Downhole gas separation and gas SLUG handling assembly

Abstract

Disclosed examples generally relate to a downhole gas separation and gas slug handling assembly. The assembly includes a housing extending between a first and second housing end, and forming a housing chamber, the housing comprising one or more ports that fluidically communicate with the housing chamber; and a dip tube positioned within the housing chamber, wherein the dip tube is positionable at a slanted orientation within the housing.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to, and the benefit of, Canadian Patent Application No. 3,248,227, filed on Oct. 9, 2024, entitled “GAS SLUG HANDLING SYSTEM,” which is incorporated herein by reference in its entirety.FIELD

[0002] Various examples are described herein that generally relate to downhole equipment used in oil and gas wells, and in particular, to a downhole gas separation and gas slug handling assembly and a method of deploying or using thereof.BACKGROUND

[0003] Hydrocarbons are typically extracted from production wells, which include production tubing linking a subterranean formation (referred to as a “reservoir”) to the surface, aimed at bringing hydrocarbon fluids to the surface for treatment and refinement. Often, a downhole pump is used as an artificial lift method to elevate liquid hydrocarbons (often mixed with water) to the surface.

[0004] A challenge in operating the downhole pumps is that the production fluids often contain a significant amount of free and entrained gas. When the free gas is suctioned by the pump, it affects the pump's performance and reliability. Entrained gas can evolve to form free gas due to pressure reductions upstream of the pump intake.

[0005] Centrifugal pumps, in particular, are vulnerable to the presence of free gas, as they rely on fluid density to achieve a desired pressure increase. Consequently, an excess of free gas at the pump entrance diminishes its overall efficiency. Elastomeric progressive cavity pumps are also adversely affected by gas presence, resulting in a direct reduction in pump volumetric efficiency and an exacerbation of the hysteresis of the elastomeric stators, leading to premature pump failure.

[0006] The issue of free gas is exacerbated in wells that include inclined or horizontal sections. These sections tend to promote the formation of “gas slugs” that intermittently alternate with liquid slugs within the wellbore. As a result, the pump may encounter conditions in which it draws in predominantly gas slugs, with little or no accompanying liquid, which can impair pump performance and reduce overall lift efficiency.

[0007] The presence of free gas, as well as gas slugs, also impairs the cooling of the downhole motor, as the produced fluid typically serves as the primary cooling medium. Due to the lower specific heat capacity and convective heat transfer coefficient of gas compared to liquid, the presence of free gas or gas slugs reduces the effectiveness of heat dissipation. This can result in elevated motor temperatures, the formation of localized hot spots, and an increased risk of premature motor failure.SUMMARY

[0008] In at least one broad aspect, there is provided a gas separation and gas slug handling assembly, comprising: a housing extending between a first and second housing end, and forming a housing chamber, the housing comprising one or more ports that fluidically communicate with the housing chamber; and a dip tube positioned within the housing chamber, wherein the dip tube is positionable at a slanted orientation within the housing.

[0009] In some examples, the housing extends along an extension axis, and the dip tube is positionable at an angle relative to the extension axis.

[0010] In some examples, the dip tube comprises a first and second tube end, and (i) the first end is disposed proximal the first housing end, and (ii) the second tube end is disposed proximal the second housing end, and wherein the first tube end is positionable closer to a housing sidewall than the second tube end, such as to provide for the slanted orientation.

[0011] In some examples, the first tube end comprises an open inlet end and the second tube end comprises an open outlet end.

[0012] In some examples, the dip tube is in a fixed slanted orientation.

[0013] In some examples, the dip tube is movable within the housing chamber such that the second tube end slants under the influence of gravitational pull.

[0014] In some examples, the first housing end comprises a closed end, and the second housing end comprises an opening fluidically coupled to the second tube end.

[0015] In some examples, the second housing end comprises a blocking element surrounding the opening.

[0016] In some examples, the blocking element comprises a wall member having one or more further ports.

[0017] In some examples, the ports are positioned proximal the second housing end.

[0018] In some examples, the housing defines a first assembly portion, and the assembly further comprises: a second assembly portion comprising a second housing; and a coupling portion for fluidically coupling the first and second portions.

[0019] In some examples, the coupling portion fluidically couples a dip tube outlet to an inlet end of the second assembly portion.

[0020] In some examples, the coupling portion comprises a blocking element having a fluid passageway formed therein.

