| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a direction control drilling method which is free of a risk of a drilling error. <P>SOLUTION: Drilling in a predetermined section L<SB POS="POST">n</SB>is carried out by drilling means provided with a fixed type measuring instrument D<SB POS="POST">n</SB>in a drilling pipe 5. Then the drilling pipe 5 is moved backward and forward, and an azimuth angle variation quantity and a tilt angle are found by the fixed type measuring instrument D<SB POS="POST">n</SB>. A relative position ΔP<SB POS="POST">n-1</SB>of a tip part of the predetermined section L<SB POS="POST">n</SB>to a rear end part is found based upon those values, and further, a current position of a hole tip part is found. Here, a plurality of the fixed type measuring instruments are provided so that when one fixed type measuring instrument D<SB POS="POST">n</SB>is positioned at the hole tip part, other fixed measuring instruments are positioned at other predetermined section tip parts. Here, the relative position ΔP<SB POS="POST">n-1</SB>obtained by one fixed type measuring instrument D<SB POS="POST">n</SB>and relative positions obtained by the other fixed type measuring instruments when the relative position ΔP<SB POS="POST">n-1</SB>is obtained are summed up to find the current position of the hole tip part, and drilling in a next predetermined section L<SB POS="POST">n+1</SB>is carried out based upon the current position. <P>COPYRIGHT: (C)2013,JPO&INPIT |
