Self-operating chemical feeder for an oil well
BACKGROUND OF THE INVENTION 
     It is often desired and necessary to periodically treat producing wells with corrosion inhibitors or other types of treating chemicals. This regular treating of the well may comprise pouring a chemical from a tank of the chemical, such as the corrosion inhibitor through a conduit into a well, and manually measuring a slug of the chemical to the well. Immediately thereafter a flush fluid as a slug of higher pressure flush liquid, as water under pressure, from a suitable source must be measured out for pushing the slug of chemical to and throughout the well for treating the well, as coating all internal surfaces of the well casing and tubing with the corrosion inhibitor. This treatment must be done on a regular basis as scheduled, as once a week, if not sooner, for months and months on end, on many very remotely located wells. The personnel required to operate this oil well periodic corrosion inhibitor treatment, for example, with any degree of reliability, comprises a substantial investment and logistics problem. 
     To solve this problem, a self-operating chemical feeder system has been invented, designed, built, and put in operation on some remotely located oil wells. 
     OBJECTS OF THE INVENTION 
     Accordingly, a principal object of this invention is to provide a self-operating chemical feeder for a well for insuring well treatment on a regular basis as scheduled and for eliminating personnel time required for manual chemical treatment of the well for an extended period of time. 
     Another primary object of this invention is to provide self-operating chemical feeder for treating an oil well with measured precise slugs of corrosion inhibitor and with precise slugs of flush fluid injected behind each chemical slug for spreading the corrosion inhibitor throughout the well on a regular basis as scheduled for an extended period of time. 
     A further object of this invention is to provide a mechanism for ejecting a precise measured amount of a chemical slug and a measured slug of flush fluid for ejecting the chemical throughout an oil well on a regular basis as scheduled that is easy to operate, is of simple configuration, is economical to build and assemble, and is of greater efficiency for the saving of personnel time and for increased reliability on treating remotely located wells for an extended period of time. 
     Other objects and various advantages of the disclosed self-operated chemical feeder will be apparent from the following detailed description, together with the accompanying drawings, submitted for purposes of illustration only and not intended to define the scope of the invention, reference being made for that purpose to the subjoined claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The drawing diagrammatically illustrates by way of example, not by way of limitation, one form of the invention wherein like reference numerals designate corresponding parts in the several views in which: 
     The FIGURE is a schematic diagrammatic vertical sectional view of a self-operating chemical feeder for treating an oil well. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The invention disclosed herein, the scope of which being defined in the appended claims is not limited in its application to the details of construction and arrangement of parts shown and described, since the invention is capable of other embodiments and of being practiced or carried out in various other ways. Also, it is to be understood that the phraseology or terminology employed here is for the purpose of description and not of limitation. Further, many modifications and variations of the invention as hereinbefore set forth will occur to those skilled in the art. Therefore, all such modifications and variations which are within the spirit and scope of the invention herein are included and only such limitations should be imposed as are indicated in the appended claims. 
     The FIGURE is a vertical sectional view illustrating the chemical feeder system 10 for treating a producing oil well 11. 
     The oil well 11 is a conventional producing oil well having a casing 12 perforated at the bottom for oil to pass through it, the gravel pack 13, and perforated production tubing 14 to the surface. Here the oil passes through a separator 15 from which oil is bled off in oil line 16 and water is bled off to a flush line 17. Injection line 18 from the chemical feeder 10 injects chemical slugs as pushed forward by slugs of wash liquid down into an annulus 19 in the well. 
     While this invention is particularly conceived and designed for use with oil and gas wells, with changes and additions it possibly may be designed and adapted to other wells. 
     The chemical feeder system 10 includes a steel rack 20 for supporting a 55 gallon (209 liters) chemical tank 21, for example, with sight glass 22 for supplying the chemical to a 1/3-horsepower electric pump 23. The chemical or chemicals from the pump pass through a conventional quick acting or 1/2-inch motor snap valve, as a solenoid valve 24, and then through check valve 25 to injection line 26 which injects the chemicals into the well 10. A pressure gauge 27 is connected in the line between the pump 23 and the valve 24. A timer or electric clock 28 is connected to valve 24 for metering out a predetermined precise amount or slug of chemicals, as a corrosion inhibitor, for the well every 7 days, for example. 
     A flush line 29 supplies a predetermined precise slug of flush liquid to the injection line 26 for pushing and carrying the chemical slug through the injection line to the well 11 for treating the well, as by coating all internal surfaces thereof with the corrosion inhibitor. This precision slug of flush liquid is metered from the flush line by a conventional quick action or solenoid or 1/2-inch motor snap valve 30 controlled by a second timer or 7-day electric clock 31 mounted on the steel rack 20. Check valves 25 and 32 prevent any back flow of flush liquid or chemical in the injection line or the flush line, respectively. 
     While the flush line is illustrated as being supplied with water from the oil-water separator 15, it may be supplied from any other suitable source. 
     Likewise, while the flush in the disclosed system comes from a separate line, it may emerge from the chemical feeder system already mixed with the chemical for being transported through the ejection line to the well. In the illustrated example, the flush may circulate the chemical or chemicals from 1 to 24 hours, as required, on any one or more days each week. 
     Thus with the disclosed chemical feeder, it is insured that wells will be treated on a regular basis as scheduled and that unnecessary personnel time will be eliminated, particularly for &#34;batch&#34; type treatments, for example. 
     Thus accordingly, it will be seen that the present self operating chemical feeder operates in a manner which meets each of the objects set forth hereinbefore. 
     While only one embodiment of the invention has been disclosed, it will be evident that various modifications are possible in the arrangement and construction of the disclosed self-operating chemical feeder without departing from the scope of the invention, and it is accordingly desired to comprehend within the purview of this invention such modifications as may be considered to fall within the scope of the appended claims.