In this paper, we present a methodology to condition the prior probability field of the facies to the facies observations collected at the well locations. The prior probability field of the facies usually comes from seismic inversion and the facies observations are the result of the examination of the cores extracted at the well locations. Consequently, the prior probability field is not directly conditioned to facies observations. The presented methodology relies on a regularized form of the element-free Galerkin (EFG) method. The regularization has been introduced in order to account for the prior, whereas the EFG is an interpolation technique with a moving least squares criterion. The methodology presented here consistently updates the prior probability field of facies with the facies data collected at some locations in the reservoir domain. We present two case studies: one in which hard facies data are considered and a second where hard and soft facies observations are involved in the conditioning.@en