Apparatus For Installing Underwater Well Equipment

Abstract

An apparatus having a nozzle for propulsion and rubber centralizing and guiding ribs for installing equipment on an underwater conduit.

Description

This invention relates to an apparatus for aligning equipment relative to an underwater vertically positioned conduit.

In the installation of blowout preventers and other equipment on underwater wellheads or conduits, guidelines are generally run from the surface structure to the wellhead located at or near the sea floor. The equipment is then run on pipe and maintained adjacent the guidelines by various harness arrangements. Owing to the long lengths from the surface structure to the wellhead, wind, tides, and weather conditions, the guidelines often malfunction and do not properly align the equipment relative to the wellhead, sometimes resulting in serious damage to the wellhead.

It is therefore an object of this invention to provide an apparatus to positively align equipment relative to an underwater vertically positioned conduit. Another object is to provide an aligning apparatus that can be inserted into a conduit without damaging internal threads of the conduit. Yet another object of the invention is to provide an apparatus for aligning equipment relative to an underwater conduit wherein said apparatus can be caused to move laterally relative to the conduit in order to facilitate entry of the apparatus into the conduit. Other aspects, objects, and advantages of the present invention will become apparent from a study of the disclosure, the appended claims and the drawing.

In the drawings,

FIG. 1 is a diagrammatic view of the apparatus of this invention, the equipment being installed, and the underwater conduit or wellhead,

FIG. 2 is a diagrammatic enlarged view of the apparatus of this invention; and

FIG. 3 is a sectional view taken along line III--III of FIG. 2.

Referring to FIG. 1, a blowout preventer 2 is shown as an example of equipment to be installed by the apparatus of this invention. Conduit 4, such as drill pipe, drill collars, or the like, extends through the blowout preventer 2 and is attached to a first end 6 of the metal body 8 of the apparatus of this invention. The body 8 is elongated, made of metal, and has a chamber 10 (better seen on FIG. 3) extending therethrough. The chamber 10 is closed on a second end 12 of the body 8 and open on the first end 6 in communication with the opening of the conduit 4. Referring to FIG. 2, a plurality of spaced-apart individual metal-holding elements 14 are formed on first and second end portions 16,18 and extend along their respective end portions 16 or 18 in a longitudinally aligned direction relative to the longitudinal axis 24 of the body 8. Referring to FIG. 3, a molded rubber covering 19 is fixedly attached to the external surfaces of the first and second portions 16,18 and the second end 12 of the body 8. The molded rubber 19 on the holding elements 14, forms spaced-apart, longitudinally directed, laterally extending ribs 20 on the first and second portions 16,18 of the body 8. At least one nozzle 22 having a throat diameter less than the inside diameter of the conduit 4 is mounted on a side of the body 8 in communication with the chamber 10 for passing fluid laterally from the chamber for moving the body 8 and attached blowout preventer 2, for example, in a lateral direction.

It is preferred that there be at least three longitudinally directed, fixedly attached rubber ribs 20 on each of the first and second end portions 16,18 of the body 8. If less than three ribs are utilized, the apparatus requires close tolerance to center properly and forces exerted on the conduit by the ribs 20 are more concentrated therefore placing the conduit under a greater likelihood of being damaged during movement of the apparatus in contact therewith. The radial distance of the outer surface of each rib from the longitudinal axis 24 of the body should be slightly smaller than the inside radius of the conduit into which the apparatus is to be inserted.

