Processes, occurring during exploration of gas-oil wells in frozen rock are simulated. A system of differential equations, describing hydro and thermal dynamics of an ascending two-phase flow of a hydrocarbon system in a vertical channel taking into account phase transitions and structure of a flow is developed. Kinetics of paraffin deposits on internal walls of an elevating column of a well are considered. The effect of the heat exchange of a well within frozen rock is developed using differential equations that describe the evolution of the radius of thermal influence of the well and the radius of the melting zone. We conclude with numerical research of some preventive ways of dealing with paraffin deposits. (C) 2003 Elsevier Ltd. All rights reserved.