A distinct category of fractures

characterized by a substantial proportion

shallow angle

and contentious origin

commonly referred to n as “cake-like” fractures or “laminar cake” fractures within the second member of Xujiahe Formation of Xinchang structural belt

has been chosen as the research target. This study employs meticulous core observation

precise thin section analysis

and a comprehensive comparative assessment of both macroscopic and microscopic traits. The primary objective is to classify these “cake-shaped” fractures for the first time and elucidate their corresponding lithofacies attributes and genesis. The discussion regarding the oil and gas geological significance of these “cake-like” fractures is rooted in the distinctions in gas-bearing properties. The analysis reveals the presence of three distinct types of “cake-like” fractures: thin layer “shortcake” fractures

medium-thick layer unequal spacing fractures and medium-thick layer isometric fractures. The thin layer “shortcake” fractures manifest within isolated distributary channels with coarse-grained textures and a high quartz composition. Conversely

the medium-thick layer unequal distance fractures are evident in interbedded distributary channels exhibiting fine

medium-grained

and coarse-grained textures with a notable feldspar content. The medium-thick layer isometric fractures occur within distributary channels or estuarine bar resulting from the deposition of alternating fine and medium-grained calcareous-rich sand and calcareous-poor sand. The initial two fracture types can not only improve reservoir permeability

but also intensify the dissolution effect

leading to higher gas content

while the latter type only increases the permeability and has a limited impact on the matrix pores

resulting in lower gas content. The “cake-like” fracture phenomenon represents a composite fracture formation influenced by sedimentary environment

tectonic stress

and differential diagenesis. It defies a simple classification as a tectonic shear fracture

sedimentary bedding fracture

or stress unloading fracture. The areas with high structural position

well-developed pie fractures and favorable reservoir properties

augmented by effective fracture network fracturing technology

present promising prospects for future exploration endeavors.