... , and assembled with VFD system; the oil derrick adopts K type structure, the base adopts box ... drum, drill pump, all adopt unified driving; the derrick adopts A type or K shape structure, the ... adopts box block or helical rising structure, the derrick should be installed in lower position, and lifted ... )960(1300)960(1300)1470(2000) Oil Derrick Type and Effective Height mftA Triangle Cross Section ...