Patent EA-002432-B1 (EA)
Title: Method for transporting and installing an expandable steel tubular
Inventor: LOHBECK WILHELMUS CHRISTIANUS
IPC: E21B19/22
Filed: 1999-10-28
Abstract: 1. A method for transporting and installing a steel tubular (1), the method comprising: -flattening the tubular (1); -transporting the flattened tubular (1) to the site (6) where the tubular (1) is to be installed; and -unflattening the tubular (1); characterized in that -before positioning the tubular at said site (6) the tubular (1) is unflattened; and that -the tubular (1) is expanded along at least a substantial part of its length after the tubular (1) has been positioned at said site (6). 2. The method of claim 1, wherein the flattened unexpanded tubular (1) is wound around a reeling drum (9) before transporting the tubular (1) to said site (6) and reeled from the reeling drum (9) before unflattening the tubular (1). 3. The method of claim 1, wherein the unexpanded tubular (1) comprises a predetermined pattern of openings or weak spots (8) which open up and are deformed during the expansion process. 4. The method of claim 3, wherein said pattern is such that at opposite sides along the circumference of the tubular a longitudinal or helical series of openings or weak spots (8) is arranged which series define a longitudinal or helical band where the tubular wall is folded during the step of flattening the unexpanded tubular (1). 5. The method of claim 3, wherein the tubular (1) comprises a staggered pattern of elongate slots (8) or elongate weak areas which open up into a substantially prismatic shape during the expansion process. 6. The method of claim 1, wherein the tubular (1) is unflattened by moving the tubular into a funnel arrangement (2). 7. The method of claim 6, wherein the funnel arrangement (2) comprises a tubular opening formed by a series of rollers (3) and/or a tubular guide funnel (5), which opening has an inner diameter which is substantially equal to the outer diameter of the unexpanded unflattened tubular (1). 8. The method of claim 1, wherein the tubular (1) is inserted in its unflattened, unexpanded and substantially cylindrical or oval shape into an underground borehole or other cavity (6) and expanded alongside the inner wall (16) of the cavity (6) in order to form a tubular lining of said cavity (6). 9. The method of claim 1, wherein the tubular (1) is an oilfield tubular and is made of a formable steel grade. 10. The method of claim 9, wherein the tubular (1) is equipped with a series of bow spring centralisers (12) which are at at least one end slidably secured to the outer surface of the tubular and which centralisers (12) are also flattened when the unexpanded tubular (1) is flattened and which deform into a bow shape when the tubular (1) is unflattened. 11. The method of claim 9, wherein the tubular (1) is a slotted tubular for use in an underground borehole (6) and is provided with an impermeable wrapping (15) at locations where an impermeable expanded tubular (1) is required. 12. The method of claim 11, wherein the impermeable wrapping (15) consists of a deformable rubber sleeve and/or a scrolled sheet of an impermeable or made impermeable in-situ fabric material. 13. The method of claim 11, wherein the tubular (1) is expanded by an expandable expansion mandrel (20,30-36) which is inserted into the unexpanded unflattened tubular in its retracted shape and subsequently expanded and moved in an axial direction through the tubular (1) during the expansion process.