[0021] In some examples, the coupling portion comprises a cross-over coupler having a fluid passageway formed therein.

[0022] In some examples, the second assembly portion is configured to receive a downhole motor and at least a portion of a downhole artificial lift system.

[0023] In some examples, the assembly further comprises a tubing hanger that couples to an end of the second assembly portion.

[0024] In some examples, the tubing hanger secures the second assembly portion around a housing of the downhole artificial lift system.

[0025] In some examples, the second assembly portion comprises one or more centralizing elements disposed therein.

[0026] Other features and advantages of the present application will become apparent from the following detailed description taken together with the accompanying drawings. It should be understood, however, that the detailed description and the specific examples, while indicating preferred embodiments of the application, are given by way of illustration only, since various changes and modifications within the spirit and scope of the application will become apparent to those skilled in the art from this detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0027] For a better understanding of the various embodiments described herein, and to show more clearly how these various embodiments may be carried into effect, reference will be made, by way of example, to the accompanying drawings which show at least one example embodiment, and which are now described. The drawings are not intended to limit the scope of the teachings described herein.

[0028] FIG. 1 illustrates an example environment for deploying a downhole gas separation and gas slug handling assembly (or a “gas handling assembly”, for short), as disclosed herein.

[0029] FIG. 2A shows a longitudinal cross-section of an example configuration for the downhole gas handling assembly shown in FIG. 1, taken along the section line 2-2′ in FIG. 1;

[0030] FIG. 2B shows the gas handling assembly of FIG. 2A deployed in a downhole environment;

[0031] FIG. 2C shows a longitudinal cross-section of another example configuration for the downhole gas handling assembly shown in FIG. 1, taken along the section line 2-2′ in FIG. 1;

[0032] FIG. 2D shows the gas handling assembly of FIG. 2C deployed in a downhole environment;

[0033] FIG. 2E shows a longitudinal cross-section of still another example configuration for the downhole gas handling assembly shown in FIG. 1, taken along the section line 2-2′ in FIG. 1, and deployed downhole;

[0034] FIG. 3 shows an isolated longitudinal cross-sectional view of a lower barrel portion, of the gas handling assembly of FIG. 2A;

[0035] FIG. 4 shows an isolated longitudinal cross-sectional view of an upper barrel portion, of the downhole gas separation assembly of FIG. 2A;

[0036] FIG. 5 provides a cross-sectional view of FIG. 2B, along the section line 5-5′ in FIG. 2B; and

[0037] FIG. 6 illustrates an exemplary blocking element from different views.

[0038] Further aspects and features of the example embodiments described herein will appear from the following description taken together with the accompanying drawings.DETAILED DESCRIPTION

[0039] Disclosed examples generally relate to a downhole gas separation and gas handling assembly, and a method of deploying or using thereof.I. Definitions

[0040] Any term or expression not expressly defined herein shall have its commonly accepted definition understood by a person skilled in the art. As used herein, the following terms have the following meanings.

[0041] “Gas” refers to a fluid phase of matter not condensed into a liquid or solid state. Gases may include single-component substances or mixtures, and may be entrained or separated from a liquid.

[0042] “Gas slug” refers to a large, concentrated volume of gas that displaces or interrupts steady-state fluid flow within a conduit or wellbore, often representing a break in the continuous fluid column rather than dispersed bubbles within the fluid flow.II. General Overview

[0043] FIG. 1 shows an example environment 100 in which the disclosed examples may be deployed.

[0044] Well 102 is an oil or gas well, such as a production well that may form part of a steam-assisted gravity drainage (SAGD) system. As shown, well 102 includes a vertical section 102a, a build section 102b extending from the vertical portion, and a generally horizontal section 102c.

[0045] As is well known in the art, production tubing 108 is installed within the casing 106 which extends through the downhole well 102. Within the production casing 106 is a tubing 108 (e.g., a production tubing). Tubing 108 generally extends between an upper up hole end 108a and a lower downhole end 108b. Upper end 108a may couple to a wellhead 110, while lower end 108b extends further downhole.

[0046] In at least one example, the lower end 108b of tubing 108 couples to a pump 112, driven by a motor 114. Pump 112 operates to drive production fluids (e.g., bitumen and water) upward through the production tubing 108 to wellhead 110. For example, pump 112 draws fluids that flows into the wellbore through perforations 152 in the production liner. In some examples, pump 112 is an electrical submersible pump (ESP).

