Mud Cake Curing Technology Research Curable

There is not any cementitious material in the conventional drilling fluid filter cake and the filter cake will get dehydrated, dried-up, pulverized in the process of cement’s hydrating. Some microannulus will take shape and support a cross flow path for the formation fluid. As a result, the cementing quality of gas/oil wells will get worse and greatly influence the safe exploit. Consequently, conventional drilling fluid filter cake is a natural weak annulus in the second interface and a barrier of further raising the cementation quality in the second interface.Cementing materials in the second interface include cementing slurry, drilling fluid filter cake and the borehole wall. However, the drilling fluid filter cake is the key factor. From the perspective of filter cake, Mud To Cement (MTC) and Universal Fluid technologies are introduced to achieve the purpose of making the filter cake solidified. In the end, make the weak filter cake the enhanced area and avoid all kinds of problem caused by the filter cake.In this paper, the usual polysulfonate drilling fluid, drilling fluid treatment agent as sulfonated phenol-formaldehyde resin and sulfonated lignite resin are from tarim oilfield, activating agent such as sodium hydroxide and sodium carbonate, and the common blast furnace water quenched slag as concrete on the market are chosen. Through the optimization test of blast furnace water quenched slag, using drilling fluid treating agent to adjust the performance of the multifunctional drilling fluid, and then get a slag dosage of20%is much better. And the density, rheology, filtration loss, thickness of the filter cake can satisfy the requirement of on-site drilling in safe. Meanwhile, the cake also can be solidified well. Activator optimization results show that when the compound activator Na2CO3/NaOH/Na2SiO3is6/2/1is used in the MTC, the filter cake can be quickly solidified, also the filter cake and MTC solidified-body can avoid cracking.under different curing temperature and curing age, the solidification effect of multifunctional drilling fluid filter cake have a big difference, such as when the temperature is higher than90℃, the filter cake is easy to crack, less than50℃, the filter cake is not easy to solidify. Component analysis experimental results show that Ca5(SiO4)2(OH)2and CaCO3is generated in the filter cake solidification-body, it is the root cause of solidifying filter cake. Interface microstructure studies have suggested that the filter cake and the MTC solidification-body can solidify as a whole, and there is not any crack integration, junction interface cementation in good condition, no obvious crack on the solidification surface.