JPS58152085A - Thread compound for sour environment - Google Patents

Abstract

PURPOSE:To provide a thread compound capable of remarkably suppressing the corrosion of threads of steel in highly corrosive sour environment and preventing the leak of the inner fluid, by using an organic nitrogen compound having specific aliphatic or cycloaliphatic hydrocarbon group, as a component. CONSTITUTION:The objective thread compound contains an organic nitrogen compound having >=8C aliphatic or cycloaliphatic hydrocarbon group, as a corrosion inhibitor. The organic nitrogen compound is preferably an imidazoline compound of formulaI R1-R7 are >=8C (preferably 9-17C) aliphatic or cycloaliphatic group; other substituent groups R and H, aliphatic, cycloaliphatic or aromatic hydrocarbon group, etc.; X<-> is univalent anion , a polyamide compound of formula II R1, R2 and Rnm (m<=n) are >=8C aliphatic or cycloaliphatic hydrocarbon group , a quaternary pyridinium salt compound of formula III (R1-R6 are >=8C aliphatic or cycloaliphatic hydrocarbon group) or a quaternary ammonium salt compound of formula IV (R1-R4 are >=8C aliphatic or cycloapliphatic hydrocarbon group).

Description

[Detailed Description of the Invention] The present invention relates to a drill used in oil wells, geothermal wells, etc.
I? The present invention relates to a thread cone gland used as a sealant for the threaded parts of tubes, tubing tubes, cage/gut grooves, etc.

(Conventionally, 1japt standard 5 was used as a thread compound.
4, which consists of metal powders such as lead, zinc, and copper, graphite powder, and metal soap, was used in accordance with System 2. For sour environments (environments containing hydrogen sulfide and sulfuric acid gas) fC, a method of adding organic sulfur compounds to the compound is used to prevent the metal powder in the concrete from reacting with hydrogen sulfide. Ta. However, with the recent tightening of energy resources, highly corrosive gas or crude oil, which contains high concentrations of hydrogen sulfide and carbon dioxide gas and has a low pH, has been mined, something that had not been done before. However, in this highly corrosive sour environment, conventional Threadco/Nogland does not have sufficient anti-corrosion performance against steel materials, so there is a risk of internal fluid leaking due to corrosion of the threads. Ta.

The present invention was obtained as a result of research to improve the anti-corrosion performance of Thread Comparan R, and provides a Thread Comparan R that suppresses corrosion of threaded parts of steel materials to a high V in a highly corrosive sour environment. It is something.

The present inventors investigated the cause of severe corrosion of the north threaded part in a sour environment by filling it with conventional thread compound. It was thought that sour solution (abbreviated as "sour solution") may penetrate and reach the steel surface, causing severe corrosion. Therefore, if a corrosion inhibitor that has good anticorrosion performance in a sour environment is added to thread P concrete land, sour solution This corrosion inhibitor is eluted into the sour solution when it passes through the thread connoisseur P, and when this solution comes into contact with the steel surface,
Believing that the corrosion of steel materials can be suppressed by the action of a corrosion inhibitor, we added a corrosion inhibitor that has particularly good anti-corrosion performance in a sour environment, which the inventors have already discovered, to conventional thread cone land to prevent corrosion. When we investigated the performance,
We have discovered a threaded concrete land that has unprecedented superior anti-corrosion performance in a factory environment.

That is, the present invention relates to a thread core A round for use in a natural environment, which is characterized in that it contains an organic nitrogen compound having an alicyclic hydrocarbon group with an aliphatic terminal having 8 or more carbon atoms.

More specifically, (1) an iZ dazotun compound having an alicyclic hydrocarbon group having an aliphatic terminal group of 8 or more carbon atoms, (
2) a boria 2 do compound having an aliphatic or alicyclic hydrocarbon group having 8 or more carbon atoms; (3) an aliphatic or aliphatic compound having 8 or more carbon atoms; A quaternary pyridium salt compound having a hydrocarbon group, or (4) an aliphatic compound having 8 or more carbon atoms, contains at least one quaternary ammonium salt compound having an alicyclic hydrocarbon group. This is about a thread compound that is characterized by:

As the i2/zoline compound in the present invention, compounds having the molecular structure shown below can be used.

