High-velocity discharge equalizing system and method

Abstract

According to one embodiment of the invention, a high-velocity fluid discharge device includes tubing having one or more orifices formed therein, a shroud coupled to the tubing such that, when a fluid flowing through the tubing exits the orifices, the fluid impinges on an inside surface of the shroud, and openings at both ends of the shroud. The openings have substantially the same areas.

Description

BACKGROUND

The present invention relates generally to wellbore production enhancement operations and, more particularly, to a high-velocity discharge equalizing system and method.

Various procedures have been utilized to increase the flow of hydrocarbons from subterranean formations penetrated by wellbores. For example, a commonly used production enhancement technique involves creating and extending fractures in the subterranean formation to provide flow channels therein through which hydrocarbons flow from the formation to the wellbore. The fractures are created by introducing a fracturing fluid into the formation at a high flow rate and high pressure in order to exert a sufficient force on the formation to create and extend fractures therein. Solid fracture proppant materials, such as sand, are commonly suspended in the fracturing fluid so that upon introducing the fracturing fluid into the formation and creating and extending fractures therein, the proppant material is carried into the fractures and deposited therein, whereby the fractures are prevented from closing due to subterranean forces when the introduction of the frac fluid ceases.

In the line that transports the fracturing fluid from the pumps to the wellhead, there is typically a pipe tee that facilitates the use of a return line that transports fluid to a pit or other fluid containment when so desired. A valve that controls flow through this additional line may be inadvertently opened during high-flow and high-pressure situations, such as hydraulic fracturing. This may cause the energized fluid flowing through the line to surge out through the end, which may create undesirable reaction forces that cause the line to move uncontrollably. Anchors are sometimes used to minimize movement of the line.

SUMMARY

According to one embodiment of the invention, a high-velocity fluid discharge device includes tubing having one or more orifices formed therein, a shroud coupled to the tubing such that, when a fluid flowing through the tubing exits the orifices, the fluid impinges on an inside surface of the shroud, and openings at both ends of the shroud. The openings have substantially the same areas.

Some embodiments of the invention provide numerous technical advantages. Some embodiments may benefit from some, none, or all of these advantages. For example, according to certain embodiments, high-flow discharge of fluid due to an inadvertent opening of a valve on the line running to a pit or fluid containment during hydraulic fracturing or other high pressure operations may be equalized so as to avoid excessive movement of the end of the line, which leads to a safer environment. In some embodiments, a shield may be utilized with such an equalizing system to prevent exiting fluids from throwing projectiles on location as well as provide additional anchorage into the ground.

The features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of the exemplary embodiments that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial plan view of a production enhancement system utilizing a high-flow discharge equalizing device in accordance with one embodiment of the present invention;

FIG. 2 is a cross-sectional view of the equalizing device of FIG. 1 in accordance with one embodiment of the present invention; and

FIGS. 3A and 3B are perspective views of an equalizing device in accordance with another embodiment of the present invention.

DESCRIPTION

FIG. 1 is a partial plan view of a production enhancement system 100 utilizing a high-flow discharge equalizing device 200 in accordance with one embodiment of the present invention. In the illustrated embodiment, system 100 is being utilized to perform a hydraulic fracturing operation; however, system 100 may be utilized for any suitable well stimulation treatment or production enhancement operation in which fluid is circulated through a well (not illustrated).

System 100 includes one or more pumps 102 that deliver a fracturing fluid or other suitable fluid to a wellhead 104 via delivery line 106 having an associated valve 107. Because of the nature of hydraulic fracturing, the fluid is typically a high-flow, high-pressure fluid. In one embodiment, the fluid is flowing at a pressure of at least 100 psi and may be a gas, homogeneous foam, a liquid, or co-mingled fluid and gas. System 100 also includes a discharge line 108 having an associated valve 109 that is utilized to deliver fluid to a pit 110, which may be any suitable fluid containment, when so desired.

According to the teachings of one embodiment of the invention, system 100 includes discharge equalizing device 200 that creates a pressure-balanced exit condition for the fluid flowing out of the open end of discharge line 108 into pit 110. Details of discharge equalizing device 200 are described in further detail below in conjunction with FIG. 2.

