Abstract:

A new method for evaluating the energy of restricted and closed aquifer in over-pressured gas reservoirs is proposed in this paper.Based on the generalized material balance principle and in combination with performance of over-pressured gas reservoirs,this new method can be used to calculate multiple of aquifer—the ratio of aquifer volume to pore volume of gas-bearing zones—for a restricted and closed aquifer in over-pressured gas reservoirs.Then the aquifer energy can be evaluated by using the multiple of aquifer.By applying the method to the well X-3 in Xin Chang gas field,we evaluated the aquifer energy for the reservoirs based on a calculated aquifer multiple of 0.080 5 for the restricted and closed aquifer.The case study shows that this new method is reliable and effective.

Key words: restricted and closed aquifer, aquifer energy, material balance equation, over-pressured gas reservoir