US2438682A - Method and materials for cleaning oil wells and equipment - Google Patents

Description

' Patented Mar. 30, 1948 METHOD AND MATERIALS on CLEANING OIL WELLS AND EQUIPMENT Pearlie B. Roberts, Tyler, Tex.

No Drawing. Application August 7, 1945, Serial No. 609,491

This invention has to do with method and materials for cleaning oil wells and oil producing equipment. Specifically it is concerned with the removal of deposits and accumulations of mineral wax, par-afiin and asphalt from oil bearing rocks and sands at the horizon in the earths crust from which crude petroleum is produced, and the removal of such accumulations in pipes, tanks and oil producing apparatus generally, including pumps and oil well equipment. The employment of the cleaning method and materials results in the dispersal of solid and semi-solid accumulations of paraflin and asphalt in such manner that they are suspended and/ordissolved in the crude oil to the extent that they no longer form objectionable deposits; and the oil, of which they be- :come a part upon dispersal, may be easily ex- 6 Claims. (C1. 2528.55)

tracted from the earth, caused to fiow through pipes and'pumping apparatus and be discharged into storage tanks and pipe lines without a recurrence of the undesirable accumulations.

In the recovery of crude petroleum from strata of the earth in which the oil is found, such as from formations of sand and/or of rock, it has been a common experience to find that a productive oil well will cease to yield oil in commercial quantities after a period of time because the interstices, voids and openings within the oil bearing formations become blocked and clogged with paraflin and/or asphalt, so that in numberless cases the oil wells have been abandoned.

Ordinary methods used in attempts to clean out the formerly productive strata have, for the most part, been quite unsatisfactory. In some instances the heat of steam, piped to the oil producing strata below theearths surface, has been used to melt solid deposits of the parafiin and asphalt and allow them to be discharged through the tubing of the oil well. However, such deposits usually solidify again in the pipes and tanks through which they are conducted or in which they arestored above ground; and this is a common occurrence, especially in cold weather. Electrical heating equipment has been tried, and with much the same results. Either method is considered altogether too expensive for successful commercial use.

Further attempts have been made to treat the oil bearing formations with acid in order to cause the oil to flow again. Such treatment has little or no effect on sand formationabecause acid does not react favorably on compounds of silica. The parafiin present inhibits the action of the acid, and in some cases nullifies it altogether.

Slightly better results were had in treating limestone formations with acid. But, again, the presence of parafiin severely limited the efiectiveness of such treatment. x

Cutting and scraping tools have been resorted to to remove paraffin from oil well tubing, casing and flow lines. Usually this requires the disconnection of every length of pipe; and-it is quite expensive and slow. Obviously the oil bearing formations below the earths surface cannot be cleaned successfully with any such mechanical devices.

Asphalt or petroleum tar has been found even more tenacious and difficult to remove than parafiin, being heavier bodied and often found in hard and incrusted deposits.

When parafiin and/or asphalt accumulates in the bottom of large oil storage tanks, it frequently gets so thick and heavy that a large percentage of the oil produced is thus wasted, thickened deposits being unfit for delivery into pipe lines.

Pumps, oil lifting and delivery apparatus, sucker rods, and all paraphernalia used for lifting and delivering oil frequently get so fouled up that all of this equipment has to be taken down, disassembled and laboriously cleaned by hand before it can befurther used.

In short, the occurrence of undesirable deposits of parafiin and asphalt in the production of oil, beginningin the oil bearing formations of the earth and continuingthrough everystage of production, storage and delivery until the oil reaches the pipe lines for transportation, presents a problem of major importance and of great cost and expense in the recovery of oil. Method and means for solving this problem chemically, and of eliminating excessively expensive heat treat- 'ments and inelfectual scraping operations and much manual effort, areof great value in the petroleum industry. p j

The primary object of this invention and discovery is to clean and remove and dissolve excess deposits and unwanted accumulations of' parafi'in and asphalt from oil Wells, from exposed surfaces of oil bearing formations of the earth, from pipes and casing and tubing from oil pumping and lifting apparatus, and from now lines and storage tanks.

An object of primary importanceis to change the ordinarily insoluble paraifin and asphalt deposits into free flowing fiuids,,readily, miscible with crude petroleum to the 'extentthat they become a part thereof. l

A further object is to cause paraffin and asphalt to be again dissolved in live crude oil so that it may be lifted, stored and transported, remaining in solution in the oil all the while.

A further object is to promptly causedeposits and accumulations of paramn and asphalt to be so suspended in crude oil thattheymay be readily pumped and piped with the oil'without thereafter forming objectionable deposits.