In the operation of the apparatus of this invention to install, for example, a blowout preventer 2 on an underwater wellhead, the apparatus is attached at the first end 6 of the body 8 to a length of conduit 4. The blowout preventer 2 is removably attached to the conduit 4 by closing the pipe rams of the preventer upon the conduit 4. The apparatus and blowout preventer are thereafter lowered into the water by adding joints of conduit 4 to the string. When the second end 12 of the body 8 is at an elevation slightly higher than the uppermost portion of the vertical conduit 28 onto which the blowout preventer 2 is to be installed, a diver or underwater camera is lowered to a position near the wellhead 30 there to observe and report the relative position of the second end 12 of the body 8 and the vertical conduit 28 and wellhead 30. The conduit 4 can be turned at the surface structure to direct the nozzle 22 away from the longitudinal axis of the vertical conduit 28 and wellhead 30. Fluid can thereafter be pumped from the surface downwardly through the conduit 4 and outwardly through the nozzle 22. The force exerted by the fluid discharging from the nozzle 22 causes the second end 12 of the body 8 to move laterally relative to the vertical conduit 28 and associated wellhead 30. When the second end portion 18 is positioned over the vertical conduit 28 the apparatus and blowout preventer are lowered, causing the second end portion 18 to enter the upper portion of the wellhead 30. In order to clean foreign material from the internal threads or latching mechanism of the wellhead 30 prior to latching the blowout preventer 2 thereto, the nozzle 22 can be rotated and reciprocated over the upper portion of the wellhead 30 while discharging a pressurized stream of fluid thereupon. After the wellhead 30 is sufficiently cleaned the first end portion 16 of the apparatus is inserted into the vertical conduit 28. The ribs 20 of the first end portion 16 cause the conduit 4 and associated blowout preventer 2 to be properly aligned along the longitudinal axis of the vertical conduit 28. The blowout preventer is thereafter lowered into contact with the wellhead and latched thereto. The pipe rams are thereafter opened and the conduit 4 and the apparatus of this invention are removed therefrom.

To assure stability and proper alignment of the blowout preventer 2 or other equipment relative to the longitudinal axis of the vertical conduit and wellhead, the blowout preventer 2, for example, should be spaced from the first end 6 of the body 8 a distance of not more than 10 feet. Greater spaced-apart distances increase the moment arm of the blowout preventer relative to the first end portion 16 and can cause damage to the apparatus and wellhead during placement of the blowout preventer 2. In cases where the water depth is great, a strong current is flowing, or surface wave action is severe, it has been found that spacing of the first end portion 16 relative to the second end portion 18 of the body 8 of the apparatus a distance greater than the depth of the water facilitates handling the equipment, laterally moving the second end 12 of the body 8 relative to the vertical conduit 28 and decreases the danger of damage to the wellhead 30. In this arrangement, the second end portion 18 of the body 8 is inserted approximately 30 feet into the vertical conduit, the first end portion 16 is attached to the conduit 4 at the surface structure, additional joints of conduit 4 and the blowout preventer 2 are attached to the first end 6 of the body 8. The blowout preventer 2 is thereafter lowered to the vertical conduit as described above. When using wider spaced first and second end portions 16,18 the middle portion 26 of the body 8 of the apparatus must be separated and have connections 32 thereon for attaching conduit 4 thereto.

By utilizing the apparatus of this invention to install equipment on a vertical conduit positioned below the surface of the water, labor expenditures can be reduced, well and equipment damage can be lowered, and guideline installation can be eliminated.

Further modifications and alterations of this invention will become apparent to those skilled in the art from the foregoing discussions and accompanying drawing, and it should be understood that this invention is not to be unduly limited thereto.

Claims

What I claim is:

1. An apparatus for aligning equipment relative to an underwater vertically positioned conduit, comprising:

an elongated body having first and second ends, spaced-apart first and second end portions, a chamber closed on the second end, extending through the body and open on the first end, and a plurality of spaced-apart, longitudinally aligned holding elements formed at each end portion,

molded rubber externally covering the first and second end portions and second end of the body and being fixedly attached thereto, said rubber forming spaced-apart, longitudinally directed, laterally extending ribs on the holding elements of the first and second end portions of the body for entering and contacting the inner surface of the conduit and aligning equipment relative thereto; and

at least one nozzle mounted on a side of the body in communication with the chamber for passing fluid laterally from the chamber for moving the tool laterally relative to the conduit.

2. An apparatus, as set forth in claim 1, wherein there are at least three fixedly attached, longitudinally directed rubber ribs on each of the first and second portions of the body.

3. An apparatus, as set forth in claim 1, wherein the end portion of each rib tapers toward a longitudinal axis of the body.

4. An apparatus, as set forth in claim 1, wherein the distance between the first and second end portions of the apparatus is a length greater than the distance from the conduit to a location above the water overlying said conduit.