Patent Application
20160319653
The field of the disclosure relates generally to artificial lift systems for hydrocarbon producing wells and, more particularly, to a fluid intake for use in artificial lift systems for hydrocarbon producing wells.
Typical hydrocarbon producing wells include a wellbore for transporting materials that are withdrawn from a hydrocarbon formation. The materials pass from the formation into the wellbore and are channeled along the wellbore to the wellhead. These materials consist of one or more of gaseous, liquid, or solid phase substances.
Some wells utilize an artificial lift system to increase the production of materials from the wells. Artificial lifts systems typically include a pump that causes the materials to flow through the wellbore towards the wellhead. In at least some known wells, the flow of both liquid and gas phase materials through the wellbore results in unsteady flow regimes, i.e., the flow is not a constant stratified flow regime. As a result, gas is drawn towards and ingested by the pump, which causes a reduction in the expected operational lifetime of the pump. Additionally, the pump undergoes large load fluctuations when ingesting gas. More specifically, the pump requires a relatively large amount of power to lift large volumes of liquid during standard operation. When gas reaches the pump, the pump experiences a drop in power consumption because the pump is no longer doing as much work. Subsequently, when liquid enters the pump again, the power consumption increases significantly over a relatively short period of time. Such load fluctuations reduce pumping efficiency and further reduce the expected operational lifetime of the pump, the driver that operates the pump, and the power delivery system that supplies power to the pump.
At least some known pumps include intakes designed to draw material from a liquid portion of the flow through the wellbore. For example, a reverse shroud intake, which is used in vertical wellbores, includes an intake positioned within a cup-shaped shroud such that fluid is drawn down inside the shroud to reach the intake. A bottom orienting intake draws fluid from a bottom of the wellbore. However, to operate efficiently, known intakes require a stratified flow regime that does not normally occur in the flow of material through the wellbore. Additionally, some known intakes are relatively short, causing higher fluid velocities normal to a surface of the intake. The higher fluid velocities normal to the surface generate undesirable flow structures, such as vortices. Additionally, the higher fluid velocities normal to the surface result in relatively high pressure drops at the surface. The undesirable flow structures and high pressure drops cause gas to be drawn into the intakes and, as a result, cause the pump to operate less efficiently.
In one aspect, a fluid intake for a system is provided. The system includes a pump for pumping fluid from a well including a well casing defining a passageway for the fluid to flow therethrough in a flow direction. The fluid includes liquid and gas. The fluid intake includes a support structure defining an interior space and configured for fluid to pass into said interior space. The fluid intake further includes a porous member extending over a portion of the support structure. The fluid intake extends inside the passageway in the flow direction such that the porous member and the well casing define an annular space therebetween. The porous member defines pores for liquid to wick through. The interior space is in flow communication with the pores such that liquid wicking through the porous member passes into the interior space.
In another aspect, a method for drawing fluid from a well using a system is provided. The well includes a well casing defining a passageway. The method includes inserting a fluid intake into the passageway. The fluid intake includes a support structure defining an interior space and configured for fluid to pass into the interior space. A porous member extends over a portion of the support structure. The porous member includes a wetted surface. A pump is operated to draw the fluid through the passageway in a flow direction. The fluid includes liquid and gas. Liquid is directed along the wetted surface such that the liquid wicks through the porous member. Additionally, liquid is drawn into the interior space at a direction substantially perpendicular to the flow direction.
In a further aspect, a system for increasing production of a well is provided. The well includes a well casing defining a passageway for fluid to flow through. The fluid includes liquid and gas. The system includes a pump for pumping the fluid through the passageway in a flow direction. The pump includes an inlet. A fluid intake includes a support structure defining an interior space and configured for fluid to pass into said interior space. A porous member extends over a portion of the support structure. The porous member defines pores for liquid to wick through. The fluid intake extends inside the passageway in the flow direction such that said porous member and said well casing define an annular space therebetween. The interior space is in flow communication with the pores such that liquid wicking through the pores passes into the interior space. A connection line fluidly couples the interior space to the pump inlet.