[0047] While element 112 is referenced herein throughout as a “pump”, it will be understood that it may more broadly refer to any artificial lift system deployed downhole.

[0048] As discussed above, the presence of downhole gas slugs impairs the functioning of the pump 112 and downhole motor 114. Existing gas separation devices struggle to specifically handle larger gas slugs, allowing them to reach the pump intake and enter the pump 112. These slugs also flow around the downhole electric motor 114, exacerbating the heat transfer issues discussed above. The majority of existing gas separation devices also do not accommodate the unique drawbacks of horizontal, or near horizontal positioning of the pump 112 and motor 114, which promote the formation of gas slugs.

[0049] In view of the foregoing, disclosed examples provide for a gas handling assembly 150 (FIG. 1). The assembly 150 is believed to address a number of the drawbacks mentioned in respect of existing gas separation systems, including the ability to handle larger gas slugs.III. Downhole Gas Handling Assembly

[0050] FIG. 2A-2E provide longitudinal cross-sectional views of examples of a gas separation and gas slug handling assembly 150.

[0051] As used herein, the “gas separation and gas slug handling assembly”150 is interchangeably reference herein simply as a “gas handling assembly”150, or “assembly”150.

[0052] In some examples, the assembly is provided as a single integrated assembly, while in other cases it may be provided as separable components that are assembled together.

[0053] As provided below, in use, the assembly 150 is positioned within a hollow interior 202 of the downhole casing 106 (FIG. 2B). In some cases, the assembly 150 encapsulates the downhole motor 114, and at least an intake portion 250 of the downhole pump 112.

[0054] To that end, assembly 150 may be positioned along any portion of the wellhole 102 where the pump 112 and motor 114 are deployed. This includes any portion of the wellhole 102 disposed at an angle to the horizontal plane (e.g., build section 102b) or otherwise which is horizontal or near horizontal (e.g., horizontal section 102c). In FIG. 1, the assembly 150 is positioned along the build section 102b, which is at an angle between 0° to 90° from the vertical. As noted, horizontal or near horizontal portions of the well provide conditions for gas slug formation, and may otherwise affect the functioning of the downhole pump 112.

[0055] In use, as best shown in FIG. 2B, the gas handling assembly 150 receives a flow of production fluid 260 through one or more fluid inlet ports 212 (e.g., fluid orifices or slots 212). Production fluid 260 may be a multi-phase mixture that includes both liquid and gas phases, and which can exhibit slugging, bubbling, stratification, or other multiphase characteristics which vary based on degree of inclination and flow rates. As described herein, assembly 150 is configured to separate the gas phase and provide a predominantly liquid-rich fraction to flow to the pump intake 250.

[0056] With reference to FIG. 2A, assembly 150 generally extends between a first assembly end 204a and a second assembly end 204b, along an assembly extension axis 252.

[0057] First assembly end 204a is also referenced herein as a “downhole” end, because in use it is positioned further downhole inside casing 106. Second assembly end 204b is also referenced herein as an “up hole” end, because it is generally positioned further up hole.

[0058] As exemplified, the assembly 150 includes: (i) a lower barrel portion 206 (also referenced herein as a “first assembly portion”) defining a lower chamber 214, (ii) an upper or second barrel portion 208 (also referenced herein as a “second assembly portion”) defining an upper chamber 216; and (iii) a coupling portion 210 for fluidically coupling together the upper and lower barrels 206, 208.

[0059] Lower barrel portion 206 is disposed generally proximal the downhole assembly end 204a, while upper barrel portion 208 is disposed generally proximal the up hole assembly end 204b. While the portions 206, 208 are referenced herein as “barrels”, it is understood that the portions are not limited to any particular shape.

[0060] The remaining discussion provides a more detailed description of the lower barrel portion 206 and upper barrel portion 208.IV. Lower Barrel Portion

[0061] The following is a description of a lower barrel portion 206 that can be used alone, or in any combination or sub-combination with other features described herein, including the upper barrel portion 208.

[0062] FIG. 3 shows an isolated view of the lower barrel portion 206, according to at least one example.