Discharge equalizing device 200 may also include a shield 208 to shield any exiting fluids flowing out of discharge equalizing device 200 and also to serve as a restraint system by anchoring discharge equalizing device 200 into the ground. Although not illustrated, additional anchorage systems may be associated with discharge line 108 for anchoring discharge line 108 into the ground.

FIG. 2 is a cross-sectional view of discharge equalizing device 200 in accordance with one embodiment of the invention. In the illustrated embodiment, discharge equalizing device 200 includes a tubing 202 having a plurality of orifices 203, a shroud 204, a reinforcing pad 206, and shield 208.

Tubing 202 may be any suitable conduit operable to transport a fluid therethrough. Tubing 202 may be any suitable size and shape and may be formed from any suitable material. In one embodiment, tubing 202 has a diameter between approximately two and three inches. The fluid flowing through tubing 202 flows in the direction of arrow 210 and escapes from tubing 202 through orifices 203, as indicated by arrows 211. Orifices 203 may be any suitable size and there may be any suitable number of orifices 203. In one embodiment, there are multiple sets of orifices 203 longitudinally spaced along tubing 202, with each set of orifices 203 including a plurality of orifices equally spaced around a circumference of tubing 202. For example, orifices 203 may be spaced around the circumference of tubing 202 at an angular spacing of 30°, 60°, 90°, or 180° depending on the number of orifices in each set. Orifices 203 may also be offset from one another. The present invention contemplates any suitable arrangement of orifices 203 formed in tubing 202.

In a particular embodiment of the invention, tubing 202 may have a buffer zone 212 associated with its downstream end in which there are no orifices. Buffer zone 212 thus facilitates the reduction of the fluid shock exiting orifices 203 by smoothing the transition from zero pressure to high pressure. In other words, as fluid starts exiting orifices 203 buffer zone 212 begins to fill up with fluid so that the full pressure of the fluid does not immediately exit orifices 203, but instead builds up progressively.

Shroud 204 couples to tubing 202 in any suitable manner. Shroud 204 may be any suitable size and may be formed from any suitable material. In one embodiment, shroud 204 is formed from ten inch casing; however, other suitable diameters may be utilized. In addition, shroud 204 may have any suitable length. In the illustrated embodiment, shroud 204 couples to tubing 202 with an end cap 214 at the downstream end of tubing 202 and an entrance cap 216 at the upstream end. In order for the fluid existing in shroud 204 to exit shroud 204, end cap 214 includes a downstream opening 215 and entrance cap 216 includes an upstream opening 217. Although both downstream opening 215 and upstream opening 217 may have any suitable open areas, downstream opening 215 and upstream opening 217 have substantially the same open areas. This facilitates the pressure-balanced exit condition. In some embodiments, shroud 204 may not be uniform, but may have openings along its length.

Because the fluid flowing through tubing 202 is flowing at high velocity, and because orifices 203 have a relatively small diameter, a great force may be exerted on an inside wall 218 of shroud 204. This may cause deterioration of the wall of shroud 204 depending on many factors, such as the thickness of shroud 204, the type of material shroud 204 is formed from, the type of fluid flowing through tubing 202, the velocity of fluid, and the size of orifices 203. Therefore, reinforcing pad 206 may be coupled to an outside surface 220 of shroud 204 in a location corresponding to where the fluid impinges on inside surface 218. Reinforcing pad 206 may also couple to inside wall 218 of shroud 204 as a sacrificial insert. Reinforcing pad 206 may be any suitable size and shape, may be formed from any suitable material, and may couple to shroud 204 in any suitable manner. In lieu of reinforcing pad 206, the wall thickness of shroud 204 may be increased or the type of material that shroud 204 is formed from may be changed.

Shield 208 functions to act as a shield for any fluid exiting upstream opening 217 of shroud 204, and may also act as an anchorage system for discharge equalizing device 200 by imbedding a portion of shield 208 into the ground. Shield 208 may be any suitable size and shape and may be formed from any suitable material.

In operation of one embodiment of the invention, a high flow fluid flows through tubing 202 in the direction of arrow 210. The fluid starts exiting orifices 203 and quickly fills up buffer zone 212 before the full pressure of the fluid exiting orifices 203 starts impinging upon inside wall 218 of shroud 204 that counteracts the reaction force generated by the exiting of the fluid through orifices 203. Fluid then exits out downstream opening 215 and upstream opening 217 before being deposited into pit 110 (FIG. 1). The fluid flowing out of downstream opening 215 and the fluid flowing out of upstream opening 217 create substantially equal but offsetting forces. This offsetting of forces creates a pressure-balanced exit condition for discharge equalizing device 200 and prevents the end of discharge line 108 from moving uncontrollably. Therefore, a safer environment may be facilitated.

