川中地区大安寨段页岩油气储层测井评价指标体系

Well-logging evaluation index system of shale oil and gas reservoir of Da’anzhai member in central Sichuan Basin

四川盆地侏罗系大安寨段页岩有机碳(TOC)含量高,厚度较大,物性与含油气性均较好,开发潜力巨大,但在常规油气储层和海相页岩气储层研究中形成的孔隙度、TOC含量等关键参数计算方法和测井评价标准在该段页岩油气评价中并不适用。以岩石物理实验分析为基础,将自然伽马测井、声波时差测井和电阻率等常规测井与核磁共振、岩性扫描等测井等新技术相结合,建立了川中大安寨段页岩油气储层TOC含量、孔隙度、含气饱和度、游离烃(S1)含量等关键参数的计算模型,形成了大安寨段页岩油气储层评价指标体系,模型计算结果与岩心分析结果吻合较好,经生产实践证明该项技术应用效果明显。该研究成果能够有效地支撑四川盆地页岩油气储层的"甜点"选区、井位部署和老井上试方案优选。

Shale of Jurassic Da’anzhai member in Sichuan Basin is mostly featured by high TOC content,large thickness,and great physical property and hydrocarbon potential,which shows great development prospect.However,some methods to calculate key parameters of porosity and organic carbon content and other well-logging evaluation standards,which have been established for conventional oil and gas reservoirs and marine shale gas reservoirs,are not applicable for assessing shale oil and gas reservoirs in this formation.Based on petrophysical experimental analysis,and combined conventional well-logging data from natural gamma ray,acoustic,and resistivity logging with new technologies including nuclear magnetic resonance logging and lithological scanning logging,a model for calculating the key parameters of TOC content,porosity,gas saturation and free hydrocarbon(S1)content was established,and an evaluation index system was developed for shale oil and gas reservoirs of Da’anzhai member in central Sichuan Basin.The calculated results by the model agreed well with ones from core analysis,and the practices showed that the calculation model and the evaluation index system have an obvious application effect.The research results can provide an effective support in sweet spot selection,well-location deployment and well-testing plan optimization in old wells for shale oil and gas reservoirs in Sichuan Basin.