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Petrophysics

Petrophysics is the study if the physical properties of the rocks. The main goal of our petrophysical studies is assessment of the controlling parameters, such as porosity, pore structures, pressure, saturation and mineralogy on sonic velocity and permeability in carbonates. Understanding the relative importance of all these parameters is important to assess the uncertainties that arise when using theoretical equations to interpret or predict velocity, porosity and permeability trends from subsurface data sets.

Our current focus is to test several assumptions in rock physics. For example, experiments have revealed that the basic assumption in Gassmann’s equation, which says that the dry and wet shear moduli are constant, needs to be questioned in carbonates. A series of projects address the causes for this shear modulus variability and the effect of saturation on sonic velocity in carbonates. The results of these experiments will provide a guidance of assessing uncertainties in AVO analysis and time-lapse seismic surveys.

In earlier studies we documented the importance of pore structures on velocity at a given porosity, and qualitatively related pore types to these velocity variations. Digital image analysis of pore structures yield a quantitative way to estimate their influence on sonic velocity and permeability. In addition, high-resolution CT–scans of plug samples increases our pore structure analysis from 2-D to 3-D. Over the last years we started to assemble a data-base on dolomites and plan to focus on the sonic velocity and permeability in dolomites to get a better understanding of the petrophysical behavior of various types of dolomite.

Core material from several drill sites are used for integrated studies of the sedimentologic, diagenetic, petrophysical characteristics of oolithic grainstone bodies which determine the influence of early cementation on sonic and hydraulic properties, and the cause for the heterogeneity in such oolithic grainstone settings.

 

 

Current Projects



PETROPHSYICAL CHARACTERISTICS OF CARBONATE DRIFT DEPOSITS – MALDIVES AND IN THE CRETACEOUS MAIELLA MOUNTAINS, ITALY

10.Giddens_Petrophysics

Project Media
     
10.Gidden...sics.pdf
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File Size:2MB

 

Investigators: Emma L. Giddens, Gregor P. Eberli, Luuk Kleipool, and Ralf J. Weger

Project Objectives:

  • Delineate distribution and controls on petrophysical properties (porosity, velocity, resistivity 

    and permeability) in coarse-grained carbonate delta drifts.
  • Compare petrophysical properties of the Maldives with those in the Maiella mountains, Italy.
  • Compare the petrophysical properties of delta drift deposits vs periplatform deposits.

 

 



     

PETROPHYSICAL PROPERTIES OF A FRINGING REEF MARGIN: PLEISTOCENE DOMINICAN REPUBLIC

11.Goodin_DR

Project Media
     
11.Goodin_DR.pdf
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File Size:605KB

 

Investigators: Robert Goodin, James S. Klaus, Donald F. McNeill, Ralf J. Weger, Albertus Ditya, and Gregor P. Eberli

Project Objectives:

  • Determine the petrophysical properties (electrical resistivity, ultrasonic velocity, porosity, permeability, and density) of Pleistocene reefal carbonates within DRDP drilling phase II (cores 1, 6, 4, and 5) to expand the petrophysical survey by Ditya (2012) into previously unsampled slope and lowstand reef facies.
  • Assess the relative influence of primary depositional facies and subsequent diagenetic alteration as determined by Diaz (2017) on the measured mechanical and petrophysical properties.

 

 



     

ASSESSING LITHOCLAST DISTRIBUTION IN GRAINSTONE DRIFT DEPOSITS

12.Grasmueck_Lithoclast

Project Media
     
12.Grasmu...last.pdf
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File Size:2MB

 

Investigators: Mark Grasmueck and Gregor P. Eberli

Project Objectives:

  • Re-process and analyze all Madonna della Mazza 3D GPR cubes data with Pondview.
  • Assess lithoclasts, their textures and distribution inside the different grainstone units based on outcrop and GPR data.
  • Relate clast distribution to flow processes for a refined model for their formation within drift deposit.

 

 



     

THE EFFECT OF MICROBIAL MEDIATED PRECIPITATION ON ROCK PHYSICS

13.Weger_Microbes

Project Media
     
13.Weger_...obes.pdf
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File Size:298KB

 

Investigators: Ralf J. Weger, Mara R. Diaz, Peter K. Swart, and Gregor P. Eberli

Project Objectives:

  • To elucidate the involvement of microbes in ooid cementation processes and their potential effect on the acoustic properties of un-cemented ooid sandstone at low pressures.
  • Compare the influence of microbial mediated versus inorganic precipitated cements on acoustic velocity and rock strengths of carbonates.


     
 

 

 

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