Inversion of seismic data using information from horizontal wells is often is hampered by cumulative well- location errors. These errors can be significant and propagate to the well-log measurements in the borehole. To achieve a proper data integration and arrive at correct uncertainty estimates, we formulate the problem in a fully probabilistic framework and present a numerical approach for improving subsurface imaging using uncertain well-log data and their uncertain locations, as well as uncertain seismic data. The result is improved model error quantification in the seismic inversion process.