[0063] As exemplified, the lower barrel 206 includes a lower barrel housing body 302 (or housing 302), which surrounds and encapsulates the lower barrel chamber 214 (e.g., an annular chamber). Housing body 302 may have a tubular configuration, and may itself extend between first and second ends 304a, 304b. In some cases, housing 302 is formed of one or more pipe section joined end-to-end.

[0064] First end 304a may be the same or proximal to the downhole assembly end 204a, and may comprise a closed end. For example, the first end 304a may include a wall, a plug 266 or any other blocking member. This prevents the entry or exit of fluids into the lower barrel 206, via the first end 304a.

[0065] Second end 304b may be located more proximal to the up hole assembly end 204b, and may include an opening 376 to allow fluid communication with the upper barrel 208.

[0066] Housing body 302 also includes one or more fluid inlet ports 212. Inlet ports 212 extend around the housing, e.g., around the circumference. As explained above, ports 212 provide the inlet through which production fluid enters into the lower barrel chamber 214. In at least one example, ports 212 are disposed proximal the second end 304b of the lower barrel 208.

[0067] As further exemplified, a dip tube 310 is positioned within the lower barrel chamber 214. Dip tube 310 extends between: (i) an inlet opening end 310a, disposed proximal the first barrel end 304a; and (ii) an outlet opening end 310b, disposed proximal the second barrel end 304b.

[0068] In at least one example, the second barrel end 304b (FIG. 3) includes a blocking element 306 that surrounds the dip tube outlet 310b, or at least surrounds the housing opening 376 in fluid coupling with the dip tube outlet 310b. This ensures that no liquid exits the lower barrel 206, except through the dip tube outlet 310b. In some cases, the blocking element 306 is a plug or the like, that fits around the dip tube outlet 310b and inside the lower barrel housing 302 (see e.g., FIG. 3).

[0069] In other examples, as shown in FIG. 2C, the blocking element 306 forms a separate wall member, that also surrounds the dip tube outlet 310b (or housing opening 376). The wall member 306 can form part of the lower barrel housing 302, or a separate attachment thereto. In these cases, the wall member 306 can itself further include one or more further fluid inlet ports 212′ (see e.g., FIG. 6). In some cases, these further ports 212′ increase intake flow area into the lower barrel 206, while also allowing gas to escape.

[0070] In some examples, the dip tube 310 has a generally tubular configuration, and has a smaller diameter than the diameter of the lower barrel housing 302 (FIG. 3). The dip tube 310 may extend partway along the axial length of the lower barrel housing 302.

[0071] The open inlet end 310a of dip tube 310 may feature a perpendicular, a slanted, or a copping notch geometry. Further, the open inlet end 310a may be equipped with additional openings 318 (e.g., circular or elongated lateral openings) to provide an enhanced flow area (FIG. 3).

[0072] As exemplified in FIG. 3, the dip tube 310 is deployable or positionable at a slanted angle relative to the lower chamber 214, rather than being positioned concentrically therewithin. For instance, the dip tube inlet 310a may be positioned or positionable more proximally the inner housing side wall than the dip tube outlet 310b. This eccentric configuration produces a larger internal headspace 312 (FIG. 3) above the dip tube inlet 310a.

[0073] In some examples, the dip tube inlet 310a rests, or is configurable to rest on, or otherwise lean towards, the lower housing side 302b. Further, the dip tube outlet 310b may be concentric relative to the second housing end 304b. The dip tube 310 inclination with respect to the extension axis 252 may be in a range of between 0°<θ≤45°, and more preferably, 0.5°<θ≤2°, 0°<θ≤5°, 0°<θ≤10°or 0°<θ≤20°.

[0074] In some cases, the lower housing side 302b defines the side of the housing 202 that is in a lower position with respect of the direction of the gravitational field, even when the assembly 150 is slanted or non-horizontal. The upper housing side 302a then defines the opposing side. The slanted dip tube 310 design may be achieved in any suitable manner. For instance, the dip tube 310 may be in a fixed or rigid slanted orientation. In other examples, the dip tube 310 is permitted to move within the chamber 214 to assume a slanted orientation, such as to slant towards a lower housing side 302b.

[0075] FIG. 3 shows an example for a flexible coupling of the dip tube 310 which permits the dip tube to move inside chamber 214. As shown, the portion proximal the dip tube outlet 310b is secured to the blocking element 306 through one or more flexible couplers 268, while the dip tube inlet 310a is a free end. This allows the dip tube inlet end 310a to simply fall towards lower housing side 302b under the influence of gravity. It is also possible that the area around the dip tube inlet 310a is designed with a heavier weight, to bias it downwards into the slanted position. One or more biasing weights (not shown) may also be added, proximal the inlet end 310a, to also increase the downward bias.

