高温环境下CO_2腐蚀水泥石规律的实验研究  

Researches of CO_2 Corrosion to Cement Stone at High Temperature

作　　者：周仕明[1] 王立志[1] 杨广国[1] 杨红岐[1] 

机构地区：[1]中国石化石油勘探开发研究院德州石油钻井研究所,山东德州253005

出　　处：《石油钻探技术》2008年第6期9-13,共5页Petroleum Drilling Techniques

基　　金：国家高技术研究发展计划("863"计划)项目"高温高压高含硫气井新型防气窜防腐水泥浆体系研究"(编号:2006AA06Z209)资助

摘　　要：天然气中普遍存在二氧化碳气体,干气情况下CO2基本没有危害。但是如果地层出水,CO2会在湿环境下对井筒中的各种物质产生腐蚀。分析了在分压4.8 MPa、95℃和分压5.0 MPa、130℃、150℃的湿环境下,CO2对水泥石的腐蚀规律。通过对比分析腐蚀前后的水泥石试块的物理性能和反应产物,认为CO2腐蚀水泥石的主要产物是CaCO3,CaCO3和CO2在湿环境下进一步反应生成可溶解的Ca(HCO3)2。腐蚀后的水泥石试块强度降低,渗透率升高。腐蚀深度在低温区与温度成正比,在高温区与温度成反比。水化产物中CaAl2Si2O8.4H2O(钙长石)具有较强的抗CO2腐蚀能力。实验发现,胶乳可有效降低水泥石的腐蚀深度。CO2 exists in natural gas and has no damage in dry environment. While when formation contains water, corrosion will occur at wellbore due to CO2. CO2 corrosion mechanism to oil cement stone at pressure of 4.8 MPa and temperature of 95℃, 130℃ and 150℃ were analyzed. Based on the analysis of physical properties of cement stone and reaction products before and after corrosion, it shows that the main corrosion product is CaCO3, and resoluble Ca（HCO3）2 after CaCO3 reacting further with CO2 under wet conditions. The cement stone has lower compression pressure and higher permeability. Corrosion depth is proportional to temperature at low and middle temperature, and reversely proportional to temperature at high temperature. CaAl2 SiO2 08 · 4H2O has relatively high anti-corrosion ability, and Latex can effectively reduce corrosion depth of cement stone.

关 键 词：高温 水泥环 二氧化碳 腐蚀 抗压强度 渗透率 

分 类 号：TE256.9[石油与天然气工程—油气井工程]