非电法测井计算页岩储层含水饱和度方法研究——以涪陵页岩气田焦石坝区块为例

摘要

页岩储层属于低孔、特低渗储层,其泥质含量高、孔隙度结构复杂、普遍发育黄铁矿直接影响Archie公式计算含水饱和度精度.涪陵页岩气田焦石坝区块J4井岩心实验分析含水饱和度与非电法测井数据进行数理统计分析,显示密度测井和补偿中子测井与岩心实验分析含水饱和度相关性较好;并对密度测井与补偿中子测井进行幂函数建模,最终优选密度二次多项式拟合法计算页岩储层含水饱和度.利用密度二次多项式拟合法对研究区多口井进行含水饱和度计算,精度分析误差较小,相对误差在8％以内.证实密度二次多项式拟合法在研究区页岩气储层含水饱和度评价中具有较强的适用性.该方法也为其他地区页岩储层含水饱和度计算提供参考.%The shale reservoir belongs to the low porosity and low permeability reservoir.The high clay content,complicated pore structure and general developed pyrite affect Archie formula to calculate the water saturation accuracy of the Shale reservoirs.Analysis of the mathematical statistics of the core analysis water saturation and the non-electrical logging data in the J4 well of Jiaoshiba area in Fuling gas field,it is found the both the density logging and the compensated neutron logging have better correlation with the core analysis water saturation,and modeling density logging and the compensated neutron logging by using the density two square polynomial.The precision anal ysis with study area wells calculation results show the error is small,the relative error is less than 8％.Confirmed density logging quadratic polynomial fitting had strong applicability in the study area of shale gas reservoir evaluation.The method also provides reference for the calculation of water saturation in shale reservoirs in other areas.