Patent Application
20170037693
The field of the invention is methods of preventing dropped clamps that connect an umbilical to a drill string in a riser during a sub-sea wellhead test.
Typically during a sub-sea wellhead test the drill string extends through the marine riser and has an umbilical attached to it with clamps. The clamps comprise spaced fasteners that surround the umbilical and a cover sleeve that goes around both the umbilical and the drill pipe. With wells being drilled much deeper now there is a heightened concern that a very expensive fishing job would be undertaken if one or more of the clamps came loose and fell in the hole.
Junk catching devices have been used in the past in annular spaces. A typical design involves spaced pivoting members that allow flow in the gaps. These devices such as those shown in U.S. Pat. No. 7,188,675 FIG. 5A are meant to catch large irregularly shaped objects and frequently have gaps large enough so that elongated objects like straps that hold the umbilical to the drill pipe would get through the gaps. The traditional junk basket design that integrates a flow regime with the expectation that gravity will direct debris suspended by the fluid stream can be seen in U.S. Pat. No. 6,951,251 FIG. 1.
Traditional junk basket designs are not adaptable to situation with an umbilical strapped to a drill pipe. What is needed is a design that can be quickly slipped over the drill pipe while still allowing the umbilical to be pushed into an open slot that can thereafter be closed around the umbilical with a piece that completes the basket. In the alternative, the design for the junk basket can do double duty as an umbilical clamp to the drill pipe. Once assembled the basket is complete and has a minimal clearance around it to prevent debris from getting past the basket. There is no concern during the wellhead test for flow in in the annular space so that this clearance can be kept to a minimum to allow insertion and removal of the drill string before and after the test. Preferably more than one such assembly can be used so that for most of the time there are a plurality of such baskets in the hole or riser and if a clamp is dropped then the distance it can fall is minimized. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.
A clamp device that attaches an umbilical to a drill string incorporates a junk basket. The basket is notched to accept the umbilical and an insert piece is slipped into the notch after the umbilical is properly in position. The insert piece straddles the umbilical and is secured the balance of the basket to complete the basket. The basket can be slipped over the drill pipe and either secured directly to the outer surface of the drill pipe or against a support member that is supported off the drill pipe. One or more of such baskets can be used and they can also function as umbilical clamps. The basket can also be vertically split to allow mounting it over the drill pipe and umbilical without having to slip it over an end of the drill pipe as the drill pipe is tripped into or out of the hole.
Referring to
The device can be used in a well head test procedure where the drill pipe with the umbilical are clamped to each other and run in while the basket assembly or assemblies are put over the drill string and supported on at least one location from the drill pipe. The insert completes the basket shape and secures the umbilical to the basket. Optionally the baskets can be used instead of a clamp to hold the umbilical to the drill pipe. The basket can be in one or more pieces. A vertical split facilitates assembly to the drill pipe. If more than one basket is used the distance a clamp that is dropped can fall is reduced. To some extent the baskets serve as centralizers for the assembly of the drill pipe and associated umbilical during the wellhead test and by doing so facilitate the insertion and removal of the drill string.
In general the method encompasses delivery of two or more discrete structures together where a provision is made for catching anything the drops with a basket that is disposed in the surrounding annular space and where the basket has the additional feature of holding the structures together. Depending on the construction of the basket it can be slipped over the drill pipe and the umbilical can simply be pushed into a slot with the slot closed off around the umbilical while at the same time completing the basket shape. Multiple umbilicals or other tubular structures are also contemplated for attachment to the drill pipe.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:
