摘要
水泥浆静胶凝强度发展会造成水泥浆失重,当环空静压力和气体在环空中的流动阻力之和小于气层压力时,就会形成环空气窜的缺陷,这是发生环空气窜的主要原因。对环空中候凝水泥浆实施低压低频脉冲振动可以从3个方面防止环空气窜:①在水泥浆由液态向固态转化的过程中,脉冲振动使水泥浆保持低速运动状态,可以大幅度减小由于水泥浆静胶凝强度发展引起的水泥浆失重,有效防止环空气窜的发生;②脉冲振动可以促进水泥的早期水化,提高水泥浆早期抗窜能力;③脉冲振动可以提高水泥浆与2个界面的胶结质量,改善水泥石微观结构,使水泥石更加密实,防止气层气体通过水泥环界面和水泥石基体内部气窜。从环空气窜机理入手,分析了水泥浆水化过程中静胶凝强度发展特征,并阐述了候凝过程中脉冲振动水泥浆防止环空气窜的机理。
The development of the gel strength of cement slurry may result in the weight loss of the cement slurry.When the sum of the annular hydrostatic pressure and the annular flow friction is less than the(gas-bearing) formation pressure,annular gas channeling occurs.Application of low-volt low-frequency pulse vibration kills gas channeling in three ways: 1) cement slurry is kept in motion by the pulse vibration during its solidification;2) the early strengthening of cement slurry is accelerated by the pulse vibration,thus increasing the anti-channeling capacity of cement slurry in the early solidification period;and 3) pulse vibration improves the bonding quality of the two interfaces of cement sheaths and the micro structure of the set cement,making the whole set cement more competent and dense.
出处
《钻井液与完井液》
CAS
2009年第1期38-41,共4页
Drilling Fluid & Completion Fluid
基金
国家863课题"高温高压高含硫气井新型防气窜防腐水泥浆体系研究"(2006AA06Z209)资助
关键词
固井质量
环空气窜
静胶凝强度
失重
水泥浆
脉冲振动
Cementing job quality
Annular gas channeling
Gel strength
Weight loss
Cement slurry
Pulse vibration
