A method for simulating downhole conditions is described. The method includes receiving configuration information about a well system in a production configuration, the well system including annular fluids disposed therein and receiving heat source information associated with a heat source disposed within the well system. The method also includes simulating temperature transfer in the well system during a production scenario based at least on the configuration information and the heat source information and predicting pressure buildup in the annular fluids based on the simulated temperature transfer in the well system.