二维核磁共振技术表征页岩所含流体特征的应用——以松辽盆地青山口组富有机质页岩为例

2D NMR studies of fluids in organic-rich shale from the Qingshankou Formation, Songliao Basin

白龙辉 柳波 迟亚奥 李士超 闻迅

Longhui Bai Bo Liu Yaao Chi Shichao Li Xun Wen

页岩中已被证明含有大量可供开采的油气资源，厘清页岩中异相流体含量及赋存态对页岩油的开发至关重要。二维核磁共振技术能够对页岩中含氕（H）化合物进行无损、快速、定量检测。对松辽盆地青山口组一段页岩样品进行抽提前后、自发渗吸以及加热过程中的核磁共振检测，定量评价青一段页岩异相流体含量、赋存状态以及页岩放置时的流体散失。结果表明，在核磁二维谱图上，类固体有机质和轻质烃类主要分布于大于10 ms的上方区域，两者间基本以=0.1 ms为界，分别与有机碳含量及（游离烃）具有良好的线性关系。松辽盆地南部青一段页岩油主要以游离及吸附态赋存，页岩粘土含量越高，吸附态页岩油含量越高，游离态越少。页岩自发渗吸过程中的核磁共振检测结果表明了粘土矿物吸水膨胀作用。在页岩抽真空加热过程中，轻质烃挥发损失的同时水也大量地损失。利用密闭取心样品，结合二维核磁共振技术，可恢复其原始含油饱和度和含水饱和度。

Shale may contain a large amount of oil and gas that can be commericially exploited. Clarifying the content and occurrence of different fluids in shale is crucial to the development of shale oil. High frequency (23 MHz) two-dimensional (2D) NMR technology that can be used to quickly, nondestructively and quantitatively measure protium-containing (H) fluids in shale is employed to test shale samples (from the Qingshankou Formation in Songliao Basin) before and after extraction as well as during spontaneous imbibition and constant temperature rising experiments. The content and occurrence of different fluids in the samples as well as the loss of fluid from the samples after a period of static settlement are quantified and analyzed. The results show that on the 2D NMR maps, the signals of analogous solid organic matter and movable hydrocarbons, roughly separated by =0.1ms, are mostly distributed in the region above >10 ms. Good linear correlations can be observed between the signals and or . Oil is either free or absorbed in shale samples from the Qingshankou Formation. Higher clay content means more absorbed oil and less free oil in shale. The 2D NMR spectrum obtained during spontaneous imbibition experiment indicates water swelling of clay minerals. The vacuum heating process of the samples shows both volatilization of light hydrocarbons and significant loss of water. Samples from sealing core drilling combined with 2D NMR can be used effectively in the restoration of the original oil saturation and water saturation.

10.11743/ogg20210613