Chang-3 layer in Weibei oilfield belongs to the middle-shallow reservoir

with the buried depth of 200 ~ 1 000 m. The fractures formed diring the fracturing have complex shape with horizontal joints

vertical joints and oblique crack

which impact the evaluation of the fracturing and fracturing effects. Taking Chang-3 reservoir in Weibei oilfield as the research object

combined with the reservoir rock mechanics and crustal stress experiment

and through the analysis of logging data and fracturing construction curves

we calculated the relative values of the vertical stress and horizontal stress and reveal the formation law of fracture forms

so that to summarize the fracture formation identify and prediction technology of Chang-3 reservoir in Weibei oilfiled. When the reservoir depth was less than 450 meters

the horizontal joints formed; when the depth was more than 550 meters

the vertical joints formed; when the depth was between 450 and 550 meters

the complex fractures formed. It was recommended to conduct the mini frac testing to determine the fracture forms.