The Upper Devonian to Lower Carboniferous fluvio-lacustrine Albert Formation hosts a small oil and gas field in northeastern New Brunswick, Canada. Back-scattered electron imaging suggests that secondary porosity formed by dissolution of K-feldspars, calcic-plagioclases, and calcite and ankerite cements constitutes the dominant sandstone porosity.

Three factors were examined to explain the observed secondary porosity: organic acids and CO[2] generated from thermal maturation of organic matter, undersaturated meteoric water, and clay-carbonate reactions.

In the Albert Formation sandstones, high secondary porosity occurs in association with oxygen-rich organic matter. This porosity occurs at a temperature at which organic acids and CO[2] production is at its maximum. However, mass balance considerations do not support organic acids and CO[2] as the main mechanism for secondary porosity formation. Consideration of the timing of dissolution, its relation to unconformities, and absence of biodegradation or water washing of the crude oils also indicate that meteoric water was not the principal agent in secondary porosity formation.

We conclude that mineral-mineral reactions were probably the most important pore-forming process. This conclusion is supported by the abundances of kaolinite, mixed-layer illite/smectite, smectite, chlorite, and carbonates in the early mature, moderately porous sandstones of the Dover and Albert Mines areas compared with the more mature and more porous sandstones of the Stoney Creek oil and gas field.