Viscoelastic Surfactant Flow Degeneration And Its Feasibility As A Clean Fracturing Fluid Study

Hydraulic fracturing and enhancing technology of oil and gas wells are effective measures of renewing reservoir and effective methods of oil and gas wells increasing productivity and quantity of infusing. Fracturing fluids are important in hydraulic fracturing operations, fracturing fluids' quality is key to whether the fracturing operations success or not and a important factor of affecting the effect of increasing productivity after fracturing. There are many kinds of fracturing fluids, and water based fracturing fluids is most popular. Polymer-free fracturing fluids is a new type recently and a kind of fracturing fluids named viscoelastic surfactant fracturing fluids among those is noticed especially.Viscoelastic surfactant fracturing fluids are made of special cationic surfactant and brine in certain proportion. Comparing to ordinary polymer-fracturing fluids, viscoelastic surfactant fracturing fluids has some remarkable excellences, for example remnants fluids after fracturing can be vented mostly from strata, strata's permeativity can be almost reserved, breaker is not required, operation is very simple, few equipment is needed, fracturing fluids' cost is low relatively, and only pollutes surrounding a little, etc. Viscoelastic surfactant fracturing fluids has been used successfully in hydraulic fracturing beyond 2400 times all over the world, and its effect is very remarkable.Presently, people have make some progress in the clean-fracturing fluids technology all over the world, but in the development of clean-fracturing fluids'formulation, especially for the host crystal used in clean-fracturing fluids--fewkinds of viscoelastic surfactant is available and its cost of producing is higher and people's choice-space is narrow, all these prevent the fulids' popularization and application largely.Focusing on the oil field application, synthesized a serial of viscoelastic surfactant in laboratory, then from these surfactants and materials in hand, chosed two kind of viscoelastic surfactants as clean-fracturing fluids' direction for producing and mensurate the rheology, capacity of suspend for proppant and capacity in leakoff of the two kind of viscoelastic surfactants according to the essential capacity fracturing fluids. As a result, the two system have possessed the essential capacity as fracturing fluids and the applied potential in industry.The main content of this paper is divided into two parts. The first part is about synthesis of viscoelastic surfactants and the choice of components ofclean-fracturing fulids, and the second part is about the test of performance of clean-fracturing fulids.In this paper, for the first time, introducing Gemini surfactant to application of oil field. Adoptting method different from ordinary method which evaluatesthe fracturing fluids' capacity of suspending proppant--recur to densimeter toquantificationally test the viscoelastic surfactants fracturing fluids' capacity of suspension.