Abstract: A method and an apparatus for characterizing non-uniform spatial distribution characteristics of multi-scale geostress field are provided. The method includes: obtaining stress occurrence states at different crustal depths; obtaining deformation characteristics at the different crustal depths; calculating crustal stress field distribution characteristics using constraints of measured stress states, inverted stress states, and the deformation characteristics at the different crustal depths; and obtaining correlation and non-uniformity characterization of stresses of deep and shallow crusts, based on directions, magnitudes, stress structures, and deformation characteristics in the crustal stress field distribution characteristics. By employing the technical solution of this invention, it is possible to comprehensively evaluate occurrence characteristics of geostress, stress field non-uniform distribution characteristics, and coupling of stress fields of deep and shallow crusts.

Abstract: A method and a device for determining fracture closure pressure based on hydraulic fracturing are provided. The method includes: determining a leak-off volume of a fluid during a refrac cycle according to a fluid pressure during the refrac cycle; generating a stiffness change curve during the refrac cycle according to the leak-off volume of the fluid and the fluid pressure; and determining the fracture closure pressure according to the stiffness change curve. A hydraulic coupling mechanism and change characteristics during a pressure attenuation process are quantitatively characterized, and characteristic response corresponding to a pressure drop curve before and after the fracture closure are accurately described, thereby providing a method and a device for determining fracture closure pressure with clear physical significance and objective effectiveness.