Injection initiated fractures occur into low-permeability reservoirs when ‘closure’ pressure threshold is exceeded. This effect may cause risks of gas, oil, and water shows due to anomalously high reservoir pressure while sidetracking. Thus, while planning sidetracks, problems of analyzing and forecasting risks of overpressured zones due to fracturing initiated by injection have to be solved along with reservoir pressure monitoring. The article presents some field case studies of approbation of Rosneft’s tools for simulating injection initiated fractures. The classification of cases of injected water breakthrough along the fractures is suggested. The description of the injection initiated fracturing simulator and the method for forecasting overpressured zones for a target bed are adduced. The simulator combines hydrodynamical and geomechanical solvers to calculate a fracture’s trajectory and increment. It is noted that additional auxiliary information (results of well testing, field geophysical surveys, drilling history, etc.) should be taken into account and the workflow algorithm for forecasting risks of overpressured zones at sidetrack’s path is suggested. The example for forecasting overpressured zones for a non-target (overlying) bed by means of a specialized corporate software module is also considered. The above-mentioned corporate tools are already usable in order to increase success of sidetracking operations.
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