Safety drilling system and method for preventing collapse of water-sensitive formation in upper part of high-pressure saltwater layer

A safety drilling system for preventing collapse of a water-sensitive formation in an upper part of a high-pressure saltwater layer, comprising a wellbore extending from a surface of the earth into the water-sensitive formation, a wellhead at the surface, a downhole drilling tool, a first injection pipeline, a second injection pipeline, a first return pipeline and a second return pipeline;

• wherein the wellhead comprises, arranged in the following sequence in a direction upward from the surface;
• a drilling spool a ram blowout preventer, and a rotary blowout preventer;
• a kill manifold is connected to a first port of the drilling spool located on a first side of the drilling spool, and a first tee joint, a valve A and a throttle manifold are connected to a second port of the drilling spool located on a second side of the drilling pool;
• the downhole drilling tool comprises, arranged in the following sequence in a direction from a bottom of the wellbore toward the surface, a drill bit, a resistivity measurement nipple, a drill collar, a drill pipe, a drill string plug valve and a top drive;
• the first injection pipeline comprises a mud pump, and arranged in the following sequence moving away from the mud pump, a second tee joint, a valve B, a first high-pressure manifold, a first high-pressure hose, a valve C and the rotary blowout preventer;
• the second injection pipeline comprises the mud pump, and, arranged in the following sequence moving away from the mud pump, the second tee joint, a valve D, a second high-pressure manifold, a first vertical pipe, a valve E, a third tee joint, a water hose and the top drive;
• the first return pipeline comprises the top drive, and, arranged in the following sequence moving away from the top drive, the water hose, the third tee joint, a valve F, a second vertical pipe, a fourth tee joint, a valve G, a sand discharge pipeline, a vibrating sieve and a mud tank;
• the second return pipeline comprises the drilling spool, the first tee joint, a second high-pressure hose, a valve H, the fourth tee joint, the valve G, the sand discharge pipeline, the vibrating sieve and the mud tank.