Pressure compensation device with accumulator group for controlled pressure drilling

A pressure compensation device with an accumulator group for controlled pressure drilling, the pressure compensation device comprising an electrical flat valve, a check valve, an accumulator group, a flanged pup joint and a support base, wherein the electrical flat valve is connected to the check valve and is mounted on a top surface of the support base, the accumulator group mounted on the support base is a pre-storage pressure compensation device for controlled pressure drilling and is located at a downstream position of the check valve, a liquid inlet end of the accumulator group is connected to the check valve, and a liquid outlet end of the accumulator is connected to the flanged pup joint, wherein

• the accumulator group comprises a frame, multiple bladder type accumulators, a liquid inlet flange, cartridge valve blocks, a liquid outlet flange, a protective cover, nitrogen measuring and filling pipes, nitrogen measuring and filling ports, a main liquid pipe, Society of Automotive Engineers (SAE) flanges, connecting pipes, a pressure-measurement sensor interface, a liquid outlet pipe, a liquid pressure measurement pipe, air pressure gauges, nitrogen measuring and filling T-joints, nitrogen filling ports, a shock-proof pressure gauge, a liquid pressure-measurement sensor T-joint, and a pressure sensor;
• the accumulators are bladder type accumulators, the multiple bladder type accumulators are regularly mounted on the support base in two rows, are fixed by the frame, and are connected to the main liquid pipe through the cartridge valve blocks, the SAE flanges and the connecting pipes to form parallel liquid paths;
• the main liquid pipe has an end connected to the upstream check valve through the liquid inlet flange and another end connected to the downstream flanged pup joint through the liquid outlet end flange, and a diameter of the liquid inlet flange is smaller than a diameter of the liquid outlet flange;
• upper portions of the cartridge valve blocks are respectively connected to the accumulators, and side surfaces of the cartridge valve blocks are communicated with the main liquid pipe through the SAE flanges and the connecting pipes;
• the connecting pipes are vertically connected to the main liquid pipe on a same horizontal plane, and a diameter of each of the connecting pipes is smaller than a diameter of the main liquid pipe;
• the liquid outlet pipe is located on the side surfaces of the cartridge valve blocks and is communicated with side outlets of the cartridge valve blocks;
• the nitrogen measuring and filling ports are respectively formed in tops of the accumulators and are respectively connected to the nitrogen measuring and filling T-joints on a surface plate of the protective cover through the nitrogen measuring and filling pipes, and the nitrogen measuring and filling T-joints are respectively communicated with the air pressure gauges and the nitrogen filling ports to measure a nitrogen pressure and supplement nitrogen;
• the pressure-measurement sensor interface is formed in the main liquid pipe and is connected to the liquid pressure-measurement sensor T-joint on the surface plate of the protective cover through the liquid pressure measurement pipe, the liquid pressure-measurement sensor T-joint is communicated with the shock-proof pressure gauge and the pressure sensor to measure and sense a pressure of drilling fluid in the main liquid pipe.