Abstract
Simultaneous multiple fracturing is a new hydraulic fracturing technology by fracturing two or more parallel horizontal wells simultaneously to improve oil and gas production. Quite a few simul-fracs have been down and some of them are successful in the industry up to now. Using boundary element method and rock failure criterion, a 2D geomechanical model was built to study the fracture complexity of simultaneous fracturing.
In the paper, the differences of fracture propagating paths of fractures from simul-frac and two fractures from a stand- along horizontal well are compared. Also the effect of factors is studied, such as injection pressures, fracture spacing, and parallel well distances, on simul-frac results. With a lot of calculated graphs, the paper concludes that, for a homogeneous and isotropic rock, the two fractures form a simul-frac will propagate toward each other while the two fractures from one horizontal well will deviates away. Natural cracks in the rock may change the propagating direction of the two fractures and stop their pass through the rock to the opposite well. Natural cracks between the two fractures are always awaked, cracking, deflecting, and steering during simul-fracs, but the outside natural cracks may not be awaked and extended. The middle area between the two wells is the strong place of fracture and natural crack deflections, and interconnecting. For a better complex fracture network, the two fractures should be keep a horizontal distance and the two wells should be placed in a reasonable distance away.
The paper demonstrates that, for some formations, a simul-frac treatment can limit the propagation of the fractures, make them change their original direction, communicate with natural cracks and form a complex fracture network easily.
