The present invention generally relates to fracture tanks that store fluid to be injected into a well bore to fracture the formation around the bore. More particularly, the present invention relates to a fracture tank bearing one or more improvements in order to facilitate the use of the tank. Specifically, the present invention relates to fracture tanks having one or more improvements relating to the structural integrity of the tank or the manner in which the tank may be used or serviced.
Hydraulic fracturing is now a commonly used method for creating fractures that extend from a bore hole into the surrounding rock formations. This method may also be informally referred to as “fracing” or “hydrofrac.” Although hydraulic fracturing is perhaps most commonly employed to stimulate production from oil and gas wells, it is also applied in stimulating ground water wells, preconditioning rock for caving or inducing rock to cave in mining, as a means of enhancing waste remedial processes, to dispose of waste by injection into suitable deep rock formations, and as a method to measure the stress in the Earth.
In accordance with hydraulic fracturing processes, multiple fracture tanks are transported to a bore hole site with these fracture tanks storing the fluid that is to be employed in the hydraulic fracturing method. The fluid held in the fracture tanks is injected into the bore hole at a rate and pressure sufficient for creating or restoring fractures in the surrounding formation, thereby increasing the surface area of the formation that is exposed to the bore hole. The fractures provide a path along which fluids or gases may flow either from the formation into the bore hole (in the case of extracting fluids or gases) or from the bore hole into the surrounding formation (in the case of injecting fluid or gas into a formation). With respect to oil recovery, the fractures serve to increase the rate at which oil can flow from the surrounding formation into the bore hole for extraction.
In a given hydraulic fracturing operation, multiple fracture tanks will be required inasmuch as each tank can only hold a limited amount of fracturing fluid. The fracture tanks employed in the art are simply storage trailers that are transported to the site by a tractor truck. That is, the typical fracture tank is a trailer portion of a tractor-trailer combination. When the bore hole is located at a site having flat terrain, it is usually sufficient to simply drive the tractor-trailer combination to the desired location in the area surrounding the bore hole such that the fracture tank can be accessed and used when necessary. However, when the area surrounding the bore hole is hilly or otherwise not sufficiently flat, the tractor may be unable to transport the fracture tank (i.e., trailer) to the desired location. Similarly, if the terrain surrounding the bore hole is moist, the tractor-trailer combination often times becomes stuck. Thus, the fracture tanks can usually only be transported around a bore hole site if that site is flat and well drained, and, in hilly regions or moist/muddy soil, it has been found necessary to transport the fracturing tanks by pushing them with bulldozers.
Notably, fracture tanks of the prior art are not specifically given to being pushed around by bulldozers. Thus, a number of problems are encountered. For example, the undercarriages of the fracture tanks have transverse strengthening ribs or joists, and mud can collect between these ribs such that the fracture tank becomes bogged down and is difficult to maneuver, even with the bulldozer. Additionally, after the fracture tank is removed from the site, mud clumps can fall out from the undercarriage during road transport, and this can be dangerous for other vehicles on the road. Thus, the fracture tanks may need to be cleaned and otherwise maintenanced, increasing the costs in using such tanks.
Because the fracture tanks are not constructed for being manipulated by a bulldozer, the tanks can often become damaged by the bulldozer, again increasing the costs. The fracture tanks can become stuck in the mud in moist terrain, and the bulldozer, which is sufficiently powerful enough to move the fracture tank, can damage portions of the tank by forcing against the resistance of the mud. This is specifically true when a tank has been allowed to sit for some time, permitting the mud to dry around portions of the tank. For example, the rear wheels and spring hangers on which they are mounted can sometimes become encased in dried mud and a bulldozer pushing on the fracture tank can cause the wheels, spring hangers, or even the support beams to which they are mounted to become twisted or otherwise structurally compromised.
Water is one of the most common fracturing fluids employed in hydraulic fracturing, and, when it is employed can sometimes be drawn from local lakes and streams and the like. Thus, it is not uncommon for the fracture tanks hold not only water but algae, water plants and other debris. This debris tends to clog the outlet port of the fracture tank and must therefore be periodically removed. In the prior art, the fracture tanks have simply been cleaned by workers entering the tanks and physically removing the algae, plant matter, debris, etc.
In cold climates, the fluid held in a fracture tank may freeze, and this may result in damage to the fracture tank and/or render the tank useless for operation.
Further, because moving items by bulldozer is not a precise way to position items, it is common for one fracture tank to be pushed forcefully into another in an attempt to align the multiple fracture tanks at a desired location near the bore hole. Additionally, it is often necessary for workers to climb atop a fracture tank and safely walk from one to another, in areas where mud, rain and snow may make such walking dangerous.
Thus, there is a need in the art for a fracture tank that is easy to. manipulate in hilly and muddy terrain, that has ready means for heating, cleaning and flushing, that is easily ganged with other fracture tanks, and that is safe to walk upon, and from one to another.
In light of the foregoing, it is a first aspect of the invention to provide a fracture tank that is easy to manipulate in hilly and muddy terrain.
Another aspect of the invention is the provision a fracture tank that includes means for cleaning and flushing of the interior of the tank, to remove unwanted debris and material therefrom.
Yet another aspect of the invention is the provision of a fracture tank that includes means for heating the interior thereof, to prevent freezing of the fracture water contained therein.
Still a further aspect of the invention is the provision of a fracture tank that has a strengthened rear bumper system to accommodate engagement by a bulldozer blade for movement within a hilly or muddy terrain.
Still another aspect of the invention is the provision of a fracture tank in which the undercarriage thereof is provided with skid plates encasing the undercarriage structure and providing means for facilitating movement thereof in various environments.
