CO2-咸水-岩石反应对砂岩盖层封闭能力的影响：以鄂尔多斯盆地石盒子组为例

Advances in Geo-Energy Research, 2018, 2(4): 380-392

原文网址: http://www.astp-agr.com/index.php/Index/Index/detail?id=78 

  人为排放的大量CO2造成了全球气温升高，继而引发冰川融化、海平面上升、极端气候等一系列问题。在不放弃使用化石燃料而减小CO2排放的前提下，将CO2进行地质埋存是一种有效的方式。盖层封闭性是保证CO2长期安全埋存的关键因素。在CO2注入后的长期地质埋存过程中，CO2-咸水-岩石反应不仅能够改变储层岩石的矿物成分及其孔隙结构，而且对于盖层岩石的矿物成分及其孔隙结构具有强烈的改造作用。

本文以鄂尔多斯盆地石盒子组储层作为目标储层，应用TOUGHREACT模拟了CO2注入后的多相、多组分反应溶质运移过程，基于简化的二维地质模型研究了CO2-咸水-岩石反应对盖层封闭能力的影响。通过盖层孔隙度和渗透率相对变化率与储层孔隙度和渗透率的相对变化率的对比可以看出，CO2-咸水-岩石反应对盖层的孔隙结构和渗透率的影响更大，对盖层的封闭能力演化过程具有重要意义。特别是盖层中产生的片钠铝石沉淀，对提高盖层的封闭能力起到了积极作用。

Impacts of CO2-brine-rock interaction on sealing efficiency of sand caprock: A case study of Shihezi formation in Ordos basin

Bin Liu, Xiaofei Fu, Zhuo Li

(Published: 2018-08-10)

CorrespondingAuthor and Email: Xiaofei Fu, 760136897@qq.com

Citation: Liu, B., Fu, X., Li, Z. Impacts of CO2-brine-rock interaction on sealing efficiency of sand caprock: A case study of Shihezi formation in Ordos basin. Advances in Geo-Energy Research, 2018, 2(4): 380-392, doi: 10.26804/ager.2018.04.03.

ArticleType: Original article

Abstract：

    Large anthropogenic emission of CO2 causes earth temperature becoming higher and higher, which may lead to the melting of glaciers, the rising of sea levels, extreme weather and so on. An effective way of reducing emissions is to capture and sequestrate CO2 while not giving up the fossil fuels. Caprock seal is critical for CO2 long term storage. CO2-brine-rock interaction will change minerals composition and pore structure of both reservoir and caprock. This paper analyzes the variation trend of porosity and permeability due to CO2-brine-rock interaction in caprock of Shihezi formation in Ordos basin, where TOUGHREACT is used as simulation tool. Geological data of numerical model are acquired from core samples. Simulations show that minerals interaction plays an important role on sealing efficiency of caprock. Overall, porosity and permeability of caprock decrease with CO2 sequestration, which indicates that main mineral reaction in caprock is precipitation, and caprock sealing efficiency is enhanced.

Keywords: CO2 geological storage, CO2-brine-rock interaction, sand caprock, sealing efficiency.

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