斜坡—沉积源岩型氦气富集模式——以鄂尔多斯盆地神木气田为例

Slope—sedimentary source rock-type helium enrichment model: a case study of Shenmu Gas Field, Ordos Basin

丁振刚 刘成林 范立勇 康锐 陈践发 王海东 洪思婕 MUHAMMAD Aslam Khan

DING Zhengang LIU Chenglin FAN Liyong KANG Rui CHEN Jianfa WANG Haidong HONG Sijie MUHAMMAD Aslam Khan

中国石油大学(北京) 油气资源与探测国家重点实验室, 北京 102249 中国石油大学(北京) 地球科学学院, 北京 102249 中国石油 长庆油田分公司 勘探开发研究院, 西安 710018

State Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum (Beijing), Beijing 102249, China College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China

鄂尔多斯盆地氦气资源丰富，已在伊盟隆起、伊陕斜坡南部等地区发现高含氦、富氦天然气田，这些气田的氦气富集多与断裂发育密切相关。然而，盆地内的构造背景较为复杂，为研究盆地内不同地质背景下氦气的富集特征及控制因素，对鄂尔多斯盆地伊陕斜坡东北部开展天然气组分分析测试，并结合研究区基础地质资料及前人研究成果，对鄂尔多斯盆地神木气田上古生界的氦气分布特征及其地质影响因素进行探究。神木气田上古生界氦气含量达0.017%~0.116%，平均氦气含量为0.05%，达到含氦气田标准；氦气含量在平面上呈“西低东高”的整体分布格局，东部部分地区的氦气含量大于0.1%；氦气含量与氮气含量呈明显正相关关系，表明天然气藏中的氦气和氮气在成因和溶解—脱溶机制上可能存在必然联系。神木气田氦气的富集受多种地质因素共同影响：上古生界广泛分布的煤系烃源岩提供了充足的氦气；地壳抬升和构造反转控制了氦气的运移方向，且促进了溶解氦的脱溶和聚集；适量的载体气有助于氦气的富集。结合研究区构造背景和氦气成藏地质因素，提出了一种新的氦气富集模式，即斜坡—沉积源岩型含氦天然气富集模式，这为氦气勘探和开发工作提供了重要的理论支持。

The Ordos Basin is rich in helium resources, with high helium and helium-rich natural gas fields discovered in areas such as the Yimeng Uplift and the southern Yishan Slope. The enrichment of helium in these gas fields is often closely related to the development of faults. However, the structural background within the basin is complex. To study the characteristics and controlling factors of helium enrichment under different geological backgrounds within the basin, an analysis of natural gas composition was conducted in the northeastern Yishan Slope of the Ordos Basin. Combining basic geological data of the study area and previous research findings, the helium distribution characteristics and geological influencing factors in the Upper Paleozoic of the Shenmu Gas Field in the Ordos Basin were explored. The results showed that the helium content in the Upper Paleozoic of the Shenmu Gas Field ranged from 0.017% to 0.116%, with an average content of 0.05%, meeting the standard of a helium-containing gas field. The helium content showed a spatial distribution pattern of "low in the west and high in the east", with helium content exceeding 0.1% in some eastern areas. There was a significant positive correlation between helium and nitrogen content, indicating a possible inherent connection between the genesis and dissolution-exsolution mechanisms of helium and nitrogen in natural gas reservoirs. The enrichment of helium in the Shenmu Gas Field was influenced by various geological factors: (1) The widely distributed coal-measure source rocks in the Upper Paleozoic provided ample helium; (2) Crustal uplift and tectonic inversion controlled the migration direction of helium and promoted the exsolution and accumulation of dissolved helium; (3) An appropriate amount of carrier gas aided in helium enrichment. Based on the tectonic conditions of the study area and the geological factors controlling helium accumulation, a new helium enrichment model was proposed, the slope-sedimentary source rock-type helium-rich natural gas enrichment model, providing theoretical support for helium exploration and development.

国家重点研发计划 2021YFA0719000

https://doi.org/10.11781/sysydz2024061177