Numerical Simulation of Sonic Logging in Fractured Tight Sandstone Reservoirs
Abstract: The logging methods to evaluate the effectiveness of the tight sandstone reservoir mainly include conventional logging, imaging logging and acoustic logging. It was difficult to effectively identify the microfractures by conventional logging and imaging logging, because the width of fractures in fractured tight sandstone reservoirs was less than 100 μm, but the acoustic logging makes an qua-litative identification and quantitative evaluation to microfractures through the stoneley wave at-tenuation coefficient and other parameters. It will be of great importance to master the influencing rule of fracture of borehole acoustic field for acoustic logging data processing and interpretation by numerical simulation, researching the borehole acoustic field on tight reservoir with the fractures. The method of three-dimensional staggered grid stress and speed finite difference was applied to numerically simulate the problems of borehole acoustic field, which was aroused by point source in layer of elastic media and pore media containing inclined thin cracks. The microfractures in fractured tight sandstone reservoirs were effectively identified and evaluated by using the parameters of energy amplitude of Stoneley wave and etc. In consideration of single horizontal crack, the influence of crack width (20 - 1000 µm) on the Stoneley wave used to identify microfractures was determined, the wider the fracture was, the smaller the amplitude of Stoneley wave was. When the width of fractures was narrower (crack width was less than 100 μm), the wave-form amplitude diminished rapidly. The wider the fracture was, the bigger the Stoneley wave atten-uation would be. Nevertheless, the relationship between its waveform amplitude, attenuation and fractural width was also obtained under the condition of different porosities of porous medium in formation, that was, the bigger the porosity was, the smaller the amplitude of Stoneley wave, P-wave and S-wave was, the larger the attenuation coefficient of Stoneley wave, P-wave and S-wave was.
文章引用: 龚 丹 , 章成广 (2016) 裂缝性致密砂岩储层声波测井数值模拟。 石油天然气学报， 38， 28-35. doi: 10.12677/JOGT.2016.382012
Spring, C. and Dudley, D. (1992) Acoustic-Wave Propagation in a Cylindrical Borehole with Fractures. The Journal of the Acoustical Society of America, 91, 658-669.
Kostek, S., Johnson, D. and Randall, C. (1998) The Interaction of Tube Waves with Borehole Fractures. Part I: Numerical Models. Geophysics, 63, 800-808.
Matuszyk, P.J., Torres-Verdín, C. and Pardo, D. (2013) Frequency-Domain Fi-nite-Element Simulations of 2D Sonic Wireline Borehole Measurements Acquired in Fractured and Thinly Bedded Formations. Geophysics, 78, 193-207.
Guan, W., Hu, H. and He, X. (2009) Finite-Difference Modeling of the Monopole Acoustic Logging in a Horizontally Stratified Porous Formation. The Journal of the Acoustical Society of America, 125, 1942-1950.
 陈德华, 丛健生, 徐德龙, 等. 裂缝性地层中的井孔声场模拟[J]. 大庆石油学院学报, 2004, 28(3): 4-6, 13.
 丛健生. 利用有限差分法模拟计算具有分层和裂缝地层井内外声场[D]: [硕士学位论文]. 大庆: 大庆石油学院, 2004.
Leslie, H.D. and Randall, C.J. (1992) Multipole Sources in Boreholes Penetrating Anisotropic Formations. The Journal of the Acoustical Society of America, 91, 12-17.
Cheng, N.Y., Cheng, C.H. and Toksoz, M.N. (1995) Borehole Wave Propagation in Three Dimensions. The Journal of the Acoustical Society of America, 97, 3483-3493.
Sinha, B.K., Ergün, Ş. And Liu, Q.H. (2006) Elastic-Wave Propagation in Deviated Wells in Anisotropic Formations. Geophysics, 71, 191-202.
 林伟军, 王秀明, 张海澜. 倾斜地层中的井孔声场研究[J]. 地球物理学报, 2006, 49(1): 284-294.
 阎守国, 宋若龙, 吕伟国, 等. 横向各向同性地层斜井中正交偶极子激发声场的数值模拟[J]. 地球物理学报, 2011, 54(9): 2412-2418.