This paper describes the integrated approach to decision making on the optimized horizontal well completion with multistage fracturing (MSF) based on petrophysical, geomechanical and numerical modeling. This approach is pertinent in case of insufficient target exploration including absence of a full scale geo&hydromodel (FSGHM). The basic work process of the proposed approach is based on consistent efforts of a petrophysicist, geomechanical engineer, fracturing engineer and reservoir engineer and thus includes petrophysical and geomechanical modeling, fracturing design, numerical modeling and final planned well flow rate evaluation. The role of geomechanics in the production chain is to determine zones with the lowest and the highest fracture gradients to control fracture location and analyze fracture geometry. The basic objective of the proposed approach is to develop a set of recommendations to select: Optimized frac sleeve spacing to increase production during a certain period of well production;Optimized proppant injection volume in general and for each fracture;Recommended horizontal well paths for efficient multistage fracturing completion and reduction of the most probable risks;Frac sleeve placement with provision for the horizontal well path through the section (vertically) to optimize fracture initiation points and maximize reservoir coverage. Besides, according to the base history, costs of new target development using available production technologies can be estimated based on the completed work package. An additional objective of this approach is identification of interdependent parameters for further facilitation of downhole surveys and laboratory studies and excluding of non-informative methods. This paper gives an example of the developed method application for a prospecting and appraisal well at one of the West Siberian fields with a target characterized by extremely low permeability and uncertainty.