Digital transformation of oil and gas companies requires consistent improvement of work performance management. Oil and gas companies strive to improve work efficiency and consistently develop and implement digital products. The realization of such complicated solutions requires deep diving into current business processes and transformation of them. This paper deals with implementation of digital management system for exploration and production wells. Digital management system for exploration and production wells is based on ideology of digital twin and act as a single window and single source of data for all exploration and production wells. Digital management system covers whole construction process started from planning stage to execution and results assessment and orchestrates the exchange of data between process phases and people involved in it. Transparency provided by the digital twin improves efficiency and accelerates well construction process. Cognitive assistants based on AI and ML techniques are implemented at every stage: while planning, the assistants search analogue wells, analyze its design and complications while drilling and provide recommendations for the most optimal well design, offers the optimum drilling mud density and recommends the most suitable set of logs to cover geological section uncertainty. At the execution stage, a number of ML assistants are used to increase efficiency and reduce risks while drilling: automatic method for anomaly detection while drilling to prevent complications while drilling, machine learning based model for automatic torque and drag control to control borehole condition to predict any signs of differential stuck, key sitting and pack-off, data-driven model for drilling bit position and direction determination to predict BHA position while drilling including a blind zone, data-driven model for the identification of the rock type at a drilling bit for correct geosteering application.

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For the prediction and elimination of complications in the drilling process is considered a number of examples of the three-dimensional geomechanical model and of the near-wellbore model in order to optimize the trajectory and design of the wells. During the well trajectory planning, the key point is to forecast and minimize all possible risks associated with both geological, mechanical conditions and technological parameters. An optimal solution can be obtained with the use of a detailed geomechanical analysis. It is shown that in a number of cases, the numerical model of the near wellbore zone is more informative, in comparison with the analytical solution. The result of drilling risks minimization with help of geomechanical analysis tools is presented. A number of recommendations on wellbore construction and stability are established of the comprehensive geomechanical analysis. The discontunities that are derived of seismic field analysis are also included in the review. The image analysis, 1D geomechanical modelling, of seismic field analysis, near-wellbore numerical simulation and full 3D goemechanical modelling were used as a geomechanics tools to optimize "fishbone" trajectory. Microimages help to determine the presence of cavernousness, natural and induced fractures, geological boundaries and bedding planes. Especially useful is a tool for determining the presence of collapse in the areas of kick-off sidetracks. 1D geomechanical modeling helps to determine favorable intervals for shearing and optimal mud density. To assess the risks during the sidetracking operation, a statistical analysis of the actual data was carried out taking into account the spatial orientation of the sidetrack and the direction relative to the currently acting stress state. Stresses and gradients of caving in the intervals of cuts are refined by the near wellbore model.

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The paper is dedicated to problem of forecast of well events drilling through nonproductive reservoirs at shallow depths: mud losses, wellbore instability due to salt tectonics, mud and reservoir temperatures difference and drilling time. Problem of forecast in those zones is complicated because of insufficient amount or complete lack of core tests, well loggings and noisy of seismic data. There is three-dimensional geomechanical modeling was showed with taking into account thermal stresses and time factor in the clay and salt zones on the example of the Eastern part of the Orenburg oil and gas condensate field. Also geological features were analyzed for prediction of mud losses zones. As a result of modeling, a relationship was found between the drilling mud losses and the wells location with respect to the sides of the salt folds and domes, which are accompanied by the development of natural fracturing. While well is drilling in overbalanced conditions in these zones, fractures and faults become critical stressed, which leads to their reactivation and mud infiltration. The trajectory can not be significantly corrected in the 300-800m depths so well schematic recommendations are reduced to a warning about the zones of possible losses. Wellbore stability calculation with taking into account the temperature effect shows an increase or decrease (depending on the drilling season) of the stresses, acting on the wall of the borehole up to 10 MPa; the influence in salts is greater than in clays. Taking into account time factor showed that long-term drilling with high mud density can lead to numerous stuck pipes and tight pulles. The obtained results make it possible to clarify wellbore stability calculations and, accordingly, the intervals of borehole failures. The prediction of critical stressed zones allows to warn the intervals of drilling mud losses. Thus, due to the combination of these approaches, it is possible to reduce the nonproductive time of well drilling and choose candidate wells for an optimized well design.