SHROUDED BAND-PASS FILTER FOR OIL WELL

Abstract

Generally, embodiments described herein take the form of a shrouded band-pass filter that ensures liquid flow past the filter while reducing or minimizing gas contact with the filter. A shroud encircles the band-pass filter and is affixed to a dip tube (to which the band-pass filter is also affixed). The shroud and band-pass filter are contained within tubing within the oil well. As the pump operates, a fluid and gas mixture is drawn into the tube by operation of the pump. Gas may exit the tubing through vents while the fluid flows downward within the tubing. Fluid flows around the shroud and thus past the band-pass filter, before entering a dip tube via a strainer positioned within the shroud and above the filter. The dip tube permits the fluid to flow upward and, ultimately, out of the oil well as the pump operates.

Description

FIELD

The described embodiments relate generally to shrouded band-pass filters in oil wells. More particularly, the present embodiments relate to the use of a shroud about a band-pass filter to direct fluid flow past the filter during operation of a pump in an oil well.

BACKGROUND

In oil wells with reciprocating pumps, gas problems can cost a company valuable time, money and resources. The presence of gas in the pumping zone causes various problems like gas lock, gas pound, and gas interference, resulting in reduced pump efficiency and pump failures. To overcome these problems, down hole gas separators, such as oil anchors, gas anchors, or mud anchors, are used to divert the gas away from entering the pump intake and thus reduce pump failures and improve the pump efficiency.

Band-pass filters may be used with reciprocating pumps to alleviate problems associated with paraffin, asphaltenes, emulsions, and certain scales associated with the production of fluid from reservoirs. More particularly, band-pass filters may guide or control crystal polymorphism in oil. Band-pass filters convert a passive energy source to a spectral energy pattern tuned to be resonant with different types of molecular oscillations pertinent to oil. Tuned energy patterns convert problematic insoluble crystals to more thermodynamically stable and soluble crystals. The band-pass filter may be positioned upstream from the reciprocating pump.

SUMMARY

In embodiments, the disclosure provides down hole gas separators for use in an artificial lift system. Example down hole gas separators include a shrouded band-pass filter that can enhance treatment of production fluid from the oil well before the fluid enters the pump. The shrouded band-pass filter may be included in a dip tube assembly of the gas separator. Methods for treating production fluids using these down hole gas separators are also disclosed herein.

Some conventional artificial lift systems employ a band-pass filter to alleviate problems associated with paraffin, asphaltenes, emulsions, and certain scales associated with the production of fluid from reservoirs. The band-pass filter may be positioned upstream from the pump and in some cases may be included in a down hole gas separator. The band-pass filter relies on fluid flowing past it to operate. The more fluid from the oil well that flows past the band-pass filter, the better it operates. However, some conventional down hole gas separators are constructed such that the fluid flow path runs only partially past the band-pass filter, thereby reducing its efficiency and usefulness.

Generally, embodiments described herein take the form of a down hole gas separator including a shrouded band-pass filter that ensures liquid flow past the band-pass filter while reducing or minimizing gas contact with the filter. As compared to some conventional down hole gas separators, the down hole gas separators disclosed herein can provide a fluid flow path that directs more of the fluid entering the gas separator past the band-pass filter. In some cases, the shroud of the band-pass filter can also help to limit the gas content of the fluid that flows past the band-pass filter.

One embodiment described herein takes the form of a gas separator for use with a reciprocating pump in a well, comprising: a tube; a plug capping a lower end of the tube; a dip tube in fluid communication with the reciprocating pump, at least a portion of the dip tube positioned within the tube; a strainer at an opposing end of the dip tube from the reciprocating pump; a band-pass filter attached to an end of the strainer opposite the dip tube; and a shroud affixed to the dip tube above the strainer and the band-pass filter.

Another embodiment described herein takes the form of a gas separator for use with a reciprocating pump in a well, comprising: a tube; a plug capping a lower end of the tube; a sealing coupling attached to an upper end of the tube; a dip tube attached to the sealing coupling, at least a portion of the dip tube positioned within the tube; a strainer at an opposing end of the dip tube from the reciprocating pump; a band-pass filter attached to an end of the strainer opposite the dip tube; and a shroud affixed to the dip tube above the strainer and the band-pass filter and encircling the band-pass filter.

