The Study Of Ultra-low Permeability Low Fluorescent Drilling Fluid

Ultra-low permeability drilling fluid which have great concerns on research and development at home and broad is an new-type drilling fluid systerms at present. This systerm can form a layer of ultra-low permeability membrane on the rock surface in the short time, decrease the filter loss of drilling fluid,so as to protect the reservior effectively. Meanwhile, it is necessary to add additive in the fluid during the process of drilling,the additive itself exists fluorescence,it is possible to influence fluorescent display of oil. Therefore,the process of drilling should be decrease fluorescent grade of the drilling fluid additive in order to ensure for carrying out drilling operation smoothly.In this paper, the action principle of ultra-low permeability drilling fluid and the mechanism of fluorescent drilling fluid were analyzed and researched. Research a kind of the of ultra-low permeability treatment agent CDS for drilling fluid by using the method of graft polymerization. The experiment proves that, comparing with the same products of internal and international, the new development ultra-low permeability treatment agent have the main performance which better than the same products,and the fluorescent grade of this treating agent was lower, accord with the systerm of low-fluorescent for drilling fluid. Moreover, from macroscopic to microscopic theory, study on the structure and formation Process of ultra-low permeability membrane, the film forming velocity, Bearing Strength and the strength for the seal of film. Evaluating the different grade of the addive fluorescent and the resistivity value, Selecting the addive, defining the formula of the systerm of low- fluorescent for drilling fluid. The experiment show that the ultra-low permeability treatment agent can concentrate the formation of micelle on the rock surface. The polymeric micelle formated an ultra-low permeability membrane. It effectively seals formations of different permeability, increases formation fracture pressuse, and seals micro-fracture of permeable formation and shale stone; so as to protcet reservoir formation . This systerm had the features of the grade of low-fluorescent and the high resistivity value. Suitabled for Oil and Gas Exploration on low resistivity oil layers. It was beneficial to realize the oil fluorescent and in order to convenient for fluorescence display.