Composite liner for oilfield tubular goods

#1. Field of the Invention

#The invention generally relates to fiber-reinforced composite conduits or tubes and methods for making such conduits or tubes. More particularly, the invention is related to composite pipe liner for oilfield tubular goods which have improved corrosion resistance, and methods for making such lined tubular goods.

#2. Background Art

#FIG. 1 is a perspective illustration of one embodiment of the oilfield pipe liner of the invention.

#FIG. 2 shows a one-chamber inflatable mandrel in the inflated condition.

#FIG. 3 shows a one-chamber progressively-inflatable mandrel in a partially-inflated condition.

#A preferred embodiment for a composite liner of the invention includes a fiber “preform”. The fiber can be glass, aramid, carbon/graphite or combinations thereof. The fiber can be woven or can be in the form of a needlefelt such as a product made by Textech, N. Monmouth, Me. Generally the preform is in the shape of a tube. The preform is impregnated with a resin such as high-ductility amine-cured epoxy. The resin-impregnated preform is impressed onto the inner wall of a joint of oilfield pipe such as casing or tubing, is formed and bonded to the ends of the joint and is then cured in place on the inner surfaces of the joint of oilfield pipe, such as tubing or casing.

#The preferred embodiment of the composite liner will provide excellent resistance to oilfield chemicals, good performance in hot/wet environments prevalent in oilfield applications, and high working temperatures. The composite liner will have low void content, preferably less than about 3%, as voids in a composite liner are analogous to “holidays” in standard oilfield tubular coatings.

#Braided fiber preform is superior to other tubular composite fiber preforms (such as sew felt or mat tubes) for use as a tube joint liner because it is easily radially deformable, is relatively inexpensive, and is available in very long continuous lengths which do not require additional processing. Braided preform can also be easily custom-tailored to the particular tube lining application by selecting the weight of the tows (measured in “yield”, or length per unit weight of the fiber) used to manufacture the preform, the number of tows in the braid, and the nominal diameter of the braid. The nominal diameter of a tubular braided preform is the diameter at which the individual fibers in the braid rest at 45 degrees with respect to each another. The nominal diameter of the braided preform should be reasonably close to the inside diameter of the tubular joint to be lined, because the diameter of the preform will change most quickly for a given axial displacement at angles in the region of 45 degrees.