Study and Application of Reservoir Protection Fluid System for Drilling & Completion Using Oil-film Method

Abstract To protect reservoir during drilling, the upper drilling fluid is generally converted into reservoir protection fluid by adding proper graded temporary plugging materials based on the average radius of pore throat in reservoir, coupled with colloid filling particles. However, the fluid converted has a better temporary plugging effect on only some well section but all well sections, because of wide distribution of average radius of pore throat in reservoir. Aiming at present problems of reservoir protection drilling & completion fluid technology and reservoir characteristics such as strong heterogeneity, wide distribution of pore diameter, difficultly accurate prediction of pore diameter in reservoir etc, broad-spectrum oil-film fielding temporary plugging agent GPJ was developed and the oil-film method used for reservoir protection drilling & completion fluid systems were established. The lab evaluation and field tests showed that not only there is a good compatibility between GPJ and common drilling fluid systems but also plugging rate and recovery rate of cores treated by the developed systems both are over 90%, field test skin factor is close to zero, thus the developed systems have a better reservoir protection effect than conventional systems and can help to increase daily oil production.