The article presents the technology for assessing the risks of mud losses when drilling based on 1D geomechanical modeling in conjunction with the seismic interpretation data MOGT-3D. The work was aimed to increase wells construction efficiency by shortening non-productive period and cutting down resources spending to mud losses elimination when drilling horizontal wells. Based on a combination of seismic and geomechanical data, a methodology has been developed for estimating the equivalent circulating density values, above which the mud losses will appear during drilling. This method makes it possible to predict drilling risks and provide measures to prevent them without increasing the drilling costs. The proposed technology is applied for Srednebotuobinskoye field. In the examples considered, the forecast of mud losses was confirmed in 21 of the 29 wells. Assessing high-risk zones and predicting a safe mud weight window will allow for the development of measures at the pre-drill stage to prevent possible complications and thereby reduce non-productive time, increasing the efficiency of well construction.
In order to further improve the technique, a number of measures have been proposed, including, conducting special methods of geophysical well logging to determine the nature of zones with increased mud loss risks and clarifying the direction of maximum horizontal stress, as well as performing leak-off tests for estimations of mud loss and hydraulic fracture pressures. The seismic-geomechanical model constructed according to the proposed method can be used to solve other equally important tasks: search for zones of increased reservoir properties, the location of the ports of multistage hydraulic fracturing, risk assessment of increased wear of bits and others.
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