Morphological parameters and geological significance of the columnar fluid migration pathways in seismic profiles

Some columnar seismic anomalies with chimney structures and seepage pipes could be observed in seismic profiles. They are usually interpreted as the vertical migrating pathways of gas-bearing fluids. On the basis of comprehensive description from high-resolution seismic data, some morphological parameters of these columnar fluid migration pathways are calculated in this study. About eight important morphological parameters were systematically summarized, including the root zone level, termination level, plane shape, diameter, length/width ratio, vertical reflection offset, ellipticity, and fitting ellipse azimuth. Combined the spatial distribution pattern of morphological parameters with some special seafloor geomorphologies, such as pockmarks and mounds, and deeper structures, such as diapirs and faults, morphological parameters could be further used to reveal the geology of columnar migrating pathways for gas-bearing fluids. We divided all the parameters into five types, as (ⅰ) parameters for morphological classification of the columnar fluid flow structures; (ⅱ) parameters for reveal the genetic factors and forming mechanisms; (ⅲ) parameters for dating the episodic fluid activities; (ⅳ) parameters for defining the initial and terminal times; and (ⅴ) parameters for indirectly reflecting the relative fluid fluxes. Therefore, integrated analysis based on multi-parameters and comparisons between parameters are important for interpreting these columnar fluid migration pathways formed upon different geological background.