Azimuthal Anisotropy Processing Technology Of Wide Azimuth Seismic Data

With the fine development for oil and gas exploration and acquisition of technology,wide-azimuth seismic exploration has become a new hot spot for oil and gas exploration.Wide azimuth seismic data contains a wealth of seismic information to help identify the small faults, micro structure and high angle fracture. However, with the acquisition azimuth increases, increase in collection of lighting, led to the azimuthal velocity anisotropy related problems began to highlight. At present, the anisotropic processing is mostly aimed at the processing of VTI medium, and the azimuthal anisotropy of HTI medium is not considered,so there is higher requirments on the wide azimuth seismic data processing for the azimuthal anisotropy.To solve this problem, this dissertation firstly reviews the two classical anisotropic theory,Hudson theory and Thomsen theory from the theory of seismic wave propagation in HTI media. According to the dynamic theory of HTI medium, studies the anisotropy of the P wave reflection coefficient, travel time and velocity in HTI medium. On the basis of this,uses staggered grid finite difference numerical simulation method of HTI media of 2D3 C forward modeling, through the analysis of the wave field snapshot, single shot records and common offset distance gathers can get in HTI media elastic wave field is very complex,the existence of S-wave splitting and second splitting etc special elastic waves. HTI top interface and bottom interface of P-wave and converted wave amplitude are azimuthal anisotropy, the bottom interface of reflection wave and converted wave velocity are also the azimuthal anisotropy, the shape of approximately an ellipse. This conclusion not only can provide the ellipse fitting for the velocity analysis of HTI medium, but also can provide important reference for the prediction of fracture in the formation and development of the fracture. Finally, according to the above findings, given the sub-azimuth velocity analysis and NMO correction processing method of HTI media. The method uses the center point of ellipse fitting is not fixed and the approximate ellipse fitting parameters. From the view of the actual treatment effect, basically eliminate the large offset non hyperbolic moveout after NMO anisotropy gathers, The events are leveled. From the stack profile, reflection axis energy has been strengthened, the event are more continuous. The results show the effectiveness and practicability of this method.