Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese

Definitions

• the present invention relates to a new product constituted by a new species of drill collars which can be used for drilling oil or natural gas wells.
• the drilling of oil or natural gas wells is generally carried out using a device made up of tubular steel elements, called “rods”, arranged one after the other. Their assembly forms a “drill string”, at the end of which is the drill bit, and is possibly driven by a rotational movement.
• the elements located at the front of the train are more massive and serve, in particular, to ensure a permanent effort on the drill bit. they are called “drill sticks". Their outside diameter can reach approximately 250 millimeters and their length approximately 10 meters. These drill rods have a bore whose diameter can, for example, be of the order of 60 mm and they are assembled together by screwing.
• Sludge is injected inside the drill string to provide lubrication at the drill bit level and entrain the debris formed.
• the mud thus loaded with debris rises to the surface through the space which exists between the exterior wall of the train and the wall of the borehole.
• the drill rods are normally made of low-alloy structural steel, of the 42 CD 4 type for example, that is to say 0.42% carbon and 1% chromium, with a little molybdenum.
• the head drill collars must be made of non-magnetic steel.
• the orientation of the train is controlled from magnetic compasses (compasses), the indications of which must absolutely not be disturbed by the presence of ferro-magnetic materials.
• non-magnetic drill rods are obtained, in a very general way, by cold working (hot or cold) of stainless steels of various compositions, the balancing of the alphagenic and gammagenic elements and the structural stability are such that 'there is no presence of ferrite nor possibility of formation of martensite p ⁇ .
• Composition 1 is a composition of Composition 1:
• Composition 2 is a composition of Composition 2:
• the latter are in contact with the sludge which is injected into the drilling train and which contains large quantities of chlorides (several hundred grams per liter).
• chlorides Cr 2 Mg, Cl 2 Ca, ClNa, ClK
• the temperature at the level of the drill rods can be of the order of 100 ° C.
• constraints residual constraints and working constraints
• the object of the present invention is to be able to have non-magnetic drill collars having excellent resistance to corrosion under stress as it exists in oil drilling, using austenitic steels with structural hardening, chosen from those which have have been described in patent No. 70-20479.
• the required tensile strength and yield strength are very easily achieved after water hardening (e.g. from 1150 ° C) and structural hardening (e.g. 10 hours at 660 ° C), resulting of a precipitation of vanadium carbides.
• the magnetic permeability is less than 1.010.
• a significantly higher carbon content should be used, greater than 0.6% or 0.7% (instead of 0.25% to 0.45% in the invention), which would lead to marked degradation the ability to machine metal.
• the steel grades according to the invention have, compared to the grades currently used, the main advantage of very much higher resistance to corrosion under tension under the conditions of use of the drill collars.
• the invention makes available to the petroleum industry drill rods with the required mechanical properties associated for the first time with excellent resistance to corrosion under stress.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Earth Drilling (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9260422

Family Applications (1)

Country Status (2)

Cited By (2)

Families Citing this family (1)

Citations (7)

• 1981
  • 1981-07-10 FR FR8113597A patent/FR2509365A1/fr not_active Withdrawn
• 1982
  • 1982-07-07 EP EP82401283A patent/EP0070764A1/de not_active Ceased

Patent Citations (7)

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