Development of a novel heat- and shear-resistant nano-silica gelling agent

Abstract

Abstract The efficient and sustainable development of deep marine carbonate rock reservoirs in the Sichuan Basin has higher technical requirements for reservoir acidizing alteration technology. However, the acidification effect of deep marine carbonate rock reservoirs was hampered by the drawbacks such as uncontrollable acidification rate of the reservoir, the large friction resistance, and the great acid filtration. A novel heat- and shear-resistant nano-silica gelling agent CTG-1 is prepared based on nano-silica and combined with amide compounds. The influence of different factors on the acid filtration performance and heat- and shear-resistant capacity of carbonate rock reservoirs were analyzed, and then the mechanism of nano-silica gelling agent for acid filtration reduction in carbonate rock reservoirs is revealed. The research results showed that the filtration resistance of acid solution decreases slightly with the increase in the content of nano-silica gelling agent and reservoir pressure. The viscosity, fluid loss coefficient, and friction-reducing rate are as high as 25 mPa s, 2.4 × 10−2 m3 min1/2, and 71%, respectively, showing significantly better result than that of commonly used commercial gelling agents. The development of nano-silica gelling agent provides a reliable reference for effectively improving the acidification and stimulation effect of deep marine carbonate rock reservoirs.