Cast flapper with hot isostatic pressing treatment

Abstract

Components of a subsurface safety valve are cast instead of machined for dramatic cost savings. In particular, the flapper is cast from a 718 nickel alloy and treated with the HIP process to increase strength and corrosion resistance while reducing porosity. Other downhole valve components are contemplated to be produced by the same technique and the materials can also be varied. Depending on the specific alloys, the resulting HIP components are either superior in performance (e.g. strength, corrosion resistance) or considerably cheaper to manufacture than their wrought counterparts.

Description

PRIORITY INFORMATION [0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60 / 582,614, filed on Jun. 24, 2004.FIELD OF THE INVENTION [0002] The field of the invention is components for downhole tools that can be cast instead of machined from bar and more particularly subsurface safety valve components that are cast and treated by hot isostatic pressing (HIP). [0003] The HIP process is well known. Hot Isostatic Pressing (HIP), the simultaneous application of heat and high pressure, has become a standard production process in many industries. In the HIP unit a high temperature furnace is enclosed in a pressure vessel. Work pieces are heated and an inert gas, generally argon, applies uniform pressure. The temperature, pressure and process time are all controlled to achieve the optimum material properties. The Economics of HIPping [0004] HIP processing incorporated as an integral part of the manufacturing process reduces scrap. [0005] HIP frequently allows...

AI Technical Summary

Benefits of technology

[0013] Components of a subsurface safety valve are cast instead of machined for dramatic cost-savings. In particular, the flapper is cast from a 718 nickel alloy and treated with the HIP process to increase strength and corrosion resistance while reducing porosity. Other downhole valve components are contemplated to be produced by the same technique and the materials can also be varied. Depending on the specific alloys, the resulting HIP components are either superior in performance (e.g. strength, corrosion resistance) or considerably cheaper to manufacture than their wrought counterparts.

Problems solved by technology

In the oil and gas industry Camco now a part of Schlumberger made castings of a nickel alloy S-monel for a few downhole tool components but discontinued the practice because the resulting components were not acceptable to meet an industry standard for hydrogen sulfide service.

In fact, those skilled in the art have tried casting parts that used to be fabricated, to save production cost, but have given up in the face of the compromises required when casting the parts particularly in the areas of strength, porosity, fracture toughness and diminished corrosion resistance.

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