GB763864A - Multi-purpose derrick barge and method of use in oil well drilling and servicing - Google Patents

Abstract

763,864. Drilling earth and rock ; artificial islands. LUCAS, J. E. Sept. 2, 1954 [May, 26, 1954], No. 25486/54. Classes 68 (2) and 85. Apparatus for use in drilling and servicing under water wells comprises a barge having means to raise it above the water and carrying a derrick structure which, in its working position, has the major part of its weight supported on an independent platform spaced from the barge and raised above the water. The barge 1 has pilings or caissons 6 which are driven by hydraulic jacks 7 or by jetting into the ground below the water and then the barge raised clear of the water on the pilings. A platform 10 is suspended a suitable distance from the barge 1 by arms 51 and then pilings 63 are passed through holes 64 in the platform 10 and driven into the ground using a rotatable crane structure 11 mounted on the barge and forming part 15 of the derrick structure. The platform 10 is secured to the pilings 63. A bridge member 66 is supported on the platform 10 and barge 1. A leg 73 is pivoted to each side of the upper end of the boom 15 to form the derrick structure, these legs being lowered until the ends 75 engage releasable hooks 76 on the bridge members 66. The ends 77 of the legs 73 and the upper end of the boom 15 are adjustable in length by hydraulic rams 87 in order to position a crown block 22 vertically above a hole 72 in the platform 10. A hook 25 supports a drill string passing through the hole 72 and rotated by a turntable 71 in the usual manner. Drill pipes 96 may be stacked vertically on the bridge member 66 ready for use. When drilling is completed, or in the case of fire, the legs 73 are folded back to the boom 15, the bridge 66 drawn back on to the barge 1 which is lowered into the water, the pilings 6 drawn up, and the barge towed away (Fig. 9), the platform 10 being left as a permanent structure. In a modification Fig. 16 there is a single leg 73b and cables 110 are used to steady the derrick. When servicing the well the barge approaches tc within a short distance of the platform 10 drops two anchors 100, 101, and then approaches the platform 10 . by paying out lines 102, 103 from winches 104, 105 while it is nudged by a tug 106. When the barge is a suitable distance from the platform it is raised &c. as before.