Synthesis And Application Performaces Of Tight Oil Slippery Water Fracturing Fluid Drag Reduction Agent

Tight oil reservoir development is an important source to obtain substantial increase in crude oil production, having extremely low permeability reservoir.The common way uses volume fracturing technology by polymer-based solution with crosslinking agent to freeze gum carrying sand to achieve high purpose in order to improve reservoir flow capacity. Such gel system also has greater viscosity wich is likely to cause pore blockage and formation permeability decreases, affecting production as a result. Slippery water fracturing fluid technology can overcome these limitations, but it shows low carrying amount of sand, only by relying on large displacement to achieve fracturing effect wich increases the amount of construction resulting waste of water.Therefore, the development of a low-viscosity, water-sand ratio of slippery fracturing fluid drag reducing agent is critical. This paper is based on the synthesis of hydrophobic association polymer preparing one low viscosity, high viscoelasticity water-soluble powder drag reducing agent F-HAPAM to solve the limitations of these applications.Slippery water fracturing fluid drag reducing agent molecular structure model is designed, and functional hydrophobic monomers is preferred. Using aqueous solution radical polymerization method synthesizes the hydrophobic associative polymer drag reducing agent. The reaction conditions （such as reaction temperature, initiator, total monomer concentration, reaction time, the hydrophobic monomer concentration, etc.） of the drag reducing agent performance are analysised, determining the optimum conditions. The drag reducing agent identifys the expected product complex design through characterizing the structure of polymer. A water tight oil slippery fracturing fluid system is builded through experiments, and other additives are optimized in order to evaluate the integrated performance of the low viscosity, high carrying sand slippery fracturing fluid at the same time. Drag reducing of the agent drag performances are evaluated under different valences ions (Na⁺, K⁺, Ca²⁺, Mg²⁺), and different salinity conditions （10000ppm-60000ppm）. Experimental datas show that the drag reduction rate is up to 74.10%, resistance reduction properties is superior to other drag reducing agent at the same concentration （0.08% amount）. The rheological properties of the drag reducing agent polymer solution are tested. The results show that the polymer has a low viscosity, good aqueous viscoelastic, modulus of elasticity is much larger than the viscous modulus （G’0.8,G"0.4）making the best performances in temperature resistance, scissors cut resistance, good stability as hydrophobic monomer reachs a certain concentration range. The best solution apparent viscosity can reach to 45 mpas.Slipperiness water fracturing fluid drag reducing agent has a good effect on carrying sand. The resulting distribution of sand body can reach the maximum length forming a large-scale cracks during the construction at a concentration of 0.3%. The effects of different types of gel breaking breaker are evaluated and the redox system is the final selection. The glue residue contentis is low and small flowback fluid viscosity after fracturing, reducing the reservoir hurt. The pleiotropic agent EP105 is preferable to increase the carrying capacity by mixing with drag reducing agent. Site construction curve and swabbing liquid discharge case show that crude oil production is enhanced by 10.46m³/d achieving the purpose of slippery water fracturing which has a great promotional space.