察尔汗盐湖含钾盐储层介质渗流-溶解过程中物性参数变化特征研究
Research on the Changes in Physical Properties during the Seepage-Dissolution Process of Potassium Salt-bearing Reservoir in Qarhan Salt Lake
常文静 1袁小龙 2刘久波 3李梦玲 1朱登贤 4胡燕 3李树伟 3唐朝生 5张西营2
作者信息
- 1. 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008;青海省盐湖地质与环境重点实验室,青海西宁 810008;中国科学院大学,北京 100049
- 2. 中国科学院青海盐湖研究所,中国科学院盐湖资源综合高效利用重点实验室,青海西宁 810008;青海省盐湖地质与环境重点实验室,青海西宁 810008
- 3. 青海省柴达木综合地质矿产勘查院,青海省柴达木盆地盐湖资源勘探研究重点实验室,青海格尔木 816099
- 4. 青海盐湖工业股份有限公司,青海格尔木 816000
- 5. 南京大学地球科学与工程学院,江苏南京 210023
- 折叠
摘要
察尔汗盐湖低品位固体钾盐资源丰富,是我国钾盐工业可持续发展的重要后备资源.充分了解储卤层中钾盐矿物的溶解机理有助于提高资源开采的效率.本研究以察尔汗盐湖浅部储卤层中含有不同钾盐矿物的3种典型钻孔岩芯为研究对象,通过室内渗流溶解实验,开展储卤层中固体矿物的溶解效率、孔隙度以及渗透性变化特征模拟研究.室内渗流-溶解实验结果表明,3种储卤层中的钾盐矿物溶出率皆近100%,其中主要含光卤石的岩芯样品溶解速度最快,含钾石盐岩芯次之,含杂卤石岩芯最慢.实验过程中,溶解反应后的储卤层固相骨架皆未塌陷,表明饱和NaCl卤水起到了很好的保护作用.由于石盐析出和不溶矿物的运移堵塞,3种岩芯的孔隙度皆降低,其中含光卤石岩芯孔隙度降低了26%,含钾石盐岩芯孔隙度降低了20%,含杂卤石岩芯孔隙度降低了32%.受控于盐类矿物溶解、石盐的析出和不溶矿物的运移堵塞,各储卤层岩芯渗透性降低幅度为40%～70%,降幅显著.
Abstract
Qarhan Salt Lake is endowed with abundant low-grade solid potassium salt resources,playing a crucial role in the sustainable development of the potash industry in China.A thorough understanding of the dissolution mechanism of potassium salt minerals in brine reservoirs is essential to optimize resource exploi-tation.In this study,three representative drill cores containing different types of potassium salts from the shallow brine reservoir of Qarhan Salt Lake were selected for investigation.Through a laboratory seepage dissolution experiment,the efficiency of solid minerals'dissolution,as well as changes in porosity and per-meability of the drill cores,was simulated.The results of the percolation-dissolution experiment revealed that the potassium salt minerals in the three drill cores were totally dissolved.Among the core samples,those containing carnallite exhibited the highest dissolution rate,followed by sylvite-rich core samples,while,polyhalite-rich core samples showed the lowest dissolution rate.Throughout the experiment,the skeleton of the brine reservoirs did not collapse after the dissolution reaction,indicating effective protection provided by NaCl-saturated brine.The porosities of the three core samples declined due to halite precipita-tion and the migration of insoluble minerals.Specifically,the porosity of the carnallite-rich core decreased by 26%,while that of the sylvite-rich and polyhalite-rich cores decreased by 20%and 32%,respectively.Controlled by the dissolution of salt minerals,precipitation of halite,and migration/blockage of insoluble minerals,the core permeabilities of brine reservoirs diminished by 40%-70%.This research highlighted the importance of considering complex factors for a comprehensive understanding of the changes in the reser-voir's physical properties during the seepage-dissolution process.
关键词
储卤层/钾盐矿物/渗透系数/孔隙度/饱和指数Key words
Brine reservoir/Potassium salts/Hydraulic conductivity/Porosity/Saturation index引用本文复制引用
基金项目
青海省地矿局项目()
中国科学院"西部之光-西部交叉团队"重点实验室专项(E210DZ0202)
稳定支持基础研究领域青年团队计划(YSBR-039)
出版年
2024
NETL
NSTL
维普
万方数据