[0076] In FIG. 2C, the dip tube outlet end 310b may also extend outside of the lower barrel housing 302 to flexibly couple to a cross-over coupler 210 (via flexible elements 268), as described below.

[0077] In some cases, the dip tube 310 is designed with some degree of elasticity to allow it to bend towards the lower end, e.g., without the need for a flexible coupling 268.V. Upper Barrel Portion

[0078] The following is a description of an upper barrel portion 208 that can be used alone, or in any combination or sub-combination with other features described herein, including the lower barrel portion 206.

[0079] FIG. 4 exemplifies a configuration for the upper barrel 208, according to at least one example.

[0080] As shown, the upper barrel 208 may also include an upper barrel housing 402. In some cases, the upper barrel housing 402 comprises one or more coupled pipe sections, e.g., coupled end-to-end.

[0081] Upper barrel housing 402 may surround and encapsulate the upper barrel chamber 216, which may be a sealed chamber. In some cases, the housing 402 is tubular member forming an annular chamber 216.

[0082] As exemplified in FIG. 2B, upper barrel chamber 216 receives motor 114 and at least a portion of the pump 112, such that these elements are disposed within the upper barrel chamber 216. In at least one example, the upper barrel 208 at least receives the portion of the pump 110 defining the pump intake 250.

[0083] In more detail, the upper barrel housing 402 extends between housing ends 402a, 402b. First end 402a includes an opening fluidically couplable to dip tube 310.

[0084] Second barrel end 402b is blocked, such as using a further blocking member 408 (e.g., a plug) that includes an opening 270. Blocking member 408 can surround an upstream end of the pump 112 which extends through opening 270, and which feeds into the tubing string 108. In at least one example, blocking member 408 may be securable or fixable around the pump housing, and located downstream or beyond the pump intake 250. It may also be securable passed the pump housing, and along any portion of the tubing string 108.

[0085] In some examples, the blocking member 408 comprises a hanger coupler. The hanger coupler may include a passage 416 (FIG. 4) for a cable 418 (e.g., electric cable, or any cable for carrying instrumentation or control signals) that powers the motor 114 (FIG. 2B).

[0086] FIG. 2E exemplifies a further configuration where multiple conduits 280 are provided, forming the upper barrel portion, and which feed into the pump intake 250 and extends around the motor 114.VI. Intermediary Coupling Portion

[0087] As exemplified in FIGS. 2A, 2C and 2E, the assembly 150 can include a coupling portion or mechanism 210, which allows for fluidically coupling the lower barrel portion 206 to the upper barrel portion 208.

[0088] In more detail, coupling mechanism 210 allows fluidically coupling the dip tube outlet end 310b (FIG. 3) to the open inlet end 402a of the upper barrel 208 (FIG. 4).

[0089] Coupling mechanism 210 may be configured in any suitable manner. In FIG. 2A, the coupling mechanism 210 is a passageway 240 extending through, and formed in, the blocking element 306 (e.g., plug). Blocking element 306 surrounds the passageway and sealingly engages the ends 304b (FIGS. 3), 402a (FIG. 4) of the upper and lower barrels. In these examples, and more generally, the upper and lower barrel housings can form a continuous (e.g., same) housing element, or disconnected housing elements.

[0090] In FIGS. 2C and 2D, the coupling mechanism includes a cross-over member 308, which itself forms the fluid passageway 240. Cross-over member 308 engages the dip tube outlet 310b from one end, the upper barrel inlet 402b from the other end.

[0091] The cross-over member 308 may couple to the dip tube outlet 310b using one or more flexible connectors 268. These flexible connectors 268 may allow the dip tube 310 to flexibly move relative to the lower barrel 206, such as to assume the slanted position. The cross-over member 308 may couple to the upper barrel inlet 402b using one or more flexible connectors 269 to allow the lower barrel 206 as a whole to reorient relative to the upper barrel 208. Accordingly, the configuration in FIGS. 2C and 2E can reduce the bending strain on the pump 112 in cases where the dimensions of the assembly (outside diameters and lengths), combined with the dog leg severity of the well and the internal casing diameter, may create excessive bending stresses.

