Abstract: The easy destructive and difficult preservative properties tend to take a great risk for gas prospecting. Tectonic movement, hydraulic scouring and micro leakage become three important mechanics in destruction of a gas accumulation, of which denudation and rupture in cap rock arisen by tectonic movement could be the most serious to its destruction. The serious destruction of deep gas accumulation in Yingshan fault depression is mainly resulted from the fault movement. The primary reason for its destruction is that dispersion lost velocity is greater than that of gas source. supply into gas pool. This paper presented a model for assessment of destructive element, destructive intensity and preservative conditions of a gas accumulation. And the evaluation of the destructive element of major target zone in deep gas accumulation of Yingshan fault depression was made by using this model.

Key words: natural gas reservoir, destruction, preservation, mechanism, evaluation, Yingshan fault-depression