鄂尔多斯盆地靖边气田奥陶系碳酸盐岩气藏“似孔隙介质”参数场判识与建立方法

“Apparent porous medium” identification and establishment in the Ordovician carbonate reservoir, Jingbian Gas field, Ordos Basin

鄂尔多斯盆地靖边气田奥陶系马五1碳酸盐岩气藏主要储集空间为孔隙介质,主力气层马五12 和马五13 网状缝仅起局部沟通孔隙的作用,大量试井结果也证实马五1 气藏的储渗特征是“以孔隙介质为主,具有有限导流作用的储集类型”,因此引入“似孔隙介质”概念描述。通过建立“似孔隙介质”参数场来判识这一特征:通过概率统计分析,根据岩心分析渗透率与测井解释渗透率的差异显著性检验进行可信度评价,用岩心分析渗透率平均值作为期望值,约束整个渗透率参数场建模,避开测井解释带来的误差,只用其归一化等值线为权重,形成物性参数场。用该方法建立的参数场能较准确地反映储集层的储渗特征,大大减少模拟参数场修正工作量,具有可靠、实用等特点。

Porous medium is the main storage space of Ordovician MWi carbonate gas reservoir, Jingbian gas field, Ordos Basin. The fracture network of the major productive formations MW12 and MW13 only works for connecting pores. Well test results approved the storage and percolation characteristics of porous medium with limited conductivity. An apparent porous medium model is introduced to describe this kind of reservoir. The permeability contrast between core analysis and log interpretation is used to evaluate reliability of parameters, and the average core parameter is taken as the expectation value to constrain the model generation of parameter field, which could avoid the error from log interpretation, and only the integration contour line is weighted to perform the parameter field. The parameter field can correctly reflect the characters of the reservoir and reduce greatly the correction work of modeling parameter field.