CN103161429A - Anti-corrosion method for mechanical oil extraction shaft - Google Patents

Anti-corrosion method for mechanical oil extraction shaft Download PDF

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CN103161429A
CN103161429A CN2013101197703A CN201310119770A CN103161429A CN 103161429 A CN103161429 A CN 103161429A CN 2013101197703 A CN2013101197703 A CN 2013101197703A CN 201310119770 A CN201310119770 A CN 201310119770A CN 103161429 A CN103161429 A CN 103161429A
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inert gas
oil
pit shaft
sample
pipe
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CN2013101197703A
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陈建军
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Abstract

The invention relates to an anti-corrosion method for a mechanical oil extraction shaft, and belongs to the technical field of oilfield development and oil extraction. The anti-corrosion method comprises the following steps: the amount of inert gas needed by corrosion-free residue in oil shaft products is determined through a laboratory test; an oil pipe valve is opened firstly, an inert gas source is connected with a sleeve pipe connection pipe through a pipeline, and then a sleeve pipe valve is opened, so that the connection pipe is communicated with an annular space of an oil pipe and a sleeve pipe; the inert gas is injected into the annular space of the oil pipe and the sleeve pipe through the sleeve pipe inlet; a sample is taken from an oil pipe outlet for a laboratory test in the injection process of the inert gas; and the inert gas is injected until no corrosive residue exists in the sample of the oil pipe outlet. The anti-corrosion method is simple in operation, low in cost, and good in anti-corrosion effect. The inert gas is used for isolating the air or diluting and drying corrosive gas, metal inside the shaft or a ground conveying pipeline is effectively prevented from being corroded, maintenance frequency and cost are lowered, and work efficiency is improved.