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.
In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.
The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
“Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.
Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as “about”, “approximately”, and “substantially”, are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged, such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.
The systems and methods described herein overcome at least some disadvantages of known artificial lift systems for producing hydrocarbon wells by including a fluid intake that draws liquid from a well casing into the fluid intake while inhibiting gas from entering the fluid intake. In the exemplary embodiment, liquid enters the fluid intake at a relatively slow velocity in a direction perpendicular to the direction of fluid flow in the casing. As a result, gas travels around the fluid intake and is not drawn into the fluid intake. In the exemplary embodiment, a porous member extends over a portion of the fluid intake. Liquid wicks along and through a wetted surface of the porous member, which further slows the velocity of liquid through the perforations and inhibits gas passing into the fluid intake. As a result, exemplary artificial lift systems using the fluid intake operate with improved efficiency.
Wellbore 104 includes a casing 110 that lines wellbore 104. Casing 110 includes at least one production zone 112 where hydrocarbons from stratum 106, along with other liquids, gases, and granular solids, enter casing 110. In some embodiments, materials enter wellbore 104 in any manner suitable to enable artificial lift system 100 to function as described herein. For example, hydrocarbons enter wellbore 104 through openings (not shown) in casing 110 and substantially fill casing 110 with fluid 114. Fluid 114 contains gas substances 116 and a liquid mixture 118 containing liquids and granular solids. In the exemplary embodiment, “liquid” includes water, oil, fracturing fluids, or any combination thereof, and “granular solids” include relatively small particles of sand, rock, and/or engineered proppant materials that are able to be channeled through casing 110. Casing 110 defines a passageway 120 for fluid 114 to flow through.
Artificial lift system 100 also includes a pump 122 positioned below surface 108. Pump 122 is configured to draw fluid 114 through casing 110 such that fluid 114 flows through passageway 120 in a flow direction 124 toward pump 122. Artificial lift system 100 includes a fluid intake 126 fluidly coupled to pump 122 and configured to capture liquid mixture 118. A pump outlet 128 of pump 122 is fluidly coupled to a production tube 130 that extends from a wellhead 132 of well 102. Production tube 130 is fluidly coupled to a liquid removal line 134 that leads to a liquid storage reservoir 136. In alternative embodiments, liquid removal line 134 includes a filter (not shown) to remove the granular solids from liquid mixture 118 within liquid removal line 134. Pump 122 is operated by a driver mechanism (not shown) that facilitates pumping of liquid mixture 118 from wellbore 104. In operation, liquid mixture 118 travels from pump 122, through production tube 130 and liquid removal line 134, and into storage reservoir 136.
In the exemplary embodiment, fluid intake 126 includes an outlet end 138, a distal end 140 opposite outlet end 138, and a support structure 141. In the illustrated embodiment, support structure 141 is a cylindrical tube formed by a sidewall 142 extending between outlet end 138 and distal end 140. In alternative embodiments, support structure 141 is any structure suitable to enable fluid intake 126 to function as described herein, e.g., without limitation, a baffle and a wrapped cage. In the exemplary embodiment, outlet end 138 defines an outlet 144 fluidly coupled to a pump inlet 146 of pump 122 by a connection line 148. In the illustrated embodiment, fluid intake 126 is located in wellbore 104 at a distance from surface 108 that is greater than a distance between surface 108 and pump 122. In alternative embodiments, pump 122 and fluid intake 126 are configured in any manner suitable to function as described herein. For example, in alternative embodiments, pump 122 is part of a shroud pump system (not shown). In further alternative embodiments, pump 122 is an electrical submersible pump and fluid intake 126 is in-line between the motor and pump.
In the exemplary embodiment, support structure 141 defines an interior space 152 (shown in
In the exemplary embodiment, a porous member 156 extends over a portion of support structure 141.
