Secondary Porosity and Permeability Calculation on Heterogeneous - - PowerPoint PPT Presentation

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Secondary Porosity and Permeability Calculation

• n Heterogeneous Carbonates of Eastern

Mexico, using Borehole Images.

2018 SWS AAPG Annual Convention, April 7-10, El Paso, Texas

Fausto Vazquez, Sr. Borehole Geologist.

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Outline

• Objective
• Location
• Porosity Analysis
• Permeability Analysis
• Results Examples
• Conclusions
• References
• Acknowledgements

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Objective

To show the application of both methodologies in heterogeneous carbonates of Eastern Mexico, from the Middle Cretaceous.

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Location

Tampico-Misantla Basin “Golden Lane”

* From WEC México 2010

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Total porosity (secondary) Fractures Vugs Stylolites Solution Granular Intragranular Intergranular Moldic Dolomitization Micro Macro Mega Fenestral Algal boundstones Diagenetic Visible with borehole images

Porosity and borehole images in Carbonates

Porosity Analysis

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Porosity Model

50 % 0 FMI / Logs 50 % 0

NPHI RHOB

fTotal = fMatrix + fVugs / Molds + fFractures

Secondary Porosity

Akbar et al, ADIPEC 2000

Porosity Analysis

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Akbar et al, ADIPEC 2000

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Akbar et al, ADIPEC 2000

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(f)i = (f)ext [R ext * Ci]

1/m Porosity distribution over a 1.2 inches window Split into primary and secondary porosity is obtained by applying histogram cutoff methods (Newberry et al., 1996)

Porosity Analysis

Yamada et al, 2013

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Permeability Analysis

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Connectivity Index, using a function, is calibrated with a permeability measurement available (Magnetic Resonance, Modular Dynamic Tester, Core)

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Results: Examples

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Top of El Abra Formation, from the Middle Cretaceous. The borehole image suggests karstification towards the top, presence of conductive natural fractures and vuggy porosity. The secondary porosity analysis (in green) indicates important presence of the same. Good correlation between the permeabilities from the MDT (green dots) and from the borehole image (blue curve in the last track).

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Stylolite, compacted interval. Intercalated intervals with development of secondary porosity and

• ther more compacted,

good permeability. Interval with good primary porosity, good permeability.

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Conclusions

 Borehole images are very helpful analyzing the porosity of heterogeneous

carbonate reservoirs, and they could bring a reserve estimation more realistic.

 The textural analysis of such reservoirs, brings a permeability measurement,

that is calibrated against other sources of this parameter, getting in this way a permeability value for the whole interval logged.

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Acknowledgements

To PEMEX and Schlumberger.