Yet a further aspect of the invention is the provision of a fracture tank that may be easily ganged with other fracture tanks, that is safe to walk upon, and that accommodates ready movement of workers from one ganged tank to another.
The foregoing and other aspects of the invention that will become apparent as the detailed description proceeds are achieved by a fracture tank, comprising an undercarriage, said undercarriage comprising a load floor having a right side and a left side defining a width of the load floor, and a front and rear defining a length of said load floor, a right frame member extending along the length of said load floor to provide structural support for the undercarriage, a left frame member extending along the length of said load floor to provide structural support for the undercarriage, a right skid plate extending from said right frame member along at least a portion of the width of the load floor, a left skid plate extending from said left frame member along at least a portion of the width of the load floor, said right and left skid plates providing a flat surface for supporting the tank as it is pushed over a ground surface while resting on said right and left skid plates.
Yet other aspects of the invention that will become apparent herein are obtained by a fracture tank for oil field use, comprising an undercarriage having a pair of oppositely disposed skid plates therealong, said skid plates boxing joists of said undercarriage, a tank atop said undercarriage, said tank defined by pairs of opposed sides, ends, and a roof and floor, at least one heat pipe entering said tank at a first region thereof, and exiting said tank at a second region thereof, and a flush system comprising a perforated flush pipe extending about at least a portion of an interior of said tank, and a drain exiting said tank near said floor.
Referring now to
It will be appreciated that fracture tanks are typically pulled to a desired location at a bore hole by being towed by a tractor, when the ground is well drained and relatively flat. However, when the ground is moist or hilly or both, fracture tanks are typically moved to a desired location by being pushed by a bulldozer. Thus, in hilly and/or moist regions, a fracture tank is disconnected from the tractor and is pushed around in a form as generally seen in
The left and right skid plates 40, 42, and the load floor 14 are tapered to ensure ease of mobility in rough or muddy areas. As can be seen in
The wheel box 36 at the rear 22 of the continuous portion of the load floor 14 includes a front box wall 54 extending upwardly from the rear 22, and further includes a top box wall 56 extending rearwardly from the front box wall 54. The top box wall 56 may be considered, as already suggested above, as a continuation of the load floor 14, and, thus, the rear wall 26 of the fracture tank 10 is still properly considered as extending upwardly from the load floor 14.
Referring now to
As seen as in
When pushing and otherwise maneuvering fracture tanks in muddy regions, a situation can occur where the rear wheels of the fracture tank are buried in mud. If left to sit, the mud can then dry or even freeze in cold weather, encasing the rear wheels and making it difficult to extract them without damaging the area of the fracture tank at the wheel box. Indeed, when a bulldozer engages a fracture tank that has been encased in mud or frozen in fixed position, as just described, it is possible that the force exerted by the bulldozer to remove the wheels from the ice or dried mud can cause the spring hanger frame members to twist or otherwise be structurally warped. This can completely ruin the relationship between the wheels and the remainder of the fracture tank and frame members 16, 18 or 66, making it necessary to replace structurally compromised elements before the fracture tank can then be secured to a tractor for road transport. Thus, with reference to
Referring now to
Once so aligned, the present invention provides structures for making it easy for a worker to access a given fracture tank 10. Particularly, an anti-slip grid 84 is positioned on the exterior of the top wall 32, and is positioned near the front wall 24, where a ladder 86 is provided for ascending to the top wall 32 and onto the anti-slip grid 84. With multiple fracture tanks 10 aligned side-by-side, it will be possible for a worker to walk from one fracture tank 10 to a neighboring fracture tank, using the anti-slip grid 84. As seen in
Referring now to
The tank 34 also receives and maintains a gel pipe or pipes 95 along at least a portion of a wall thereof. The gel pipes 95 are characterized by holes or apertures 97 for the introduction of selected chemicals into the tank 34, as is well known in the art.
The front wall 24 may also be provided with heat pipe inlet ports 102, which extend through the front wall 24 to provide inlets into heat pipes 104. The heat pipes 104 extend along at least a portion of the length of the storage tank 34, and then extend through the walls, such as the roof 32, of the storage tank 34 to provide heat pipe outlet ports 106. In this particular embodiment, the heat pipes 104 extend along approximately three-fourths of the length of the storage tank 34 and then bend upwardly to extend through the top wall 32 to provide the heat pipe outlet ports 106. A heated gas can be introduced into the heat pipe inlet port to travel along the length of the heat pipes 104, thereby heating the contents of the storage tank 34 before being expelled at the heat pipe outlet ports 106. This will be particularly beneficial in colder climates where the fracing fluid held in the fracture tank 10 might freeze.
In light of the foregoing, it should be appreciated that the present invention significantly advances the art by providing a fracture tank that is structurally and functionally improved in a number of ways. While particular embodiments of the invention have been disclosed in detail herein, it should be appreciated that the invention is not limited thereto or thereby inasmuch as variations on the invention herein will be readily appreciated by those of ordinary skill in the art. The scope of the invention shall be appreciated from the claims that follow.
Number | Name | Date | Kind |
---|---|---|---|
3685458 | Price et al. | Aug 1972 | A |
3918736 | Hickman | Nov 1975 | A |
4318549 | Pletcher | Mar 1982 | A |
4603733 | Loevinger | Aug 1986 | A |
4819955 | Cobb | Apr 1989 | A |
4948519 | Zeh | Aug 1990 | A |
5232246 | Page | Aug 1993 | A |
6152492 | Markham et al. | Nov 2000 | A |
6173991 | Piona et al. | Jan 2001 | B1 |
Number | Date | Country | |
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20100147860 A1 | Jun 2010 | US |