摘要
为解决凝析气藏开采中反凝析液堵塞损害和低渗、特低渗储层液相圈闭损害,气润湿方法近年来成为研究热点,然而岩石的润湿性改变后,其表面对CH4的吸附能力变化不容忽视。为此,对气润湿反转前后固体对CH4的吸附能力变化进行了实验和量子化学研究。采用AST系列煤层气吸附/解吸实验装置对气润湿反转前后石英砂对CH4的吸附能力进行测试,并依据所提出的液润湿和气润湿岩石表面原子簇模型,利用量子化学从头计算法(HF-3-21G)计算了2种润湿性表面与CH4分子的相互作用关系,包括吸附势阱和吸附距离。在同等平衡压力条件下,气润湿石英砂对CH4的吸附量约比液润湿石英砂低1个数量级;量子化学研究结果表明,气润湿反转后的固体表面对CH4分子的吸附能力减弱,吸附距离增加约1 nm,CH4分子在液润湿岩石和气润湿岩石表面均为单分子层物理吸附。
In recent years,the 'gas-welling' method has became a hotsput to address the problems nf lypical formation damage in condensate gas reservoirs and low or extra-low permeability resenoirs such as condensate blocking and aqueous trapping.However,changes in the wettability would affect the CH_4 absorbability of rocks.In this paper,experimental and quantum chemical study is conducted on the GH_4 adsorbahility changing with wettability reversal,AST CBM adsorption/desorplmn device is used to test the quartz sand's CH_4 adsorbabilily before and after gas wetting reversal.Based on the cluster models of liquid/gas wettabilily proposed,the relation between both wettability surfaces and GH_4 molecule is calculated by at) initio method(HF-3-21G),including adsorption potential well and distance.The CH_4 adsorbahility of gas- welling quartz sand is one order smaller than that of waterwetting quartz sand under equivalent equilibrium pressure.The quantum chemical calculations show that CH_4 molecule in both water-wetting and gas- wetting surfaces is monomolecular layer and physical adsorption.
出处
《特种油气藏》
CAS
CSCD
北大核心
2014年第1期98-101,155-156,共4页
Special Oil & Gas Reservoirs
基金
国家自然科学杰出青年科学基金项目"多孔介质油气藏气润湿性基础理论研究"(50925414)
国家高技术研究发展计划("863"计划)"致密砂岩气高效钻井技术研究"(2013AA064803)
国家自然科学基金面上项目"复杂地质条件下
提高井壁稳定性新方法研究"(51074173)
关键词
气润湿性
固体表面
吸附
CH4
量子化学
从头计算法
吸附势阱
gas-wettability
solid surface
adsorption
CH_4
quantum chemistry
abinitio method
adsorption potential well