[0092] In at least one example, the passageway 240 formed in the coupling mechanism 210 fans out or expands at the end coupling to the upper barrel 208. This allows the fluid flow from the narrower diameter dip tube 310 to flow into the entire volume of the larger upper barrel chamber 216.VII. Centralizing Motor Elements

[0093] In at least one example, the motor 114 is centralized within the upper barrel chamber 216. For example, in FIG. 2B, the motor 114 may be aligned with the central assembly axis 252. The purpose of this centralization is to ensure maximum fluid flow 260b around the entire surface area of the motor 114. This allows even and effective cooling to the motor 114 and reduces the risk of hot spots that could damage the motor 114.

[0094] Various techniques can be used to center the motor 114 within the upper barrel chamber 216. In the exemplified case, one or more centralizing elements 412 (FIG. 2B) are provided. In some cases, they are provided inside and coupled to the upper barrel chamber 216 (FIG. 4). In other cases, they may be provided directly on the motor housing.

[0095] Each centralizing element 412 can extend between the motor casing and the upper barrel housing 402. Centralizing elements 412 can be, for example, fins, vanes, or other similar structures.

[0096] In some cases, and without limitation to theory, the centralizing elements 412 are designed for reducing pressure losses, optimizing the flow pattern around the electric motor to enhance heat transfer possibly inducing a swirl motion, and facilitating the homogenization of the liquid-gas mixture entering the pump. Accordingly, the centralizing elements 412 can comprise various structures designed to ensure efficient and uniform fluid distribution while minimizing flow disruptions in the annular chamber.VIII. Method of Deploying Gas Separation Assembly

[0097] In some examples, the method of deploying the gas handling assembly 150 involves receiving or inserting the motor 114 and pump 112 into the upper barrel chamber 216 (FIG. 2A). In these cases, at least the pump intake 250 is disposed within the upper barrel chamber 216. Once received therein, the tubing hanger 408 (FIG. 4) may be coupled to the upper barrel end 402b, to secure the upper barrel 208 to the pump housing.

[0098] The gas handling assembly 150 is then positioned downhole within the well casing 106, such that the lower barrel 206 is positioned further downhole than the upper barrel 208. The assembly 150 as a whole (or at least the lower barrel 206) settles eccentrically within the downhole casing 106 under the influence of gravity, such as to position it proximal or in contact with a lower casing wall 106b. In some cases, the extension axis 252 generally coincides with the axis of the pump assembly. Further, axis 252 may be eccentrically positioned with respect to the axis 256 of casing 106.IX. Alternative and / or Specific Examples

[0099] In at least one example, the gas handling assembly 150 may simply comprise only the lower barrel portion 206. In these cases, the lower barrel portion 206 is couplable to any other external member(s), such as a member that provides an enclosed housing around at least the pump intake 250 (e.g., any motor housing element). In these cases, external member can fluidically couple to the dip tube outlet 310b. X. Example Mode of Operation

[0100] Without restriction or limitation to particular theory, the following is a discussion of an expected mode of operation for the gas handling assembly 150 when deployed in a downhole environment.

[0101] As explained herein, an appreciated advantage of the assembly 150 is that it operates downhole under both semi-steady-state and transient flow conditions:

[0102] (a) Semi-steady-state flow conditions are characterized by a relatively continuous liquid flow that is entrained with smaller gas bubbles or pockets.

[0103] (b) Transient flow conditions are characterized by the presence of larger gas slugs 262 (FIG. 1), that otherwise are devoid of liquid. As noted above, gas slugs are common in horizontal or near horizontal well sections, and pose challenges to pump operation because their ability to entirely disrupt liquid flow.

[0104] As exemplified in FIGS. 2B, 2D and 2E—in downhole operation, assembly 150 is eccentrically positioned downhole more proximal to the lower casing side 106b than the upper casing side 106a (FIG. 5). This is a result of gravitational pull that causes the assembly 150 to settle along the lower casing side 106b.

[0105] An advantage of this eccentric positional configuration is to assist in initial gas separation. This is because, as shown in FIGS. 2B and 5, the eccentric positioning produces a larger upper headspace 264 above the assembly 150. The larger headspace 264 facilitates gas separation as the buoyancy of larger gas bubbles are likely to cause them to float above the inlet ports 212 and flow past the assembly 150.

