GB2394980A

GB2394980A - Well pump apparatus wih improved liquid quality

Info

Publication number: GB2394980A
Application number: GB0402085A
Authority: GB
Inventors: Richard C Jackson; Michael E Judkins
Priority date: 2000-03-29
Filing date: 2001-03-29
Publication date: 2004-05-12
Anticipated expiration: 2021-03-29
Also published as: GB0402085D0; GB2394981A; GB0402091D0; GB2394980B; GB2394981B

Abstract

A well pump and pipe assembly in a well having regions of low and high contamination includes flow control disks coupled to the pipe and positioned between the regions of low and high contamination. The disks form a barrier that allows suction to be enhanced in the region of low contamination and inhibited in the region of high contamination, thus improving liquid quality.

Description

METHOD FOR IMPROVING WELL QUALITY

FIELD OF THE INVF,NT1ON

s The present invention generally relates to wells such as water wells and oil wells, and specifically relates to methods for improving the quality of the liquid (c.g., water or oil) removed from wells.

10 BACKGROUND OF TIlE INVENTION

In 1976, the IJnited States Environmental Protection Agency (EPA) promulgated interim drinking water standards under the Safe Drinking Water Act (SDWA). In 1991, the EPA proposed revisions to the 1976 requirements, and in 1996 the SDWA was amended. The amended SDWA established a list of contaminants to be regulated under 15 primary standards and secondary standards. The primary standards are based on hea] tl effects and the secondary standards are based on aesthetics. The standards establish a maximum contaminant level for several contaminants.

One group of contaminants that is regulated under the SDWA is called radionuclides, including radium, gross alpha, and uranium. The primary standards for 20 these three radionuclides are 5 pCi/L, 15 pCi/L and 30 pCi/L, respectively. Other contaminants that are generally undesirable include arsenic, iron, and others. It can he appreciated that it would be desirable to have a method for reducing the level of contaminants in water that is withdrawn from a water well.

Similar to water wells, oil coming from oil wells can he contaminated. For 25 example, oil contaminants can include sand, paraffin, water, or minerals. While contamination of oil is not typically a health hazard, the value and usefulness of contaminated oil is typically significantly less than that of cleaner oil. Therefore, it can be

appreciated that it would be desirable to have a method for reducing the level of contaminants in oil that is withdrawn from an oil well.

SUMMARY OF TIlE INVENTION

5 According to the invention there is provided a well pump and pipe assembly positioned in a.vell, comprising: a well having a region of low contamination and a region of high contamination; a well pipe positioned in the well; a well pump coupled to the well pipe; and flow control disks coupled to the pump and pipe assembly and positioned substantially between the region of low contamination and the region of 10 high contamination.

This may improve the quality of liquid drawn from a well. The embodiment to be described is based on the recognition that liquid within a given well is actually a mixture of liquid from different sections (e.g., depths) within the well, and that the quality of the liquid can vary significantly between sections. For example, water coming from one 15 section of a water well could have significantly higher levels of radionuclides than water coming from a different section of the well. Under normal operation of a well, the liquid pumped from the well is a mixture of liquid from various sections. In accordance with the embodiment, the well bore is modified and the well equipment is specifically constructed so that more of the "cleaner" liquid is pumped from the well compared to the more 20 ''contaminated'' wafer.

In order to increase the amount of cleaner liquid coming from the well, the embodiment includes sampling the liquid from the well to determine which sections of the well produce the cleanest liquid. After the various sections of the well have been identified and labeled (e.g., according to their relative amount of contaminants), the well 25 equipment is modified to enhance the amount of liquid being drawn fiom the cleaner

i sections of the weld and to reduce the amount of liquid drawn from the more contaminated sections of the well. This can be accomplished using a suction flow control device. The suction flow control device includes suction elements that are vertically spaced within the well in order to distribute the suction from the pump along the vertical length of the well.

5 The embodiment positions the elements at or near the cleaner sections of the well. More specifica'!y, the embodiment utilizes a suction control device so that the suction created by the pump is enhanced in the sections of the well that produce cleaner liquid and is inhibited in the sections of the well that produce more contaminated liquid. By virtue of this design, the contamination level of the liquid being pumped from the well is reduced.

10 In order to decrease the amount of liquid flowing from one section of the well to another section of the well (e.g., from a more contaminated section to a less contaminated section), the pump equipment can be provided with flow control disks that extend radially from the suction now control device (or other part of the pump and pipe assembly) and toward the inner surface of the well. These flow control disks provide a barrier between a 15 more contaminated section and cleaner section, thereby reducing the amount of mixing of liquid from the two sections.

With specific regard to water wells, the embodiment is also based on the theory that a large amount of the radionuclides found in water is caused by the contamination of the mineral cake found within the well. In a preferred embodiment of the invention, the 2() mineral cake is at least partially removed from the wall of the well, resulting in lower contamination of the water and also a high flow rate of water. Then, the well equipment is modified (e.g., using suction control devices and flow control disks) to enhanced flow from the cleaner sections of the well.

