Question

In a carbonate reservoir, which specific diagenetic process increases porosity by replacing calcite with a mineral that occupies less volume and creates crystal-interstices?

Accepted Answer

The diagenetic process described is dolomitization. This process occurs when magnesium-rich fluids percolate through a limestone reservoir and chemically replace calcium carbonate (calcite) with dolomite. A molecule of dolomite occupies approximately 12 to 13 percent less volume than the equivalent amount of calcite it replaces. This volume reduction, known as molar volume shrinkage, creates new void spaces within the rock fabric. Additionally, because dolomite crystals often grow as rhombs rather than interlocking tightly like calcite, they leave behind small openings between the crystals called crystal-interstices. Together, this volume reduction and the resulting intercrystalline porosity significantly increase the overall permeability and storage capacity of the carbonate reservoir.

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In a carbonate reservoir, which specific diagenetic process increases porosity by replacing calcite with a mineral that occupies less volume and creates crystal-interstices?

The diagenetic process described is dolomitization. This process occurs when magnesium-rich fluids percolate through a limestone reservoir and chemically replace calcium carbonate (calcite) with dolomite. A molecule of dolomite occupies ap....