Abstract: A method of treatment of a subterranean formation penetrated by a wellbore, where the well has a plurality of previously stimulated intervals includes: a) pumping a viscous pill into a well with pressure curve registration by a wellhead pressure sensor; b) determining a depth (L) of treatment fluid entry point and depth uncertainties (L); c) generating a water hammer at the wellhead which excites tube waves; d) determining the depth (L) of the treatment fluid entry point and the depth uncertainties (L) by processing a water hammer by high frequency pressure monitoring method; e) determining a tube wave velocity from a combination of data from (b) to (d); f) performing a fracturing treatment; and g) generating a water hammer at the wellhead at the end of the fracturing treatment (f) with refined depth of treatment fluid entry point and with lower uncertainty.

Abstract: A method for temporary isolation of a well interval is proposed, the method comprising: pumping a first slurry into the well, the slurry comprising a viscous carrier fluid, degradable particulates, and degradable fibers, until a first filter cake is formed; and pumping a second slurry into the well, the slurry comprising a viscous carrier fluid, non-degradable particulates, and degradable fibers, until a second filter cake is formed. The first and the second slurries are not mixed when pumped into the well. To ensure optimum interval isolation, the ratio of the volume of the first slurry to the volume of the second slurry should be in the range 1:5 to 2:1. A method for hydraulic refracturing within an interval with several hydraulic fractures and a non-damaging well killing method are also proposed. The technical result is manifested in no formation damage and degradation of the sealing layer formed.

Abstract: A horizontal well may be refractured or reactivated by generating a geomechanical model to estimate the stress level in the formation; identifying zones with high, medium, and low stress levels in the formation; isolating existing fractures in the horizontal well; injecting a fracturing fluid into the well to create at least one new fracture in a zone with a low stress level and packing the created fracture with proppant to increase the stress level in the zone; isolating the at least one newly created fracture; initiating refracturing in the zone with the high and/or medium stress level; identifying a location of the refracturing crack in the zone with the high and/or medium stress level; and developing the refracturing crack and packing it with proppant.

Abstract: A method for temporary isolation of a well interval is proposed, the method comprising: pumping a first slurry into the well, the slurry comprising a viscous carrier fluid, degradable particulates, and degradable fibers, until a first filter cake is formed; and pumping a second slurry into the well, the slurry comprising a viscous carrier fluid, non-degradable particulates, and degradable fibers, until a second filter cake is formed. The first and the second slurries are not mixed when pumped into the well. To ensure optimum interval isolation, the ratio of the volume of the first slurry to the volume of the second slurry should be in the range 1:5 to 2:1. A method for hydraulic refracturing within an interval with several hydraulic fractures and a non-damaging well killing method are also proposed. The technical result is manifested in no formation damage and degradation of the sealing layer formed.

Abstract: A method of refracturing in a horizontal well may comprise: generating a geomechanical model to estimate the stress level in the formation; identifying zones with high, medium, and low stress levels in the formation around the well based on the generated geomechanical model of the formation; isolating existing fractures in the horizontal well; injecting a fracturing fluid into the well to create at least one fracture in a zone with a low stress level and packing the created fracture with proppant to increase the stress level in the zone; isolating at least one fracture created at stage (d); initiating refracturing in the zone with the high and/or medium stress level identified at stage (b); identifying the location of the refracturing crack relative to the zones of high, medium, and low stress levels in the formation around the well; developing the refracturing crack and packing it with proppant. A method of reactivating an injection horizontal well is also provided.