The Experimental Study and Evaluation of Roofrock of Natural Gas

Roofrock is the prerequisite for the accumulation of light hydrocarbon, and displacement pressure is one of the key parameters in roofrock evaluation. In the past, because of the time penetrating through clay rock was neglected, the calculated-pressure penetrating through clay rock was too large to accord with the true displacement pressure of rock. This paper deals with the relationship between pressure and time penetralting through clay rock. It shows that time penetrating through clay rock relates to that of pressure functionly. The method of getting rock displacement pressure is also studied mainly through experiments on clay rock and it is proved that the method is effective and practical. According to experimental results and practical data, the criterion for roofrock evaluation of natural gas is put forward. The evaluation table may give accordance to evaluate the prospect of a region.