Mineralogy Performance: What the Literature Says about GreenZyme® EOR

When operators working mixed-mineralogy reservoirs ask whether GreenZyme is effective when the primary rock mineral is not quartz, the answer from the published literature is both direct and consistent. c not the mineral surface itself.

This means wettability alteration occurs wherever that oil-wet coating exists, regardless of whether the underlying grain is quartz, feldspar, calcite, or clay. The following studies, spanning limestone, clay-cemented sandstone, carbonate-rich shale, and argillaceous heavy oil reservoirs, document that performance across multiple rock types, research institutions, and field conditions. The short answer is yes, it works — and the library has direct evidence across multiple mineral types.

Evidence From Literature and Field Performance:

1. Clay-Rich and Carbonate-Rich Shale — URTeC 2019 (OU Study)

The Woodford shale cores tested included both clay-rich and carbonate-rich samples. The paper explicitly states: "There was no significant difference in the EOR performance between the two categories of rocks." Wettability alteration and oil recovery improvement were consistent regardless of dominant mineralogy.

2. Limestone / Carbonate — SPE-112355 (Calgary/Shengli)

Contact angle measurements were run on both sandstone and limestone surfaces. On sandstone, the wettability shift was fast and dramatic (94° → 0° in 30 hours). On limestone, the shift was slower but still meaningful (133° → 115° over 30 hours). The mechanism works on carbonate surfaces — it just operates on a different timescale, which has operational implications for soak time design.

GreenZyme effect on Sandstone and Limestone, SPE112355

3. Clay-Bearing Sandstone — Baise Oilfield & Bergen PhD

Baise reservoir clays were predominantly Kaolin and Illite (70–85% of clay fraction), with some Chlorite. GreenZyme achieved 85.7% success rate across five distinct blocks in this clay-rich environment. The Bergen dissertation also tested enzyme on clay-bearing cores without noting mineralogical sensitivity as a limiting factor.

4. Heavy Mineralogy, High Resin/Asphaltene Sandstone — Shengli Y8 (SPE-112355, Y8 Papers)

The Y8 reservoir is characterized by argillaceous cement, high sulfur, high resin (35–38%) and high asphaltene content — a chemically complex matrix where the binding between oil and rock is dominated by organic-mineral interactions, not just quartz surface chemistry. Enzyme consistently removed organic blockage and altered wettability in this environment across 6+ wells.

5. Dagang — Mixed Lithology, Multi-Block (SPE-107128)

Lab tests used cores from four different blocks with varying mineralogy. The paper concludes: "Production performance with the modified enzyme is not associated with oil properties" — and the same logic extends to rock type, as the mechanism targets the oil-rock interface, not a specific mineral surface.

The Core Mechanism Argument

GreenZyme does not work on quartz specifically — it works on the oil-rock bond regardless of what mineral is beneath it. The enzyme targets the organic film (resins, asphaltenes, wax) adhering to the rock grain surface and breaks that adhesion by shifting the surface from oil-wet to water-wet. That oil-wet condition can exist on quartz, feldspar, carbonate, clay, or mixed-mineral surfaces. The enzyme doesn't care what mineral is underneath — it cares about the oil coating on top of it.