In another embodiment of the invention, illustrated in FIG. 3B, tubing 302 is shown with equally spaced orifices 303 and no shroud 204 exists. In this embodiment, the fluid flowing through tubing 302 exits through orifices 303, and since these orifices have equal open areas and equally spaced, then the forces caused by the fluid flowing out of orifices 303 offset each other, thereby facilitating a pressure-balanced exit condition.

In another embodiment of the invention, which is not illustrated in the figures, tubing 202 does not have orifices 203 formed therein and no shroud 204 exists. In this embodiment, a tee is coupled to the end of tubing 202 so that when the fluid flowing through tubing 202 exits the end orifice of tubing 202, it exerts a force on the inside of the tee and then flows out both ends of the main branch of the tee. If these ends of the tee have equal open areas, then the forces caused by the fluid flowing out of the ends offset each other, thereby facilitating a pressure-balanced exit condition.

FIGS. 3A and 3B are perspective views of a discharge equalizing device 300 in accordance with another embodiment of the present invention. Discharge equalizing device 300 is similar in function to discharge equalizing device 200; however, discharge equalizing device 300 includes a collection tank 308 that supports both ends of a tubing 302. In the illustrated embodiment, discharge equalizing device 300 includes tubing 302 having one or more orifices 303, a shroud 304, a pair of shields 306a, 306b, a lifting eye 307, a removable plug 310, and collection tank 308.

The description of tubing 302, orifices 303, and shroud 304 is substantially similar to the discussion of tubing 202, orifices 203, and shroud 204 as found in FIG. 2 and, hence, is not described again.

Shields 306a, 306b, are also similar to shield 208 of FIG. 2; however, in the embodiment illustrated in FIG. 3A, shield 306a is placed adjacent an upstream opening 317 of shroud 304 and shield 306b is placed adjacent a downstream opening 315 of shroud 304. Shields 306a, 306b create a symmetry in discharge equalizing device 300 that facilitates the balancing of the resultant forces from fluid exiting upstream opening 317 and downstream opening 315.

The ends of tubing 302 may be coupled to collection tank 308 in any suitable manner. Collection tank 308, along with lifting eye 307, facilitates the portability of discharge equalizing device 300. As such, discharge equalizing device 300 may be mounted on a truck, trailer, a skid, or other suitable vehicle for easy transportation.

Although collection tank 308 may have any suitable size and shape, in one embodiment, collection tank 308 includes a top 314 disposed underneath tubing 302 and shroud 304 to collect the fluids exiting shroud 304. In a particular embodiment, top 314 has a concave surface to assure that forces on collection tank 308 are downward. In any event, top 314 includes a plurality of drain holes 316 that direct the fluid down into collection tank 308. Collecting fluid in collection tank 308 also facilitates added weight to discharge equalizing device 300, which aids in anchoring the device. A drain 318 may be coupled near a bottom of collection tank 308 to facilitate the draining of the fluid contained therein.

As illustrated in FIG. 3B, tubing 302 may include a buffer zone 320 that functions in a similar manner to buffer zone 212 of tubing 202 (FIG. 2). Removable plug 310 functions as a clean-out for tubing 302 and may be any suitable removable plug that couples to the downstream end of tubing 302 in any suitable manner.

In operation of one embodiment of the invention illustrated in FIGS. 3A and 3B, fluid having a high velocity flows through tubing 302 in the direction as indicated by arrow 322. The fluid starts exiting orifices 303 and eventually fills up buffer zone 320 before the full pressure of the fluid is exiting out orifices 303. The fluid impinges upon the inside surface 323 of shroud 304 and exits shroud 304 via downstream opening 315 and upstream opening 317 before hitting shields 306a and 306b. The fluid is then directed in all directions and some of the fluid collects on top 314 of collection tank 308. The fluid then drains through drain holes 316 into collection tank 308 where it may be stored or drained off using drain 318. As described above, the fluid exiting orifices 303 exerts a force on the inside surface 317 of shroud 304 that offsets the reaction force generated by the fluid flowing out of orifices 303. This may create a pressure-balanced exit condition for tubing 302.

