Staged fracturing horizontal well water-flooding fracture interval and well spacing determining method

The invention provides a staged fracturing horizontal well water-flooding fracture interval and well spacing determining method. The method comprises the following steps of first, calculating limit control radius of target oil reservoir according to limit control radius of low permeability oil reservoir, second, calculating fracture interval when limit control radius is one half of the fracture interval, third, optimizing a rational specific value between the fracture half-length and the fracture interval, fourth, calculating the fracture half-length according to the rational specific value between the fracture half-length and the fracture interval, and fifth, calculating rational oil-water well interval with the rational oil-well interval equaling the total sum of the fracture half-length and the limit control radius. Rational fracture interval and oil well spacing can be quickly and simply determined for the staged fracturing horizontal well and oil field application adaptability is enhanced by the use of the method; new method is provided for determination of staged fracturing horizontal well water-flooding fracture interval and well spacing; and staged fracturing horizontal well water-flooding can be guided in a reasonable and scientific way.