Mechanical properties of EVA-modified cement for underground gas storage
Mechanical properties of EVA-modified cement for underground gas storage
复制标题
DOI：
10.1016/j.jngse.2015.11.013
复制
发表时间：
2015-11
影响因子：
--
通讯作者：
Yuanguang Yang;Bin Yuan;Qinliang Sun;Tang Xin;Yingquan Xie
中科院分区：
文献类型：
--
作者：
Yuanguang Yang;Bin Yuan;Qinliang Sun;Tang Xin;Yingquan Xie
地下储气库（UGS）是一种用于全年平衡供需链的人工气藏。水泥环具有低弹性、硬脆性和多孔性，在运行周期中会经历机械应力和热应力的循环，并可能产生裂缝。这些裂缝可能导致储气通过套管后面和地层之前的水泥输送，甚至可能成为微裂缝的来源。因此，对水泥护套的力学性能有更高的要求。在这项工作中，使用了一种新材料来防止水泥裂缝，提高水泥在低应力下的弹性和在高应力下的变形能力，减少UGS井完井水泥中的孔隙数量，减少裂缝扩展。实验结果表明，在水泥中掺入EVA会降低水泥的抗压强度，但会显著提高水泥在高应力下的韧性和变形能力以及在低应力下的弹性变形恢复性。此外，EVA的加入显著降低了大孔隙的减少。
Underground gas storage (UGS) is an artificial gas reservoir used for balancing the supply-demand chain throughout the year. During its operation cycle, the cement sheath experiences cyclic mechanical stress, and thermal and may crack due to its low elasticity, hard brittleness, and porosity. These cracks could lead to the transmission of stored gas through the cement behind the casing and before the formation and can even be a source of micro-cracks. Therefore, the mechanical properties of the cement sheath have higher requirements. In this work, a new material was used to prevent cement cracking, improve cement elasticity at low stress and deformability at high stress, reduce the number of pores and reduce the crack propagation in the cement used for completion of UGS wells. The experimental results showed that mixing EVA into cement decreases the compressive strength, but significantly improves the toughness and deformability at high stress and the elasticity deformation restorability at low stress. Moreover, the addition of EVA results in the remarkable reduces reduction of macropores.