GB1341047A - Means for guiding equipment to an offshore submerged well head - Google Patents

Abstract

1341047 Wells &c SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ NV 15 March 1971 6882/71 Heading E1F Equipment is guided into an offshore, submerged wellhead by a guide funnel 7 at least part of which is movable relative to a base 4. In Fig. 1, the funnel 7 is frusto-conical and mounted for vertical movement on members 5B which telescope within members 5A against the force of springs 6. A tubing string 15 lowered from a surface vessel is manoeuvred into approximate alignment with the well axis just above the funnel by a lateral water jet 20, controlled from the surface using information from a sonar device 16 which detects hemispherical reflectors such as 9. The sonar device is withdrawn by its cable, and the string 15 lowered into the funnel so that a guiding head 21 is directed into the well entrance. The string is lowered far enough into the well to prevent inadvertent withdrawal, and equipment comprising a marine riser 12, blowout preventer 13 and coupling member 14 lowered along the tubing so that the preventer lands on the rim of the funnel and depresses it against the force of the springs 6 to enable the member 14 to be coupled to the wellhead 1 (Fig. 3, not shown). The reflectors are pivoted downwards by the preventer. In an alternative embodiment, Fig. 4, the guide funnel comprises a part 32 supported by legs 31 on a concrete base 30 and plates 33 pivotable outwards in the manner of petals (see 33A) against the force of telescoping springs 35. The plates 33 remain in the closed position to guide the head 21 into the well but are forced open by the passage of the riser coupling member 14. The funnel is a truncated pyramid and may comprise three or more plates 33. The reflectors may be on the base or fixed on the guide funnel. The guiding head 21 may be replaced by a bumper head as described in Specification 6446/71.