The article describes the comparative characteristics of different repeated hydraulic fracturing technologies in horizontal wells such as one-stage conventional re-fracturing, SpotFrac technology, fracking with diverting agents, and iFrac. We present the results of efficiency analysis of re-fracturing technologies tests in horizontal wells performed by specialists of Slavneft-Megionneftegas in 2015–2018. The successful execution of multistage refracking in horizontal well is justified using estimation of additional in-situ stresses caused by injection of propping agent. First stage fracture creating and propping results in closure pressure increasing in the fracture initiating area. This effect depends proportionally on the fracture geometry and can allow initiating the subsequent fractures in other ports in a horizontal well. Also, an algorithm is proposed to determine the sequential stimulation intervals in horizontal well on each stage of re-fracking and to estimate the number of re-stimulated fracturing ports. This algorithm includes such stages as stress field calculation along the horizontal wellbore and fracture design. All calculations are performed using corporate software RN-GeoSim, RN-GRID, RN-KIN. The algorithm of fracture initiating intervals determination is tested on the well No. 1 of the oilfield in Western Siberia. We show that the same fracturing port was stimulated two times during three fracturing stages. Verification of calculations is made using mini-frac data and the accuracy of calculations is about 1 %.
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