Study The Characters Of The Carboxymethyl Guar Gum Fracturing Fluid Composited With Nano Materials

In recent years,with the continuous exploitation of oil and gas resources and the progress of exploration technology,more and more unconventional reservoir have been explored and developed.For the development of these reservoirs,the higher requirements are imposed on conventional guar fracturing fluids,but due to the limitation of guar gum molecular chain structure,it is difficult to directly improve its performance.Therefore,it is necessary to adopt new ways to improve the performance of guar gum fracturing fluids.In this paper,the measures to improve the temperature resistance and shear resistance of fracturing fluid at home and abroad were extensively investigated,the mechanism of enhancing the performance of hydrogels and surfactant fracturing fluids by using nano-materials were used for reference,and we will add the nano-materials into the carboxymethyl guar gum fracturing fluid,expect to improve the rheological and mechanical properties of guar gum fracturing fluid by this new method of nano hybrid.Firstly,the surface modification of zero dimensional nano-silica,one dimensional multi-walled carbon nanotubes and two dimensional graphite powder was carried out to enhance the miscibility of nano-materials and guar gum solution.The FT-IR results show that the surface of nano-materials are connected with a large number of hydrophilic groups.The nano hybrid carboxymethyl guar gum fracturing fluid with uniform appearance can be obtained through mechanically stir,supplemented ultrasonic vibration.Through the comparison of viscosity value of three kinds of nano hybrid fracturing fluid system to optimize the crosslinking ratio and the nano-materials concentration,using Haake Mars ? rheometer and FR-108C servo tensile machine test the rheological properties and mechanical properties respectively of three kinds of nano hybrid fracturing fluid systems under the best crosslinking ratio and the best nano-material concentration,as well pristine fracturing fluid.As shown in the results,apparent viscosity,temperature resistance property,viscoelastic property and mechanical property increase obviously compared with pristine fracturing fluid when adding nano-materials,which indicates that adding nano-materials can improve the performance of fracturing fluid,but different nano-materials are different in improving the performance of fracturing fluid,the viscosity,tolerance temperature,elasticity modulus and tensile strength of the nano-silica hybrid fracturing fluid are maximum,the apparent viscosity increased by about 90mPa·s at room temperature,and the tolerance temperature increased by 20?.Microanalysis by SEM and TEM show that is because the different forms of nano-materials in carboxymethyl guar gum fracturing fluid network structure:nano-silica play a role of nuclear and skeleton in guar gum fracturing fluid network,MWNTs-OH wind round guar gum molecular chain,GO is inserted into the structure of guar gum.The interaction between the nano-silica with guar gum is the strongest,so the performance of guar gum fracturing fluid was improved most obviously by nano-silica.The proppant carrying capacity and breaking property of the optimal nano-silica hybrid guar gum fracturing fluid meet the requirements of site construction,moreover,the damage degree of nano hybrid fracturing fluid is studied by core displacement device and diversion instrument,it is found that the damage to natural core permeability and proppant filling layer conductivity is significantly less than that of pristine fracturing fluid,it indicates that nano-silica added to fracturing fluid can reduce damage of fracturing fluid to reservoir,it meet the low damage requirements of unconventional reservoir development process.The hybrid fracturing fluid,which obtaine by adding nano-materials to carboxymethyl guar gum,have very good rheological and mechanical properties.Nano hybrid is a new method to improve the temperature resistance and shear resistance of fracturing fluid.