Research And Development Of Expandable Pipes And Their Heat Treatment Technology

Expandable tubular technology is a revolution in the oil drilling industry.Its central advantage can reduce the size of drilling eye,and it is used in the whole process of casing repairation?completion and oil extraction.it is known as a key technology of oil drilling industry in the 21th century.The research of expandable tubular material is the important issue in the expandable tubular technology,which restrict the development of expandable tubular technology to some extent.Because the expandable tubular is used in the deep well and ocean,the expandable tubular not only satisfy the necessary expansion technology,but also withstand the high stress and complex work situation.Therefore,the expandable tubular material should have the enough strength?high ability of uniform deformation?good toughness and the resistant of corrosion and abrasion.This paper mainly study the choice of material and heat treatment of expandable tubular with 10%and 20%uniform elongation,and finally find a way of reasonable composition and heat treatment that meets different expandable tubular.The main results were as followed:(1)Intercritical heat treatment is the effective way to get reversed austenite.Meanwhile,in order to guarantee the partion of alloy elements,some insulation time was needed.The steel with different alloy element has different perfect heating temperature and insulation time.(2)To the common expandable tubular(UEL?10),which material can choose the com mon low alloy steel.The general composition is that:C:0.03?0.15%?Mn:0.5?2.0%?Si:0.2?1.5%.Meanwhile,some alloy elements such as Ni?Cr?Cu?Mo were added on the basi s of specific property.This tubular was intercritical quenched(heating temperature:760?820?,insulation time:0.5-2h),the yield strength is 400-600MPa,tensile strength:500-800MPa,uniform elongation:10%?20%,yield ratio ?0.7.(3)To the expandable tubular(uniform elongation ?20%),the tubular material chooses the medium manganese steel.The common composition system:C:0.02?0.1%?Mn:2.0?6.0%?Si:0.2?0.5%.The reasonable heat treatment for the tubular is:heating temperature is 20?40?higher than Ac1,insulation time 2-12h.After intercritical annealing,the properties of tubular were as followed:yield strength is about 400 MPa,tensile strength 600-800MPa,uniform elongation?20%,yield ratio?0.7.(4)In order to satisfy the demand of toughness of common expandable tubular.The steel was tempered after intercritical quenching.While the tubular has the high strength and plastic property,higher toughness was obtained.