Quantitative evaluation method for fault vertical sealing ability and its application

The vertical sealing ability of fault is mainly determined by the displacement pressure of filler in fault, while the displacement pressure has some relation with the diagenesis grade being controlled by the positive pressure exerted on the fracture surface. A quantitative method for evaluating the vertical sealing ability of fault was proposed. The positive pressure in the break point and the buried depth of strata corresponding to the pressure exerted on the fracture surface are calculated according to the relationship between geostatic pressure and buried depth of strata. The displacement pressure of filler in the fracture corresponding to the buried depth of strata is determined according to the relationship between the displacement pressure of caprock and buried depth. The vertical sealing ability should be the combination of displacement pressure of fillers in the fractures and porous fluid overpressure of strata. The filling degree of oil and gas in trap can be predicted by comparing the vertical sealing ability of fault and closure altitude of trap. This method is applicable to Kuche Depression.