HYDRAULIC FRACTURE HEIGHT GROWTH CONTROL

摘要

A method is given for creating a fracture, in a subterranean formation, that has a fluid flow barrier at the top, at the bottom, or at both the top and the bottom. The method is applied before or during a conventional hydraulic fracturing treatment and is used to limit undesired vertical growth of a fracture out of the productive zone. A lower- viscosity pad fluid is used to initiate the fracture; a higher-viscosity fluid containing barrier particles is then injected; a lower- viscosity particle-free fluid is then injected to promote settling (or rising) of the barrier particles and to finger through the slug of barrier particles and cut it into an upper and lower portion. If the barrier is to be at the bottom of the fracture, the barrier particles are denser than the fluids; if the barrier is to be at the top of the fracture, the barrier particles are less dense than the fluids. Optionally, between the barrier transport stage and the subsequent lower- viscosity stage, there may be a stage of a higher viscosity particle-free fluid that pushes the barrier particles farther into the fracture. To provide both upper and lower particles in one treatment, the pad stage may be of higher-viscosity, or the barrier particles may include particles less dense than, and more dense than, the fluid.