gassmann's fluid substitution (Gassmann 1951), solid substitution refers to computing elastic moduli of a rock with a solid pore fill from moduli of the same rock with a different pore fill (air, fluid, or solid).…”

Section: Introductionmentioning

confidence: 99%

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A dual‐porosity scheme for fluid/solid substitution

Glubokovskikh

Gurevich

Saxena

2016

Geophysical Prospecting

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Estimating the impact of solid pore fill on effective elastic properties of rocks is important for a number of applications such as seismic monitoring of production of heavy oil or gas hydrates. We develop a simple model relating effective seismic properties of a rock saturated with a liquid, solid, or viscoelastic pore fill, which is assumed to be much softer than the constituent minerals. A key feature of the model is division of porosity into stiff matrix pores and compliant crack‐like pores because the presence of a solid material in thin voids stiffens the rock to a much greater extent than its presence in stiff pores. We approximate a typical compliant pore as a plane circular interlayer surrounded by empty pores. The effect of saturation of the stiff pores is then taken into account using generalized Gassmann's equations. The proposed model provides a good fit to measurements of the shear stiffness and loss factor of the Uvalde heavy‐oil rock at different temperatures and frequencies. When the pore fill is solid, the predictions of the scheme are close to the predictions of the solid squirt model recently proposed by Saxena and Mavko. At the same time, the present scheme also gives a continuous transition to the classic Gassmann's equations for a liquid pore fill at low frequencies and the squirt theory at high frequencies.

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Section: T H E U V a L D E E X P E R I M E N Tmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A dual‐porosity scheme for fluid/solid substitution

Glubokovskikh

Gurevich

Saxena

2016

Geophysical Prospecting

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“…The resulting seismic events can also excite resonances in the conduit if located close to its walls [Neuberg et al, 2006;Shimomura et al, 2006;Thomas and Neuberg, 2012], similarly to seismic waves trapped in low-velocity waveguides [van der Baan, 2009]. Sudden changes in temperature at depth can also lead to fracturing, such as during magma or hydrothermal fluid intrusion in volcanoes [Burlini et al, 2007;Konstantinou and Schlindwein, 2003] or steam injection in reservoirs [Chopra et al, 2010;Maxwell et al, 2007]. Fluid movements can induce pressure variations through sudden inflow or outflow [Ferrick et al, 1982;Chouet et al, 2005;Lesage et al, 2006;De Barros et al, 2011] or due to overall unsteady fluid flow [Ferrick et al, 1982;Rust et al, 2008].…”

Section: Source Effectsmentioning

confidence: 99%

Interpretation of resonance frequencies recorded during hydraulic fracturing treatments

Tary

Baan

Eaton

2014

J. Geophys. Res. Solid Earth

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Hydraulic fracturing treatments are often monitored by strings of geophones deployed in boreholes. Instead of picking discrete events only, we here use time‐frequency representations of continuous recordings to identify resonances in two case studies. This paper outlines an interpretational procedure to identify their cause using a subdivision into source, path, and receiver‐side effects. For the first case study, two main resonances are observed both at depth by the downhole geophones and on the surface by two broadband arrays. The two acquisition networks have different receiver and path effects, yet recorded the same resonances; these resonances are therefore likely generated by source effects. The amplitude pattern at the surface arrays indicates that these resonances are probably due to pumping operations. In the second case study, selective resonances are detected by the downhole geophones. Resonances coming from receiver effects are either lower or higher frequency, and wave propagation modeling shows that path effects are not significant. We identify two possible causes within the source area, namely, eigenvibrations of fractures or non‐Darcian flow within the hydraulic fractures. In the first situation, 15–10 m long fluid‐filled cracks could generate the observed resonances. An interconnected fracture network would then be required, corresponding to mesoscale deformation of the reservoir. Alternatively, systematic patterns in non‐Darcian fluid flow within the hydraulic fracture could also be their leading cause. Resonances can be used to gain a better understanding of reservoir deformations or dynamic fluid flow perturbations during fluid injection into hydrocarbon and geothermal reservoirs, CO2 sequestration, or volcanic eruptions.

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“…Many processes take place during migration that can modify the original oil characteristics. These processes are biodegradation, water washing, oxidation, deasphalting/evaporation, and preferential migration of lighter components Chopra et al (2010).…”

Section: Heavy Oil Formationmentioning

confidence: 99%

Experimental and Numerical Simulation of Combined Enhanced Oil Recovery with In Situ Upgrading in a Naturally Fractured Reservoir

Chávez-Morales

Pereira‐Almao

2016

Day 2 Thu, October 20, 2016

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The purpose of this research work is to show laboratory experiments conducted at 1500 psi and 350°C, experimentally simulating a reservoir located in the Gulf of Mexico. The experiments conducted used a novel process that involved a hot fluid to be injected with an ultra-dispersed nano catalyst. The results obtained showed that API gravity can be improved permanently as well as its viscosity, with the advantage of no coke or solid deposits formation. Laboratory analyses showed that by using this new process it is possible to enter into the matrix zone, expelling at least partially the oil confined inside. As a consequence of the temperature increase, matrix rock may expand and expel its oil; while temperatures decrease, the pores in the matrix could be contracted, generating additional oil expulsion from this area. As a consequence of this expansion-contraction in the reservoir the reserves could be increased. Also, a change in the permeability appears due to the temperature increases. The present study was focused in oil matrix extraction and in situ oil upgrading from a naturally fractured reservoir of heavy oil as a result of a hot fluid injection with nano catalyst. Moreover, the effects of capillary pressure, mobility, viscous effects, wettability, and gravitational drainage on the process were analyzed. Another aspect that was studied is how the thermal expansion generated as a consequence of the process that could expel the oil confined in the matrix.

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1. Heavy-Oil Reservoirs: Their Characterization and Production

Cited by 17 publications

References 76 publications

A dual‐porosity scheme for fluid/solid substitution

A dual‐porosity scheme for fluid/solid substitution

Interpretation of resonance frequencies recorded during hydraulic fracturing treatments

Experimental and Numerical Simulation of Combined Enhanced Oil Recovery with In Situ Upgrading in a Naturally Fractured Reservoir

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