论文部分内容阅读
近几年来,振幅随炮检距变化(AVO)分析已经成功地用于预测储层性质和流体含量,在某些情况下,能提供气—水界面、气—油界面的空间位置。在这篇文章中,我们证明,3-D,AVO方法也可用于描述裂缝性储层的性质。给出裂缝密度变化的空间位置。在新墨西哥州San Juan盆地的Cedar Hill矿区Fruitland组地层的裂缝性煤层中生产甲烷气因为煤层缺乏原生渗透率,裂缝的存在则是生产甲烷气的决定性因素。为了有助于描述煤层的储层性质,在这块地区采用的是3-D多分量地震勘探。本次研究中,多分量数据体的叠前F波振幅资料用来圈定煤层气储层中大泊松比差异(或高裂缝密度)的区域边界。而震源-接收点方位分选则用于检测煤层裂缝系统引起的方位各向异性的优选方向、两种模拟方法(使用射线追踪和反射率)预测裂缝性煤层带对角度有关的P波反射率的影响对水平层状地层模型建立了合成共中心点(CMP)道集,模型所用的弹性参数取自声波测井和密度测井。由各向异性模拟方法模拟煤层中裂缝密度的变化。与砂岩—煤层界面有关的大声阻抗差异决定了P波反射率响应。对于计算模型来说,这些差异的影响远远超过各向异性差异的影响。由3—D数据体得到的9个大面元的地震AVO分析证实了模型的预测,具有AVO截距的范围指示低速煤层可能与应力释放带有关。具有AVO梯度的范围辨别大泊松比差异的煤层带,并因而识别煤层气储层中的高密度裂缝带。3-D AVO成果和储层泊松比变化图结合这些响应生成包括断裂程度和其可能的应力条件的储层图件。震源接收点方位分选被用于测定煤层裂缝系统引起的方位各向异性的优选方向。
In recent years, the amplitude versus offset variation (AVO) analysis has been successfully used to predict reservoir properties and fluid contents, and in some cases can provide spatial locations for gas-water interfaces and gas-oil interfaces. In this article, we show that the 3-D, AVO method can also be used to characterize fractured reservoirs. The spatial location of crack density change is given. Methane gas production in fractured coal seams in the Fruitland Formation in the Cedar Hill mine, San Juan Basin, New Mexico The presence of fractures is a determining factor in the production of methane gas because of the lack of primary permeability. To help characterize the reservoir properties of the coal seams, 3-D multi-component seismic surveys are used in this area. In this study, the pre-stack F-wave amplitudes of multi-component data bodies are used to delineate regional boundaries with large Poisson’s ratio differences (or high crack densities) in CBM reservoirs. The source-receiver azimuth sorting is used to detect the preferred direction of azimuthal anisotropy induced by the coal seam fracture system. Two simulation methods (using ray tracing and reflectivity) are used to predict the angle-dependent P-wave reflectivity of the fractured coalbed Synthetic center point (CMP) gathers have been established for horizontal stratigraphic models using elastic parameters derived from sonic logging and density logging. The variation of crack density in coal seam is simulated by anisotropic simulation method. The loud impedance difference associated with the sandstone-coal seam interface determines the P wave reflectivity response. For computational models, the impact of these differences far outweighs the effects of anisotropic differences. Seismic AVO analysis of nine mesobuffets from 3-D data body confirmed the prediction of the model, and the range with AVO intercept indicates that low-velocity coal seam may be related to stress release band. Areas with AVO gradients discriminate large Poisson’s ratio coal seam zones and thus identify high-density fracture zones in CBM reservoirs. 3-D AVO Results and Reservoir Poisson Ratio Variation Plots of these maps together with these responses generate reservoir maps that include the degree of fracture and its possible stress conditions. The azimuth sorting of the focal point of the seismic source is used to determine the preferred direction of azimuthal anisotropy caused by the fracture system of coal seam.