Fracturing a stress-altered subterranean formation

A system for fracturing a subterranean formation, the system comprising:

• a plurality of injection tools installed in a well bore in a subterranean formation, each of the plurality of injection tools controlling a flow of fluid from the well bore into an interval of the subterranean formation based on a state of the injection tool, the plurality of injection tools comprising a first injection tool controlling a first flow of fluid into a first interval, a second injection tool controlling a second flow of fluid into a second interval, and a third injection tool controlling a third flow of fluid into a third interval, the second injection tool installed in the well bore between the first injection tool and the third injection tool;
• and
• an injection control subsystem that controls the states of the plurality of injection tools by sending control signals from the well bore surface to the plurality of injection tools through a signaling subsystem installed in the well bore, each of the control signals changing the state of one of the injection tools to modify the flow controlled by the injection tool,
• the subterranean formation comprising:
• a zone of altered stress anisotropy, the stress anisotropy of the zone altered by the first flow of fluid into the first interval and the third flow of fluid into the third interval;
• and
• a fracture network in the zone of altered stress anisotropy, the fracture network formed by the second flow of fluid into the second interval.

A method of fracturing a subterranean formation, the method comprising:

• altering stresses in a subterranean formation adjacent a horizontal well bore by creating a plurality of fractures in the subterranean formation along the horizontal well bore;
• sending a plurality of control signals from a well bore surface through a signaling subsystem to a plurality of injection tools installed in the horizontal well bore to select a plurality of states for the plurality of injection tools;
• and
• injecting fluid into the stress-altered subterranean formation through one or more of the plurality of injection tools in each of the states to create a fracture network in the subterranean formation.