The paper presents the results of studies of the effects of geomechanical factors on development of reservoirs confined to poorly cemented Tulskian sandstones. The study aims to assess the risks of irreversible reservoir changes in the interwell space due to deformations resulting from stresses beyond the elastic limit when reservoir pressure changes, provide recommendations on optimal bottomhole pressures for injection wells to ensure maximum injectivity, and determine critical drawdowns which result in carryover of solids into the wellbore for production wells. The results are based on 1D and 3D/4D geomechanical modeling. Input data used to build a geomechanical model included laboratory core study data and well logging data. Determination of elastic and strength properties, their dependence on other reservoir parameters and well logging data for each production target is a unique challenge. The paper presents the findings of geomechanical research efforts. The results of hydraulic fracturing processes analysis, downhole equipment maintenance data, reservoir pressure history, and well log interpretations were also used as input data. Laboratory core studies yielded the dependences on the parameters of radioactive logging methods (normalized gamma-ray logging, gamma-ray neutron logging) for estimation of geomechanical properties. Changes of the minimum horizontal stress with reservoir pressure variations were determined, recommended injection well overbalance ranges were obtained, analysis of solids carryover was conducted as well as calculations of critical drawdowns for production wells. Probability of irreversible reservoir changes in the interwell space for poorly cemented rocks was analyzed. Geomechanical modeling was conducted in GMS corporate software package of Tatneft PJSC.
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