CAJ | 학술논문

非常规资源逐渐成为我国油气勘探的重要领域，其“源储一体”的特性使得对源岩特别是有机碳含量的连续定量评价成为关键。传统测井评价方法均是基于测井资料的间接评价，受多种因素影响，计算结果有一定的不确定性。本文利用快中子与地层元素原子核发生反应产生的非弹性散射伽马能谱和俘获伽马能谱，通过谱分析技术获取地层元素含量，根据与无机碳相关的钙、镁等元素含量确定无机碳含量，从总碳含量中扣除无机碳含量可直接提供高精度的有机碳含量信息。借助于蒙特卡罗数值模拟方法，建立了6种四川盆地龙马溪组和筇竹寺组页岩地层模型，模拟不同地层条件下的混合伽马能谱，并利用模拟元素的标准伽马能谱对模拟能谱进行谱解析。模拟结果表明，本文的方法可直接提供高精度的有机碳含量，有机碳含量大于2％时，其计算值相对误差小于6％。
비상규자원축점성위아국유기감탐적중요영역，기“원저일체”적특성사득대원암특별시유궤탄함량적련속정량평개성위관건。전통측정평개방법균시기우측정자료적간접평개，수다충인소영향，계산결과유일정적불학정성。본문이용쾌중자여지층원소원자핵발생반응산생적비탄성산사가마능보화부획가마능보，통과보분석기술획취지층원소함량，근거여무궤탄상관적개、미등원소함량학정무궤탄함량，종총탄함량중구제무궤탄함량가직접제공고정도적유궤탄함량신식。차조우몽특잡라수치모의방법，건립료6충사천분지룡마계조화공죽사조혈암지층모형，모의불동지층조건하적혼합가마능보，병이용모의원소적표준가마능보대모의능보진행보해석。모의결과표명，본문적방법가직접제공고정도적유궤탄함량，유궤탄함량대우2％시，기계산치상대오차소우6％。
Unconventional resources gradually become the important domain of oil and gas exploration in China ,in w hich the evaluation of source rock ,especially the total organic carbon content (TOC ) ,is critical due to the“source and reservoir in one body” . Conventional evaluation methods of TOC based on logging data are all indirect ones ,and calculated results involve some uncertainties as they are affected by various influential factors .In this paper ,inelastic gamma spectra and capture gamma spectra were recor‐ded with the gamma ray detector ,and elemental contents in formation were derived with spectral analysis technique .After that ,the total inorganic carbon content (TIC ) ,which is calculated with the TIC‐related elemental contents ,was deducted from total carbon content ( TC ) to directly determine TOC . According to the characteristics of shale in Longmaxi and Qiongzhusi formation of Sichuan basin ,Monte Carlo method was em‐ployed to build 6 formation models ,gamma spectra under different formation conditions were simulated ,and then the simulated gamma spectra were analyzed with elemental standard gamma spectra .The simulation results demonstrate that the method mentioned in this paper can directly provide high‐accuracy results of TOC ,and the relative error of calculated value is less than 6% w hen TOC is more than 2% .