基于三维坐标旋转的流体因子构建方法及其应用

A fluid factor construction method based on 3D rotation and its application

随着油气勘探开发的深入,基于地震数据的流体检测显得愈加重要,但基于二维坐标旋转构建的流体因子会受孔隙度、泥质含量、储层间差异等因素的影响,烃检结果仍然存在多解性,而且储层饱含不同流体时在纵、横波阻抗旋转投影的结果上时常有较大的重叠区。由于含烃储层往往具有低密度特征,因此联合纵、横波阻抗及密度在三维空间内通过坐标旋转来构建流体因子,可以进一步提高饱含不同流体的疏松砂岩储层的区分度。基于此,提出了基于三维坐标旋转的流体因子构建方法:首先通过高精度的弹性参数反演方法获得高可靠性的弹性参数,同时利用三维旋转,以含水饱和度曲线为约束条件,通过寻优方法确定反映烃类异常的最佳角度;最后通过三参数来构建流体敏感因子,进而提升流体预测精度。在渤海渤中B油田某区块滚动勘探中的应用表明,本文方法能有效提高油田围区的流体识别精度,降低储层孔隙度等非烃因素对流体识别的干扰,为后续滚动勘探提供有力的技术支撑,在类似地区具有一定的工业推广应用价值。

With the deepening of oil and gas exploration and development,it is increasingly necessary to detect fluids based on seismic data.However,pre-stack fluid factors based on 2 D rotation are often affected by factors such as porosity,shale content,and difference between reservoirs,which leads to great uncertainties for hydrocarbon detection.What＇s more,when reservoirs are saturated with different fluids,there are often large overlaps in the rotational projections of P-wave impedances and S-wave impedances.Since reservoirs saturated with hydrocarbons tend to have low density,we can construct fluid factors in3 D space through coordinate rotation in combination of P-wave impedance,S-wave impedance and density,which can further improve the discrimination of loose sandstone reservoirs containing different fluids.For this reason,this paper proposes an innovative method for constructing fluid factors based on 3 D rotation.Firstly,the high-reliability elastic parameters inversion method is used to obtain high-reliability elastic parameters.At the same time,with water saturation curves as a constraint,the 3 D rotation optimization method is used to determine the optimal angle for reflecting hydrocarbon anomalies.Finally,fluid sensitive factors are constructed by three parameters to improve fluid prediction accuracy.The application in the B oilfield of the Bozhong area of the Bohai sea shows that this method can effectively improve the accuracy of fluid detection in areas surrounding the oilfield and reduce the interferences caused by reservoir porosity.Thus it provides strong technical support for subsequent rolling exploration and has certain industrial application value in similar areas.