Study on system of broad-spectrum oil-film temporary plugging drilling fluid

Key words:  oil film  broad-spectrum temporary plugging  reservoir protection  drilling fluid

Abstract:

To achieve the objective of protecting reservoir during drilling, the common means is to add proper graded temporary plugging materials, coupled with colloid filling particles in upper drilling fluid based on the average radius of pore throat in reservoir, which converts upper drilling fluid to reservoir protection fluid. However, in practice due to wide distribution of radius of pore throat, the converted fluids exert good shielding temporary plugging effects only at certain intervals, and can not exert function of protecting reservoir. Aimed at th0 resa^oir of severe heterogeneity, wide pore radius distribution and unpredictability of pore radius, the method of using GPJ bit^-spectrum temporary plugging agent for temporary plugging purpose was put forward based on the lab pollution evaluaticai results of core samples. The lab evaluation aiid field tests show that the drilling fluid system not only has broad-spectrum temporary plugging effect, but ^Iso bears the function of reservoir protection, thus increasing daily oil production greatly.