ABSTRACT:

Beside a more intensive use of the Lean Profile technique for drilling applications, moreover know as the innovative technique to safely run the same well tubulars into a smaller hole, the conventional casing centralization still needs to be perfected both from a technical and commercial point of view. Particularly in deviated wells, the reduced clearance between casing and hole does not allow the use of standard centralisers because of its basic design associated to the stop collars dimensions; on the other hand, the use of more sophisticated centralization systems, such as intercasing centralisers, undesirably increase the casing stiffness with possible problems when RIH As a possible solutions to overcome such a constraints a novel concept of centralisers has been developed based on the use of composite materials. These materials adhere directly to the outer casing wall, forming a blade which offers the desired stand off, by adjusting the thickness of the composite as well as the shape or form to suit the specific centralization program. This application also allows the use of slim hole centralisers without any outer stop rings or centraliser bands around the outer diameter of the pipe and thus the O.D. remains unchanged without further flow restrictions for fluid circulation. Furthermore being its elasticity higher than casing, possible problems related to casing-centralisers stiffness have been dramatically reduced The composite materials have been lab tested, practical wear tests in the field and installed in 3 wells to date with very promising results confirmed by cement bond logs. The composite material and application methods is still being evaluated and improved to satisfy virtually any requirement or condition.

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