ALCOHOL DEFOAMING AGENT USED IN METHOD FOR RECYCLING FOAM FOR FOAM DRILLING

摘要

Disclosed is an alcohol defoaming agent used in a method for recycling foam for foam drilling. The alcohol defoaming agent comprises at least a lower alcohol having a structural formula of R-OH, R being alkyl containing four or five carbon atoms, and preferably one or more of n-butanol, isobutanol, n-pentanol, isopentanol and neopentanol. The alcohol defoaming agent also comprises tributyl phosphate, the volume ratio of the lower alcohol to tributyl phosphate being 1:5 to 5:1. The lower alcohol has the functions of defoaming and stabilizing foam. When the method is used to recycle foam, only the lower alcohol needs to be added for defoaming, and a defoamed base fluid can be foamed again and used for drilling. If the volume of the lower alcohol accounts for 5% or more of the foam base fluid after the lower alcohol is repeatedly recycled, the lower alcohol is removed, and a foaming agent is added for foaming, so as to realize repeated recycling of the foam base fluid. The removed lower alcohol can be reused. The lower alcohol does not have selectivity for the foaming agent and has a high defoaming rate. The alcohol defoaming agent can reduce foam drilling costs and is environmentally friendly.