Fractal Characteristics of Lacustrine Tight Carbonate Nanoscale Reservoirs

The complexity and heterogeneity of pore structure greatly affect gas-liquid accumulation and transport, and the fractal theory has been proven to be an effective approach for studying nanoscale reservoirs in shale, coal, and tight sandstones. However, researches on fractal characteristics and control mechanisms for the lacustrine tight carbonate have received little attention. Lacustrine tight carbonate samples from the Jurassic Da’anzhai Member in the Sichuan Basin in China were systematically investigated focusing on the fractal characteristics and control mechanisms of storage spaces, minerals, diagenesis, and paleoenvironments. The fractal dimensions can be separated into two different and valid parts including D1 (2.515–2.785, average 2.652) and D2 (2.424–2.562, average 2.485), and the correlation between them is negative rather than positive. The average pore diameters exhibit a positive correlation with D1 and a negative correlation with D2, and the storage space is positively correlated with D2 a...