METHOD FOR DETERMINING THE ACOUSTIC CHARACTERISTICS OF A MUD FILTER CAKE

摘要

In order to determine the acoustic characteristics of a mud filter cake in a well, the pressure response to low-frequency harmonic pressure oscillations is recorded using at least one acoustic sensor. A phase shift in the undamped pressure oscillations recorded by the acoustic sensor relative to pressure oscillations of a source of oscillations and the ratio of the amplitude of the pressure oscillations recorded by the sensor to the amplitude of the initial pressure signal are determined from the signal produced. The thickness of the mud filter cake is determined and, on the basis of the values produced, the piezoconductivity of the mud filter cake and/or the mobility of a fluid are determined.