不同养护条件对胶结界面抗气窜强度的影响规律

Studies of the Influences of Different Curing Conditions on the Anti-Gas Channeling Ability of Bonding Interfaces.

设计了水浴、空气和先空气后水浴等3种养护条件,利用自行研制的胶结界面抗气窜强度实验仪,研究了不同养护条件对固井胶结界面抗气窜强度的影响规律。试验结果表明:对于相同的水泥浆体系,在含水保水的养护条件下,胶结界面的抗气窜强度较高,耐久性好;而在无水或缺水的养护条件下胶结界面的抗气窜强度很低,即使延长养护时间,界面强度仍然不会提高;胶乳防气窜水泥浆只有在含水的环境中养护才能发挥作用,而在缺水的条件下其抗气窜强度还不如油井水泥净浆;缺水状态会破坏天然气井固井水泥环的界面胶结强度并引起抗气窜强度的降低,是天然气井投产后发生气窜的一个重要原因之一。该结果对研究新的天然气井防气窜理论和方法有重要的启示和指导意义。

Three curing conditions-water bath,air,and water bath after air-were designed to study their influences on the anti-gas channeling ability of bonding interfaces of cement on a self designed testing device.The experiments showed that for the same cement slurry system,the bonding interface had a better anti-gas channeling ability and a longer life period under water bath condition.Under air condition(no water),the bonding interface had a low anti-gas channeling ability,even under a lone time of curing.Latex anti-gas channeling cement slurry worked only under water-enriched condition,and was inferior to oil well cement slurry in anti gas channeling under conditions without water.It was concluded that the anti-gas channeling ability of cement bonding interfaces would become unacceptable without the presence of water.