A Study On Effect Of Acoustic Impedances Of Layered Medium On Amplitude Of Acoustic Logging Curve

Cementing operation is an important link to oil-gas well construction, cementing quality is the direct influence factor of development of oil-gas field, and cementing quality evaluation is the key precondition of using and protecting well correctly. Now acoustic logging technology is wildly used to evaluate cementing quality in most of oilfields in our country, and acoustic logging technology has been played a crucial role in cementing quality evaluation.With in-depth research of cementing quality detecting technology, it is found that some interferes are existed in using acoustic signal to evaluate cementing quality, so in sometimes the test result from logging curve are not consistent with the real cementing quality, and cementing quality would not be guaranteed absolutely perfect. In this paper, the effect of influence factors on acoustic propagation is adequately considered when cementing quality evaluated with logging curve is studied.In this paper, through analyzing the acoustic propagation path, mechanism of acoustic propagation in layered medium is researched, model of layered medium in different interface is established to the question of acoustic logging, acoustic intensity that propagated to each interface is calculated, expression of relative acoustic intensity in each interface is deduced, and effect of acoustic impedances of layered medium on relative acoustic intensity is analyzed, so quantification relation of effect of acoustic impedances of layered medium on acoustic energy is obtained. Therefore, acoustic impedances amendment is needed when using acoustic logging curve to evaluate cementing quality, and validity guarantee for the veracity of cementing quality evaluation.