Junction stability analysis for a fishbone wellbore

Abstract

The results of three-dimensional poroelastic modeling of the junction area of multilateral boreholes for wellbore stability estimation of the fishbone are presented. The situations with the main wellbore orientation along with the minimum and the maximum horizontal stresses in sandstone with character and reduced strength were considered. The ranges of permissible depression on the reservoir are determined for the fishbone in production mode. When it is planned to conduct the sidetrack in the sandstone with reduced strength, the safe mud pressure exceeding the pore pressure was defined. It was shown that in the case of the formation of a mud cake on the wellbore walls, the pressure drop could be reduced by 40% with junction area stability preserving.