ZJ50/3150D E-drilling rig can be used to explore and develope 5000m deep oil/gas wells in domestic and overseas oilfields. Principle and Features of Rig Structure: Drilling rig models and basic technical parameters conform to Chinese petroleum industry standards. All main components conform to API specifications. The drilling rig is equipped with a complete diesel generator set as the power source and uses the DC electric drive mode (by means of AC-SRC-DC) and the "one-to-two." control mode. These two modes feature advanced mechnical properties and convenient and reliable control, fully satisfying the needs of modern drilling technology. The closed drawworks with internal variable drive is used to carry out the stepless variable drive through four gear shifts. The one-piece rotary drive case drives the rotary table through a cardan shaft. The drill floor is smooth and spacious. These two 9m high substructures (the front substructure and the rear substructure ) of parallelogram type can be assembled on the ground. Besides, the open-front mast is used.