Measurements Of Third-order Elastic Constants In Nylon And Acoustic Velocity Around Hole With Stress

In the field, there are a lot of broken wells are cased hole, cased hole broken in the front if we are able to make a determination wells week exclusive stress, which has great significance for oil exploration cost savings and reduced. However, for embedded bore hole circumference speed model under steel case distribution of less.The paper nylon-based sample of this material were measured third-order elastic modulus of nylon, perforated circumferential velocity distribution of pore model, and the peripheral speed of the hole in case of the embedded steel pipe distribution. This article first borehole model, model in a hole under stress concentration, shear wave velocities hole different azimuthal angles of weeks to map out the theoretical distribution pipe case, the results show that embedded steel will affect the velocity distribution of the hole periphery; Secondly, pale yellow nylon, white nylon, black nylon three samples were measured under different stress the shear wave velocity. Formula based on sound bombs and third order least squares pickup nylon elastic modulus and shear wave velocities measured by the theoretical value picked up third-order elastic modulus and velocity calculated for comparison. The results show that: the theoretical results are in agreement with the experimental results, the speed of sound changes nylon is not obvious, and is different from the sound effect playing rock, shear wave velocity decreases with increasing speed compressive stress. And the polarization direction of light yellow nylon material with uniaxial stress directions are parallel and perpendicular to the two shear stress occurs with the increase cross phenomenon. The reason is that the cross has a pale yellow nylon intrinsic anisotropy, with the increase of stress-induced anisotropy stress gradually offset the intrinsic anisotropy intersects with the further increase in stress-induced stress anisotropy highlights. Again, the use of a light yellow nylon, white nylon, black nylon nylon three kinds of sample types of wellbore model and embedded steel models, experimental measurements were peripheral speed different aperture hole week uniaxial stress distribution under different azimuth angles and graphics, and on the white nylon and longitudinal wave measurements and theoretical curves were compared pale yellow nylon. Seen from the vertical and horizontal velocity wellbore model: the existence of a significant hole nylon material azimuthal anisotropy especially black nylon material, although the uniaxial stress will affect the speed, but under uniaxial stress herein intrinsic anisotropy dominates. Pale yellow nylon case hole peripheral velocity distribution of significant change, but due to uneven medium itself is not consistent with the law of the extreme value theory appears, after embedding steel, not embedded when compared with shear wave velocity changes, indicating that after embedding steel stress distribution in the hole changed. Inconsistencies holes theoretical and experimental aspect of the case from the sample itself, the other from the experiment, although more types of samples, the stress load is large enough to read more of the norm, but because of the sound of nylon elastic effect is small, low sensitivity to stress, so the result is not satisfactory, of course, due to limited conditions, the accuracy of the measurement results of the experiment due to systematic errors can not be ignored, despite the theoretical and experimental measurements have inconsistencies, but for us to be able to experiment a better understanding of the hole periphery of the sound field to provide a basis; Finally, based on the phase dispersion analysis is a new method of dispersion curves(slowness) extraction, the extraction process, without any unknown parameters, entirely dependent on the measured data, so this is a big advantage of this approach, and hand to use data extracted by this method dispersion curves.