[0106] In some cases, only the lower barrel 206 is positioned eccentrically with respect to the casing 106. This ensures that an upper headspace 264 is provided at least above the fluid inlet ports 212.

[0107] Continuing with reference to FIG. 2B, the lower barrel 206 receives the flow of production fluid 260, via the one or more fluid inlet ports 212. Production fluid 260 may include a mix of liquid and gas, as well as larger gas slugs 262.

[0108] Fluid which enters through the inlet ports 212 flows into the lower barrel chamber 214. Inside the lower barrel chamber 214, the blocking element 306 (FIG. 2B) diverts the flow path 260 by 180° towards the first barrel end 304a to form the diverted flow path 260a (FIG. 2B).

[0109] Once the diverted flow path 260a flows towards the first barrel end 304a, it is again deflected by 180° such that it flows into the open dip tube inlet 310a. Accordingly, the dip tube 310 receives a further deflected flow path 260b (FIG. 3). The deflected fluid flow 260b then continues inside the dip tube 310 towards the dip tube outlet 310b.

[0110] The appreciated advantage of this design is that, because the fluid flow reverses direction more than once, it induces separation of the smaller gas bubbles entrained in the liquid flow. Accordingly, in “semi-steady-state” fluid flow conditions, the exemplified design separates the gas bubbles by slowing and diverting the fluid flow. The remaining deflected fluid flow 260b inside the dip tube 310 is then largely a liquid-rich flow medium.

[0111] To this end, the slanted design of the dip tub 310 has a number of appreciated advantages, both in semi-steady-state and transient fluid flow conditions.

[0112] Under semi-steady-state flow conditions, the larger headspace 312 (FIGS. 3 and 5) above the dip tube inlet 310a facilitates further gas separation. The internal headspace 312 provides a similar a gas separation function to the external headspace 264 (FIG. 2B). In these cases, the inlet ports 212 serve a further purpose in allowing release of gas bubbles.

[0113] Under transient flow conditions, the slanted dip tube 310 mitigates against gas slugs 262. For instance, as shown in FIG. 2B, if a larger gas slug 262 enters into the lower barrel 206, it may entirely disrupt the liquid flow. In these cases, the larger gas slugs entirely surround the inlet ports 212. This, in turn, forms a gas-liquid interface 218 inside the lower chamber 214.

[0114] As larger or more gas slugs 262 enter into the lower chamber 214, the gas-liquid interface 218a is pushed further down. When the gas-liquid interface 218b is pushed down, two things occur: (i) as the dip tube inlet 310a (FIG. 3) is slanted downwards, it is more likely to be submerged below the liquid interface portion, therefore it continuous receiving liquid rather than gas; and (ii) the interface 218, being pushed rearwardly, forces more liquid to flow into the dip tube inlet 310a. As such, the dip tube 310 continues providing a liquid-rich feed through the dip tube 310 and into the upper barrel 208, irrespective of the presence of gas slugs 262. This, in turn, provides a continuous liquid supply to the pump 112 while also providing a liquid-rich flow around the motor 114 for cooling.

[0115] In view of this, the slanted dip tube 310 configuration provides a period of stable operation to the entire pump assembly while gas slugs pass the region surrounding the inlet ports 212. Once the gas slugs move toward the top of the well, liquid slugs coming from the formation, and liquid falling back from the annulus formed between the production tubing 108 and the casing 106, enter the lower chamber 214 to restore the internal liquid level.

[0116] In some examples, the replenishment of the liquid in the chamber 214 is also facilitated by one or more fluid inlets 212 disposed on a lower housing side 302b (FIG. 3), which allow for fluid to enter from below thereby while the gas occupying the upper portion of the chamber 214 escapes through one or more fluid inlets 212 disposed on an upper housing side 302a.

[0117] Still reference FIG. 2B, inside the upper barrel 208, the liquid-rich fluid flow 260b travels towards the second barrel end 402b (FIG. 4), and past and around the motor 114 and seal 410, towards the pump intake 250. This fluid path allows the fluid to cool down the motor 114, as it drives towards the pump intake 250. The blocking member 408 (FIG. 4) may ensure that the fluid flow 260b is forced into the pump intake 250, and is otherwise prevented from leaking out.XI. Interpretation

[0118] Various systems or methods have been described to provide an example of an embodiment of the claimed subject matter. No embodiment described limits any claimed subject matter and any claimed subject matter may cover methods or systems that differ from those described below. The claimed subject matter is not limited to systems or methods having all of the features of any one system or method described below or to features common to multiple or all of the apparatuses or methods described below. It is possible that a system or method described is not an embodiment that is recited in any claimed subject matter. Any subject matter disclosed in a system or method described that is not claimed in this document may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such subject matter by its disclosure in this document.

