Integration In The Tarim Oilfield Drilling Fluid System Solid

The mud cake can’t cure with cement ring together and the performances of drilling fluid and cementing fluid will be affected when they contact with each other because of their different chemical compositions.As a result,the cementing quality of gas/oil wells will get worse,and provides convenience for the breakthrough of oil,gas and water,which will greatly influence the safe exploit finally.The Tarim oilfield’s mud cake is loose and thick,it makes the cement slurry and borehole wall can’t formed well,the water in mud cake will be absorbed by the cement stone under the complex environment,it makes the mud cake cracking,and provides channels for interlayer cross flowing,which affects the cementing quality seriously.The research of a set of drilling-cementing-integrated working fluid system can improve cementing second interface bond quality.With the help of potential active material and other admixtures can ensure drilling fluid work normal and will form a mud cake with curing agent.Add more curing agent and active agent can turn curable drilling fluid to curable cementing fluid.The activator in curable cementing fluid can cure the mud cake while cementing.At the same time cementing fluid can solidify by its activator and cure with mud cake.The research defines the kind and amount of curing agent and admixtures in curable drilling fluid and curable cementing fluid.,and investigate the performances of them with the help by qualitative and quantitative methods.Analysis potential active material by combining with the chemical composition and activity excitation mechanism determine blast furnace slag as the curing agent.The results show that fluid viscosity,water loss and mud cake thickness increasing when the amount of BFS increasing,the function of curable drilling fluid properties is much better when the complex proportion of Chengdu S75:Chengdu S95is7:3,20%in total.Due to the mud cake of curing drilling fluid can solidify with curable cementing fluid together,so choose curable cementing fluid as cementing fluid Activator complex as CJ:SJ:PHJ is7:2:1and70%BFS in total get a better performance of curable drilling fluid and curable cementing fluid.The curable cementing fluid is directly converted by the curable drilling fluid,so they can cure as a whole without bad compatibility.The integration curable cementing fluid can cure the mud cake and the bond strength is quite well.According to XRD,the reason of making the two cured together is the solidify product of curing mud cake and curable cementing fluid both have C-S-H gel and CaCO3.Studies show that drilling-cementing-integrated working fluid can cure the mud cake and cured bodies together well,it is likely that the boding quality problem of the second interface is expected to be solved.The cured body’s volume shrinkage of curable cementing fluid is smaller than low-density cement paste,which will improve the poor second interface bonding quality due to the micro-annulus problem caused by cement paste volume shrinkage.