基于成因法的氦气资源评价新方法在晋中盆地的应用及意义

A new genesis method-based methodology for helium resource evaluation: Application to the Jinzhong Basin and its geological implications

  • 摘要:
    背景 氦气是一种战略紧缺资源,其主要赋存在天然气之中。我国氦气资源评价处于起步阶段,而且整体勘探开发程度较低,特别是在天然气勘探空白区或未探明氦气储量的盆地,建立氦气资源评价方法势在必行。其中,成因法基于氦气生成、运移和富集过程模型,具有模型简明、参数获取便捷和评价快速等优势。然而,现有成因法主要聚焦于单一氦源岩生氦总量估算,普遍忽略了多源生氦特征、氦气从源岩释放的效率(排氦系数)和运移富集效率(运聚系数),进而导致资源量评价结果普遍较高、准确性较低。
    方法 在氦气成因理论的基础上,创新性地引入排氦系数和运聚系数,运用野外调查和室内分析的手段,明确计算过程中各参数的确定方法,继而建立了一套基于成因法的系统性氦气资源评价新方法。并以晋中盆地为评价区,对该方法进行实例验证。
    结果和结论 建立了成因法氦气资源量计算公式与参数确定方法,基于国内外典型富氦盆地和气田的实验和计算,明确了各类氦源岩排氦系数达80%以上、稳定成藏系统氦气最大运聚系数为3.7%,运用该方法得出:(1) 晋中盆地潜在储层之下氦源岩的生氦总量为556亿m3,自成藏系统形成以来的氦气资源量为3.442 0亿m3;(2) 该方法丰富了我国氦气资源评价体系,为低勘探区氦气资源评价提供了方法依据;(3) 以晋中盆地为代表的我国中小盆地普遍富氦,氦气资源潜力巨大,有望成为未来氦气资源勘探突破的重要潜力区。

     

    Abstract:
    Background Helium, a strategic resource in short supply, primarily occurs in natural gas. In China, helium resource assessment remains in its nascent stage, and limited helium exploration and exploitation have been conducted in general. Most especially, for regions experiencing no natural gas exploration and basins where helium reserves remain unproven, it is essential to develop reliable methods for helium resource evaluation. Among various approaches, genesis methods, based on models of helium generation, migration, and enrichment processes, offer advantages including simple models, accessible parameters, and rapid assessment. However, existing genesis methods focus primarily on the estimation of the total amount of generated helium from a single helium source rock, generally neglecting the characteristic of multi-source helium generation, the helium release efficiency of source rocks (i.e., helium expulsion coefficient), and helium migration and enrichment efficiency (i.e., migration–accumulation coefficient). These omissions tend to induce overestimated resources and reduced accuracy.
    Methods This study developed a genesis method-based, systematic methodology for helium resource evaluation. The helium expulsion coefficient and migration–accumulation coefficient were innovatively introduced into the new methodology based on helium genesis theories. Furthermore, methods for determining the values of various parameters were proposed through field observations and laboratory analyses. Finally, the new methodology was applied to the Jinzhong Basin for verification.
    Results and Conclusions  A formula for calculating helium resources based on the genesis method was established, and methods for determining the parameters in the formula were also proposed. Experiments and calculations of representative helium-rich basins and gas fields in China and abroad reveal that various helium source rocks exhibit helium expulsion coefficients exceeding 80% and that stable helium accumulation systems show a maximum migration-accumulation coefficient of 3.7%. The new methodology was applied to the Jinzhong Basin, revealing that the total amount of generated helium from helium source rocks in the basin is 55.6 billion m3 and that the helium resources produced by the helium accumulation systems since their formation are 0.34 billion m3. The proposed methodology enriches the helium resource evaluation system of China, providing a methodological basis for helium resource evaluation in areas undergoing limited helium exploration. Medium-small basins in China, exemplified by the Jinzhong Basin, generally contain helium and thus hold great helium resource potential. These basins are expected to become significant potential regions for achieving helium exploration breakthroughs in the future.

     

/

返回文章
返回