[0119] Furthermore, it will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the embodiments described herein. Also, the description is not to be considered as limiting the scope of the embodiments described herein.

[0120] It should also be noted that the terms “coupled” or “coupling” as used herein can have several different meanings depending in the context in which these terms are used. For example, the terms coupled or coupling may be used to indicate that an element or device can electrically, optically, or wirelessly send data to another element or device as well as receive data from another element or device. As used herein, two or more components are said to be “coupled”, or “connected” where the parts are joined or operate together either directly or indirectly (i.e., through one or more intermediate components), so long as a link occurs. As used herein and in the claims, two or more parts are said to be “directly coupled”, or “directly connected”, where the parts are joined or operate together without intervening intermediate components.

[0121] It should be noted that terms of degree such as “substantially”, “about” and “approximately” as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree may also be construed as including a deviation of the modified term if this deviation would not negate the meaning of the term it modifies.

[0122] Furthermore, any recitation of numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term “about” which means a variation of up to a certain amount of the number to which reference is being made if the end result is not significantly changed.

[0123] The present invention has been described here by way of example only, while numerous specific details are set forth herein in order to provide a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that these embodiments may, in some cases, be practiced without these specific details. In other instances, well-known methods, procedures and components have not been described in detail so as not to obscure the description of the embodiments. Various modification and variations may be made to these exemplary embodiments without departing from the spirit and scope of the invention, which is limited only by the appended claims.

Claims

1. A gas separation and gas slug handling assembly, comprising:a housing extending between a first and second housing end, and forming a housing chamber, the housing comprising one or more ports that fluidically communicate with the housing chamber; anda dip tube positioned within the housing chamber, wherein the dip tube is positionable at a slanted orientation within the housing.

2. The assembly of claim 1, wherein the housing extends along an extension axis, and the dip tube is positionable at an angle relative to the extension axis.

3. The assembly of claim 1, wherein the dip tube comprises a first and second tube end, and (i) the first end is disposed proximal the first housing end, and (ii) the second tube end is disposed proximal the second housing end, andwherein the first tube end is positionable closer to a housing sidewall than the second tube end, such as to provide for the slanted orientation.

4. The assembly of claim 3, wherein the first tube end comprises an open inlet end and the second tube end comprises an open outlet end.

5. The assembly of claim 3, wherein the dip tube is in a fixed slanted orientation.

6. The assembly of claim 3, wherein the dip tube is movable within the housing chamber such that the second tube end slants under the influence of gravitational pull.

7. The assembly of claim 1, wherein the first housing end comprises a closed end, and the second housing end comprises an opening fluidically coupled to the second tube end.

8. The assembly of claim 7, wherein the second housing end comprises a blocking element surrounding the opening.

9. The assembly of claim 8, wherein the blocking element comprises a wall member having one or more further ports.

10. The assembly of claim 1, wherein the ports are positioned proximal the second housing end.

11. The assembly of claim 1, wherein the housing defines a first assembly portion, and the assembly further comprises:a second assembly portion comprising a second housing; anda coupling portion for fluidically coupling the first and second portions.

12. The assembly of claim 11, wherein the coupling portion fluidically couples a dip tube outlet to an inlet end of the second assembly portion.

13. The assembly of claim 11, wherein the coupling portion comprises a blocking element having a fluid passageway formed therein.

14. The assembly of claim 11, wherein the coupling portion comprises a cross-over coupler having a fluid passageway formed therein.

15. The assembly of claim 11, wherein the second assembly portion is configured to receive a downhole motor and at least a portion of a downhole artificial lift system.

16. The assembly of claim 15, further comprising a tubing hanger that couples to an end of the second assembly portion.

17. The assembly of claim 16, wherein the tubing hanger secures the second assembly portion around a housing of the downhole artificial lift system.

18. The assembly of claim 11, wherein the second assembly portion comprises one or more centralizing elements disposed therein.

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