Drilling tool capable of reducing combining exterior angle difference measurement error of directional drilling tool

• Main Authors: LIU BIN, XIA YAN, ZHANG JIE, DENG YUANZHOU, QIAO KAICONG, YUAN GUANGJIE
• Format: Patent
• Language: Chinese; English
• Published: 05.02.2014
• Subjects: EARTH DRILLING; EARTH DRILLING, e.g. DEEP DRILLING; FIXED CONSTRUCTIONS; MINING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR ASLURRY OF MINERALS FROM WELLS

The utility model discloses a drilling tool capable of reducing a combining exterior angle difference measurement error of a directional drilling tool. The drilling tool comprises an MWD short joint (1), a nonmagnetic drill collar (2) and a bent screw rod (3), wherein the MWD short joint (1), the nonmagnetic drill collar (2) and the bent screw rod (3) are sequentially connected, the upper end of the MWD short joint (1) is provided with a directional key (4), and the outer wall of the end, connected with the bent screw rod (3), of the nonmagnetic drill collar (2) is provided with a directional groove (5). The drilling tool has the advantages that the included angle theta 1 between the directional key of the MWD short joint and the directional groove in the nonmagnetic drill collar can be measured on the ground conveniently and accurately, and after the nonmagnetic drill collar and the bent screw rod are connected on a drill floor, the angle difference theta 2 between the directional groove in the nonmagnetic d