用改进的ISA方法消除井筒存储效应影响

针对井筒存储效应对ISA（Inverse Solution Algorithm）试井分析方法的影响，利用拉普拉斯反褶积法对实际试井资料进行处理。用地层的变流量过程代替井筒存储效应，对同时测得的井底压力和流量，使用拉普拉斯反褶积方法求出所需要的准确的压力导数，达到消除井筒存储效应的目的；如果不能够同时测得井底的压力和流量，在拉普拉斯反褶积过程中，把井筒存储系数始终当成一个常量来考虑，并以该存储系数来定义变化的流量，然后用拉普拉斯反褶积积分法处理井筒压力和流量，得到压力响应，再通过Stehfest算法将解转换到实空间，这样处理后得出的压力导数结合ISA方法算得的渗透率分布更符合真实的地层情况。该法有助于提高有井筒存储效应影响的实际试井资料分析的准确性。图4表1参12

Eliminating wellbore-storage effects by improving ISA technique

In order to overcome the effects of wellbore storage in the ISA(Inverse Solution Algorithm) well testing,the Laplace deconvolution method is applied to deal with practical well testing data.The paper substitutes changing rate process for wellbore storage effect,and applies the Laplace transform deconvolution method to deal with the rate and pressure data of bottom hole and get real pressure derivative data.If the rate and pressure data cannot be tested both,rate is defined with wellbore storage coefficient that can be obtained with the analysis of initial pressure data.In the same way,the Laplace transform deconvolution method is applied to get real pressure derivative data in Laplace transform.Stehfest numerical inversion algorithm is used to get real pressure derivative data in real spatial.The distribution of permeability based on the resultant pressure derivative and ISA satisfactorily reflects the stratigraphy.The new method is conducive to improving the analysis of well testing with the wellbore-storage effects.