It is also believed that practicing the embodiment will reduce the rate at which the 25 mineral cake re-forms on the walls of the bore. More specifically, the strategic use of a

! suction flow control device as described above will result in a wider distribution of energy throughout the well. This results in slower-moving water, and a corresponding decrease in pressure drop at the w ails of the bore. It is theorized that the decreased pressure drop will result in less precipitation of minerals.

BRIEF DESCRIPTION OF THE DRR,NGS

Fig. I illustrates a cross section of a water well prior to being treated accordin;, to the method of the present invention.

Fig. 2 illustrates the water well ot Fig. 1 with the mineral cake removed.

10 Fig. 3 illustrates the water well of Fig. I with suction flow devices and flow control disks installed on the end of the pump.

Fig. 4 is a flow chart that represents one embodiment of the process of the present invention. I 5 DETAILED DESCRIPTION OF THE PREFERRF,D F, MBODIMENT

Figs. 1-4 illustrate one embodiment of the present invention as used in connection with the treatment of a water well for purposes of reducing the level of radionuclides in water pump from the well. Of course, it should be understood that other contaminants could be removed using the same of similar process. T he illustrated embodiment utilizes a 2() two- phase process to reduce contamination of water pumped from a water well.

Phase I includes gatherin, data regarding historical well performance, sampling and logging the characteristics of water from different sections of the well, and cleaning the well. Data gathering involves collecting and reviewing historic data about the well.

This data includes hydraulic, water chemistry, and geologic information. In the event that 25 recent data is not available at different flow rates, this data can he collected prior to

removing the pump. The primary purpose of this step in the process is to provide a base line against w hich future data can be compared in order to determine whether the process is successful.

Prior to proceeding with the sampling and logging portion of the process, the | 5 pumping equipment is removed, and a small submersible pump is inserted into the well.

Logging, of the well includes measuring the size of the well along the length of the we!! using a caliper log, measuring the flow rate of the well along the length of the well using a spinner log, and measuring the radiation of the well along the length of the well using a gamma log. The use of these logging techniques is well known in the water well field. In

10 addition, down hole televising can be used to look for any irregularities in the well (e.g., fractures, plugging, etc.). Finally, water samples are collected from various sections of the well and at various flow rates in order to determine the quality of the water coming from each section.

Once the different strata are logged and sampled, the entire formation can be 15 cleaned to remove the mineral cake within the well (see Fig. I). Water wells typically develop a mineral cake along the inside surface of the well bore due to the precipitation of minerals. For example, it is well known that calcium carbonate commonly cakes along the inner surface of many wells due to the pressure drop at that location. It is theorized that carbonate cake also contains radioactive minerals and other contaminants and that the 20 levels of radiation in the cake will increase over time. It is believed that the radioactive minerals could solubilize and contaminate water flowing through the mineral cake. In this regard, removal of the mineral cake has been found to decrease the level of radionuclides in the corresponding water.

Removal of the mineral cake can be accomplished by many different techniques, 25 including explosives, chemicals, or any other appropriate technique. In the preferred

embodiment, the mineral cake is removed using a high-pressure air gun provided by Bolt Technology Corp. of Norwalk. Connecticut under the trademark Airburst (RTM). A more detailed disclosure of the Airburst technology is set forth in US Patent No. 5,579,845,

which is incorporated herein by reference in its entirety. The Airburst technology utilizes! 5 pressure waveforms and a mass displacement within a well bore in order to break loose the mineral cake Font the well bore. The r.incral calc can then be suctioned front the bottom of the well.

In order to further enhance the beneficial characteristics of the process, the cleaning of mineral cake can be performed specifically in those areas that were identified 10 as having low contamination levels in the above-described logging and sampling procedure. More specifically, the Airburst technique can be performed at selected locations within the well, thereby removing mineral cake from specific locations within the well. Removal of the mineral cake will result in higher flow of water from those sections of the well. In order to further enhance flow, those sections of the well can also 15 be cleaned using a chemical cleaning process. The specific chemicals used in typical cleaning processes arc letdown in the art, and are not the subject of the present patent application. Upon completion of the cleaning process, additional logging and sampling can be performed in order to confirm that contaminated levels within the well, particularly at the 20 selected sections of the well, are lower than existed prior to treatment.

Phase 11 of the process includes modification of the pump structure in order to promote flow of water from the areas of the well that have low contamination. More specifically, referring to Fig. 3, a series of suction control devices are used to focus the suction of the pump at specific areas within the well. The suction control devices in the 25 illustrated embodiment are sold by Sand Control Technolo,ies, Inc. of Fort Worth, Texas

under the trademark Aquastream (RTM). A more detailed disclosure of the Aquastream

device is set forth in US Patent No. 4.94,319 which is incorporated herein by reference in its entirety. Each Aquastream device is positioned at an area that has been previously identified as having low contamination. The Aquastream devices are separated from each 5 other by a piping in the fond of PVC blank. The piping is preferably positioned at areas of iLe well that have been previously identified as ? oducing u atcr having high contamination. By positioning the Aquastream devices at the selected locations, it can be seen that flow of water from the areas of low contamination will be enhanced, and flow of water from the areas of high contamination will be inhibited.

