A simple method is presented for calculating (predicting the amount of compaction land resulting subsidence) from the pressure drop in formation due to production, i.e., the increase in the effective pressure p(e) (p(e) = p(t) - p(p), where p(t) is the total overburden pressure and p(p) is the fluid or pore pressure). This work is based on extensive data collected in Russia. For example, large petroliferous areas in Western Siberia became marshlands as a result of fluid withdrawal. One should remember that sophisticated methods, such as FSMT (direct measurement of rock compaction by wireline tools in situ) and GPS (measurement of surface subsidence by satellite microwave Doppler techniques), are not yet available in many areas of the world.