US3661784A - Method of protecting metal surfaces against abrasive wear in submersible pumps - Google Patents

Abstract

SOLUTIONS OF WATER SOLUBLE AND/OR DISPERSIBLE OXYALKYLATED QUATERNARY FATTY AMINES NOT ONLY OFFER PROTECTION AGAINST ABRASIVE WEAR TO SUBMERGED METAL SURFACES, SUCH AS IN SUBMERSIBLE OIL WELL PUMPS, BUT ALSO THROUGH THEIR ANTI-BACTERIAL AND CORROSION INHIBITING ACTION OFFER PROTECTION AGAINST CORROSION AND BACTERIAL DETERIORATION OF THE PUMP.

Description

United States Tatent O ABSTRACT OF THE DISCLOSURE Solutions of water soluble and/or dispersible oxyalkylatedquaternary fatty amines not only offer protec- "tion' against abrasive wear to submerged metal surfaces, such as in submersible oil Well pumps, but also through their anti-bacterial and corrosion inhibiting action olfer protection against corrosion and bacterial deterioration of the pump.

Inrecent years hydraulic pumping systems for oil wells havelgone into widespread commercial use. These systerns utilize subsurface pumps which are positioned within the .oil well casing near the production stratum. The moving parts of these pumps operate with very close tolerances, and'the problem of abrasive wear is severe, especially when a brine or saline solution is employed. lirines are not ordinarily usable as hydraulic fluids because of their corrosive nature.

Chemical agents for use in lubricating submersible oil well pumps should be water-soluble or dispersible so that they can be introduced into the aqueous hydraulic fluid at the surface of the well, and the chemical agent must be adsorbed on the metal surfaces to be lubricated as the hydraulic fluid circulates over these surfaces. The chemical agent, after adsorption on the metal surfaces must function as a highly effective lubricant, that is, it 'must reduce abrasive wear between the surfaces. The

lubricant should also have the property of remaining on the metal surfaces under a high applied pressure or torque, as would be generated between the relative moving metal surfaces of the pumps. In other words, the lubricant should have good boundary properties to minimize wear and to prevent any increase in the tolerances of the contacting parts, and it should also be effective as an extreme pressure lubricant so that it is not squeezed off of the surfaces or desorbed at torques of greater than 60 to 80 inch-pounds.

Inoil production there exists a great number of solutes which" are very corrosive to the submerged pumps, for example, salts such as NaCl, CaCl BaCl sulfates of such rnetals'and gases, such as H 5, which are very corrosive to the metals commonly used in oil, water and gas "production. In addition to corrosion, damage is also caused by bacteria, such as sulfate reducing bacteria, which attack the metal surface of the pumps and in so doing produces colonies of bacteria (black slime) and hydrogen sulfide, which is the product of the bacteria, atscram the metal surface. Both bacterial attack and H 8 destroy the metal. Thus an ideal subsurface pump lubricant, or more properly stated a pump protectant, is one that not only lubricates the metal parts but also protects against corrosion including that resulting from bacterial attack on the metal construction of the pump. Formulations lwhich afford both lubricating and anti-bacterial action are ordinarily achieved by using individual ingredients each of which does a particular job. However, the use of a sole agent which would perform both functions would have a definite advantage over formulations containing multiple components.

. Ihave now discovered that solutions of water soluble and/or dispersible oxyalkylated quaternary fatty amines 3,661,784 Patented May 9, 1972 ICC not only offer protection to submerged metal surfaces, such as in submersible oil well pumps, against abrasive wear but also offer, through their anti-bacterial and corrosion inhibiting action, protection against deterioration of the pump due to corrosion and bacterial action.

The compositions employed in this invention are oxyalkylated quaternary fatty amines capable of being dissolved and/or dispersed in an aqueous medium. They may be represented by the following general formula represents the quaternary ammonium group, R represents substituted group comprising the quaternary ammonium substitution which are preferably hydrocarbon such as alkyl, aryl, cycloalkyl, alkenyl, etc., but preferably alkyl; OA represents the oxyalkyl group such as derived from ethylene oxide, propylene oxide, butylene oxide, etc., as homo, hetero, block, etc. units: the sum of a+b=4 so as to make up the substitution units necessary for a quaternary group, Z comprises an optional group which is employed to end cap the oxyalkylation group such as an acyl group, a fractional acyl group having unreacted carboxyl group, i.e.

ether group, sulfonate, sulfate, etc., groups, salts thereof, etc.

