Skip to Main Content

Abstract

After two decades of research, secondary porosity remains one of the most controversial topics in clastic sedimentary petrology and reservoir quality assessment. Although the ubiquity of such porosity in sandstones of all ages worldwide is unquestionable, fumdamental disagreements remain as to its practical importance, origin, and effect on reservoir quality prediction.

It appears that the significance of secondary porosity and its impact on sandstone reservoir quality is frequently overemphasized. This can be attributed to two factors:

  1. the subjective nature of the criteria used in defining and quantifying secondary porosity

  2. the erroneous assumption that the presence of secondary porosity automatically results in a net increase of total porosity and permeability

A critical review of processes thought to be responsible for secondary proposity generation suggests that meteoric water influx provides the most effective leaching mechanism. Importantly, some of this porposity can be preseved during deeper burial, particularly in sandstones with high percentages of non-ductile grains. Silicate hydrolysis is probably the most important porosity-generating process in the deep subsurface. However, porosity created by this process is mostly “redistributional” (the volume increase produced by dissolution of minerals is counterbalanced by a similar volume decrease generated by precipitation of pore-filling diagenetic phases representing products of the dissolution reactions). The importance of organic acids as a quantitatively important porosity- enhancing medium is not clear.

The presence of secondary porosity does not appear to significantly affect the accuracy of empirical predictions in many sandstones for two reasons:

  1. The extent of secondary porosity and permeability generation and

You do not currently have access to this chapter.

Figures & Tables

Contents

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal