An automatically degradable fiber at reservoir temperature could be used to temporarily block artificial or natural fractures effectively. After injecting diverting clean fiber into the fracture, net pressure in the blocked fracture will be remarkably increased. Then it forces the artificial fracture to re-orientate, i.e. fractures are initiated and propagate in another direction. This stimulation technology will improve the stimulated volume of hydrocarbon reservoirs. In the blocking process, the fiber cake zone will be formed in the fracture. It will produce an additional pressure drop when hydraulic fracturing fluid is injected through the blocked fracture. It is the basis for optimizing the critical parameters of design program of fiber-assisted diverting fracturing to understand the influential factors of additional pressure drop induced by the fiber cake. Because additional pressure drop is related with many factors, it is very difficult to optimize the critical parameters of fiber-assisted diverting fracturing. In this paper, on the basis of the physical model of the blocking, the mathematical model of additional pressure drop induced by fiber cake is deduced and calculated by adopting the classical theory of hydraulic fracturing. The change rule of its influential factors is numerically simulated. The results show that low injection rate, small fracture width and high viscosity will be beneficial to increase the additional pressure drop and improve the temporary blocking effect. According to the propagation criterion of tensile fracture, the relationship between the bottom hole pressure increment and the required length of additional fiber is obtained. Excellent linearity between them is achieved.

fiber  /  diverting fracturing  /  mathematical model  /  skin factor of fiber cake  /  additional pressure drop