Abstract:

In view of the lost—circulation physical property of Luohezu sandstone in Eastern Gansu axes of Changqing Oilfield，an esperimental study is made by using the bridge—shielding principle. A reasonable bridge plugging system is set up on the basis of the adjustment of the size distribution of calcium ,carbonate and the choice of water—loss control agent as filling agent. The tests both in lab and on site show that this system can improve the compressive strength of the lost—circulation formation and meet the needs of drilling and well cementation project construction.

Key words: Shielding, Loss circulation control, Loss circulation material, Bridge plugging, Changqing Oilfield