碳酸盐矿物微量稀土元素测试新技术开发及应用

Development and applications of new techniques for tests of trace elements and rare earth elements in carbonate minerals

胡安平 梁峰 罗宪婴 王永生 乔占峰 贺训云 沈安江

Anping HU Feng LIANG Xianying LUO Yongsheng WANG Zhanfeng QIAO Xunyun HE Anjiang SHEN

微量稀土元素在成岩环境重建和成岩流体演化示踪中具有重要的应用价值，溶液法是目前该领域较为成熟且常用的测定方法，但存在粉末样品需求量大，导致只能对多个微区成岩组构混合样进行测试；样品化学处理流程复杂、用时长且耗酸量大；测试精度有待提高。这些局限性在一定程度上制约了该技术的推广应用。依托国家能源碳酸盐岩油气重点实验室平台，开展了碳酸盐矿物微量稀土元素测试新技术的研究与开发，并取得了3项重要成果：①实现溶液法碳酸盐矿物微量稀土元素测试技术的升级，通过优化化学处理流程，使粉末样品需求量从50 mg降低至10 mg，满足了微组构取样和测试的要求。同时，样品处理时间缩短，耗酸量从10 mL降至2 mL，数据相对误差从5 % ~ 10 %降至2 % ~ 5 %。②基于RESOlution激光剥蚀系统、iCAP TQ三重四极杆电感耦合等离子体质谱仪和QuadLock平台，成功开发了微量稀土元素激光面扫描成像新技术。该技术将检测含量下限从（1 ~ 10） × 10级降至10级以下，图像空间分辨率从≥ 5 µm提升到≤1 µm，图像扫描和处理时间效率提高到原来的10倍。③微量稀土元素激光面扫描成像新技术的开发拓展了应用领域，除用于微区组构成岩环境重建及成岩流体演化示踪研究外，还可用于激光U-Pb同位素绝对年龄测定，提高测年成功率和精度。此外，该技术还用于研究微量稀土元素含量及其比值与矿物阴极发光（CL）特征的耦合关系。微区组构的微量稀土元素测试新技术的开发为碳酸盐岩储层成因研究提供了有力的技术支持。

Trace elements and rare earth elements （REEs） are of great value in reconstructing diagenetic environments and tracing the diagenetic fluid evolution. Presently， the solution method is recognized as a well-established， commonly used analytical method， but due to its high demand for powdered samples， it is only applicable to mixed samples of multiple diagenetic microfabrics with relatively low accuracy. With the support of the State Energy Key Laboratory for Carbonate Oil and Gas， we conduct the research and development of new techniques for analyzing trace elements and REEs in carbonate minerals， achieving three significant outcomes. First， upgrading the technique for testing trace elements and REEs in carbonate minerals with solution method. The required quantity of powdered samples gets reduced from 50 mg to 10 mg， meeting the sampling and testing requirements of microfabrics. Moreover， less time is needed for sample analysis and tests， so does the acid consumption， falling from 10 mL to 2 mL， resulting in a lower relative error of analysis and tests of 2 % ~ 5 % from 5 % ~ 10 %. Second， developing a new continuous laser mapping technique for trace elements and REEs using a laser ablation system and a triple quadrupole inductively coupled plasma mass spectrometer （ICP-MS） platform. With this technique， the lower limit of detection content is reduced from 1-10 ppb to a sub-ppb level， while the spatial resolution of images rises from ≥ 5 µm to ≤ 1 µm， and the time efficiency for image scanning and processing is increased by 10 times. Third， besides its applications in reconstructing the diagenetic environments of microfabrics and tracing the diagenetic fluid evolution， this new technique developed can improve the success rate and accuracy of laser-ablation U-Pb isotopic absolute dating.

10.11743/ogg20250203