页岩油气储层矿物和有机碳及含气量中子测井方法研究

Currently Shale oil and gas become the development hot spot of hydrocarbon resources exploration and its evaluation method is different from conventional oil and gas reservoir. Total organic carbon content, mineral content and other key geologic factors are the main evaluation content. A multi-detectors measuring system composed of D-T pulsed neutron source, one LaBr3 crystal and two He-3 detectors is designed to acquire inelastic, capture energy spectrum and thermal neutron time spectrum. Then a new pulsed neutron elements logging method which can determine the contents of mineral, organic carbon and gas directly in the same time is developed. Optimal structure parameters of the instrument are obtained by Monte Carlo simulation to form measuring method. Through physical experiment and Monte Carlo simulation, standard gamma energy spectrums are established and analysis method of energy spectrum is studied to determine elements content. The conversion relation of elements content with mineral is established to realize the determination of minerals content. The content of C can be got by the analysis of inelastic gamma energy spectrum and transformation relation between mineral and inorganic carbon is established to form the method determining organic carbon content. Inelastic gamma counts ratio, capture gamma counts ratio of further detectors and thermal neutron counts ratio of near and far detectors in different shale gas formation are simulated to build the method determining gas content. Logging influence factors are studied to form interpretation method and develop software. Finally, a new neutron logging method which can determine mineral content, organic content and gas content is formed to supply measuring means for the evaluation of shale oil and gas.

页岩油气是当前油气资源勘探开发热点，其评价方法与常规油气藏不同，总有机碳、矿物含量等关键地质要素是主要评价内容。设计一种由D-T脉冲中子源和1个LaBr3晶体、2个He-3管组成的多探测器测量系统，采集非弹、俘获伽马能谱及热中子时间谱，形成一种能够同时直接测量矿物、有机碳和含气量的脉冲中子元素测井新方法。利用蒙特卡罗方法模拟，得到仪器结构优化参数，形成测量方法；通过物理实验和蒙特卡罗模拟相结合建立标准伽马谱，研究能谱解析方法确定元素含量，建立元素和矿物含量转化关系，确定矿物含量；通过非弹伽马能谱解析确定C含量，建立矿物和无机碳含量关系，形成有机碳含量确定方法；模拟研究不同页岩气地层超远伽马探测器非弹与俘获伽马计数比及近远探测器热中子计数比，建立含气量确定方法；研究测井影响因素形成解释方法，开发软件；最终形成确定矿物、有机碳和含气量的中子测井新方法，为页岩油气评价提供测量手段。

针对页岩油气储层地球化学特征，建立基于D-T可控中子源的多参数脉冲中子多参数测量方法，以应用于储层元素、矿物、有机碳含量及含气量计算。脉冲中子仪器探测系统由1个高分辨率LaBr3伽马探测晶体及两个He-3中子管组成，可同时测量地层俘获伽马能谱、非弹伽马能谱、伽马时间谱及热中子时间谱。利用蒙特卡洛与物理实验相结合的方法，建立一套适用于页岩储层的元素标准谱。通过对俘获及非弹伽马能谱解析方法研究，准确计算地层元素含量，建立元素和矿物含量转换关系，形成一种有机碳含量直接确定方法。通过非弹俘获计数比与热中子计数比响应关系，建立一种在低孔条件下具有较高灵敏度的含气量确定方法。通过此脉冲中子多参数测量及评价系统研究，为页岩油气储层勘探与开发提供新的测量手段。