10 In order to further decrease the amount of water flowing from the more contaminated sections of the u ell to the less contaminated sections of the well, the pump equipment can be provided with flow control disks that extend radially from either the Aquastream devices or the piping. The flow control disks extend toward the inner surface of the well bore to provide a barrier within the well. This barrier reduces the amount of 15 mixing of liquid between the various sections within the well, thereby further reducing the amount of contaminated water that is pumped from the well. The shape and size of the disks can he chosen to substantially match the shape of a particular well configuration. In addition, the disks can be made from any appropriate material, such as a polymeric material, PVC, elastomeric material (e.g., wire-reinforced rubber), metal, or any other 20 material that provides desired barrier.

The foregoing description of the present invention has been presented for purposes

of illustration and description. Furthcnnore, the description is not intended to limit the

invention to the fonm disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and the skill or knowledge of the relevant art, are 25 within the scope of the present invention. The embodiments described herein are further

l intended to explain best modes l;nown for practicing the invention and to enable others skilled in the art to utilize the invention in such, or other, embodiments and with various modifeations required by the particular applications or uses of the present invention.

5 This application is a divisional application, divided from GB 2 377 957. The following numbered clauses were the claims of.hc parcot application as f;.led. These clauses are subject-matter (but not claims) of the present divisional application and may be claimed in the divisional application.

I () I. A method of improving the quality of liquid coming from a well that has a pump and pipe assembly, the method comprising: identifying a region of the well that is low in contamination and a region of the well that is high in contamination; and modifying the pump and pipe assembly so that suction of the assembly is 15 enhanced in the region that is low in contamination and inhibited in the region that is high in contamination.

2. The method of claim 1, wherein identifying includes logging the well bore.

20 3. The method of claim 2, wherein logging includes at least one process selected from the group consisting of caliper logging, spinner logging, and gamma togging. 4. The method of claim 1, wherein identifying includes sampling the liquid in 25 the well in multiple regions.

l 5. The method of claim 4, wherein sampling includes testing the level of contamination of liquid sampled from multiple regions of the well.

5 6. The method of claim 1, further comprising cleaning the well in the region of low contamiriatior, more than the region of high contamination.

7. The method of claim 6, wherein cleaning includes removing sediment from an inner wall of the well.

8. The method of claim 7, wherein removing includes producing a pressure wave within the well in the region of low contamination.

9. The method of claim 1, wherein modifying the pump and pipe assembly 1 5 includes: coupling a Suction control device to the pump and pipe assembly; and positioning the suction control device in the region of low contamination.

1(). The method of claim 9, wherein the SUCtiOil control device comprises an 20 Aquastream suction flow control device.

11. The method of claim 1, wherein identifying includes identifying at least two regions of low contamination, and wherein modifying the pump and pipe assembly inc]udcs: coupling a first suction control device to the pump and pipe assembly;

positioning the first suction control device in one of the regions of]Oh contamination; coupling a second suction control device to the first suction control device; and 5 positioning the second suction control device in another of the regions of low contamination.

12. The method of claim I, wherein modifying the pump and pipe assembly includes forming a barrier between the region of low contamination and the region of high I O contamination.

13. The method of claim 12, wherein forming; a barrier includes: attaching a flow control disk to the pump and pipe assembly; and positioning the flow control disk in a location that is substantially between 15 the region of low contamination and the region of high contamination.

14. The method of claim I, wherein the well is a water well.

15. The method of claim I, wherein the well is an oil well.

16. A well pump and pipe assembly positioned in a well, comprising: a well having at least two regions ot low contamination; a well pipe positioned in the well; a well pump coupled to the well pipe; and

a first suction control device coupled to the well pipe and positioned in one of the regions of low contamination, and a second suction control device coupled to the first suction control device and positioned in another of the regions of low contamination.

5 17. The well pump and pipe assembly positioned in a well as claimed in claim 16, wherein the first and second StCtiQn control devices comprise Ac,tastream suction flow control devices.

18. The well pump and pipe assembly positioned in a well as claimed in claim 10 16, wherein the well includes a region of high contamination, and further comprising flow control disks coupled to the pump and pipe assembly and positioned substantially between a region of low contamination and the region of high contamination.

19. A well pump and pipe assembly positioned in a well, comprising: 15 a well having a region of low contamination and a region of high contamination; a well pipe positioned in the well; a well pump coupled to the well pipe; and flow control disls coupled to the pump and pipe assembly and positioned 20 substantially between the region of low contamination and the region of high contamination. 90. The well pump and pipe assembly positioned in a well as claimed in claim 19, wherein the flow control disks are substantially annular in shape and substantially fill a 25 gap between the pUlMp and pipe assembly and the wall of the well.

Claims

1. A well pump and pipe assembly positioned in a well, comprising: a well having a region of low contamination and a region of high contamination; 5 a well pipe positioned in the well; a well pump coupled to the 'Nell pipe; and flow control disks coupled to the pump and pipe assembly and positioned substantially between the region of low contamination and the region of high contamination.

2. The well pump and pipe assembly positioned in a well as claimed in claim 1, wherein the flow control disks are substantially annular in shape and substantially fill a gap between the pump and pipe assembly and the wall of the well.