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为减少管波对采集数据的影响,井间地震采用了定向震源,其能量辐射特性影响接收波场的能量分布与后续成像效果.研究定向震源的正演模拟并分析能量辐射特性,为井间地震成像过程中能量补偿提供基础数据.采用圆形震源阵列法,在近源区内按照质点与震源点连线的方向设置振动函数强度,水平方向能量最强,垂直方向能量最弱,模拟的辐射能量具有随方向改变的特点.实际井间地震能量方向性非常强,因而同时采用吸收衰减层法进一步减弱纵向的地震波能量.吸收衰减层法在震源周围设置具有衰减因子的海绵层,通过不同方向设定不同的衰减因子来控制震源的方向特性.衰减因子采用了渐变函数,保证海绵层边界不产生人为反射干扰.将圆形震源阵列法与吸收衰减层法联合进行双层介质模型和实际速度场模拟,得到的炮记录方向性更加明显.两种方法的有机结合,能够更好地模拟井间定向震源.在圆形震源阵列法可行性验证基础上,分析了阵列半径对接收波场能量的影响,初步确定了模拟定向震源的最佳阵列半径.通过分析方向性参数和井间距对接收波场能量分布的影响,获得了定向震源激发下接收波场的能量分布,为在井间地震偏移成像中进行能量补偿建立了基础.
In order to reduce the influence of tube wave on the collected data, the cross-well earthquake uses a directional source, and its energy radiation characteristics affect the energy distribution and subsequent imaging effects of the received wave field.The forward modeling of the directional source and the energy radiation characteristics are studied, In the process of seismic imaging, energy compensation provides the basic data.Using circular array method, the intensity of vibration function is set in the near source region according to the connection direction of particle and source point, the energy in the horizontal direction is the strongest and the energy in the vertical direction is the weakest. The radiant energy has the characteristics of changing with the direction of the actual seismic cross-well directionality is very strong, so at the same time using the absorption attenuation layer method to further reduce the longitudinal seismic energy absorption attenuation layer method around the source is provided with a damping factor sponge layer, The direction of the set of different attenuation factor to control the direction of the source characteristics of the attenuation factor using a gradual function to ensure that sponge layer boundary does not produce artificial interference interference.Founded circularly polarized array method and absorption attenuation layer method combined with two-layer medium model and the actual Velocity field simulation, the recorded gun direction is more obvious. The two methods of organic combination, can Which can well simulate the well-directional directional source.On the basis of the feasibility verification of the circular source array method, the influence of the array radius on the received wave field energy is analyzed and the optimal array radius of the simulated directional source is preliminarily determined. By analyzing the directionality The influence of parameters and well spacing on the energy distribution of the received wavefield is obtained, and the energy distribution of the received wavefield excited by the directional source is obtained, which provides a basis for energy compensation in crosswell seismic imaging.