... circulation sealing mechanism lost circulation materials formation damage return permeability solids invasion geothermal energy petroleum engineering Static fluid loss tests are conducted daily during drilling operations to assess the drilling fluid’s ability to seal off permeable formations...

... are all investigated. The results show that the fractured cores suffer a more serious damage degree and exhibit lower return permeability ratio, compared with the porous cores. And the damage degree of fractured cores is proportional to the fracture width and pressure difference. The solids invasion...