The disclosure also provides a method of treating a fluid, the method comprising receiving a fluid from an oil well in a gas separator, the fluid from the well comprising a mixture of a hydrocarbon fluid and a gas, producing an at least partially degasified fluid by directing the fluid from the oil well towards a lower end of the gas separator, and producing a treated fluid by directing the at least partially degasified fluid along a flow path between an exterior surface of a band-pass filter of the gas separator and an interior surface of a shroud of the gas separator.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

FIG. 1 illustrates a sample gas separator incorporating a shrouded band-pass filter.

FIG. 2 illustrates another sample gas separator incorporating a shrouded band-pass filter.

FIG. 3 illustrates a method for treating a fluid using a shrouded band-pass filter.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.

Generally, band-pass filters are used in oil wells and oil fields to help alleviate problems associated with paraffin, asphaltenes, emulsions, and certain scales associated with the production of fluid from reservoirs. Further, band-pass filters may guide favorable crystal polymorphism in oil, as well as reducing interfacial tension in oil between the constituents of oil and water. In oil wells and fields, band-pass filters stabilize molecular dispersions, and promote molecular solubility, of numerous constituents of oil. In some cases, the band-pass filter is characterized such that when exposed to a passive external energy source, the band-pass filter oscillates, tuning the filter to be in resonance with the different types of molecular oscillations pertinent to fluids of interest in oil wells. In some examples, the band-pass filter is formed at least in part of a suitable metal alloy.

Many oil wells that use reciprocating pumps to pump oil employ a band-pass filter. The band-pass filter may be positioned upstream from the reciprocating pump and in some cases may be included in a down hole gas separator. The band-pass filter relies on fluid flowing past it to operate. However, the fluid flow paths in some conventional down hole gas separators at least partially bypass the band-pass filter, thereby reducing its effectiveness. As compared to these conventional down hole gas separators, down hole gas separators including a shrouded band-pass filter as described herein can provide a fluid flow path that directs more of the fluid within the gas separator past the band-pass filter.

Generally, embodiments described herein take the form of down hole gas separator including a shrouded band-pass filter that ensures liquid flow past the band-pass filter while reducing or minimizing gas contact with the band-pass filter. When gas is suspended in the fluid that flows past the band-pass filter, the band-pass filter may be less effective and less efficient. Therefore, the shrouded band-pass filters described herein can also further improve the efficiency of treatment of fluid within the gas separator for paraffin, asphaltenes, emulsions, scales, and the like.

The down hole gas separators disclosed herein may be part of an artificial lift system that includes a reciprocating pump. In embodiments, at least one element of the reciprocating pump moves within well tubing positioned within the casing. The well tubing may provide a conduit for fluid from the oil well to be transported to the surface and in some cases may define a barrel of the pump. In some instances, an inlet of the reciprocating pump is positioned downstream of (e.g., above) the zone where production fluid enters into the casing, also referred to as a fluid entry zone. In some examples, the reciprocating pump is a sucker pump.

The down hole gas separator may be coupled to an inlet of the reciprocating pump so that treated fluid exiting the gas separator enters the pump. In some embodiments, the down hole gas separator includes a dip tube assembly. In some examples, the dip tube assembly includes a dip tube, a band-pass filter coupled to the dip tube, and a shroud at least partially surrounding the band-pass filter. A proximal end of the shroud may be affixed to the dip tube and the shroud may extend over at least a portion of the band-pass filter to a distal end. The distal end of the shroud may also be referred to as an upstream end of the shroud or a lower end when the dip-tube assembly has a generally vertical orientation.

The down hole gas separator also typically includes an outer tube at least partially surrounding the dip tube assembly. The outer tube, which is also referred to herein simply as a tube or alternately may be referred to as a housing, may define one or more openings through which fluid from the oil well enters the gas separator. The outer tube may also define one or more vents for gas to exit the gas separator (e.g., into an annular space between the tubing and the casing). In some cases, the openings through which fluid enters the gas separator also function as vents for gas to exit the gas separator while in other cases the fluid entering the gas separator may enter through certain openings while the gas evacuates through others. The down hole gas separator (or an inlet of the gas separator) may be located downstream from (e.g., above) the fluid entry zone, within the fluid entry zone, or a combination of these.

As the pump operates, fluid from the oil well is drawn into the tube of the gas separator by operation of the pump. The fluid from the oil well is typically a mixture including gas and a hydrocarbon fluid (e.g., oil). The fluid entering the gas separator may be directed towards an upstream (e.g., lower) end of the gas separator and may flow between an exterior surface of the shroud and the tube of the gas separator. When the dip tube has a generally vertical orientation, the fluid entering the gas separator may fall towards the lower end of the separator. At least some of the gas suspended in the fluid that flows into the gas separator can separate from this fluid as it falls and exit the tubing through vents in the tube of the gas separator. Therefore, an at least partially degasified fluid can be produced within the gas separator.