Polyquaternaries, such as d-i-, tri-, etc. quaternaries can also be employed for example of the general formula where 0 0 f). F (T); m 1x z z lb L-Jh m where a+b-=3, m is an integer l, 2, 3, etc., B is a linking group such as alkylene, alkylene-o-alkylene, alkarylalkyl, etc., i.e. a hydrocarbon group, a hydrocarbon group containing other elements, etc.

Typical examples include the following:

69 mmomnnx e amuoanmtx o 0 G3 amuoAnii-niion x 6 RN omnd-n-dornax ea ammo A ,,so,11 x

9 e RN[(OA)nSOaH]2X etc.

The following illustrates where R is other than hydrocarbon such as 9 IEIO( i!CHgbP-(OA) 11X and salts thereof where the N-carboxylate unit is derived from chloracetic acid. Other chloracids can also be employed.

Polyquaternary may be illustrated as follows:

Y=Alkylene, aryl, alkarylalkylene, alkylene-O-alkylene, etc.

These diquaternaries can also be acylated, etherified, 4O sulfated, sulfonates, etc. and salts formed therefrom in the manner of the monoamines.

All of the above quaternaries may have any suitable anion X which may be halides, sulfates, carboxylates, etc., but preferably chlorides.

The n value of alkylene oxides added in the above formulas may vary widely depending on the particular compound, the system in which it is employed, etc., such as from 1-100 or more, such as from 1-50, for example from 1-25, but preferably 1-10, with optimum results of from 3-5.

The R groups may have 1-30 or more carbons and preferably have at least 1 fatty group, i.e. 7-30, but preferably 12-18 carbons and also at least 1 lower alkyl such as methyl group.

A preferred group of compounds has general formula h-W R-N x u-10H where R has 12-18 carbon atoms and X is an anion which may be halides, sulfates, carboxylates, etc., but preferably chlorides.

where R R R and R are selected from the group consisting of hydrogen, an aliphatic, cycloaliphatic, aryl, etc., group for example ethylene oxide, propylene oxide, butylene oxide, amylene oxide, octylene oxide, styrene oxide,

4 methyl-styrene oxide, cyclohexene oxide (where R and R are joined to make a ring), etc.

Equivalents of alkylene oxides can also be employed, for example alkylene carbonates, i.e., ethylene carbonate, propylene carbonate, butylene carbonate, etc. In addition, alkylene oxides of the glycide, methyl glycide type can also be employed.

Commercially available quaternary compounds are limited by their solubility in any given solvent thus requiring the use of various solubilizers and/or wetting agents or surfactants to overcome this deficiency. However, such use often detracts from the function of the quaternary group as to surface bonding, surfactancy and/or bactericidal action. However, by oxyalkylating the quaternary compound itself, the compound has the desired modification built into the molecule itself rather than being exteriorly modified by mixture with another distinct and separate compound.

By the proper addition of the proper type and amount of alkylene oxides, the water solubility and/or dispersibility can be increased or decreased. For example, by employing a hydrophilic alkylene oxide, such as ethylene oxide, water solubility and/or dispersibility can be increased. By employing a hydrophobic alkylene oxide, ie other than ethylene oxide, such as propylene oxide, butylene oxide, etc., the water solubility and/or dispersibility can be decreased. In general, it is desirable to add no more alkylene oxide than is necessary to obtain the desired properties. Stated another way, the quaternary compound should be modified to achieve the desired balance of lubricity, bactericidal action, surfactancy and corrosion inhibition properties.

The following compound which gave the proper bal ance of lubricity, corrosion inhibiton, and bactericidal action is employed to illustrate the present invention.

