Study and Application on the Oil-Film Method Used for Reservoir Protection Drilling and Completion Fluid Systems

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 the reservoir, coupled with colloid filling particles. However, the fluid converted has a better temporary plugging effect on only some well sections because of the wide distribution of the average radius of pore throat in the reservoir. Aiming at present problems of reservoir protection drilling and completion fluid technology and reservoir characteristics such as strong heterogeneity, wide distribution of pore diameter, difficultly accurate prediction of pore diameter in reservoir, etc., a broad-spectrum oil-film fielding temporary plugging agent was developed with the oil-film method used for reservoir protection drilling. Completion fluid systems were established. The laboratory evaluation and field tests showed that there is good compatibility between the broad-spectrum oil-film fielding temporary plugging agent and common drilling fluid systems, as well, the plugging rate and recovery rate of cores treated by the developed systems are both over 90% and the field test skin factor is close to 0; thus, the developed systems have a better reservoir protection effect than conventional systems and can help to increase daily oil production.