US 2349536 A
Description (OCR text may contain errors)
May 23, 1944- C. c. BANcRoF-r 2,349,536
APPARATUS FOR PREVENTING CLOGGING OF OIL WELLS Filed NOV. 7, 1941 M ,Zgz 26 Patented May 23, 1944 APPARATUS FOR PREVENTING CLOGGING F OIL WELLS Charles C. Bancroft, Reno, Nev.
Application November 7, 1941, Serial No. 418,180
This invention relates to apparatus for preventing clogging of subterranean wells, and more particularly to the prevention of accumulations of parailin and like asphaltic or bituminous materials in oil wells.
In the operation of oil wells, it has been found that parailn and other asphaltic or bituminous materials tend to collect on the pump tubing and around the structure in the lower part of the well. This accumulation builds up gradually until the well is substantially closed, so that proper flow of oil therethrough is seriously interfered with. When this occurs, it is necessary to stop production of the Well, and to clean the deposits therefrom before proper production can be resumed. v
The present invention has for one of its objects the provision of apparatus for preventing accumulations of such material in a well which might interfere with its proper production.
Another object oi.' the invention is to provide for the heating of the pump tubing in the lower part of the well to prevent accumulations of material thereon.
Still another object of the invention is to provide apparatus for circulating a heated liquid in heat transferring relationship to the pump tubing of a well to heat the same.
The above and other objects, advantages and novel features of the invention will be apparent from the following description when read in connection with the accompanying drawing, in which:
Figure 1 is a diagrammatic view illustrating one installation for preventing clogging of the well; and
Figure 2 is a similar view of an alternative construction.
As shown in Figure l, an oil well having a casing I0 therein is provided with a pump tube I2 extending to the bottom thereof and terminating in a perforated or screened portion I4, through which oil from the bearing strata may enter the pump tube. The tube I2 extends out of the upper end of the well and is provided with suitable pump means, indicated generally at I6. for withdrawing liquid through the tube.
In order to heat the pump tube adjacent the lower part of the well to prevent accumulations of parailin or the like thereon, there is provided. according to the present invention, a coil I8 of copper tubing or the like, wrapped around the pump tube adjacent the lower part of the well. If desired, the coil may partially cover the perforated portion I4 and may have its turns spaced to permit the iiow of oiltherebetween. The coil I8 is preferably formed of relatively small copper tubing and is permanently installed on the pump tube at the time it is placed in the well. One end of the coil I8 is connected by a pipe 20 which may be a steel tube with a high pressure storage tank 22 for heated liquid, such as oil, to be circulated through the coil. It will be noted that the pipe 20 extends into the well between the casing Ill and the pump tube I2. The opposite end of the coilis connected to a similar tube 24, likewise extending out of the well between the casing and the pump tube. It will be seen from the drawing that the coil is wrapped double with a return bend at its lower end and with both tubes 20 and 24 connected to its upper end so that a minimum space is required.
Oil to be circulated through the coil is heated in a heater, indicated at 26, the oil being circulated therethrough by a pump 28 from the lower part of a storage tank 30, the heated oil from the heater flowing into the upper part of the storage tank. From the top of the storage tank, heated oil is withdrawn through a pipe 32 by a high pressure pump 34, and is forced by the pump under high pressure into the high pressure storage tank 22. A by-pass 36, having a pressure relief valve 38 therein, preferably connects the storage tanks 22 and 30 to limit the pressure which can be built up in the storage tank 22. The pipe 24 is connected to the lower end of the storage tank 30, and may, if desired, be provided with a pressure gauge 40, to indicate the pressure in the return line from the well.
In operation, oil heated by the heater is withdrawn from the storage tank 30 by a pump 34, and is forced under high pressure into the tank 22. From this tank, it flows through the pipe 20 into the coil I 8 and through the coil, thereby heating the pump tube and the adjacent parts in the lower portion of the well to a temperature above the melting point of the paraiiin or other bituminous or asphaltic compounds. From the coil, the oil returns through the pipe 24 to the low pressure storage tank 30, to be recirculated.
I have found that the oil should be heated to a temperature of approximately 400 F., and should be forced into the tubing at a pressure of approximately 2000 pounds per square inch. For the normal well, a circulation of about barrels per day will keep the pump tubing and the adjacent parts at a high enough temperature so that paraiiin and the like will not accumulate thereon. Thus, by the use of the present invention, the well may be kept clear and open indefinitely, thereby eliminating the necessity for periodic cleanings.
Figure 2 illustrates an alternative construction, the parts therein corresponding to like parts in Figure l being indicated by the same reference numerals.
In this construction, the pump 28 withdraws oil through a pipe I2 from the oil storage tank, which may be a tank supplied from the well by the pump I6. This oil is forced through the heater 26 into the low pressure storage tank 30 and is pumped into the well by the pump 34 through the pipe 20 in the manner described in connection with Figure 1. From the pipe 20, the heated oil flows through the coil I 8 to`heat the pump tube I2 and the surrounding parts, and returns from the coil through a pipe u, which is tapped into the pipe l2, as shown.
In this construction, it is necessary to provide only one pipe extending into the well to conduct heated oil to the coil, the oil after circulating through the coil passing into thefpump tube l2 and being withdrawn from the well by the main pump I6. Otherwise, the system operates in substantially the same manner as that of Figure 1.
While two embodiments of the invention have been shown and described in detail, it will be understood that these are illustrative only, and are not intended as a. definition of the scope of the invention, reference being had for this purpose to the appended claims.
What is claimed is:
l. Apparatus for preventing the clogging of oil weils having pump tubing therein which comprises a coil of pipe coiled around the lower end of the tubing in contact therewith within the Well, an elongated pipe for conducting heated liquid through the well into said coil to heat the tubing, and conduit means to conduct liquid from the coil into said tubing.
2. Apparatus for preventing the clogging of oil wells having pump tubing therein which comprises a coil of pipe coiled around the lower end of the tubing in contact therewith within the well, an elongated pipe for conducting heated liquid through the well into said coil to heat the tubing, conduit means to conduct liquid from the coil into said tubing, and means above the well for heating liquid, and a pump for forcing the heated liquid through said pipe and coil and into the tubing.
CHARLES C. BANCROFT.