裂缝气藏物质平衡方程

在均质气藏物质平衡方程的推导过程中，假设之一是气藏的储层物性和流体物性是均匀分布的，对于基质和裂缝具有相似的储集能力的裂缝气藏，这个假设不再成立，由于裂缝的压缩性比基质要高，裂缝和基质的孔隙度值随压力的变化不相同，裂缝和基质中的束缚水饱和度也不相同，所以在裂缝气藏的物质平衡方程的建立过程中，必须考虑双孔隙系统，分别考虑裂缝和基质的储层物性和流体物性。据此推导了一种新的裂缝性气藏物质平衡方程，实例计算表明，采用该方程可有效计算气田储量，方法简单易行。

MATERIAL BALANCE EQUATION OF FRACTURED GAS RESERVOIRS

In the process of derivation for Material Balance Equation of homogeneous gas reservoirs, one of the assumptions is the physical property of reservoir and fluid is even in the reservoir. For the fractured gas reservoirs which matrix and fractures have similar storage capacity, the assumption is no longer valid because the compressibility of fractures is higher than that of matrix; the porosity variation of fractures and matrix is different when the pressure changes; and the irreducible water saturation of fractures and matrix is not equal. So, in the process to build the Material Balance Equation for fractured gas reservoirs, the dual porous system should be considered. The physical property of reservoir and fluid should be considered respectively for fractures and matrix. According to the considerations, it is derived a new Material Balance Equation of fractured gas reservoirs. Calculation by real cases shows the equation can calculate reserves of gas fields effectively. The method is simple and easy to use.