CN100566922C - CO 2And H 2The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment - Google Patents

Abstract

The present invention relates to the OCTG technical field, be specifically related to CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment.The present invention overcomes the problem that prior art exists, and technical scheme provided by the invention is: a kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment comprises the steps successively, I, steel-making: utilize the energising electric arc furnaces DRI and the pig iron to obtain mother metal, and mother metal refining in ladle furnace is secondary alloyed then, and final degasification; II, rolling:, obtain the correct size that requires by this step; III, heat treatment and finishing.Compared with prior art, advantage of the present invention: the material list that utilizes the present invention to prepare reveals good CO ₂/ H ₂S corrosion resistance and economy in the down-hole application process, can replace ordinary carbon steel; Cost is no more than 1.5 times of ad eundem conventional oil shell material, but the high efficiency of being brought is many.

Description

CO 2And H 2The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment

Technical field:

The present invention relates to the OCTG technical field, be specifically related to CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment.

Background technology:

Along with going deep into of oil-gas field development, contain CO ₂/ H ₂The oil gas well quantity of S is more and more, and the accident that the tubing and casing corrosion damage causes frequently takes place, and badly influences the safety in production of oil gas field, and deeply being on the rise along with exploitation.At CO ₂/ H ₂The safeguard procedures that S corrosion is taked mainly contain: adopt corrosion resistant material (comprising the steel alloy that uses fiberglass and high alloy composition), the corrosion inhibiter and adopt anticorrosion coat of annotating.But because corrosion inhibiter filling process complexity, long-term investment is very high, and the breakage in the coat use can cause problems such as local corrosion hidden danger, and safest safeguard procedures still are to use corrosion resistant material.But fiberglass undercapacity, high-alloy steel one-time investment are too big.Especially at containing CO simultaneously ₂And H ₂The oil gas well of S substantially all will adopt two phase stainless steel or abros according to the present scheme of material selection of any one steel mill, this means that only the input of the tubing and casing of every mouthful of well is just high more than 15 times than general material.

Summary of the invention:

The present invention will provide a kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment.

For overcoming the problem that prior art exists, technical scheme provided by the invention is: a kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment comprises the steps successively,

I, steel-making

Raw material (wt%) comprises C:0.18～0.24%, Si:0.25～0.50%, Mn:0.45～0.55%, P:0.01～0.015%, S:0.003～0.005%, Cr:2.95～3.10%, Mo:0.40～0.75%, Cu:0.10～0.25%, Ni:0.009～0.05%, Al:0.015～0.055%, Ti:0.010～0.035%, B:0.0018～0.0024%, Nb:0.03～0.06%, V:0.05～0.10%, controlled composition (wt%) is: As≤0.020%, Sn≤0.015%, Sb≤0.010%, N≤0.007%, Ca handles, and the Ca/S ratio is 1.5; Surplus is Fe.

The mother metal that utilizes the energising electric arc furnaces directly to reduce Fe acquisition low concentration residue and be mingled with, with mother metal refining in ladle furnace, secondary alloyed then, and final degasification, wherein: feeding abnormal processing of Si-Ca silk field trash is to make the manganese sulfide inclusion nodularization, reduce the stepped crack sensitivity of HIC, Ca/S is than 〉=1.5;

II, rolling:, obtain the correct size that requires by this step;

III, heat treatment and finishing: abundant austenitizing in stove at first, austenitizing temperature is 840～910 ℃, temperature retention time 30～50 minutes, obtain uniform microstructure tissue by temper, 650～720 ℃ of temperatures, tempering insulation time 60～100 minutes, quenching velocity is 80～100 ℃/s, the total length cooling rate is even, and the small and dispersed globular carbide that is organized as that increases temperature tempering that quenches is distributed on the ferrite matrix.

Oil annular tube steel is containing CO ₂/ H ₂In the S solution, following anode reaction can take place:

Fe→Fe ²⁺+2e

Simultaneously, at CO ₂/ H ₂In the process of S corrosion, the corrosion rate of steel in the cathode reaction process control, is mainly concerned with H ⁺, H ₂CO ₃, HCO ₃ ^-, H ₂S, HS ^-Reduction:

2H ⁺+2e→H ₂

2H ₂CO ₃+2e→2HCO ₃ ^-+H ₂

2HCO ₃ ^-+2e→H ₂+2CO ₃ ^2-

2H ₂S+2e→2HS ^-+H ₂

2HS ^-+2e→2S ^2-+H ₂

Total electrode reaction is:

Fe ²⁺+CO ₃ ^2-→FeCO ₃

Fe ²⁺+S ^2-→FeS

Work as P _CO2/ P _H2S＜20 o'clock, hydrogen sulfide corrosion accounted for leading; Work as P _CO2/ P _H2S＞500 o'clock, carbon dioxide corrosion accounted for leading; 20＜P _CO2/ P _H2S＜500 o'clock, corrosion was controlled jointly by carbon dioxide and hydrogen sulfide.

