MULTIFACTORIAL FILTRATION IN TECHNOGENICALLY ALTERED NEAR-BOREHOLE ZONES OF RESERVOIRS
M.I. Epov1, N.N. Mikhailov2,3,4, О.Е. Аксютин5, V.N. Sokotuschenko2, O.M. Ermilov2,6
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Gubkin Russian State University of Oil and Gas, Moscow, Russia
3Institute of Oil and Gas Problems, Russian Academy of Sciences, Moscow, Russia
4M.V. Lomonosov Moscow State University,Moscow, Russia
5PJSC “Gazprom”, Saint Petersburg, Russia
6LLC “Gazprom Dobycha Nadym”,Nadym, Russia
Abstract
A new concept for multivariate modeling of filtration in anthropogenically altered near-borehole zones (NBZs) is presented. It integrates mechanical colmatation, filtration deformation of skeleton, thermobaric expansion of rock-forming minerals, and capillary entrapment of fluids. A generalized multiplicative permeability model has been developed:
allowing for the description of the radial and pressure distributions of filtration parameters. Based on an analysis of a system of continuity equations and Darcy’s law with variable coefficients, integral relationships for calculating the skin factor and well flow rate are derived. It is established that failure to account for the combined effects of these mechanisms leads to systematic relative errors (up to 40–50 %) in productivity forecasts in zones of maximum anthropogenic impact. A differentiated approach to selecting inflow stimulation methods is proposed based on identifying the dominant mechanism of NBZ damage. |
