Methods for in-depth fluid diversion and stage by stage fluid diversion systems

A method for in-depth fluid diversion in a heterogenous reservoir, wherein the method comprising:

• a first step comprising:
• simultaneously introducing a preformed particle gel (PPG) material and a shrinking agent comprising a salinity water having a salinity of from 50,000 (parts per million) ppm to 360,000 ppm to a first position in a high-permeability zone comprising fractures that can be packed by the PPG material having a particle size of from 0.05 millimeters (mm) to 10 mm via an injection well;
• terminating the introduction of the PPG material and the shrinking agent;
• and
• flowing water having a salinity of from 50 ppm to 5,000 ppm into the high-permeability zone via the injection well, thereby contacting the water with the PPG material to form water-swelled PPG particles within the fractures of the high-permeability zone at the first position, wherein the water-swelled PPG particles in the high-permeability zone can pack the fractures, thereby generating a fluid diversion to control the water flow to an adjacent low-permeability zone, wherein the low-permeability zone is substantially free of fractures capable of being packed by the PPG material having the particle size of from 0.05 mm to 10 mm;
• one or more second steps comprising:
• terminating the introduction of the water having the salinity of from 50 ppm to 5,000 ppm;
• reintroducing the shrinking agent comprising the salinity water having the salinity of from 50,000 ppm to 360,000 ppm via the injection well to the first position, thereby contacting the shrinking agent with the water-swelled PPG particles within the fractures to convert the water-swelled PPG particles to shrunken PPG particles, wherein the shrunken PPG particles are released from the fractures, thereby flowing to a second position of the high-permeability zone;
• terminating the introduction of the shrinking agent comprising the salinity water;
• and
• reintroducing the water having the salinity of from 50 ppm to 5,000 ppm into the high-permeability zone, thereby contacting the water with the shrunken PPG particles to convert the shrunken PPG particles to the water-swelled PPG particles within the fractures of the high-permeability zone at the second position, thereby regenerating the fluid diversion to control the water flow to the adjacent low-permeability zone.