Development And Performance Evaluation Of A New Type Of Low-damage Fracturing Fluid

Nowadays the requirements for the performance of fracturing fluid improve gradually in the fracturing treatment, but the widely used guar gum fracturing fluid has many shortcomings, and since 2011, the rise price and tight supply of the guar gum, eventually prompted many domestic and foreign oilfield chemistry workers to research on new fracturing fluid to replace guar gum. Synthetic polymer is a hot direction to instead guar gum, but usually the shear resistance is poor, and can't meet the high requirement for the shear resistance of thickener in hydraulic fracturing treatment.This paper based on the comprehensive investigation and the analysis of the research status for fracturing fluid at domestic and foreign, put forward the star polymer as thickener for fracturing fluid, and the main work of this paper are as follows:(1) Through the investigation of the star polymer synthesis method,the synthesis route that use dendrimer multifunctional initiator as core to initiation acrylamide monomers polymerization to star polymer was confirmed, and the dendrimer initiator and star polymer were characterized by corresponding method. Research results show that the synthetic route using dendrimer multifunctional initiator as core synthesis of star polymer is feasible. The initiator type and concentration, the monomer concentration, the functional monomer concentration, the hydrophobic monomer concentration were optimized.(2) Use star polymer as thickener for new low-damage fracturing fluid, acorrding the industry standards and literature recommendation methods to screen the type and amount of thickener, crosslinker, breaker, cleanup additive, clay stabilizer, the formulation of new low-damage fracturing fluid was determined.(3) Acorrding the industry standards and literature recommendation methods, evaluation of the performance of the new low-damage fracturing fluid was conducted, Experimental results show that the new low-damage fracturing fluid has excellent temperature and shear resistant performance, good rheological and viscoelastic properties, good gel-breaking and flowback performance, no residue, strong proppant carrying capacity, little filtration, low damage to core permeability, most performance index can meet the industry standard's recommended values.The new low-damage fracturing fluid not only can meet the requirements for fracturing fluid performance in hydraulic fracturing treatments, but also further improve the water base fracturing fluid system. The new low-damage fracturing fluid can provide a strong guarantee for the hydraulic fracturing treatment's wide use in oil and gas field, and has great significance for promoting the economic development of the conventional, unconventional oil and gas field with low permeability.