In some cases, the presence of the shroud in the gas separator can help to limit contact between the band-pass filter and gas separated from the fluid. In some cases, a top or upper portion of the shroud may have holes formed therethrough, also referred to herein as through-holes. These holes may be large enough that gas can pass through the holes but fluid does not. The shroud may be sintered, for example, to define appropriately sized holes. This may provide more efficient separation of any gas from fluid within the shroud.

A treated fluid may be produced by directing the at least partially degasified fluid along the band-pass filter. The shroud can help to ensure flow of the at least partially degasified fluid past the band-pass filter. In some embodiments, the shroud can define a flow path along and/or onto the band-pass filter. For example, the shroud may define a flow path between an exterior surface of the band-pass filter and an interior surface of the shroud. As an additional example, the shroud may define holes through at least a portion of its body, such a lower portion of its body, which define additional flow paths towards the band-pass filter. These through-holes may further enhance fluid flow past the band-pass filter.

The treated fluid may be directed into and through the dip tube and into the inlet of the reciprocating pump. In some examples, an inlet end of the dip tube may define openings to allow the treated fluid to enter the dip tube. In additional examples, the dip tube assembly may also include a strainer positioned between and coupled to the dip tube and the band-pass filter, and the treated fluid may enter the dip tube via the strainer. The strainer is also positioned within the shroud and downstream of (e.g., above) the band-pass filter. The dip tube permits the treated fluid to flow into the inlet of the reciprocating pump and, ultimately, upward and out of the oil well as the pump operates.

Shrouded band-pass filters may be used with gas separators in an oil well and generally operate as described above.

These and other embodiments are discussed below with reference to FIGS. 1-3. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only and should not be construed as limiting.

FIG. 1 illustrates a sample gas separator 100 including a shrouded band-pass filter. The view of FIG. 1 is a cross-sectional view showing the gas separator 100, a reciprocating pump 125, and several elements of an oil well 105. The gas separator 100 includes features that reduce the amount of solids in the fluid exiting the gas separator as compared to the fluid entering the gas separator from the well and therefore may also be referred to as a mud anchor. The gas separator 100 is positioned down hole in the oil well 105. The oil well 105 includes a casing 107 and a fluid entry zone 109 where fluid from the reservoir 102 can enter the oil well 105.

The gas separator 100 includes a tube 110 capped by a plug 115 (or, in some cases, a one-way valve), a dip tube 120 in fluid communication with the pump 125, a strainer 130 at an opposing end of the dip tube 120 from the pump 125, a band-pass filter 135 attached to an end of the strainer 130 opposite the dip tube 120, and a shroud 140 affixed to the dip tube 120 above the strainer 130 and the band-pass filter 135. In other words, the strainer 120 is attached to a lower end of the dip tube when the dip tube has a generally vertical orientation. A proximal end of the shroud 140 is attached to the dip tube in the example of FIG. 1. At least a portion of the shroud 140 generally extends downward within the tube 110 toward the plug 115 and past an end of the band-pass filter 135. In the example of FIG. 1, an upper portion of the shroud extends outward from the dip tube and then a lower portion of the shroud extends over part of the dip tube, the strainer, and the band-pass filter. The lower portion of the shroud may define an annular space between an interior surface of the shroud and an exterior surface of the band-pass filter. In some embodiments, the shroud 140 may terminate such that its end (i.e., its lower end) is coplanar with a portion of the band-pass filter 135 rather than extending beyond it.

As shown in the example of FIG. 1, the reciprocating pump 125 is positioned within tubing 112 and can move up and down within the tubing 112. The seating nipple 150 may snug the pump against the tubing. In some cases, the attachment of the dip tube 120 to the reciprocating pump 125 can cause the gas separator to move up and down the well due to the movement of the reciprocating pump 125.

In additional examples, not all the elements of the reciprocating pump 125 travel within the tubing 112 due to the action of the pump. Therefore, the gas separator need not travel up and down the oil well 105 when it is coupled to a stationary element of the pump. For example, when the reciprocating pump 125 includes a plunger and a traveling valve, the plunger and the traveling valve may travel up and down within the tubing 112 and a standing valve may remain stationary within the tubing during operation of the reciprocating pump. In such an example, the sealing nipple 150 may retain an inlet to the pump in a fixed and sealed position within the tubing 112, such as through seating of a standing valve defining the inlet on the sealing nipple 150. The sealing nipple 150 may have any form suitable for providing the desired sealing and retention properties for various elements of the pump. In some cases, the tube 110 of the gas separator 100 may be part of the tubing 112.

