致密砂岩储层物性参数预测方法研究

致密砂岩储层不同于常规砂泥岩储层,具有低孔、低渗等特征,其地震弹性参数和储层物性参数的关系复杂,储层的岩石物理确定性建模和反演难度大。为了有效预测致密砂岩储层的物性参数,基于岩石物理敏感性参数分析结果,采用核贝叶斯判别法,构建了孔隙度、孔隙尺度和渗透率预测技术流程。首先考虑孔隙尺度对渗透率的影响,提出了等效孔隙尺度求取方法;进而展开岩石物理敏感性参数分析,得到对储层物性敏感的弹性参数;最后利用核贝叶斯判别法求取储层物性参数。所构建的致密砂岩储层孔隙度、等效孔隙尺度和渗透率预测技术流程,保证了渗透率预测的准确性。测井和地震资料试验结果表明预测的孔隙度和渗透率均与测井数据匹配良好,该方法能够有效识别砂岩储层并刻画其孔渗特征,对油气田的勘探开发具有重要的指导意义。

Tight sandstone reservoirs exhibit low porosity,low permeability,and more complicated relationships between seismic elastic parameters and reservoir physical parameters than conventional reservoirs,which result in challenging rock physics deterministic modeling and inversion.Based on the analysis of reservoir physical properties,a prediction process for porosity,pore scale,and permeability of tight sandstone reservoirs was built,which used the kernel-Bayes discriminant method.First,considering the relationship between the permeability and the pore scale,an equivalent pore scale method was proposed.Then,an analysis of reservoir physical properties was performed to identify the sensitive elastic parameters.Next,the kernel-Bayes discriminant method was adopted to predict the petrophysical properties;logging and seismic data were used to verify the feasibility of the method.The predicted porosity and permeability were well-matched with the well-log data.Thus,we determined that this method could effectively identify the sandstone reservoir and describe its porosity and permeability.The proposed prediction method for physical properties in tight sandstone reservoirs is significant for the exploration and development of oil and gas fields.

国家科技重大专项“叠前弹性反演与优质储层地震预测技术研究”(2016ZX05002-005-003)和中国石油大学(北京)科研基金项目(2462018QZDX01)共同资助。