鄂尔多斯盆地某地区石盒子组低渗透天然气储层产能测井预测

在油气田勘探与开发中，低渗透储层产能测井预测是一个关键也是一个难点。依据测井、测试和岩心实验资料，首先针对自然生产与压裂生产的不同生产措施，确定物性下限，孔隙度10%、渗透率1×10^-3μm²为自然生产储层物性下限，孔隙度6%、渗透率0.1×10^-3μm²为储层产能物性下限；然后根据生产情况，将产能分为自然生产、压后产气大于10 000m³/d、压后产气3 000～10 000m³/d和压后无产4个等级，总结常规测井响应特征，采用自然伽马与密度—中子视石灰岩孔隙度差值结合储层孔隙度、渗透率建立产能分级预测模型；其次由渗流力学和毛管理论可知，压后每米无阻产气量与可动流体孔隙度呈现指数关系，利用核磁共振测井确定储层有效流动孔隙度，建立压后每米无阻产气量测井定量预测模型；最后将产能测井预测模型应用于鄂尔多斯盆地某地区石盒子组低渗透天然气储层的产能预测，预测结果与测试结果符合很好，压后定量预测结果与测试结果相对误差均在10%以内。

Productivity log forecasting of low permeability gas reservoir of Shihezi Formation in X area of Ordos Basin

The process of oil-gasfield exploration and development,productivity log forecasting of low permeability gas reservoir is a key and difficult point.On the basis of log,testing and core experimental data,firstly,according to the different production measure,the lower limit of reservoir physical property is determined.Reservoirs with porosity and permeability greater than 10% and 1×10^-3μm²,respectively,have natural productivity,and reservoirs with porosity and permeability less than 6% and 0.1×10^-3μm²,respectively,have no productivity.Secondly,according to the production condition,productivity is divided into natural productivity,post-frac AOF>10 000m³/d,post-frac AOF 3 000-10000m³/d and post-frac without production.Their log characteristics of different productivity levels are studied,and using GR,φ_D-N,porosity and permeability,four productivity levels can be forecasted.Then followed by permeation fluid mechanics and capillary theory,the relationship of post-frac AOF per meter and efficient flow pore,calculated by NMR,is index,and the model can be established.Finally,productivity of low permeability gas reservoir of Shihezi Formation in X area of Ordos Basin is calculated and the forecast results accord with test results well,and the relative error is less than 10%.