基于铀裂变中子探测的页岩气有机碳和含气量测井理论基础研究

项目名称： 基于铀裂变中子探测的页岩气有机碳和含气量测井理论基础研究

项目编号： No.41504099

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 天文学、地球科学

项目作者： 王新光

作者单位： 中国石油大学（华东）

项目金额： 20万元

中文摘要： 页岩气储层具有极低孔渗、非均质性强且“源储一体”的特征，有机碳含量和含气量是其核心评价内容，现有测井技术无法满足页岩气勘探开发的要求，能同时准确测量有机碳含量和含气量的脉冲中子测井方法成为研究的关键。本项目拟采用理论分析、数值模拟和实验测量相结合的研究方法，以脉冲中子源在地层中产生的铀裂变中子场和慢化中子场分布理论为基础，研究页岩含气地层中中子能量、时间、空间分布规律，阐明利用铀裂变中子确定有机碳含量的测井响应机理，明确页岩气储集层的脉冲中子响应特征，设计由D-T脉冲中子源、超热中子和热中子探测器组成的脉冲中子测量系统，建立裂变中子和慢化中子计数率、寿命等多参数联合反演算法及仪器参数优化方法，结合数值模拟和物理实验，进一步验证测井方法和仪器关键参数的合理性，最终提出能同时测量页岩气有机碳含量和含气量的脉冲中子测井实施方案，为适用于页岩气层的脉冲中子测井仪器研发奠定理论基础。

中文关键词： 铀裂变；中子探测；有机碳；页岩气含量；响应机理

英文摘要： Shale gas reservoirs have the characteristic of extremely low porosity and permeability, strong heterogeneity and self-contained source-reservoir. Organic carbon content and gas content are the core evaluation content. However, the present logging technology cannot address the need of shale gas exploration. It has become important to develop the pulsed neutron logging technology which can accurately measure organic carbon content and gas content simultaneously. Our approach consists of theoretical analysis, numerical simulation and laboratory measurement. Based on the diffusion theory of uranium fission neutron and slowing-down neutron produced by pulsed neutron source, we will study energy, time and spatial distribution of secondary neutron in shale gas reservoir. Through this study, we want to describe the logging mechanism of determining organic carbon content with uranium fission neutron, and the pulsed neutron response characteristics in shale gas reservoir. With the results, we will design a pulsed neutron measuring system composed of a D-T pulsed neutron source, epithermal neutron and thermal neutron detectors. The analysis will develop a multi-parameter joint inversion algorithm with the count rates and neutron lifetime of fission neutron and slowing-down neutron, and a computation method for optimizing the key parameters of the logging instrument. The numerical simulation and physical experiment will further rationalize designed logging method and optimized instrument parameters. The purpose of this project is to propose an implementation scheme of pulsed neutron logging technology, determining organic carbon and shale gas content simultaneously. The project results will provide a theoretical foundation for the development of pulsed neutron technology in shale gas reservoir.

英文关键词： uranium fission;neutron detection;organic carbon;shale gas content;response mechanism