Method and apparatus for managing variable density drilling mud

摘要

A method and system for drilling a wellbore is described. The syste includes a wellbore with a variable density drilling mud, drilling pipe, a bottom hol assembly disposed in the wellbore and a drilling mud processing unit in flui communication with the wellbore. The variable density drilling mud has compressibl particles and drilling fluid. The bottom hole assembly is coupled to the drilling pipe while the drilling mud processing unit is configured to separate the compressibl particles from the variable density drilling mud. The compressible particles in thi embodiment may include compressible hollow objects filled with pressurized gas an configured to maintain the mud weight between the fracture pressure gradient an the pore pressure gradient. In addition, the system and method may also manag the use of compressible particles having different characteristics, such as size, during the drilling operations.