As shown in FIG. 1, a fluid and gas mixture is drawn from the reservoir 102 into the oil well 105 through the fluid entry zone 109. Fluid and gas from the oil well 105 may enter the tube 110 of the gas separator 100 through one or more openings 162 in the tube 110 as schematically depicted by the arrow. The fluid and gas entering the gas separator 100 can fall toward the plug 115, generally through negative pressure created by reciprocation of the pump 125 in the oil well 105. As the fluid and gas mixture fills the tube 110, gas may separate and exit the tube through one or more of the openings, as schematically depicted by the arrow showing gas exiting through the opening 164. Generally, some openings are higher along the tube wall than others, thus permitting the gas to exit. The gas may exit into a space between the tubing 112 and the casing 107. The fluid and gas mixture may enter through certain openings (intake openings) while gas evacuates through others (vent openings), although this is not necessary. In some cases, the openings in the tube 110 may have the form of slots.

As the fluid fills the tube 110, it is forced to flow around the shroud 140 and thus past the band-pass filter 135 on its way to the strainer 130, through which it enters the dip tube 120. The flow of the fluid, which is at least partially degassed, around a lower end of the shroud 140 is schematically depicted by the lower curved arrow in FIG. 1. Thus, the fluid is forced past the band-pass filter 135 by the shroud 140 along a fluid flow path schematically depicted by the straight arrow in FIG. 1. The fluid continues on its way to the strainer 130 and dip tube 120, as depicted by a curved arrow, and ultimately its exit from the oil well. The fluid flow path past the band pass filter ensures good contact between the fluid and the band-pass filter 135, thereby increasing the efficiency and operation of the band-pass filter in treating the fluid. Further, a significant portion of the gas separates from the fluid within the gas separator prior to the fluid contacting the band-pass filter 135, again increasing the efficiency and functionality of the band-pass filter.

In some embodiments the shroud 140 may have holes/flow paths defined through at least a portion of its body. This may permit better fluid flow through the shroud and past the band-pass filter. For example, a lower portion of the shroud 140 may be slotted or pierced to define fluid flow paths or otherwise enhance fluid flow.

As yet another option, a top or upper portion of the shroud 140 may have holes formed therethrough. These holes may be large enough that gas can pass through the holes but fluid does not. The shroud may be sintered, for example, to define appropriately sized holes. This may provide more efficient separation of any gas from fluid within the shroud.

FIG. 2 illustrates a sample gas separator 200 including a shrouded band-pass filter. The view of FIG. 2 is a cross-sectional view showing the gas separator 200, a reciprocating pump 225, and several elements of the oil well 205. The gas separator 200 is positioned down hole in the oil well 205. The oil well 205 includes a casing 207 and a fluid entry zone 209 where fluid from the reservoir 202 can enter the oil well 205.

The gas separator 200, like the prior-discussed gas separator, includes an external tube 210 capped by a plug 215 (or, in some cases, a one-way valve), a dip tube 220 attached to a sealing coupling 245 positioned near one end of a reciprocating pump 225, a strainer 230 at an opposing end of the dip tube 220 from the pump 225, a band-pass filter 235 attached to an end of the strainer 230 opposite the dip tube 220, and a shroud 240 affixed to the dip tube 220 above the strainer 230 and the band-pass filter 235. The dip tube 220 is typically in fluid communication with the pump 225. As with the gas separator of FIG. 1, the shroud 240 generally extends downward within the tube 210 toward the plug 215 and past an end of the band-pass filter 235. In some embodiments, the shroud 240 may terminate such that its end is coplanar with a portion of the band-pass filter 235 rather than extending beyond it.

