Patent Application
20110266374
The field of this invention is completion tools for subterranean use and more particularly those tools used in gravel packing and fracturing subterranean locations and designs to minimize erosion damage from slurries flowing through and entering an annular space around the tool.
Well completions that need sand control involve a series of screens with an isolation packer above and a crossover tool that extends through a bore in the packer mandrel that allows gravel slurry to be delivered through the tubing and ultimately into the annular space around the screens as the carrier fluid returns to the surface through the crossover tool and up the outer annulus above the production packer. The path for the delivered gravel slurry is through a first series of ports to get out through the tubing and then into an annular space defined around the tubing by the packer skirt or lower extension assembly. The slurry then exits ports in the packer skirt to get to the annulus around the screens in the producing zone. The erosive nature of the gravel slurry causes excessive wear at the ports both at the tubing and at the packer skirt opening.
Prior efforts at controlling such damage from erosion included placing of hardened inserts in openings in softer metal components to protect the edges of the openings in the softer metal as shown in U.S. Pat. No. 6,491,097. Earlier a hardened sleeve with ports that overlay ports in a weaker surrounding housing were used to prevent erosion of the openings in the surrounding housing as shown in U.S. Pat. No. 5,636,691. Other solutions attempted to configure the flowing stream into a circular or helical pattern to reduce the erosion from impact of slurry that exited ports in a housing. This feature can be seen in U.S. Pat. No. 7,185,704. Other designs used a pivoting baffle plate that responded to slurry flow stream impact to redirect it away from an opposing casing wall as shown in U.S. Pat. No. 7,559,357. Other designs to reduce erosion involved a spinning member that received impact of the slurry flow and was caused to spin to take the energy out of the flowing slurry stream while protecting the housing wall behind the spinning member as described in U.S. Pat. No. 7,096,946. A stationary component with a spiral ridge or projection to induce swirl in the slurry flow is shown in US Publication 20090301710 A1.
Some of the offered designs in the past had moving parts that presented mechanical reliability issues in slurry service. Others put openings in hardened sleeves or hardened inserts directly adjacent to openings in the softer metal housings in an effort to protect the edges of the softer metal by making smaller holes in the hardened sleeve or inserts in the openings in the wall of the softer metal. This also caused resistance to flow so that higher slurry velocities occurred or the drift diameter through the tool was reduced. To avoid the issues with the above described prior designs, the present invention seeks to provide in a design with no moving parts a path for the slurry that redirects its flow direction in the course of spacing apart the soft metal components from the hardened flowpath that reorients the slurry stream. By getting the slurry to travel along the insert in a nearly parallel orientation, the housing walls are protected from any severe erosion as opposed to the prior efforts described above where the slurry exited in intimate contact with the edges of openings in the softer metal of a surrounding housing. Applications for a crossover housing and a subsequent outlet to an annular space around the screens are contemplated. These and other aspects of the present invention will become more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while appreciating that the full scope of the invention is determined by the appended claims.
An outlet member is preferably made from a hardened material and is cut from a tubular shape at an angle of preferably 5 degrees. At its upper end it is cut away so that slurry flow can exit ports in a hardened sleeve and impinge directly onto the upstream portion of the insert. The impingement changes the flow stream angle as the flow continues through a fully tubular middle segment of the insert that leads out to an elongated exit ramp whose downstream end sits preferably flush with the outer housing wall so as to protect the insert from mechanical shocks and retain the insert axially when slurry flows through it. Other external details aid in fixation when in use. Applications in a crossover housing and in a surrounding housing before reaching the annulus outside of a screen assembly are contemplated.
Referring to
The housing 32 has a series of parallel ribs 34 that are on the outside of the sleeve 18 and located between rows of holes 20. These ribs have lower end shoulders so that a pair of ribs 34 presents spaced locating shoulders 36 and 38 on which the inlet portion 12 is supported. Ribs 34 have an outer ridge 40 to serve as a travel stop for cover sleeve 42. Ribs 34 also have an external groove 44 in which sits an o-ring or clamp, snap ring or other fastener 46 that abuts the outer wall 48 of inlet segment 12. This is best seen in
Slant cut 50 is on the transition portion and it is put there to allow the transition portion 14 to fit up to the inside surface of the cover sleeve 42 as compensation for the slant mounting of the insert with respect to the axis of the housing 32. The transition portion 14 is further defined by a 360 degree structure along a plane defined by the outlet surface 52. The top 54 of surface 52 is preferably located axially even with or below the lower end of sleeve 42 but not further out radially than sleeve 42 so that the exiting slurry flow will not directly impact the sleeve 42 even if there are small eddy streams as the main body of the flow continues toward the outlet portion 16.
Referring to
Depending on the position of the lowermost opening 20 with respect to the transition 56 of edges 24 and 25 it may or may not be possible for a flow stream to go straight out of the opening defined by surface 52 without making a turn. Preferably, the lowest hole 20 is far enough above the transition 56 so that all flow out of the openings 20 impacts the inlet portion 12 and turns to align with the opening defined by surface 52 at the transition portion 14.
The exit portion 16 continues from transition portion 14 with opposed edges 58 and 60 that end at lower end 62. Lower end 62 is in a recess 64 that has a lower end 66 and acts as a lower travel stop for the insert 10. As seen in
Sleeve 18 has a non-hardened extension sleeve 74 so that the two can be shifted in tandem to close the slurry openings in the housing 32 by positioning the sleeve 74 opposite the ribs 34.
In the preferred application of the insert 10 an array is located around a hardened sleeve 18 which defines an annulus around the exit of a crossover tool for gravel packing. The housing 32 is part of the lower extension sleeve of a packer also not shown but the arrangement of these accessory components is known to those skilled in the art. An array of inserts 10 is disposed under the cover 42 of the housing 32. In another application the array of inserts 10 can be located in wall openings of a crossover housing.
The construction of the insert allows for a gravel or other slurry exit path that avoids impinging softer surrounding surfaces as the insert 10 has an inlet portion 12 that collects the slurry stream exiting hardened openings and defines a hardened path about said openings 20 to funnel the slurry flow through the transition portion 14 where the angle of the flow with respect to the surrounding housing 32 axis is very small and preferably in the range of about 5 degrees but can vary from about 2-20 degrees. While the passage size and housing dimensions can dictate the length of the insert 10 its slope with respect to the housing axis of housing 32 should not exceed the slope of the cut for the openings 20. The slight angular exit from the inserts 10 and the presence of the outlet portion 16 further protects the soft components of housing 32 from impingement of the slurry stream and what impingement there is occurs at such a small angle of contact that even high slurry flows such as 70 barrels per minute, with flow variable depending on the application size, do not create erosion that is of any concern. Thus the outlet from the surrounding housing such as 32 is spaced apart from the openings 20 in the interior structure 18 such that the insert can be shaped to create a flowpath that is resistant to erosion while reorienting the flowing slurry stream. Using the outlet portion 16 the exterior structure such as surface 70 is protected from erosive action because the slight angular exit angle of the insert 10 allows the slurry flow to be nearly parallel to the outer housing so that the impact angle is at a minimum and further directs the slurry into the annulus and down to the region of the gravel screens without significant erosive contact with a surrounding casing when it is a cased hole that is being gravel packed or fractured. When used in an application such as a crossover housing the small exit angle can reduce or eliminate the need for a blast liner in a surrounding housing as the erosive effects will be attenuated or even eliminated. While the preferred application is screen frac packing for sand control, other subterranean applications are contemplated where the flowing stream is capable of erosion.
The preferred material for the insert 10 is tungsten carbide although other hard materials that resist erosion from slurries are contemplated.
The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below.