However, at least one of the substituents R3 to Rv is an aliphatic or alicyclic hydrocarbon group having 8 or more carbon atoms, preferably 9 to 17 carbon atoms. Substituents R that do not fall under this category are hydrogen, aliphatic hydrocarbon group, alicyclic hydrocarbon group, aromatic hydrocarbon group, -R"-OR, -几"-OH, -B"
-8H, -R"-ooOH*1-C-R"-000H 1 0B -00ONm.

Here, N': hydrogen, aliphatic hydrocarbon group, alicyclic hydrocarbon group or aromatic hydrocarbon group, R': aliphatic, alicyclic or aromatic divalent hydrocarbon group, X: 1 or more It is a positive integer. Note that in the O molecular structure of the imidazoline collar conductor, X represents an i*o anion (for example, chlorine ion, bromine ion, etc.).

As the polyamide compound, one having the following molecular structure can be used.

〒ysm R,0ONII(OH,OH,N)noOR.

However, the substituents "1 m *"1, ILnl, ++
・-'#lLnm(ws At least one of (,m) is an aliphatic or alicyclic hydrocarbon group having 8 or more carbon atoms, preferably 9 to 17. And, 20 conditions for substituents that do not KII*J is the same as for imidacilline compounds.

Next, as a quaternary py9dinium salt compound, one having the molecular structure shown below can be used.

However, at least one of the substituents ~B is an aliphatic or alicyclic hydrocarbon group having 8 or more carbon atoms, preferably 9 to 17 carbon atoms. Conditions for substituents B and X that do not fall under these conditions are the same as for the imidacilline compound.

Further, as the quaternary ammonium salt compound, compounds having the following molecular structure can be used.

However, at least four of the substituents R3 to R40 are aliphatic or alicyclic hydrocarbon groups having preferably 8 or more carbon atoms and preferably tail to 11 carbon atoms. However, the conditions for the substituent 凰 and

The present inventors have already discovered that all of the four types of *0 compounds listed here exhibit a particularly excellent corrosion inhibiting effect on steel materials when added to a sour solution (Japanese Patent Application No. 1983). -166933 to 54-1661137), but since these compounds have high solubility in water, even if they exist in the thread compound, they are easily eluted into the sour solution that permeates the compound, and can effectively suppress corrosion of steel materials. . In other words, imidacillin compounds, polyamide compounds, quaternary pidginium salt compounds, or quaternary ammonium salt compounds eluted in the sour solution contain intramolecular K.
It has nitrogen atoms that can be strongly adsorbed to 111 steel materials and long-chain hydrocarbon groups that can form an adsorption layer thick enough to block chemical substances that cause corrosion (hereinafter referred to as corrosive species) from steel materials. Therefore, corrosion of steel materials caused by sour solution can be sufficiently suppressed. The range of the number of carbon atoms in the hydrocarbon group in each compound system mentioned above is determined by the minimum length of the long chain hydrocarbon group necessary to shield it from corrosive steel materials, and this allowable range is Compounds having a lower number of carbon atoms can only form a thin adsorption layer on the steel surface, and cannot sufficiently cut off corrosive species by Kml. However, compounds with extremely long hydrocarbon groups are generally expensive and have low solubility in water, so they are not preferred in practice.

On the other hand, as the base material to which these corrosion inhibitors are added, thread compounds specified in BamPI Standard 5m2 or products compliant therewith can be used.

Other materials can also be used as long as they are excellent in the seizure performance of the threaded portion, sealing performance, friction characteristics, and stability of the contact land itself.

Threadco 7 Nogland according to the present invention contains a corrosion inhibitor that has particularly excellent anticorrosion performance in sour environments, so it can be used in sour environments by being filled into one thread of a steel pipe. A major feature is that the corrosion inhibitor in the thread compound is eluted into the product by the sour solution that enters through the minute gaps in the thread compound, and steel O corrosion is sufficiently suppressed. This is extremely significant industrially in that it can completely eliminate the risk of internal fluid leaking from the threaded portion, which has traditionally been a major problem in sour environments.