In the example of FIG. 2, the gas separator 200 includes a sealing coupling 245. The sealing coupling is coupled to the tube 210 as well as the tubing 212. The sealing coupling 245 may allow gas to flow from a lower face of the sealing coupling to a side surface of the sealing coupling. As an example, the sealing coupling 245 is ported such that gas may escape the gas separator 200 through the sides, but not through the upper face, of the coupling. The sealing coupling may restrict flow of a fluid (e.g., a hydrocarbon liquid) from the lower face to an upper face of the sealing coupling. Fluid, therefore, is directed around the shroud 240 and past the band-pass filter 235 to the strainer 230 as schematically shown by the arrows in FIG. 2. The shroud 240 thus ensures that substantially all fluid passes the band-pass filter, thereby ensuring its efficient operation. Fluid flows past the band-pass filter 235, as schematically depicted by the straight arrow, and into the strainer 230, as schematically depicted by a curved arrow. The fluid then flows up along the dip tube 220 and past the sealing coupling 245. The fluid then flows into a chamber associated with the pump 225, where it is pulled up the oil well 205 to be expelled at the surface. In some cases, the chamber may be positioned below the pump, and in other cases, the chamber may be positioned behind one or more elements of the pump (such as a plunger).

In additional examples, not all the elements of the reciprocating pump 225 travel within the tubing 212 due to the action of the pump. For example, when the reciprocating pump 225 includes a plunger and a traveling valve, the plunger and the traveling valve may travel up and down within the tubing 212 and a standing valve may remain stationary within the tubing 212. In such an example, the sealing nipple 250 may retain an inlet to the pump in a fixed and sealed position within the tubing 212 and in some cases may be coupled to the sealing coupling 245. Furthermore, the fluid chamber may be defined between the traveling and the stationary elements of the reciprocating pump 225. The sealing nipple 250 may have any form suitable for providing the desired sealing and retention properties for various elements of the pump.

In certain embodiments, the gas separator 200 includes intake/vent openings (e.g., 262, 264) at its upper end (e.g., the end closest to a surface of the oil well) that permit fluid to enter the separator 200 during an intake cycle of the pump 225. The openings in the tube 210 may be similar in function and shape to the openings in the tube 110 previously described with respect to FIG. 1 and that description is not repeated here.

In some embodiments, the gas separator 200 holds approximately four times the volume displayed by the pump 225 during a single intake stroke. In a similar fashion as previously described with respect to the gas separator 100, gas separates from the fluid from the well in the separator 200 and can leave the separator in the form of bubbles or other exhaust through the openings in the tube 210, prior to fluid reaching the shroud 240. Gas can also leave the separator 200 through the sealing coupling 245. As fluid reaches the shroud 240 (or the portion of the tube 210 surrounding the shroud 240), its flow velocity increases, thereby forcing solids to fall past the shroud towards the plug 215. These solids can discharge into a mud joint (and effectively exit the separator system) while the at least partially degassed fluid enters a space between the band-pass filter 235 and the shroud 240. The at least partially degassed fluid can flow past the band-pass filter and the fluid so treated can then flow up through the strainer 230, into the dip tube 220 and through the pump 225 to exit the oil well 205.

Accordingly, in the embodiments shown in both FIG. 1 and FIG. 2, the shroud ensures fluid flows around the band-pass filter instead of bypassing it, thereby enhancing operation of the band-pass filter. Additional details regarding the construction and operation of the band-pass filter can be found in: U.S. application Ser. No. 16/317,490, filed Jul. 13, 2017; PCT Application No. PCT/US2017/041944, filed Jul. 13, 2017; U.S. Provisional Patent Application No. 62/361,654, filed Jul. 13, 2016; U.S. Provisional Patent Application No. 62/367,430, filed Jul. 27, 2016; and U.S. Provisional Patent Application No. 62/502,016, filed May 5, 2017, the contents of which are incorporated by reference as if fully disclosed herein.

FIG. 3 illustrates a method for treating a fluid using a shrouded band-pass filter as described herein. The method 300 includes an operation 310 of receiving a fluid from an oil well in a gas separator. The fluid from the oil well may comprise a mixture of a hydrocarbon fluid and a gas. The operation of receiving the fluid from the oil well into the gas separator may comprise receiving the fluid from the oil well through the opening in a tube of the gas separator. In some embodiments, the opening is located above a fluid entry zone of the oil well. The tube typically at least partially surrounds the dip tube, the band-pass filter, and the shroud and may be similar to the tubes 110 and 210 previously discussed with respect to FIGS. 1 and 2.

The method 300 further includes an operation 320 of producing an at least partially degasified fluid. The operation 320 may include directing the fluid from the oil well toward a lower end of the gas separator. As previously discussed, the shroud may limit contact between the band-pass filter and gas separated from the fluid during the operation of producing the at least partially degasified fluid. Gas may exit the gas separator through a vent in a tube of the gas separator during the operation of producing the at least partially degasified fluid. The tube typically at least partially surrounds the dip tube, the band-pass filter, and the shroud and may be similar to the tubes 110 and 210 previously discussed with respect to FIGS. 1 and 2.