Although some embodiments of the present invention are described in detail, various changes and modifications may be suggested to one skilled in the art. The present invention intends to encompass such changes and modifications as falling within the scope of the appended claims.

Claims

1. A fluid discharge device comprising:

tubing having one or more orifices formed therein;

a shroud coupled to the tubing such that, when a fluid flowing through the tubing exits the orifices, the fluid impinges on an inside surface of the shroud; and

openings at both ends of the shroud, wherein the openings have substantially the same areas.

2. The device of claim 1 further comprising a reinforcing pad coupled to a surface of the shroud in a location corresponding to where the fluid impinges on the inside surface.

3. The device of claim 1 wherein the one or more orifices comprise a plurality of orifices equally spaced around a circumference of the tubing.

4. The device of claim 3 wherein the orifices are spaced around the circumference of the tubing at an angular spacing selected from the group consisting of 30 degrees, 60 degrees, 90 degrees, and 180 degrees.

5. The device of claim 1 wherein the one or more orifices comprise a plurality of orifices spaced along a length of the tubing.

6. The device of claim 1 wherein the tubing includes a buffer zone in which there are no orifices.

7. The device of claim 1 wherein the fluid is flowing at a pressure of at least 100 psi.

8. The device of claim 1 further comprising a shield coupled to an outside surface of, and surrounding, the tubing at a location upstream from the shroud.

9. The device of claim 1 further comprising a pair of shields coupled to an outside surface of, and surrounding, the tubing, the pair of shields disposed adjacent opposite ends of the shroud.

10. The device of claim 1 further comprising a selectively removable plug coupled to a downstream end of the tubing.

11. A fluid discharge method comprising:

receiving a fluid flow in a tubing;

directing the fluid out through one or more orifices of the tubing;

impinging the fluid on an inside surface of a shroud surrounding the tubing;

directing the fluid out through at least two openings on opposite ends of the shroud; and

using the reaction force caused by the fluid flowing out one of the openings to offset a reaction force caused by the fluid flowing out of the other opening to stabilize the tubing.

12. The method of claim 11 further comprising collecting the fluid exiting the openings of the shroud.

13. The method of claim 11 further comprising causing the openings to have substantially the same area.

14. The method of claim 11 further comprising reinforcing a surface of the shroud in a location corresponding to where the fluid impinges on the inside surface.

15. The method of claim 11 wherein the fluid is flowing at a pressure of at least 100 psi.

16. The method of claim 11 further comprising anchoring the tubing into the ground.

17. A fluid discharge device comprising:

tubing having a plurality of orifices spaced around a circumference of the tubing;

a shroud coupled to the tubing such that, when a fluid flowing through the tubing exits the orifices, the fluid impinges on an inside surface of the shroud;

openings at both ends of the shroud, wherein the openings have substantially the same areas;

a pair of shields coupled to an outside surface of, and surrounding, the tubing, wherein the pair of shields are disposed adjacent opposite ends of the shroud; and

a collection tank disposed below the shroud and operable to collect the fluid exiting the opposite ends of the shroud, wherein the collection tank supports opposite ends of the tubing.

18. The device of claim 17 further comprising a reinforcing pad coupled to a surface of the shroud in a location corresponding to where the fluid impinges on the inside surface.

19. The device of claim 17 wherein the orifices are equally spaced around the circumference of the tubing.

20. The device of claim 17 wherein the orifices are spaced along a length of the tubing.

21. The device of claim 17 wherein the tubing includes a buffer zone in which there are no orifices.

22. The device of claim 17 wherein the fluid is flowing at a pressure of at least 100 psi.

23. The device of claim 17 further comprising a selectively removable plug coupled to a downstream end of the tubing.

24. The device of claim 17 wherein the collection tank includes a drain coupled near a bottom of the collection tank.

25. The device of claim 17 wherein the collection tank includes a concave top with a plurality of drain holes.

26. A fluid discharge method comprising:

receiving a fluid flow in a tubing;

directing the fluid out through at least two orifices equally spaced around a circumference of the tubing; and

using the reaction force caused by the fluid flowing out at least one of the orifices to offset the reaction force caused by the fluid flowing out an opposite orifice to stabilize the tubing.