The Study Of The Acoustic Logging Of The Cement Weak Transition Zone

Accurately grasp the acoustic response of weak cementing transition area is conductiveto improve the cementing quality of acoustic logging detection accuracy. And accuracy ofcementing quality evaluation can ensure cementing work smoothly, it play an importantguiding role to the future development of production.In this paper, there is an analysis of causes of interface transition zone through thehydration, condensation and hardening of cement. And the microstructure of interfacetransition zone has been study by using scanning electron microscopy and X-ray diffraction.On the base of analysis the primary study of the well physics model, the article establish anew well model on the base of the wave equation, and the cement weak transition zone wasconsidered. we worked out the pressure function and field potential function with it’s generalsolution. Make the calculation of Fourier transform (FFT) and inverse discrete Fourier (IFFT)to the field potential function with Matlab, we get the pressure function of the wellconsidering the cement weak transition zone, then build relations between the porositythickness and pressure function. Through the change of porosity and thickness values, weobtain the corresponding full wave curve, and at last achieve the influence of the weakness ofthe cement, that is the value of the porosity and thickness on the acoustic response.