The Construction And Performance Evaluation Of Temperature-Resistant Anionic Gemini Surfactant Cleaning Fracturing Fluid

Hydraulic fracturing construction is one of the important measures to increase special oil and gas field production.The performance of fracturing fluid has a direct influence on the success of the fracturing fluid fracturing or not.The traditional polymer fracturing fluid has some problems such as uncomplete broken glue and reservoir permeability damage.The viscoelastic surfactant(VES)cleaning fracturing fluid has simple constitution which can deliver proppant with low viscosity,flow back quickly and thoroughly and make less damage to oil and gas.However,there are still some problems such as poor biodegradability and the damage of adsorption on the oil and gas seepage channel.And the conventional anionic thickening cleaning fluid has high dosage and poor temperature(80?)stability and other deficiencies.These limit the further application of cleaning fracturing fluid.Compared with the traditional single-chain surfactants,the new Gemini surfactant has the advantages of higher surface activity,lower critical micelle concentration and formation rock adsorption loss.And in thickening cleaning fracturing fluid,the anionic Gemini surfactants have more advantages of reducing the adsorption loss and wetting reverse damage and low concentration.Using the self-made anionic Gemini surfactant as the research object,the effect of molecular structure and temperature on the viscosity of anionic Gemini surfactant was tested by rheometer,and the optimum anionic Gemini surfactant,DS-18-3-18,was optimized.The optimal formulation of anionic Gemini surfactant cleansing fluid was determined by using the control variable method to optimize the additives such as sodium chloride,potassium chloride,sodium benzoate and nano-particles: 4% DS-18-3-18 + 3% dodecanal with high temperature resistance(1?,25.24 m Pa.s).Then,the flow curves of the anionic Gemini surfactant DS-18-3-18 solution and the cleaning fracturing fluid system were tested by viscoelasticity test.And the cleaning fracturing fluid system were also has temperature and shear test and gel breaking test and sand carrying test.The results show that the viscoelastic solution and the fracturing fluid system have high storage modulus,with excellent viscosity,significant viscoelastic effect.Anionic Gemini Surfactant DS-18-3-18 Fracturing fluid in fracturing fluid has good high temperature shear stability and can be used for 100 ? formation fracturing;it can quickly break the glue,and broken glue viscosity are less than 5 m Pa · s with no residue;it has a significant effect(<5 cm · min-1),which meets the requirements of site construction.