In the last decade the significant change in the strategic planning process of the oil companies was observed. The evaluation engineering offers many methods for determining fair-market-value of a hydrocarbon property (FMV). All of them fall into four general categories: comparative sales, rule of thumb, income forecast, replacement cost. The paper presents main problems connected with the determination of prospects FMV, the rules to estimation FMV of hydrocarbon producing property with one of the decline curve models: constant-percentage, harmonic or hyperbolic. In the last part of the article the author presents the concept of managing the value of a geological property.