Hereinafter, the effects of the thread compound according to the present invention will be specifically illustrated using PIK.

[Example 1. ] The following compounds were used as corrosion inhibitors.

(Corrosion Inhibitor I) An imidacillin compound having the following molecular structure.

However, B: Coconut oil fatty acid residue (corrosion inhibitor I) An imidacillin compound having the following molecular structure.

(Corrosion Inhibitor M) An inodacillin compound having the following molecular structure.

However, R: soybean oil fatty acid residue (X food suppressant y) A boria compound having the following molecular structure.

o.

B-0ONROM, 0%-ROB, OR, N-OR,
O to NI (00-Juku, R: Polymerized linseed oil fatty acid residue (corrosion inhibitor V) Quaternary Pi9 having the following molecular structure
Zinium salt compounds.

(Corrosion inhibitor ■) A quaternary ammonium salt compound having the following molecular structure.

ζ Straw corrosion inhibitor was added to the base material having the composition shown in Table 1.
Weight: 9G) was added to create a thread cone gland. For comparison, the first test without adding corrosion inhibitor was used.
Thread compounds with the composition shown in the table were also subjected to experiments.

Table 1 Basic composition: Apply these thread cone glands evenly to a cold-rolled copper plate (Ni: t8w thickness x 755w @ x 1505w length). A test piece was prepared by sealing it with paint.

Thereafter, these test pieces were immersed in a N Muro 1 solution (PH approximately 3) having the composition shown in Table 2 at 60° C. for two weeks to examine the anticorrosion performance of the thread compound in a sour environment.

The amount of corrosion was calculated according to the following 2.

Amount of corrosion (■)”XtX.

fe ta L s xe: Thread Konnozo Ranr
Thickness of cold rolled steel sheet measured before coating (average value of 9 measurements).

x,: Thickness of cold rolled steel plate measured after removing thread connoun r and rust after immersion (average value of measurements at 9 points).

Table 2 Composition of NAOI solution (Note) WAG rich solution solution This is a test solution assuming the harsh sour environment that exists in reality.

The results of this corrosion test are shown in Table 3.

Table 3 Corrosion test results As is clear from Table 3, steel materials coated with conventional thread compound undergo severe corrosion in a short period of time in a harsh sour environment, whereas the corrosion inhibitor of the present invention was added. Thread Connokun rt* coated steel exhibits good wear resistance.

[Example 1] The following compounds were used as corrosion inhibitors.

(G Eating Suppressant I) Isedashicin compound having the following molecular structure.

However, R = coconut oil fatty acid residue (corrosion inhibitor I) A having the following molecular structure (corrosion inhibitor ■) Quaternary pyridine having the following molecular structure
PM salt compound.

5-(
% by weight) to create a thread compound. For comparison, a thread compound R4 experiment with the same composition as shown in Table 1 without adding a corrosion inhibitor was used.

A steel pipe for chaping with an outer diameter of 73 mm was used as the test material, and the threaded part was coated with the above-mentioned Thread Connozo Land, and then the threaded part was tightened with a torque of 1000 mΩ.
Connected steel pipes. ``With a tensile force of 3 Kf/a'' applied to this steel pipe, a shoulder OB solution with the composition shown in No. 2* was poured inside, an internal pressure of 300 forces was applied, and the tube was kept at 60°C for 6 months. The results of this experiment are shown in Table 4. Leakage from the threads and corrosion of the threads were investigated.

As is clear from Table 4, the thread cone gland to which the corrosion inhibitor according to the present invention has been added has excellent thread sealing performance and anticorrosion performance in sour conditions.

Agent Patent Attorney Masaaki Akizawa 2 others

Claims (2)

[Claims] (1) A thread cone gland for sour environments characterized by containing an organic nitrogen compound having a fatty acid or alicyclic hydrocarbon group having 8 or more carbon atoms. (2) The organic nitrogen compound containing an aliphatic or alicyclic hydrocarbon group having 8 or more carbon atoms is an imidacillin compound, a polyamide compound, a quaternary pyridium salt compound, or a quaternary ammonium salt compound. The thread cone land for sour environments as claimed in claim 1, which is more than 100% seed.