This Project uses a collaborative filtering recommender system to predict the True Vertical Depth (TVD) of formation tops in the subsurface. We are given two data sets one from Wyoming and one from Norway. We must predict the TVD of formation top depths to model the subsurface faster and at a lower cost. This optimization of subsurface modeling using the recommender system facilitates oil production in these areas. In this recommender system, we use alternating least squares matrix factorization, with the items of interest being depth and formation. Both of these items are standardized before we conduct matrix factorization the data sets.