摘要：Pore-scale squirt flow is one major mechanism that results in seismic wave dispersion and attenuation. Most existing squirt models only consider the local fluid flow between stiff pores and micro-cracks, but the squirt effects of micro-cracks with different pore aspect ratios are often being overlooked. Therefore, the classical squirt model is extended to investigate the fluid flow between pores with different aspect ratios. We first calculate the bulk compressibility of micro-cracks by using the aspect ratio distribution extracted from pressure-dependent dry ultrasonic velocities. Then, squirt flow effects between micro-cracks is modeled according to the pressure relaxation in the pore space. The global fluid flow in the stiff pores is described by Biot theory. The extended theoretical model considers the interaction between stiff pores and cracks, the Biot global flow in stiff pores, and also the squirt fluid flow effects among micro-cracks. The high- and low-frequency limits of the extended model are consistent with Mavko-Jizba and Gassmann equation, respectively. Modeling results of the extended model is consistent with the laboratory ultrasonic measurements for sandstones and most of the tight carbonate samples. In addition, velocity dispersion and attenuation predicted by using the extended model indicate that the squirt flow may play an important role at seismic and logging frequencies. The modeled velocities grow from low frequency to high frequency slowly and no obvious fast change is observed, which is significantly different from those predicted by classical models. At low differential pressure, the squirt flow mechanism dominates the dispersion and attenuation. However, Biot global flow mechanism gradually stands out with increasing pressure and, as a result, the dispersion and attenuation decline.
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ISSN号：0001-5733

卷、期、页：v 64,n 3,p1034-1047

发表日期：2021-03-10

影响因子：0.811100

期刊分区（SCI为中科院分区）：三区

收录情况：SCIE（科学引文索引网络版）,EI（工程索引）

发表期刊名称：Acta Geophysica Sinica

参与作者：Deng, Jixin

通讯作者：欧阳芳,肖增佳,赵皓,任静

第一作者：赵建国,李智,贺艳晓

论文类型：期刊论文

论文概要：欧阳芳,赵建国,李智,肖增佳,贺艳晓,Deng, Jixin,赵皓,任静，Modeling velocity dispersion and attenuation using pore structure characteristics of rock，Acta Geophysica Sinica，2021，v 64,n 3,p1034-1047

论文题目：Modeling velocity dispersion and attenuation using pore structure characteristics of rock