摘要
油井水泥石高温力学性能衰退会对深层油气井安全性及服役寿命造成很大影响。研究水泥石高温强度衰退规律将有助于改善水泥石的长期高温力学性能。硅溶出是造成水泥石高温力学性能衰退的主要原因之一,但未引起重视。重点研究了温度对不同晶态硅溶解度的影响,并结合高温加砂水泥石抗压强度进行分析。结果表明,硅溶解度随温度上升而增加,相同温度下非晶硅的溶解度远大于晶体硅;随硅溶解度的增大,水化前期的硅溶解促进水泥石早期高温抗压强度发展,高温反应后期水化产物会发生硅溶出,造成水泥石高温强度衰退;静态水中水泥石高温抗压强度比动态水中更高且更加稳定;养护环境中硅饱和程度高,水泥石的高温力学性能更稳定。从高温硅溶出角度分析,以晶体硅为主,少量非晶硅为辅的不同晶态硅将有助于保持水泥石高温力学性能稳定。
The decline of the high temperature mechanical properties of set cement in oil wells has significant influences on the safety of deep reservoirs and the life span of the wells.Studies on the decline patterns of set cement’s high temperature strengths help to improve the long-term high temperature mechanical properties of the set cement.Silica leaching,one of the important factors leading to the decline of cement’s high temperature mechanical properties,has not yet been taken seriously.In this study,the effects of temperature on the solubility of different crystalline silicas have been investigated,and the compressive strength of the set cement with sand at elevated temperatures analyzed.It was proved that the solubility of silica increases with increase in temperature,and the solubility of non-crystalline silica is much larger than the solubility of crystalline silica.With the increase in the solubility of silica,the dissolution of silica in the early stage of hydration promotes the development of the early-stage high temperature compressive strength of the set cement.In the late stage of the high temperature reaction,silica leaching takes place in the hydration products,resulting in decline of the high temperature strength of the set cement.The high temperature compressive strength of set cement in static water is higher and more stable than the high temperature compressive strength of set cement in dynamic water.A high silica saturation in a curing environment helps make the high temperature mechanical properties of set cement more stable.Based on the analysis of silica leaching at high temperatures,it was found that treatment of cement slurries with sand comprising mainly crystalline silica and minor content of non-crystalline silica help improve the stability of high temperature mechanical properties of the set cement.
作者
耿晨梓
姚晓
代丹
黎学年
姜涛
闫联国
吴学超
GENG Chenzi;YAO Xiao;DAI Dan;LI Xuenian;JIANG Tao;YAN Lianguo;WU Xuechao(College of Materials Science and Engineering,Nanjing Tech University,Nanjing,Jiangsu 211816;Cosl Oilfield Chemical Research Institute,Yanjiao,Hebei 065201;Jiangsu Drilling Company,Sinopec East China Engineering Company,Yangzhou,Jiangsu 226152)
出处
《钻井液与完井液》
CAS
北大核心
2020年第6期777-783,共7页
Drilling Fluid & Completion Fluid
基金
中海油田服务有限公司项目“水泥石热衰退规律研究”(G2017A-0521G523)资助
江苏高校优势学科建设工程资助项目(PAPD)。
关键词
加砂水泥
晶体硅
非晶硅
硅溶出
抗压强度
固井
固井质量
Cement with sand
Crystalline silica
amorphous silicon
Silica leaching
Compressive strength
Well cementing
Quality of well cementing job