Description

Mechanical oil recovery pit shaft method of inhibiting corrosion
Technical field
The present invention relates to a kind of mechanical oil recovery pit shaft method of inhibiting corrosion, belong to oil field development oil production technology field.
Background technology
Three aspects, corrosion source of pit shaft inner sleeve, oil pipe, sucker rod and other downhole tool of mechanical oil well: the external stratum output object that adds of external (as air) burn into stratum output object (as hydrogen sulfide, carbon dioxide) burn into corrodes.For many years, for solving the mechanical oil well etching problem, people have invented multiple processing method: 1 cladding process: a coating corrosion-resistant coating, b steel surface carry out preservative treatment, c increases internal lining pipe ... etc.; 2 neutralizations (or substituting) method: a anode protector, b filling corrosion inhibiter, c inhibition rod etc.Due to the complexity of source of corrosion composition, mutually superpose and interaction and well in constantly destroy the reasons such as passivating film and diaphragm when producing when STRESS VARIATION and operation, these methods can only make etching problem obtain partial rcsponse, problem and can not get basic solve and the ubiquity expense is high, the problem of weak effect.Up to the present, people also do not find the method for thorough solution etching problem.
In the mechanical oil recovery process, when the strata pressure of oil well can not give rise in the situation on ground by the liquid of demand with the down-hole, will liquid in well be given rise to ground with the method for the machineries such as plunger displacement pump, electric submersible pump, screw pump, enter the surface line induction system through the oil pipe gate.Due to low pressure dynamic monitoring and pressure balanced needs, often open sleeve gate, air just enters in pit shaft.
The pump operation of mechanical oil recovery down-hole is complete open take out after, along with the liquid level of the pit shaft inner sleeve annular space air that constantly descends enters thereupon.Under the environment of humidity, internal surface of sleeve pipe, oil-pipe external wall constantly are corroded, and the diaphragms such as the passivating film of generation come off in alternation and oscillating load and frequent operation again, and corrosion is proceeded again, and so circulation, make the continuous attenuation of tube wall.1 millimeter of the every attenuation of tube wall its tension, anti-ly squeeze outward, more than internal pressure strength reduces (73 millimeters oil pipes 18% of Φ, 139.7 millimeters sleeve pipes 10% of Φ), the inspection pump light maintenance operation of the oil pipe leakage that causes thus; The oil well reconditioning services such as (the casing failure major part except bad break all corrode cause) gets, casing replacing and casing patching all cause huge loss to the oil field, cause oil well to scrap when serious; The diaphragm chips such as the passivating film that comes off threaten for again the normal operation of oil well pump.
Summary of the invention
The present invention be directed to the defective of the existing anticorrosion technique of mechanical oil well, provide a kind of method simple, the mechanical oil recovery pit shaft method of inhibiting corrosion that cost is low, effective.
Realize the foregoing invention purpose by the following technical solutions: a kind of mechanical oil recovery pit shaft method of inhibiting corrosion, carry out in accordance with the following methods:
A, chamber test is determined in output content from oil well without the needed amount of inert gas of corrosion residue by experiment;
B, first open the oil pipe gate, then with pipeline, the inert gas source of the gas is connected with the cover pipe connected pipe, then open sleeve gate its tube connector is communicated with the annular space of sleeve pipe with oil pipe;
C, by sleeve pipe import inert gas injecting in the annular space of oil pipe and sleeve pipe;
D, in the inert gas injecting process from oil pipe outlet sample examination, the injection rate of inert gas is to be as the criterion without the residual thing of corrosion in oil pipe outlet sample.
Directly apply mechanically the inert gas requirement of the successful well of having constructed for the mechanical oil well of close block, close hole condition.
When not containing corrosive gas in pit shaft: equal inert gas injecting in the annular space of oil pipe and sleeve pipe before oil well begins to produce and during normal production, its injection rate can replace out the air in the annular space of oil pipe and sleeve pipe and remain that the cased well mouth pressure is as 0.1-4MPa as standard during take normal production;
When pit shaft contains corrosive gas: the inert gas injecting in the annular space of oil pipe and sleeve pipe of production limit, oil well limit, allowing it sneak in output content from oil well discharges from the oil pipe outlet, the inert gas that the injection rate reference laboratories is determined is 1 times of etching extent not, takes out sample with the oil pipe outlet and is as the criterion without the residual thing of corrosion.
During carry out laboratory experiment:
A, having ready conditions when carrying out high pressure physical property sample, prop up in experiment lab simulation pit shaft situation with the ground layer original output object sample number of obtaining, add respectively an equal volume and the metal identical with composition in pit shaft to corrode accurate experiment in each sample: first isolated air observed 7 days; Second passes into the inert gas that is doubled in sample volume, observes 7 days; The 3rd passes into the inert gas that is twice in sample volume, observes 7 days; By that analogy, until determine the not etching extent of inert gas;
B, when not having condition to carry out high pressure physical property sample, from wellhead sampling or get the pit shaft sample number by the way of well-flushing and prop up in experiment lab simulation pit shaft situation, add respectively an equal volume and the metal identical with composition in pit shaft to corrode rough experiment in each sample: first isolated air observed 7 days; Second passes into the inert gas that is doubled in sample volume, observes 7 days; The 3rd passes into the inert gas that is twice in sample volume, observes 7 days; By that analogy, until determine the not etching extent of inert gas, the injection rate of inert gas, is taken out sample with the oil pipe outlet and is as the criterion without the residual thing of corrosion more than 1 times greater than this amount when practice of construction.
Inert gas not etching extent refers to the amount of the inert gas that need to inject in the annular space of oil pipe and sleeve pipe during the corrosion reaction of metal in corrosive gas and pit shaft.