Example A HzcHzo) XH RN 01 (CHzCH20) II Ex. B: Ex. C:

Cocoamine Tallowamine (C Ex. D: Hydrogenated tallowamine Ex. E: Hexadecylamine They all exhibit the properties of lubricity, corrosion inhibition and antibacterial action, particularly against sulfur reducing bacteria.

USE EXAMPLES In practicing the method of this invention, the lubricating compound is dissolved or dispersed in water or in a saline brine, or more generally in the aqueous phase of a fluid medium, which may consist of an oil and brine mixture, or a pumpable drilling mud having an aqueous phase, etc. The concentration of the lubricating agent in the water or the aqueous phase of the fluid medium should be sufficient to provide for the coating of the metal surfaces to be protected against abrasive wear. Usually, the water of aqueous phase should contain at least 50 ppm. (parts per million) of the lubricating compound, and in most applications, it will usually be preferable to employ at least ppm. of the lubricating compound. Usually, it will not be necessary or desirable to use concentrations greater than 500 to 1000 ppm. For use in oil well subsurface pumps where the lubricating compound is introduced into the brine employed as the hydraulic fluid, concentrations of from 50 to 500 p.p.m. 'are satisfactory. For example, good results have been obtained in such applications with concentrations ranging from 100 to 200 p.p.m. The aqueous phase containing the lubricating compound is contacted with, or preferably circulated over, the metal surface to be protected against abrasion. If desired, the surface may be continually treated with the water or aqueous phase containing the lubricating compound, thereby tending to maintain the desired protective layer or film of the lubricating compound during operation of the pump or similar apparatus.

The method of this invention is further illustrated by its application to the lubrication of subsurface hydraulic pumps in oil Well production operations. The oxyalkylated quaternary ammonium compound is employed as a lubricant in the aqueous power fluid at a concentration of from 150 to 200 p.p.m. The power fluid may be salt water or fresh water. Before circulation to the subsurface pump, the power fluid will be kept in one or more surface tanks, and is therefore convenient to introduce the lubricating agent into the fluid while it is under surface storage. For a so-called open system the fluid will only be circulated once, and therefore it is a simple matter to achieve the desired concentration introducing the lubricating agent into the fluid before it is circulated. For a closed system where the aqueous hydraulic fluid is recirculated after it has been separated from the oil, there may be some residual lubricating agent in the fluid, and it may be desirable to add only sufficient lubricating agent to make up the concentration to the desired level before the fluid is recirculated. Alternatively, a higher than necessary concentration can be employed for the initial circulation, such as a concentration of 500 to 600 p.p.m., and the fluid can be recirculated until the concentration drops below the desired level for maximum lubricating protection. With this procedure, make-up lubricating agent need only be added periodically. If desired, an auxiliary corrosion inhibitor can also be incorporated in the circulating fluid. The procedure just described is applicable to various commercial subsurface pumps, such as those supplied by the Fluid Packed Pump (10., a division of the National Supply Company, or by Kobe, Inc.

While in the foregoing specification this invention has been described in relation to certain preferred embodiments thereof and many details have been set forth for the purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to other applications and embodiments and that many of the details described herein can be varied considerably without departing from the basic principles of the invention.

Having thus described my invention what I claim as new and desire to obtain by Letters Patent is:

1. The process of simultaneously lubricating and protecting subsurface metal surfaces in abrasive wear contact against corrosion and bactericidal action characterized by adding an oxyalkylated quaternary amine salt to water or a saline brine, said amine salt being Eto),H Raf (EtO) H where R is alkyl or alkenyl of 12-18 carbon atoms, x is 1-10, y is 1-10 and X is a halide.

2. The process of claim 1 Where R is stearyl, the sum of x and y is about 3 and X is chloride.

3. The process of claim 1 where R is tallow, the sum of x and y is about 3 and X is chloride.

References Cited UNITED STATES PATENTS 2,738,325 3/1956 Rydell 252-8.55 D

2,344,886 3/1944 Lieber 252-34 X 2,759,975 8/1956 ChiddiX et a1 25234 X FOREIGN PATENTS 261,036 11/1963 Austrialia 252390 DANIEL E. WYMAN, Primary Examiner W. J. SHINE, Assistant Examiner US. Cl. XJR.