Application evaluation of formation protection techniques in BH oilfield.

Reservoir clay mineral form analysis and reservoir sensitivity experiments showed hat the plugging of extrinsic solid-phase particle and scaling in oil-well were main reservoir damage types in BH oilfield. All kinds of fluid in the well, such as completion fluid, kill-fluid and perforating fluid should be free solid or low solid fluid with low filter loss or leakage and good compatibility with formation and formation fluid. Formation protection effectiveness of all kinds f using completion fluid, kill-fluid and perforating fluid indicated that the completion fluid(polymer sulfonated drilling fluid + 2%~3% oil soluble temporary plugging agent) used largely can meet the need of reservoir protection, and kill-fluid or perforating fluid are composed of free water, 0. 5%~1% clay stabilizer and 0. 2% thickening agent, when formation pressure coefficient s less than 1, 1%~3% oil soluble temporary plugging agent should be added to prevent loss of pressure well liquid to formation. [ABSTRACT FROM AUTHOR]