基于宽方位地震数据的煤层裂隙预测方法研究

Study on coal seam fracture prediction method based on wide azimuth seismic data

沁水盆地煤储层中裂隙系统较发育,裂隙的走向、密度和发育范围控制着其渗透性和运移方向,查明地下裂隙的发育情况对煤层气的开发和压裂具有重要意义。基于裂隙发育地区具有明显的HTI方位各向异性的特点,利用宽方位高密度地震数据携带方位角信息的特征,在处理过程中开展OVT面元划分、五维规则化和OVT域叠前时间偏移等技术,获得携带方位信息的高保真度的OVT道集;在解释中利用OVT道集中随方位角变化的振幅和时差属性,采用拟合椭圆的方法对地下裂隙的走向和强度进行了预测。获得的裂缝预测结果与地下构造有较高的吻合度,并在井位部署和压裂过程中取得了较好的效果。

The fracture system in coal reservoirs in the Qinshui Basin is relatively well developed.The strike,density and development range of the fractures control its permeability and migration direction.Finding out the development of underground fractures is of great significance to the development and fracturing of coalbed methane.Based on the obvious characteristics of HTI azimuth anisotropy in fractured areas,this paper uses the characteristics of wide-azimuth and high-density seismic data to carry azimuth information,and develops OVT panel division,five-dimensional regularization and OVT domain pre-stack time during processing.Migration and other techniques are used to obtain high-fidelity OVT gathers carrying azimuth information;in the interpretation,the amplitude and time difference properties of OVT gathers with azimuth angle are used in the interpretation,and the direction and strength of underground fissures are measured by the method of fitting ellipses.prediction.The obtained fracture prediction results are in good agreement with the underground structure,and good results have been achieved in the process of well site deployment and fracturing.