Особенности численного решения задач геомеханики месторождений с негладкими решениями методом конечных элементов

  • Авторы: Дубиня Н.В.Вершинин А.В.Пирогова А.С.Тихоцкий С.А.
  • Журнал: Геофизические исследования
  • Том: 23
  • Номер: 1
  • Год издания: 2022
  • Издательство: ИФЗ РАН
  • Местоположение издательства: М.
  • Первая страница: 30
  • Последняя страница: 48
  • DOI: 10.21455/gr2022.1-3
  • Аннотация: The problem of numerical modeling of stress-strain state of rock masses in the cases of non-smooth rheological properties of these masses and non-smooth boundary conditions is considered. The problem emerges from the need to estimate the potential drilling risks at the early stages of hydrocarbon field development. Conventionally, at the early stages of HC field development we estimate the drilling risks based on the preliminary mechanical models built from the exploration seismic data. From the interpretation of seismic data, we get either the models of continuous prop-erties (e.g. the results of conventional seismic inversion) or the structural models that describe the configuration of layer boundaries. Estimates of the elastic and mechanical properties may be as-signed to the geological layers and objects in the structural models. In that case, the models of me-chanical properties of the subsurface have discontinuous boundaries. The current study is focused on such discontinuous models of mechanical properties of rocks. Usage of such models leads to the need to state boundary conditions as discontinuous functions within the framework of geomechanical modeling. Hence, standard numerical modeling techniques should be revisited so that they can incor-porate discontinuous (non-smooth) mechanical models with non-smooth boundary conditions. The study presents the results of the geomechanical modeling for discontinuous models of the mechani-cal properties built from the reflection seismic data acquired in the Russian Arctic shelf. The esti-mation of stress-strain state of rocks is completed for several models that contain typical geologi-cal objects associated with potential risks for the offshore drilling in the research area. Finite ele-ment method is applied to compute the stresses in the models that contain permafrost and gas-bearing intervals in the near-surface. Numerical calculations are carried out using Fidesys compu-tational software. It is shown that discontinuous models of mechanical properties require adjust-ments in the numerical modeling approach. Discontinuous spectral elements are needed to proper-ly simulate stresses and strains fields in such models.
Made on