Reasonable process of the present invention can make the richness of Cr in corrosion products film long-pending, forms stable amorphous state Cr (OH) ₃Film has just formed the corrosion product layer of rich Cr, and such low Cr steel reaches stable corrosion rate and wants early manyly than ordinary carbon steel level low alloy steel, therefore has superior anti-CO ₂/ H ₂The S corrosive power, anti-CO ₂Corrosive power also is greatly improved.Simultaneously, increase the low-temperature transformation structural constituent, form carbide particle and highdensity dislocation knot that disperse distributes, dislocation is played pinning effect, improved the anti-H of steel ₂The ability of S stress corrosion cracking (SSC) can be by the detection of resisting sulfide stress corrosion cracking standard NACE0177-2003 and anti-hydrogen induced cracking (HIC) standard NACE 0284-2005.In this technology, organizational controls is the key that obtains desired properties.

Product according to preparation technology's manufacturing of the present invention can partly replace 13Cr stainless steel tubing and casing, is a kind of satisfied anti-CO that has ₂The non-API steel-grade bushing of resisting sulfide stress corrosion cracking is had both in corrosion, can contain CO at the same time ₂And H ₂Use in the environment of two kinds of corrosive gas of S, reduce CO ₂Local corrosion speed is more than 30%, its anti-CO ₂/ H ₂The S corrosive power is current 3～4 times of using carbon steel.3～5wt%Cr steel applied widely, expection can be used for P _CO2Dividing potential drop≤0.035MPa, P _H2SDividing potential drop 0.01～1MPa, the sour environment condition of temperature t≤150 ℃ is at P _H2SDividing potential drop≤0.01Mpa, P _CO2Dividing potential drop 〉=0.035MPa, temperature t≤150 a ℃ environmental condition has anti-SSC and certain anti-CO ₂Etching characteristic.

The material list that utilizes the present invention to prepare reveals good CO ₂/ H ₂S corrosion resistance and economy in the down-hole application process, can replace ordinary carbon steel, and its outstanding behaviours is in the following aspects:

● be compared to carbon steel and low-alloy steel,, improved anticorrosive behavior, enlarged oil well service life by prolonging the well workover time limit;

● under the moderate corrosion condition,, reduced cost entire life than 13Cr steel and corrosion resistant alloy;

● guarantee the safety operation operation, do not carry out early stage well-repairing work;

● in the inadequate water injection well of deoxygenation, also show gratifying resistance to corrosion;

● when corrosion rate significantly is lower than carbon steel and low-alloy steel, still have relatively thick, improved and salvaged operation.

● the cost benefit height: cost is no more than 1.5 times of ad eundem conventional oil shell material, but the high efficiency of being brought is many.

The specific embodiment:

To explain the present invention by specific embodiment below.

Embodiment 1: a kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment comprises the steps successively,

I, steel-making: raw material comprises following component (wt%), C:0.20%, Si:0.37%, Mn:0.47%, P:0.011%, S:0.003%, Cr:2.95%, Mo:0.67%, Cu:0.11%, Ni:0.009%, Al:0.036%, Nb:0.044%, Ti:0.03%, B:0.002%, V:0.07%; Control composition (wt%) is: As:0.012%, and Sn:0.008%, Ca handles, and the Ca/S ratio is 1.5; All the other are iron.

The mother metal that utilizes the energising electric arc furnaces DRI and the pig iron to obtain the low concentration residue and be mingled with, with mother metal refining in ladle furnace, secondary alloyed then, and final degasification, wherein: feeding abnormal processing of Si-Ca silk field trash is to make the manganese sulfide inclusion nodularization, reduce the stepped crack sensitivity of HIC, Ca/S is than 〉=1.5;

II, rolling: rolling is second basic step that obtains the high-quality steel.By this step, can obtain the correct size that requires.Strict control valve wall thickness of the operation of rolling and caliber deviation are in 10%, adopt continuous tube rolling and plug rolling technology to guarantee after heat treatment, can to obtain accurate physical dimension, final size obtains by sizing mill, and pipe thickness and caliber deviation are in 10%.Survey meter can provide accurately and fast online pipe thickness to measure.