An object of major importance is to effect' the foregoing objects through chemical action and 3 without the use of applied heat and without manuallabor it f The mehod which I employ to effect the foregoing objects is that in which a chemical preparation, which I have compounded, is introduced into the oil Wells, pipes, pumps, apparatus, storage tanks, and other equipment used inthe pm duction, piping, pumping and storing of crude oil, to free and suspend and dissolve the parafiin and asphalt deposited therein so that it may readily flow away with the oil. 1

I practice this method by introducing a few gallons of my compound into the top of oil wen casing or tubing, then; allowing chemical rection. to. occ r. -,an c t nue, for a Pe i d 9 sever -1. hours, usua1 y..o er..ni t. u p red which annotb moved ..w o l .W t b n be ause .otthe. r senc f vr f a d/Or sphaltadhering tenaciously to the rods and tubing will be found free and capable of movement after the ,tr.eatment has continued for a few hqurs. flhen by addin m e or t e hemical pr p ra ion and start the p m to 996 ate, I cause the discharge of these undesirable ac um la ions. queh a elve ett e pp-f t 1 hep ilwell.

' pt tigrg.tpeiatisgith ve assented tor '30 a brief period, the discharge becomes so liquefied mfg the ;611 ,wen itself a d the 3? th r eefl Heath n. he. nsle teb e si or and asphalt therein; and they are rendered pair and capable of normal use withfi. e t .4. "By u of this method the solids of petroleum ar made page; nd j 'issqivjeu in the normal petroleum liquid to ch an -extent that 'the crude oil into-which th yl 'are returned will be freely t e preparation into wit i hfiinical compound admitted to the pipe lines as conimercm crude oil. Thus, these solids are no longer waste materia1's,-e pensi fe to eliminate. They are translate'd 1 again into their originalflstate as compohentp'arts:oflsaleable oil, :atgreat profit and advantage What wason'ce 'a problemiand Iexpe'nsTe is madean 'as'setanda matter of profit bythe employment of the method and materials here'disclosed... H

The chemical compound used is non-inflammable; andit doescnoinjury or damage to the ea'sin'g..-tubing,. rods,- pumps,v pipes. .or. tanks. Th'eyare .Jall -rendered. clean, .and. their. surfaces are freed; from .these undesirable accumulations and there is no harmful 'leffect on the metallic surfaces ofthe equipment treated.

. method :requires theusegof fresh or free lowing, .crude oil to be mixed together. with th chemical compound .to. createcan ,efiect iv'e agent fmldetachingthe solid deposits of petroleum and ssolvingthem... -,,..The crude.ypetrole m ma rei trod ced by ouring or pumpingpit into the Vessel to be cleaned or intg a ;condui t leading to the surfac s; to be ..-c en nemetrol m. m r. be

used have been applied to the surfaces or substances to be treated. When petroleum already occurs asinan oil well flow lines, pipes, tanks and equipment, .then the chemicalsare simply poured into the liquid petroleum. The cleaning and dissolving action begins at once.

The chemical compound, which I have prevpagred is made by mixing one or more of the basic hydroxides of the metals of greater ac- .tivity innthe electromotive series, such as those of sodium and/or potassium, in aqueous solution, together with one or more chemicals of the benzene ring, such as phenol, cresol or 5w t t e. re. emos tt re: an

e (illit 'ffctil/e as con ilibn l lfs of this t is rather ore if vs to use a 'strong solutron o'fnmetallic .hydrox dc, althoughjhatisa matter of efonve'n rice. ,Iiikewise, thestrength of the ph sugar 'hydroii'yl mpound edis a matth ro'n rpr ber b Jee- "esnemea be i be see together. f' found that potassium hydrox de is 'iiforeeffective 'in .01 'nirig the eigposedjsjur'face s. of limestone. formations from which oil is -beingproduced; andstai um ydr fi;.. m e Asa c mmer ia lr'j ep i .-Y i 61 I em gyeb tsq el au ter but thesepfoportignsmay be varied "to suit c'o'ndltionsas they ar efound. ran n giide'i'sfnfot readily dissolved th quan it -bi. Water added, i j 'a b {were quickly dissolved by heating the miiiture Oi it m y be freadiiy dissolved byaddirig thelhydroifyl compgund, there gbei ng a To emieal ."heat {from the reaction which hastens 'th'e maliiiig 'of the sowtion.. a

Any one of the three were ii at I named may be usedri nthe mixture; 'oiftwb or three of them 6g net "injth'e mixture. whe n twqpr inp're are used together, the proportion between them is not very important. The important"h arouse oiieorbothfoi the hydrogsides w th. one or more "(if the "phenom er Q iilfi dQQt-i' dfi'ff et qrii g y ht t Pe T l h i on p rt he ette as ip.:? 'e 3 5 portions the w ght of the water addedis'riot takeninto'accou'nt. V v

.. ,lieweyeatt -.ps rqr i as. For stance theguzgture ot thefchemicals,Tachinconcentratd commercial form, may -eir'ip'lo'y from to 90% of hydroxide and from 10% to 90% of hydroxyl compound or phenol.

