Improving plugging performance of oil based slurry

Oil based slurry is an ordinary selective water shutoff material. The incomplete displacement of oil in hardened slurry does great harm to the pore structure and mechanical properties. Based on oil based slurry formulation optimization, hydrate volume percent in set oil based slurry was increased to improve interfacial bonding strength and to reduce detrimental pore ratio, then better strength of set oil slurry. Some admixtures which may affect the compressive strength of hardened oil based slurry were studied to improve the mechanical properties and the specimen with 1%FeCl₃ + 5% silica fume + 3%F17A added showed the best results. SEM and MIP analyses showed that the mechanical property enhancement came from the improvement of pore structure, mainly the decrease of large pores and the increase of compact density.