This anti-corrosion method is simple to operate, and cost is low, favorable anti-corrosion effect, can completely cut off air or utilize inert gas dilution and dry corrosive gas by enough inert gases, prevent that effectively the metal that reaches feed-line inside, ground in pit shaft is corroded, reduce frequency of maintenance and expense, increase work efficiency.
Description of drawings
Fig. 1 is shaft structure schematic diagram in the present invention.
In figure: oil pipe gate 1, sleeve gate 2, sleeve pipe 3, oil pipe 4, sucker rod 5, stratum production fluid liquid level 6, oil well pump 7, stratum production fluid 8, the annular space 9 of oil pipe and sleeve pipe, sleeve pipe import 10, cover pipe connected pipe 11, oil pipe outlet 12.
The specific embodiment
The present invention will be further described below in conjunction with drawings and Examples.
referring to accompanying drawing 1, mechanical oil recovery is by oil well pump 7 and the sucker rod 5 that is arranged in pit shaft, stratum production fluid 8 to be given rise to ground from the down-hole, after controlling, oil pipe gate 1 enters in ground feed-line 1, in generative process, between oil pipe 4 and sleeve pipe 3, annular space is that stratum production fluid liquid levels 6 in the annular space 9 of oil pipe and sleeve pipe fluctuate, air not cracked ends sleeve gate 2 is sneaked in the stratum production fluid 8 of high salinity, will cause like this: a makes formation fluid have corrosivity, b makes and contains hydrogen sulfide, the corrosive gas formation fluid corrosion rates such as carbon dioxide are accelerated, sleeve pipe 3 inwalls that corrosion is moist, oil pipe 4 outer walls.
The corrosion rate of pit shaft inner metal component and effect and the airborne oxygen content that enters in the pit shaft sleeve have direct relation.The present invention is that concrete grammar is realized according to following step by with inert gas, that air and pit shaft is isolated or the corrosive gas in pit shaft is diluted and dry mode is carried out anticorrosionly:
A, at character and the content of the output object (containing gas) of laboratory assay mechanical oil well oil pipe outlet 12, determine in output content from oil well without the needed amount of inert gas of corrosion residue; The output object of laboratory assay can be also bottom-hole samples.The amount of the inert gas that need to inject in the annular space of the oil pipe of pit shaft and sleeve pipe when referring to metal in corrosive gas and pit shaft corrosion reacts without corrosion residue needed amount of inert gas in output content from oil well, the i.e. not etching extent of inert gas.In output content from oil well without the reason that is as the criterion of corrosion residue to be: 1. fluid export from the stratum output to oil pipe that the metal in pit shaft of part corrodes, the properties of samples distortion that might oil pipe exports; 2. the fluid flow state during due to laboratory test and the fluid flow state in pit shaft probably have more different, and the change of flow state of fluid also affects the inert gas requirement; Therefore, although substantially determined the amount of inert gas injecting, for precision is high, final still to be as the criterion without the corrosion residue in output content from oil well.
B, with pipeline, inert gas source of the gas (container or gas making machine) is connected with the cover pipe connected pipe, overlaps pipe connected pipe and be communicated with the annular space of sleeve pipe with oil pipe; Inert gas container comprises inert gas tank or inert gas car etc., inert gas preferred nitrogen.
C, the switch by controlling sleeve gate inert gas injecting in the annular space of oil pipe and sleeve pipe, its injection rate with the definite inert gas in laboratory not etching extent be as the criterion.
Laboratory test:
A, having ready conditions when carrying out high pressure physical property sample, propping up in experiment lab simulation pit shaft situation with the ground layer original output object sample number of obtaining, adding respectively an equal volume and the metal identical with composition in pit shaft to corrode accurate experiment in each sample:
First: isolated air was observed 7 days;
Second: pass into the nitrogen that is doubled in sample volume, observed 7 days;
The 3rd: pass into the nitrogen that is twice in sample volume, observed 7 days;
……
Until determine the not etching extent of nitrogen;
B, when not having condition to carry out high pressure physical property sample, from wellhead sampling or get the pit shaft sample number by the way of well-flushing and prop up experiment lab simulation pit shaft situation (first testing of fluid export from the stratum to the oil pipe and the residual thing amount of corrosion of pit shaft metal reaction), add respectively an equal volume and the metal identical with composition in pit shaft to corrode rough experiment in each sample:
First: isolated air was observed 7 days;
Second: pass into the nitrogen that is doubled in sample volume, observed 7 days;
The 3rd: pass into the nitrogen that is twice in sample volume, observed 7 days;
……
Until determine the not etching extent of nitrogen, the injection rate of nitrogen is measured (the properties of samples distortion of consideration oil pipe outlet) more than 1 times greater than this when practice of construction), the result of laboratory test of oil pipe outlet during according to injection, the injection rate of minimizing or increase nitrogen.
The not etching extent of inert gas refers to the amount of the inert gas that need to inject in the annular space of oil pipe and sleeve pipe during the corrosion reaction of metal in corrosive gas and pit shaft.
Detect through the laboratory, when not containing corrosive gas in pit shaft: equal nitrogen injection in the annular space of oil pipe and sleeve pipe before oil well begins to produce and during normal production, its injection rate can be replaced out the air in the annular space of oil pipe and sleeve pipe and remain that the cased well mouth pressure (can not allow again air enter pit shaft simultaneously to be advisable not affect the stratum production fluid) as 0.1-4MPa as standard during take normal production, with this realize air and pit shaft isolated and anticorrosion;
Detect through the laboratory, when pit shaft contains corrosive gas: the nitrogen injection in the annular space of oil pipe and sleeve pipe of production limit, oil well limit, the inert gas that its injection rate is determined with the laboratory not etching extent and well head takes out sample and is as the criterion without the residual thing of corrosion, is used for dilution and dry corrosive gas with this nitrogen that injects.

