柴达木盆地涩北一号气田低阻气层测井解释方法

On Log Interpretation Method for Low Resistive Gas Zone in Sebei-1 Gas Field, Caidam Basin

通过对柴达木盆地涩北一号气田岩心实验及测井资料综合分析 ,认为造成该地区低阻气层的主要原因在于高含以附加导电性强的蒙脱石为主的泥质 ,再加上岩性细、储层束缚水含量高、矿化度高等因素。在此基础上 ,结合相渗实验 ,提出依据常规测井计算地层束缚水饱和度的模型 ,并根据泥质含量、含水饱和度和束缚水饱和度 3个参数建立相应的解释标准来判识低阻气层。经 5个已知层的检验 ,上述方法在涩北一号气田识别低阻气层的准确率可达 10 0 %。

Comprehensive core experiments and log data analysis display that the main causes resulting in the low resistive gas reservoirs in Sebei-1 gas field, Caidam Basin, are the high shales which are mainly composed of montmorillonites with high added conductivity, fine grain structures, high bound water saturation and high salinity water. Based on the above analysis and combined with the relative permeability experiments , proposed is a new method to determine the volume of irreducible water from the conventional logging data, and established is a corresponding interpretation standard identifying the low resistive gas zones according to the three parameters (namely shale content, water saturation and bound water saturation). Field log examples in five low resistive gas zones proved that interpretation accuracy of the above method and standard reaches 100 percent , which shows the method is feasible.