The characteristics of unconventional reservoirs are manifested primarily in low porosity and low rock permeability, which in gas reservoirs is lower than 0.1 mD (0.1E-15 m2), while oil reservoirs are categorized as unconventional if the permeability is lower than 1 mD (1E- 15 m2). The key indicator of the production possibilities of wells in these reservoirs is the flow to the well, which, in addition to permeability and porosity, mainly depends on effective thickness, initial pressure and the characteristics of pore channels. Hydrocarbon production forecasting from such reservoirs is based on production models for the flow of fluid from the reservoir into the well through a vertical fracture or through a horizontal well, which are analogously applied to multiple fractured horizontal wells. With these types of stimulated wells, different forms of flow occur, such as early and late radial, early and late linear, bilinear and pseudo-radial flow, for which there are solutions for pressure in the well, based on which the production characteristics of the well can be determined, i.e. software set up production models for production forecasting. The success of the hydraulic fracturing process, as a precise stimulation activity that is limited to the action of the fluid in the initiation and progression of the fracture in the reservoir rock, affects the production possibilities of the well, because they also depend on the final height and half-length of the fracture. Therefore, in oil and gas engineering, special attention is paid to monitoring the progress of the fracture. Although the increase in public interest in fracturing in some countries has resulted in significant fear and misunderstanding of what is happening underground, all data indicate that fracturing in adequately constructed wells is not a threat to fracture penetration into groundwater and that other risks generally do not have a significant impact on environmental pollution.