For the purpose of defining the two oxides named, as a class, it will be noted that the molecular weight of sodium hydroxide is generally accepted as being approximately 40, and that of potassium hydroxide as 56. There appears to be only two more active metals in the electromotive series than potassium and sodium; and these are lithium, the hydroxide of which has a molecular weight of 24, and rubidium, the

hydroxide of which has a molecular weight of Therefore, it may be said that, of the electromotive metals more active than hydrogen, there will be used in this compound only such hydroxides, of said metals, that have a molecular weight between 39 and 57.

In speaking of phenol when used in this s'pecification it is intended to comprehend its broadest sense, meaning to include the phenols as a class (the hydroxy derivatives of benzene, naphthalene and other aromatic hydrocarbons).

In speaking of a mixture as consisting essentially of certain substances, I mean that it is necessary to have these substances in the mixture and that they are essential thereto and that the mixture is essentially these substances; but I do not intend to exclude minor amounts of other ingredients which have no efiect in producing the ultimate objects of the use of the mixture or of the method employing it. Inert materials, coloring, odors and non-essential substances may also be present in my mixture.

The method here delineated and the materials here disclosed have been found very efiective in greatly increasing the recovery of petroleum from oil wells which have become congested with solid and semi-solid deposits from petroleum. Wax, parafiin, asphalt and tar are the great offenders; and through my invention and discovery these may be liquefied so that they will again flow with the oil and become a part thereof. A great economic loss of petroleum products is prevented.

Conduits and oil producing and storing and transporting equipment are cleaned and rendered free of obstructions and kept so. Waste is eliminated. A great saving of time, labor, and expense results from the employment of my discovery; and oil field materials, machinery and equipment are given longer life through its use.

I claim:

1. The method of liquefying solids deposited from petroleum, in which said deposits are treated with a mixture consisting essentially of a chemical selected fromthe group consisting of sodium hydroxide and potassium hydroxide, said chemical representing from 10% to 90% of the mixture, a phenol representing from 90% to 10% of the mixture, and sufficient water to dissolve the mixture, said treatment being accomplished in the presence of crude oil.

2. The method of dissolving the solids of parafin and asphalt deposited from petroleum and re-introducing said dissolved materials into stable union with crude petroleum, which consists of the treatment of such solids by a mixture consisting essentially of a substance selected from the group consisting of sodium hydroxide and potassium hydroxide, said substance representing from 10% to 90% of the mixture, and a phenol representing from 90% to 10% of the mixture, and suiiicient water to dissolve the mixture, such treatment being made in the presence 6 of crude oil and continuing until said solids are dissolved.

3. The method of removing paraflin and asphalt deposited from petroleum by treating such deposits with a mixture consisting essentially of a substance selected from the group consisting of sodium hydroxide and potassium hydroxide, said substance representing from 10% to of said mixture, a phenol representing from 90% to 10% of said mixture, and suificient water to dissolve the mixture, said treatment being made in the presence of crude oil.

4. The method of dissolving and recapturing solids deposited from petroleum by treating them with a mixture consisting essentially of a substance selected from the group consisting of sodium hydroxide and potassium hydroxide, said substance amounting to from 10% to 90% of the mixture, a phenol amounting to from 90% to 10% of the mixture, and suflicient water to dissolve the mixture, said treatment being carried on in the presence of crude oil until said solids are dissolved therein.

5. The method of dissolving and recovering solids deposited from petroleum by treating them with a mixture consisting essentially of a substance selected from the group consisting of sodium hydroxide and potassium hydroxide, said substance representing from 10% to 90% of the mixture, cresol representing from 90% to 10% of the mixture, and sufficient water to dissolve the mixture, said treatment being carried on in the presence of crude oil until said solids are dissolved therein.

6. The method of dissolving and recovering solids deposited from petroleum by treating them with a mixture consisting essentially of a substance selected from the group consisting of sodium hydroxide and potassium hydroxide, said substance representing from 10% to 90% of the mixture, naphthol representing from 90% to 10% of the mixture, and sufiicient water to dissolve the mixture, said treatment being carried on in the presence of crude oil until said solids are dissolved therein.

PEARLIE B. ROBERTS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,199,271 Hawley Sept. 26, 1916 1,439,128 Runge Dec. 19, 1922 1,534,167 Deavitt Apr. 21, 1925 2,010,800 Adams et a1. Aug. 13, 1935 2,107,288 Curran Feb. 8, 1938 2,172,083 Herbsman Sept. 5, 1939 2,342,656 Frye et al. Feb. 29, 1944 2,356,205 Blair et a1. Aug. 22, 1944 2,356,254 Lehmann et a1. Aug. 22, 1944 2,386,605 Harton et a1. Oct. 9, 1945 OTHER REFERENCES Morgan et al., Extraction of Phenols from Tar Oils, Industrial and Engineering Chemistry, vol. 17; pages 696-700, July 1925.

Morris, Chemical Cleanout of Oil Wells in California, The Oil Weekly, April 19, 1937; pages 23, 24, 26, 28, 30, 32 and 34.

King, Chemical Treatment of Wells in Trinidad, The Petroleum Engineer, October 1943; pages 174, 176, and 178.