Влияние толщины стенок обсадных труб на распределение напряжений в приствольных зонах добывающих скважин

Abstract

The influence of the thickness of casing walls in oil and gas producing wells on the values of effective radial, angular (tangential) and vertical stresses caused by the existence of a depression funnel around these wells and affecting the filtration characteristics of the formation in the bottomhole zones of wells has been studied by mathematical modeling methods. It is established that the sum of radial and angular stresses near the borehole does not depend on the thickness of the casing walls, which affects only the ratio of the values of these stresses. It is shownthat this ratio significantly affects the filtration conductivity of bottom-hole zones of producing wells, especiallyin the development of carbonate reservoirs belonging to the type of fractured-porous rocks. Based on the conducted studies, it was concluded, in particular, that for rocks with a high value of the Poisson’s ratio, it is most rational to use casing pipes with a large wall thickness. This will contribute both to reducing the magnitude of angular compressive stresses in the rock and to reducing the intensity of rock creep processes in the bottomhole zones of wells.To reduce radial compressive stresses, it is rational to use casing pipes with a small thickness of their walls.Keywords: producing wells, depression funnel, carbonate rocks, casing pipes.