Secondary Porosity and Permeability Calculation on Heterogeneous - PowerPoint PPT Presentation

Secondary Porosity and Permeability Calculation on Heterogeneous Carbonates of Eastern Mexico, using Borehole Images. 2018 SWS AAPG Annual Convention, April 7-10, El Paso, Texas Fausto Vazquez, Sr. Borehole Geologist. Schlumberger-Private

Outline • Objective Location • Porosity Analysis • Permeability Analysis • Results Examples • Conclusions • References • Acknowledgements • Schlumberger-Private

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

Location Tampico-Misantla Basin “Golden Lane” * From WEC México 2010 Schlumberger-Private

Porosity Analysis Porosity and borehole images in Carbonates Total porosity (secondary) Diagenetic Fractures Fenestral Micro Algal Macro Mega Solution Dolomitization boundstones Vugs Stylolites Granular Moldic Intragranular Intergranular Visible with borehole images Schlumberger-Private

Porosity Analysis Porosity Model 50 % 0 50 % 0 NPHI FMI / Logs RHOB f Total = f Matrix + f Vugs / Molds + f Fractures Akbar et al, ADIPEC 2000 Secondary Porosity Schlumberger-Private

Akbar et al, ADIPEC 2000 Schlumberger-Private

Akbar et al, ADIPEC 2000 Schlumberger-Private

Porosity Analysis 1/m ( f ) i = ( f ) ext [R ext * Ci] Yamada et al, 2013 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) Schlumberger-Private

Permeability Analysis Schlumberger-Private

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

Results : Examples Schlumberger-Private

Top of El Abra Formation, from the Middle Cretaceous. The borehole image suggests karstification towards the top, presence of conductive natural fractures and vug gy 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). Schlumberger-Private

Stylolite, compacted interval. Intercalated intervals with development of secondary porosity and other more compacted, good permeability. Interval with good primary porosity, good permeability. Schlumberger-Private

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. Schlumberger-Private

Acknowledgements To PEMEX and Schlumberger. Schlumberger-Private