Experimental Study on Water-rock Reactions with CO2 Fluid in a Deep Sandstone Formation under High Temperature and Pressure  

作　　者：LI Chengze CHEN Guojun LI Chao TIAN Bing SUN Rui SU Long LU Yingxin WANG Lijuan 

机构地区：[1]Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China [2]Key Laboratory of Petroleum Resources Research,Gansu Province,Lanzhou 730000,China [3]University of Chinese Academy of Sciences,Beijing 100049,China [4]Inner Mongolia University of Science and Technology,Baotou,Inner Mongolia 014000,China [5]CNOOC Research Institute Co.,Ltd.,Beijing 100028,China

出　　处：《Acta Geologica Sinica(English Edition)》2021年第1期268-279,共12页地质学报（英文版）

基　　金：supported financially by the National Science and Technology Major Project of the Ministry of Science and Technology of China(Grant No.2016ZX05026-007-005)。

摘　　要：Qiongdongnan Basin has a tectonic geological background of high temperature and high pressure in a deep reservoir setting,with mantle-derived CO2.A water-rock reaction device was used under high temperature and high pressure conditions,in conjunction with scanning electron microscope(SEM)observations,to carry out an experimental study of the diagenetic reaction between sandstone at depth and CO2-rich fluid,which is of great significance for revealing the dissolution of deep clastic rock reservoirs and the developmental mechanism of secondary pores,promoting deep oil and gas exploration.In this study,the experimental scheme of the water-rock reaction system was designed according to the parameters of the diagenetic background of the deep sandstone reservoir in the Qiongdongnan Basin.Three groups of single mineral samples were prepared in this experiment,including K-feldspar samples,albite samples and calcite samples.Using CO2 as a reaction solution,a series of diagenetic reaction simulation experiments were carried out in a semi-closed high temperature and high pressure simulation system.A field emission scanning electron microscope(SEM)was used to observe the microscopic appearance of the mineral samples after the water-rock reaction,the characteristics of dissolution under high temperature and high pressure,as well as the development of secondary pores.The experimental results showed that the CO2-rich fluid has an obvious dissolution effect on K-feldspar,albite and calcite under high temperature and high pressure.For the three minerals,the main temperature and pressure window for dissolution ranged from 150℃to 300℃and 45 MPa to 60 MPa.Scanning electron microscope observations revealed that the dissolution effect of K-feldspar is most obvious under conditions of 150℃and 45 MPa,in contrast to conditions of200℃and 50 MPa for albite and calcite.Through the comparative analysis of experimental conditions and procedures,a coupling effect occurred between the temperature and pressure change and the dissolution

关 键 词：deep reservoir high temperature and pressure CO2-rich fluid DISSOLUTION Qiongdongnan Basin 

分 类 号：P618.13[天文地球—矿床学]