In the exemplary embodiment, fluid intake 126 extends inside passageway 120 in flow direction 124 such that porous member 156 and casing 110 define an annular space 150 therebetween. Accordingly, support structure 141 and porous member 156 separate interior space 152 from annular space 150. Support structure 141 allows fluid to flow into interior space 152 such that interior space 152 is in flow communication with annular space 150. In the illustrated embodiment, openings 153 facilitate liquid flowing into interior space 152. In alternative embodiments, support structure 141 and openings 153 have any configuration suitable for fluid to pass into interior space 152.
In the exemplary embodiment, sidewall 206 forms a cylinder having a circular cross-sectional shape and defining an interior space 208. In alternative embodiments, sidewall 206 has any shape suitable for fluid intake 200 to function as described herein. Fluid intake 200 further includes an outer surface 234 and an inner surface 236. Perforations 210 extend through sidewall 206 between outer surface 234 and inner surface 236 such that interior space 208 is in flow communication with the exterior of fluid intake 200. In some embodiments, any of perforations 210 have any shape and are disposed anywhere suitable to enable fluid intake 126 to function as described herein. In the exemplary embodiment, perforations 210 have a substantially circular shape and are spaced around the circular perimeter of sidewall 206. As a result, liquid enters fluid intake 200 throughout the entire perimeter of sidewall 206.
With reference to
In the exemplary embodiment, perforations 210 are arranged in a first row 212, a second row 214, a third row 216, a fourth row 218, and a fifth row 220. In alternative embodiments, perforations 210 are arranged in any manner suitable to enable fluid intake 126 to function as described herein. For example, in one embodiment, perforations 210 are randomly dispersed throughout sidewall 206. In the exemplary embodiment, first row 212 is spaced a first distance 222 from outlet end 202, second row 214 is spaced a second distance 224 from outlet end 202, third row 216 is spaced a third distance 226 from outlet end 202, fourth row 218 is spaced a fourth distance 228 from outlet end 202, and fifth row 220 is spaced a fifth distance 230 from outlet end 202. Each row 212, 214, 216, 218, 220 is successively closer to outlet end 202. As a result, first distance 222 is greater than second distance 224, third distance 226, fourth distance 228, and fifth distance 230. Also, second distance 224 is greater than third distance 226, fourth distance 228, and fifth distance 230; third distance 226 is greater than fourth distance 228 and fifth distance 230; and fourth distance 228 is greater than fifth distance 230. Due to length 232 and the arrangement of perforations 210 in first row 212, second row 214, third row 216, fourth row 218, and fifth row 220, liquid enters perforations 210 at a reduced velocity. The reduced velocity minimizes pressure losses from fluid flow entering interior space 208 and traveling through interior space 208.
Additionally, in the exemplary embodiment, the cross-sectional areas of some perforations 210 are different along length 232 to account for pressure variations along length 232 and to maintain an even flow through fluid intake 126. In alternative embodiments, the cross-sectional areas of all perforations 210 are the same or different. In the exemplary embodiment, perforations 210 in first row 212 have similar cross-sectional areas to each other which are different from the cross-sectional areas of perforations 210 in second row 214, third row 216, fourth row 218, and fifth row 220. Likewise perforations 210 in second row 214, third row 216, fourth row 218, and fifth row 220, have cross-sectional areas that are similar to perforations in the same respective rows and different from perforations 210 in different rows. Additionally, perforations 210 are arranged in order of decreasing cross-sectional area such that perforations 210 having the largest cross-sectional area are closest to distal end 204 and perforations 210 having the smallest cross-sectional area are farthest from distal end 204. Accordingly, perforations 210 in first row 212 have a greater cross-sectional area than perforations 210 in second row 214, third row 216, fourth row 218, and fifth row 220. Perforations 210 in second row 214 have a greater cross-sectional area than perforations 210 in third row 216, fourth row 218, and fifth row 220. Perforations 210 in third row 216 have a greater cross-sectional area than perforations 210 in fourth row 218 and fifth row 220. Perforations 210 in fourth row 218 have a greater cross-sectional area than perforations 210 in fifth row 220.
