页岩释气过程中碳同位素的分馏特征

Carbon isotope fractionation characteristics during shale gas release

陶成 翟常博 俞凌杰 申宝剑 王杰 杨华敏

TAO Cheng ZHAI Changbo YU Linjie SHEN Baojian WANG Jie YANG Huamin

中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126 页岩油气富集机理与有效开发国家重点实验室, 江苏 无锡 214126

Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Wuxi, Jiangsu 214126, China

钻井现场开展页岩岩心解吸气同位素监测，由于损失气样品缺失，而不能得到岩心气体释放全过程同位素的变化规律。通过加工岩心甲烷高压饱和-解吸装置，并接入色谱-同位素质谱联机系统，满足在线实时监测解吸气甲烷碳同位素变化的要求。在此基础上，开展页岩岩心释气的正演模拟实验，发现了解吸气甲烷碳同位素先期稳定、后期变轻后逐渐变重的变化规律，揭示了岩心中游离气和吸附气的相态转化、二者混合比例的动态演化与同位素变化趋势的相关性，表明同位素在页岩气开发状态的示踪方面具有应用潜力。

The isotope monitoring of desorption gas from shale cores was carried out at the drill site. Gas is lost during core recovery and thus the isotope variation for the whole process of gas release from shale cores cannot be obtained. A high pressure methane saturation-desorption device was developed and connected to the chromatographic-isotope mass spectrometry system to monitor the carbon isotope change of released CH4 on-line. The isotopic curves of releaed methane were initially stable, and then tended to become lighter and finally heavier, which was related to the phase transformation and the mixing ratio of free gas and adsorbed gas. Isotopes have potential applications in monitoring shale gas development.

国家科技重大专项 2016ZX05060;国家自然科学重点基金 U1663202

https://doi.org/10.11781/sysydz202001113