Laboratory Experimental Research On The Effects Of Gas Saturation On Ultrasonic Properties In Carbonate

On 20 carbonate samples laboratory ultrasonic transmission testing under different gas saturation from Sichuan Basin show that: (1) With the increase of gas saturation, the P-wave velocity and V-p/V-s both show a decreasing tendency, while S-wave velocity almost unaffected; (2) Following the gas saturation increase, ultrasonic attenuation show an increasing trend while the increasing trend is different between P-wave and S-wave, the attenuation of P-wave is firstly increasing and then reducing which has a maximum value when gas saturation in the range of 0.4-0.6 while the attenuation of S-wave increase in approximate linear rule change range increases. S-wave variation amplitude is lower than P-wave; (3) The ultrasonic wave frequency has some influence on the V-p/V-s. The main distribution of V-p/V-s is varied with different frequencies, general rule is that Sg=0% greater than Sg=100%; (4) With the P-wave test frequency increases, the influence of gas saturation on ultrasonic attenuation aggravated; (5) This article segmented statistics ultrasonic velocity and attenuation response at different gas saturation which settle the theoretical base for indicating gas horizon utilizing acoustic logging data. When practical application, other relevant parameters must be combined with consideration, only in this way can lead to a more accurate assessment of reservoir.