Well 300 includes a well casing 322 defining a passageway 324 for a fluid 325 containing liquid and gas to flow through. Liquid flow is represented by arrows 326 and gas flow is represented by arrows 328. Passageway 324 has a cross-sectional area 330. In the exemplary embodiment, cross-sectional area 330 is a circular shape. In alternative embodiments, cross-sectional area 330 has any shape suitable to enable fluid intake 302 to function as described herein. In the exemplary embodiment, intake 302 extends in passageway 324 in the flow direction such that intake 302 obstructs a portion of cross-sectional area 330 along a portion of the length of well casing 322. As a result, sidewall 304 and well casing 322 define an annular space 332 therebetween. Sidewall 304 separates annular space 332 from interior space 311. Accordingly, liquid mixture 313 flows from annular space 332 through porous member 314 and perforations 306 into interior space 311.
The shape of annular space 332 is determined, at least in part, by sidewall 304, well casing 322, and the position of intake 302 in passageway 324. In the exemplary embodiment, annular space 332 has a crescent shape in cross-section. In alternative embodiments, annular space 332 has any shape suitable to enable intake 302 to function as described herein, e.g., without limitation, a ring shape, c-shape, oval shape, circular shape, elliptical shape, and rectangular shape. Additionally, annular space 332 has a cross-sectional area 334 that is any size suitable to enable intake 302 to function as described herein.
In the exemplary embodiment, passageway 324 has a central axis 336 extending longitudinally through the center of passageway 324. In some embodiments, intake 302 is positioned in any position in relation to central axis 336 suitable to enable intake 302 to function as described herein. In the exemplary embodiment, intake 302 is positioned eccentrically in relation to central axis 336. In some alternative embodiments, intake 302 is positioned centrally in passageway 324 such that central axis 336 extends through a center of intake 302.
As shown in
As best seen in
In reference to
The method further includes drawing liquid flow 326 into interior space 208 at a direction substantially perpendicular to flow direction 124. In the exemplary embodiment, liquid flow 326 is drawn through perforations 154 in sidewall 142. In the exemplary embodiment, liquid flow 326 is drawn through perforations 154 in first row 212, second row 214, third row 216, fourth row 218, and fifth row 220. In alternative embodiments, liquid flow 326 is drawn into interior space 208 in any manner suitable to enable artificial lift system 100 to function as described herein. Additionally, liquid flow 326 is drawn into interior space 208 at a velocity of less than about 0.5 m/s. In alternative embodiments, liquid flow 326 is drawn into interior space 208 at any velocity suitable to enable artificial lift system 100 to function as described herein. Pump 122 draws liquid flow 326 flow through interior space 208 in flow direction 124 towards outlet end 138, which includes outlet 144 fluidly coupled to pump inlet 146.
The above-described systems and methods provide for enhanced artificial lift systems for producing hydrocarbon wells by including a fluid intake that draws liquid from a well casing into the fluid intake while inhibiting gas from entering the fluid intake. Liquid enters the intake at a relatively slow velocity in a direction perpendicular to the direction of fluid flow in the casing. As a result, gas travels around the fluid intake and is not drawn into the fluid intake. In the exemplary embodiment, a porous member extends over a portion of the fluid intake. Liquid wicks along and through a wetted surface of the porous member, which further slows the velocity of liquid through the perforations and inhibits gas passing into the fluid intake. As a result, exemplary artificial lift systems using the fluid intake operate with improved efficiency.
An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) minimizing ingestion of gas; (b) decreasing the pressure drop along surfaces of a fluid intake; (c) inhibiting solid particles entering a fluid intake; (d) facilitating stratified fluid flow in a well; and (e) increasing the uniformity of fluid flow inside a fluid intake.
Exemplary embodiments of apparatus and methods for operating an artificial lift system are described above in detail. The methods and apparatus are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the methods, systems, and apparatus may also be used in combination with other pump systems, and the associated methods, and are not limited to practice with only the systems and methods as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other applications, equipment, and systems that may benefit from improved fluid flow.
Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. Moreover, references to “one embodiment” in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.
This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
