Distribution characteristics of carbonate fractures in Wuxiang County

Formation thickness plays an important role in the development of structural fractures in carbonate rocks. There is a certain relationship between the fractal dimension of structural fractures and the density of fracture surface, which can quantitatively describe the development degree of structural fractures. Generally speaking, the fractal dimension increases with the increase of fracture surface density. Under the same density of fracture surface, the larger the fractal dimension, the more uniform the fracture distribution and the worse the permeability of carbonate formation.

Carbonate rock is a modern word, which refers to the general name of rocks composed of carbonate minerals formed by deposition, mainly limestone and dolomite. Carbonate rock is formed by supersaturation of bicarbonate solution in nature and precipitation of carbonate pepper from water. Modern and ancient carbonate deposits are mainly distributed in the clear and warm shallow shelf environment and the coastal areas without river injection at low latitudes. This is because carbonate supersaturated precipitation needs to discharge CO2, and the increase of seawater temperature and the decrease of seawater depth are beneficial to the reduction of CO2 partial pressure in water and the promotion of bicarbonate supersaturated precipitation. In addition, warm shallow sea environment, biological development and algae photosynthesis all need to absorb CO2, which also promotes the saturation and precipitation of CaCO3. Benthic organisms and plankton also directly construct calcareous bones through biochemical and biophysical effects, forming biocarbonates. Mechanical action plays an important role in the formation of carbonate rocks. Once the carbonate sediments was deposited in the shallow sea, it was transformed, winnowed and differentiated by the energy of the hydrodynamic belt, and various beach bar granular carbonate sediments were formed mainly by mechanical action. At the same time, waves, tidal currents and storm currents stir the basin, prompting the rapid release of CO2 in seawater, bringing sufficient nutrients to fresh water, accelerating biological reproduction, and thus depositing carbonate.