基于空变数据的相控贝叶斯-序贯高斯模拟方法

传统的地质统计学估计和模拟方法在整合测井和地震数据时, 笼统地采用静态空间的数据, 而未考虑样点与待模拟点空间沉积的变化以及岩相变化对样点取值影响的问题, 尤其是储层空间非均质性强、井分布不均匀时。基于贝叶斯-序贯高斯算法, 针对碎屑岩储层, 研究了一种基于空间变化数据的相控模拟方法。首先, 定义一个随待模拟点位置变化而动态变化的空间三维球体模型, 将空间数据的选择从静态的一维柱体拓展到该球体。然后, 在考虑物源方向的情况下, 采用变差函数工具对三维球体模型内的数据进行筛选。同时, 利用沉积相进行约束, 进一步提高样点取值的精确性。最后, 采用反距离加权算法确定样点的权重。川西坳陷东坡实际工区资料的应用表明, 基于空变数据的相控贝叶斯-序贯高斯模拟方法, 平面上河道模拟展布形态与地震属性一致性较好, 剖面上河道清晰连续, 分辨率也得到提升, 盲井模拟结果与测井数据吻合率达到92%, 验证了方法的准确性。对比不同硬件配置的应用结果表明, 该方法适应于不同性能的硬件条件, 验证了方法的实用性。

Traditional geostatistical estimation and simulation use static spatial data indiscriminatingly when integrating well and seismic data without considering spatial sedimentary variation across sampling points and the points to be simulated and the influence of lithofacies change on sampling values, particularly when there are strong spatial heterogeneity of reservoirs and uneven distribution of wells.For tight clastic reservoirs, we propose a facies-controlled simulation method using space-variable data based on a Bayesian-sequential Gaussian algorithm.A 3D spherical model is defined to vary dynamically with the position of the point to be simulated, which changes spatial data from a 1D column to the 3D sphere.Based on the direction of sedimentary source, the data in the 3D spherical model are screened using a variogram function; meanwhile, sedimentary facies are used as the constraints to improve the accuracy of sampling values.The weights at the sampling points are determined using inverse distance weighting.Our method was applied to the east slope of the west Sichuan Depression and yields improved-resolution images of continuous channels which are consistent with seismic attributes.The coincidence rate between the simulation results of the blind well and the logging data was 92%, which verifies the accuracy of the method.In addition, the method is demonstrated to be practical because it applies to different hardware configurations.