Research On Silicate Drilling Fluid And Grouting Materials

Silicate is widely used in drilling engineering as additives, especially for silicate drillingfluid system and grouting material.In addition to oil-based drilling fluid and synthetic-base drilling fluid, silicate drillingfluids are generally considered as the most effectively drilling fluid systems, which can solvethe problem of complex formation and wall instability. Application on SZK004proves thatsilicate drilling fluid can protect the wall, inhibit shale hydration, and solve hole collapseproblems effectively. However, there still exists some shortcomings: the formula of silicatedrilling fluid mostly rely on experience of workers, the solid content tends to be high etc.,influencing the performance of silicate drilling fluid.Based on the detailed investigation on the basis of the relevant literature and experiment,using bentonite, silicate, KCl, Na-CMC, polyalcohol as silicate drilling fluid additives, withthe method of orthogonal experiment, considering the effect of density, rheology, filtrationand other performance factors, additive and adjustment the amount of the indicators meet theoptimal value, the anti-sloughing silicate drilling fluid formula is:5%silicate, bentonite3%,pH12, KCl3%, Na-CMC0.4%, polyalcohol2%. Different formation require drilling fluidperformance requirements are also different, it must adjust additive proportion according tothe formation.When big fractures, caves or collapse formation appear, which are difficult forconventional drilling fluid to closure and control, it is required grouting materials to pluggingfracture, protecting formation. Silicate grouting materials can enhance the engineeringmechanics strength and hydraulic properties of formation to improve the bearing capacity ofthe formation. Using ethyl acetate and formamide as gelling agent can adjust the gel time in alarge range, and greatly increase the mechanical strength. Using sodium dodecyl sulfonate asemulsifier can effectively solve the solubility problems of sodium silicate and organic gellingagent. By the orthogonal experiment, the sodium silicate gelling time and pumpability andsand body strength are analyzed, getting the main influencing factors. Finally, we get the geltime of0.5～9h controllable, high sealing strength, good mechanical performance(sand bodystrength reached6.89MPa), simple configuration, convenient construction, non-pollution newgrouting material.