The method 300 further includes an operation 330 of producing a treated fluid by directing the at least partially degasified fluid along a flow path between an exterior surface of a band-pass filter of the gas separator and an interior surface of a shroud of the gas separator. As previously discussed, the shroud ensures that fluid flows around the band-pass filter instead of bypassing it, thereby enhancing operation of the band-pass filter. In some cases, the action of the band-pass filter may produce favorable crystal polymorphs and/or reduced interfacial tension between the constituents of oil and water in the treated fluid.

In some embodiments, the method further comprises an operation of directing the treated fluid through a dip tube of the gas separator. In some examples, the method comprises directing the treated fluid through a strainer of the gas separator and into the dip tube. The treated fluid may pass through the dip tube and into an inlet of a reciprocating pump.

The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Claims

1. A gas separator for use with a reciprocating pump in a well, comprising: a tube;a plug capping a lower end of the tube;a dip tube in fluid communication with the reciprocating pump, at least a portion of the dip tube positioned within the tube;a strainer at an opposing end of the dip tube from the reciprocating pump;a band-pass filter attached to an end of the strainer opposite the dip tube; anda shroud affixed to the dip tube above the strainer and the band-pass filter.

2. The gas separator of claim 1, wherein the shroud extends downward within the tube toward the plug and past an end of the band-pass filter.

3. The gas separator of claim 2, wherein the shroud defines a fluid flow path past the band-pass filter.

4. The gas separator of claim 3, wherein: the fluid flow path is a first fluid flow path; andthe shroud further defines a second fluid flow path into the strainer.

5. The gas separator of claim 3, wherein an upper portion of the tube defines a gas vent.

6. The gas separator of claim 3, wherein a lower portion of the shroud defines at least one through-hole.

7. The gas separator of claim 1, wherein the dip tube is attached to an inlet of the reciprocating pump.

8. A gas separator for use with a reciprocating pump in a well, comprising: a tube;a plug capping a lower end of the tube;a sealing coupling attached to an upper end of the tube;a dip tube attached to the sealing coupling, at least a portion of the dip tube positioned within the tube;a strainer at an opposing end of the dip tube from the reciprocating pump;a band-pass filter attached to an end of the strainer opposite the dip tube; anda shroud affixed to the dip tube above the strainer and the band-pass filter and encircling the band-pass filter.

9. The gas separator of claim 8, wherein the sealing coupling allows gas to flow from a lower face of the sealing coupling to a side surface of the sealing coupling.

10. The gas separator of claim 9, wherein the sealing coupling restricts flow of a hydrocarbon fluid from the lower face to an upper face of the sealing coupling.

11. The gas separator of claim 8, wherein a lower portion of the shroud defines an annular space between an interior surface of the shroud and an exterior surface of the band-pass filter.

12. The gas separator of claim 11, wherein an upper portion of the shroud extends outward from the dip tube to the lower portion of the shroud.

13. The gas separator of claim 8, wherein the dip tube is in fluid communication with an inlet to the reciprocating pump.

14. The gas separator of claim 8, wherein the gas separator further includes a mud joint.

15. A method of treating a fluid, the method comprising: receiving a fluid from an oil well in a gas separator, the fluid from the oil well comprising a mixture of a hydrocarbon fluid and a gas;producing an at least partially degasified fluid by directing the fluid from the oil well toward a lower end of the gas separator; andproducing a treated fluid by directing the at least partially degasified fluid along a flow path between an exterior surface of a band-pass filter of the gas separator and an interior surface of a shroud of the gas separator.

16. The method of claim 15, wherein the shroud limits contact between the band-pass filter and gas separated from the fluid during the operation of producing the at least partially degasified fluid.

17. The method of claim 15, wherein: the method further comprises directing the treated fluid through a strainer of the gas separator and into a dip tube of the gas separator.

18. The method of claim 17, wherein: gas exits the gas separator through a vent in a tube of the gas separator during the operation of producing the at least partially degasified fluid, the tube at least partially surrounding the dip tube, the band-pass filter, and the shroud.

19. The method of claim 17, wherein: the operation of receiving the fluid from the oil well into the gas separator comprises receiving the fluid from the oil well through an opening in a tube of the gas separator, the tube at least partially surrounding the dip tube, the band-pass filter, and the shroud and the opening located above a fluid entry zone of the oil well.

20. The method of claim 15, further comprising an operation of directing the treated fluid through a dip tube of the gas separator and into an inlet of a reciprocating pump.