松辽盆地徐家围子断陷沙河子组致密气储层参数解释方法

Interpreting method of Shahezi-Formation tight gas reservoir parameters in Xujiaweizi Fault Depression of Songliao Basin

针对松辽盆地沙河子组致密气储层物性差、岩性多样、孔隙结构复杂、储层参数解释精度低的问题,通过测井响应机理研究,首先以岩心和薄片资料为基础,通过刻度测井曲线后选取关键参数,建立了基于“主成分”和成像测井的岩性识别方法;再在骨架参数确定基础上,采用中子、密度孔隙度计算不受含气影响的密度曲线,以此计算有效孔隙度;最后通过分析砂岩和砂砾岩的孔—渗关系、岩电实验资料后,根据不同的特征,分岩性建立了渗透率及含气饱和度解释模型。通过新井取心及试气资料验证,岩性识别、孔隙度、渗透率及含气饱和度解释精度高。该方法已应用到储量提交中,为油田提交致密气储量提供了可靠参数。

Aiming at the problems of poor physical properties,diverse lithology,complex pore structure and low interpretation precision reservoir parameters of the tight gas reservoirs in Shahezi Formation of Songliao Basin,through the study of the logging response mechanism,firstly,based on the core and thin section data,the key parameters were selected after calibrating the logging curves,and the lithology identifying method was established based on“the principal component”and imaging logging;secondly,based on the determination of the skeleton parameters,the neutron and density porosity were used to calculate the density curve which is not affected by the gas content,and then the effective porosity was calculated;finally,based on the analyses of the pore-permeability relationship between the sandstone and conglomerate and moreover the experimental data of the rock electricity,the interpreting models of the permeability and gas saturation were established according to different lithological characteristics.Through the coring and gas test data verification of the newly drilled wells,the interpreted precisions of the lithology identification,porosity,permeability and gas saturation are pretty high.The method has been applied to the reserve submission and has provided the reliable parameters for the submission of the tight gas reserves in the oilfields.