Preparation Of Organic Titanium Crosslinker And Its Application In Modified Konjac Glucomannan Fracturing System

According to the characteristics of low permeability oilfield, to preparation an organic titanium crosslinking to improve the temperature performance of fracturing fluid, and find optimal dosage and the best synthesis process in the synthesis reaction. For the specialization of guar gum, find the konjac gum to replace guar gum, and make the konjac gum modified by the isopropyl, to improve the temperature resistance capacity.(1)It showed that optimal dosage and the best synthesis process was30%butyl titanate, the weight ratio of two ligands was2:1,30%triethanolamine, reaction temperature was85℃, reaction time was3h(2)The fourier transform infrared spectroscopy results showed that the bimolecular nucleoplilic-substitution was occurred in the molecular chains, and the carboxymethyl was successfully introduced. The X-ray diffraction showed that the ionic bond was introduced into molecular chains and the structure of konjac gum become more complex, so the crystallinity was decreased. The thermo gravimetric analysis showed the thermal stability of modified konjac gum was improved. The differential scanning calorimetry showed the interaction molecular force of the system was increased, so the strength of modified konjac gum was increased.(3)The laboratory evaluation showed:The heat resistance test showed, when the temperature was80℃, the viscosity of modified konjac gum was126mPa·s, which was better than the konjac gum; the shear resistance performance test showed, when the temperature was80℃, the viscosity of modified konjac gum was maintained at120mPa·s, which was higher than the unmodified konjac gum; the rheological tests showed the viscoelastic property of modified konjac gum were also improved; The test of residue showed, the residue of modified konjac gum was274mg/L, more better than the419mg/L of the unmodified konjac gum. The surface tension of the modified konjac gum was24.17mN/m, the interfacial tension was0.71mN/m, both better than the unmodified konjac gum35.62mN/m and0.96mN/m. The damaging rate of the modified konjac gum was24.39%, better than the rate33.63%of the konjac gum. These all shows that modified konjac gum has better flowback capacity, and make less damage to the reservoir. The test of sand suspension performance showed, the sand settling speed of modified konjac gum was0.15mm/s, which is also better than that of the konjac gum.