Abstract: With the development of shallow reservoirs, horizontal fracture has emerged, and the research on horizontal fracture has become one of the most important aspects of hydraulic fracturing research. Many fruitful studies have been done on simulating horizontal fracture extension. But all the models neglect the effects of leakoff on the distribution of flowing rate and
pressure in fracture, which significantly deviate from the practical simulation treatment. Combining the relative knowledge of hydrodynamics, elasticity mechanics and principle of material equilibrium, and based on cell mechanical analysis, this paper presents a new model simulating horizontal fracture propagation which takes the effects of leakoff on the distribution of flowing
rate and pressure in fracture into account, and the numerical solution of the model by newton iteration is developed too. The calculating results show that the model and its solution are stable and reliable. Compared to the results calculated by those models neglecting the effects of leakoff, the model predicts a shorter and narrower horizontal fracture.

Key words: horizontal fracture, fracture extension, hydraulic fracturing, leakoff