III, heat treatment and finishing: can obtain best microstructure tissue by heat treatment.Abundant austenitizing in stove at first, austenitizing temperature is 840～880 ℃, temperature retention time 30 minutes obtains uniform microstructure tissue by temper, 650～720 ℃ of temperatures, tempering insulation time 60 minutes.The cooling of quenching production line should be accelerated, and quenching velocity is 80 ℃/s, and the total length cooling rate is even.The small and dispersed globular carbide that is organized as that quenching increases temperature tempering is distributed on the ferrite matrix.

Embodiment 2:

A kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment comprises the steps successively,

I, steel-making:

Comprise following component (wt%), C:0.22%, Si:0.50%, Mn:0.50%, P:0.015%, S:0.004%, Cr:3.10%, Mo:0.42%, Cu:0.15%, Ni:0.05%, Al:0.044%, Nb:0.047%, Ti:0.03%, B:0.002%, V:0.09%; Be controlled to and be divided into: As:0.014%, Sn:0.01%, Ca handles, and the Ca/S ratio is 1.5; All the other are iron.

The mother metal that utilizes the energising electric arc furnaces DRI and the pig iron to obtain the low concentration residue and be mingled with, with mother metal refining in ladle furnace, secondary alloyed then, and final degasification, wherein: feeding abnormal processing of Si-Ca silk field trash is to make the manganese sulfide inclusion nodularization, reduce the stepped crack sensitivity of HIC, Ca/S is than 〉=1.5;

II, rolling: strict control valve wall thickness of the operation of rolling and caliber deviation are in 10%, adopt continuous tube rolling and plug rolling technology to guarantee after heat treatment, can to obtain accurate physical dimension, final size obtains by sizing mill, and pipe thickness and caliber deviation are in 10%.Survey meter can provide accurately and fast online pipe thickness to measure.

III, heat treatment and finishing: abundant austenitizing in stove at first, austenitizing temperature is 900～910 ℃, temperature retention time 50 minutes obtains uniform microstructure tissue by temper, 680～710 ℃ of temperatures, tempering insulation time 100 minutes.The cooling of quenching production line should be accelerated, and quenching velocity is 100 ℃/s, and the total length cooling rate is even.The small and dispersed globular carbide that is organized as that quenching increases temperature tempering is distributed on the ferrite matrix.

Claims (1)

1, a kind of CO ₂And H ₂The preparation technology of the corrosion resistant low-chromium tubing and casing in the S coexisted environment comprises the steps successively,

I, steel-making

Raw material (wt%) comprises C:0.18～0.24%, Si:0.25～0.50%, Mn:0.45～0.55%, P:0.01～0.015%, S:0.003～0.005%, Cr:2.95～3.10%, Mo:0.40～0.75%, Cu:0.10～0.25%, Ni:0.009～0.05%, Al:0.015～0.055%, Ti:0.010～0.035%, B:0.0018～0.0024%, Nb:0.03～0.06%, V:0.05～0.10%, controlled composition (wt%) is: As≤0.020%, Sn≤0.015%, Sb≤0.010%, N≤0.007%, Ca handles, and the Ca/S ratio is 1.5; Surplus is Fe;

Utilize the energising electric arc furnaces directly to reduce Fe and obtain the mother metal of low concentration residue and strap clamp foreign material, with mother metal refining in ladle furnace, secondary alloyed then, and final degasification, wherein: feeding abnormal processing of Si-Ca silk field trash is to make the nodularization of manganese sulfide inclusion thing, reduce the stepped crack sensitivity of HIC, make the Ca/S of end product compare 〉=1.5;

II, rolling:, obtain the correct size that requires by this step;

III, heat treatment and finishing: abundant austenitizing in stove at first, austenitizing temperature is 840～910 ℃, temperature retention time 30～50 minutes, obtain uniform microstructure tissue by temper, 650～720 ℃ of temperatures, tempering insulation time 60～100 minutes, quenching velocity is 80～100 ℃/s, the total length cooling rate is even, and the small and dispersed globular carbide that is organized as that increases temperature tempering that quenches is distributed on the ferrite matrix.