Claims (5)

1. a mechanical oil recovery pit shaft method of inhibiting corrosion, is characterized in that, carries out in accordance with the following methods:
A, chamber test is determined in output content from oil well without the needed amount of inert gas of corrosion residue by experiment;
B, first open the oil pipe gate, then with pipeline, the inert gas source of the gas is connected with the cover pipe connected pipe, then open sleeve gate its tube connector is communicated with the annular space of sleeve pipe with oil pipe;
C, by sleeve pipe import inert gas injecting in the annular space of oil pipe and sleeve pipe;
D, in the inert gas injecting process from oil pipe outlet sample examination, the injection rate of inert gas is to be as the criterion without the residual thing of corrosion in oil pipe outlet sample.
2. mechanical oil recovery pit shaft method of inhibiting corrosion according to claim 1, is characterized in that, directly applies mechanically the inert gas requirement of the successful well of having constructed for the mechanical oil well of close block, close hole condition.
3. mechanical oil recovery pit shaft method of inhibiting corrosion according to claim 1, it is characterized in that, when not containing corrosive gas in pit shaft: equal inert gas injecting in the annular space of oil pipe and sleeve pipe before oil well begins to produce and during normal production, its injection rate can replace out the air in the annular space of oil pipe and sleeve pipe and remain that the cased well mouth pressure is as 0.1-4MPa as standard during take normal production;
When pit shaft contains corrosive gas: the inert gas injecting in the annular space of oil pipe and sleeve pipe of production limit, oil well limit, allowing it sneak in output content from oil well discharges from the oil pipe outlet, the inert gas that the injection rate reference laboratories is determined is 1 times of etching extent not, takes out sample with the oil pipe outlet and is as the criterion without the residual thing of corrosion.
4. mechanical oil recovery pit shaft method of inhibiting corrosion according to claim 1, is characterized in that, during carry out laboratory experiment:
A, having ready conditions when carrying out high pressure physical property sample, prop up in experiment lab simulation pit shaft situation with the ground layer original output object sample number of obtaining, add respectively an equal volume and the metal identical with composition in pit shaft to corrode accurate experiment in each sample: first isolated air observed 7 days; Second passes into the inert gas that is doubled in sample volume, observes 7 days; The 3rd passes into the inert gas that is twice in sample volume, observes 7 days; By that analogy, until determine the not etching extent of inert gas;
B, when not having condition to carry out high pressure physical property sample, from wellhead sampling or get the pit shaft sample number by the way of well-flushing and prop up in experiment lab simulation pit shaft situation, add respectively an equal volume and the metal identical with composition in pit shaft to corrode rough experiment in each sample: first isolated air observed 7 days; Second passes into the inert gas that is doubled in sample volume, observes 7 days; The 3rd passes into the inert gas that is twice in sample volume, observes 7 days; By that analogy, until determine the not etching extent of inert gas, the injection rate of inert gas, is taken out sample with the oil pipe outlet and is as the criterion without the residual thing of corrosion more than 1 times greater than this amount when practice of construction.
5. the described mechanical oil recovery pit shaft of any one method of inhibiting corrosion according to claim 1-4, it is characterized in that, described inert gas not etching extent refers to the amount of the inert gas that need to inject in the annular space of oil pipe and sleeve pipe during the corrosion reaction of metal in corrosive gas and pit shaft.
CN2013101197703A 2013-04-09 2013-04-09 Anti-corrosion method for mechanical oil extraction shaft Pending CN103161429A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110306976A (en) * 2019-07-01 2019-10-08 西南石油大学 Inert gas injection manages annular space band compression experiment device and its experimental method
CN116146153A (en) * 2023-04-20 2023-05-23 天津市益彰石油科技发展有限公司 Coaxial double-cylinder drag reduction lifting device

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481020A (en) * 1982-06-10 1984-11-06 Trw Inc. Liquid-gas separator apparatus
WO1999063201A1 (en) * 1998-06-01 1999-12-09 Atlantic Richfield Company Method and system for separating and injecting gas in a wellbore
US6761215B2 (en) * 2002-09-06 2004-07-13 James Eric Morrison Downhole separator and method
CN201041023Y (en) * 2007-05-29 2008-03-26 中国石油天然气股份有限公司 Gas-liquid mixed injection method liquid level-lowering induced spraying construction device
RU2327866C2 (en) * 2006-06-22 2008-06-27 Закрытое Акционерное Общество "Новомет-Пермь" Gas separator
CN102839939A (en) * 2012-08-25 2012-12-26 中国科学院武汉岩土力学研究所 Supercritical CO2 resistant packer

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4481020A (en) * 1982-06-10 1984-11-06 Trw Inc. Liquid-gas separator apparatus
WO1999063201A1 (en) * 1998-06-01 1999-12-09 Atlantic Richfield Company Method and system for separating and injecting gas in a wellbore
US6761215B2 (en) * 2002-09-06 2004-07-13 James Eric Morrison Downhole separator and method
RU2327866C2 (en) * 2006-06-22 2008-06-27 Закрытое Акционерное Общество "Новомет-Пермь" Gas separator
CN201041023Y (en) * 2007-05-29 2008-03-26 中国石油天然气股份有限公司 Gas-liquid mixed injection method liquid level-lowering induced spraying construction device
CN102839939A (en) * 2012-08-25 2012-12-26 中国科学院武汉岩土力学研究所 Supercritical CO2 resistant packer

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110306976A (en) * 2019-07-01 2019-10-08 西南石油大学 Inert gas injection manages annular space band compression experiment device and its experimental method
CN110306976B (en) * 2019-07-01 2022-03-08 西南石油大学 Inert gas injection control annular pressure experiment device and method
CN116146153A (en) * 2023-04-20 2023-05-23 天津市益彰石油科技发展有限公司 Coaxial double-cylinder drag reduction lifting device

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Application publication date: 20130619