拟稳定流动期压力恢复常规分析的精确公式

Exact Formula for Pressure Buildup Analysis During the Pseudo-steady Flow Period

根据油藏拟稳定流动特点，运用叠加原理，推导出了拟稳定流动期压力恢复常规分析的精确公式，并表明常规经典分析方法──MDH法和霍纳法的计算公式是精确公式的两个实用近似式。与精确公式比较，用MDH公式分析得到的结果：K值偏大，S值相同。用霍纳公式分析得到的结果：省略项大于零时，K值偏大，P*值偏小；否则，K值偏小，P*值偏大。由精确公式中的P*定义关系式可直接导出MBH公式。而对低渗透油藏，用修正霍纳公式分析拟稳定流动期压力恢复资料，其结果更准确可靠。

According to the characteristics of pseudo-steady period,by using the superposition method the exact formula for pressure buildup analysis during the pseudo-steady flow period is deviated. It appears that the approximate formula of this one. By comparing the exact formula with the normal method,we found:the result of MDH method is that K is larger and S is equal;the result of Horner's method is that if neglect term is lager than zero,K is bigger,P* is smaller,conversely K is smaller, P* is bigger. The definition relationship of P* can be derived directly by MBH formula. For low perrneability reservoir,the result of modified Horner's formula for the pressure buildup during the pseudo-steady period is reliable.