This present application relates generally to conveyor system apparatuses and methods. The conveyor system disclosed herein provides a supply conveyor and a return conveyor in material flow communication. The supply conveyor transfers and releases a portion of material to a second source. The return conveyor re-circulates to the supply conveyor any portion of material unreleased such that the supply conveyor may re-transfer and release the unreleased portion of material to the second source.

FIELD OF INVENTION

This present application relates generally to handing material and conveying material to different sites and more specifically to material handling during fracturing operations.

BACKGROUND

Hydraulic fracturing is a stimulation treatment routinely performed on oil and/or gas wells. “Fracturing” refers to the method of pumping a fluid into a well until the pressure increases to a sufficient level to fracture the subterranean geological formations. A propping agent or “proppant” is injected, along with a hydraulic fluid, into the wellbore to maintain open the newly formed fractures extending from the wellbore in generally opposing directions. The proppant remains in place once the hydraulic pressure is removed and therefore props open the fracture to enhance flow in the wellbore.

Proppants can be made of virtually any generally solid particle that has sufficient particle strength, sphericity and size. Silica-containing material, like sand, and ceramic materials have proved to be especially suitable for use in hydraulic fracturing.

Typically, in any hydraulic fracturing system, a large amount of such proppant is required. Increasing technology and improved techniques have resulted in the use of greater volumes and higher concentrations of proppant in hydraulic fracturing systems in the oil field. This increased use of proppant has created the demand for more dependable proppant handling equipment capable of moving large amounts of proppant from on-location storage units to a blending apparatus with little or no spillage. The equipment must also provide a steady, even flow of proppant to the blender to prevent fluctuations in the concentration rates pumped down into the wellbore.

It can be difficult to effectively transport proppant, or some other material, to a desired location at a steady flow rate with little or no spillage. Typically, transportation of the proppant occurs by a conveyor at some predetermined volumetric flow rate. The volumetric flow rate transferring the proppant must be tightly coordinated with the volumetric flow rate of the proppant exiting the conveyor. If the proppant exits the conveyor at a volumetric flow rate less than the rate at which it is being transferred, proppant buildup occurs. Monitoring the proppant buildup to prevent spillage typically requires either human interaction or a complex electronic or hydraulic system comprising sensors and control components.

DETAILED DESCRIPTION

Referring now to the drawings, wherein like reference numbers are used herein to designate like elements throughout the various views and various embodiments, which are illustrated and described. The figures are not necessarily drawn to scale, and in some instances the drawings have been exaggerated and/or simplified in places for illustrative purposes only. In the following description, the terms “upper,” “upward,” “up-hole,” “lower,” “downward,” “below,” “down-hole” and the like, as used herein, shall mean: in relation to the bottom or furthest extent of the surrounding wellbore even though the well or portions of it may be deviated or horizontal. Where components of relatively well-known designs are employed, their structure and operation will not be described in detail. One of ordinary skill in the art will appreciate the many possible applications and variations of the present invention based on the following description.

The exemplary methods, apparatuses and compositions disclosed herein may directly or indirectly affect one or more components or pieces of equipment associated with the preparation, delivery, recapture, recycling, reuse, and/or disposal of the disclosed compositions. For example, and with reference toFIG. 1, the disclosed apparatuses, methods and compositions may directly or indirectly affect one or more components or pieces of equipment associated with an exemplary fracturing system10, according to one or more embodiments. In certain instances, system10includes a fracturing fluid producing apparatus20, a fluid source30, a proppant source40, and a pump and blender system50and resides at the surface at a well site where a well60is located. In certain instances, fracturing fluid producing apparatus20combines a gel pre-cursor with fluid (e.g., liquid or substantially liquid) from fluid source30, to produce a hydrated fracturing fluid that is used to fracture the formation. The hydrated fracturing fluid can be a fluid for ready use in a fracture stimulation treatment of well60or a concentrate to which additional fluid is added prior to use in a fracture stimulation of well60. In other instances, fracturing fluid producing apparatus20can be omitted and the fracturing fluid sourced directly from fluid source30. In certain instances, the fracturing fluid may comprise water, a hydrocarbon fluid, a polymer gel, foam, air, wet gases and/or other fluids.

Proppant source40can include a proppant for combination with the fracturing fluid. The system may also include an additive source70that provides one or more additives (e.g., gelling agents, weighting agents, and/or other optional additives) to alter the properties of the fracturing fluid. For example, the other additives can be included to reduce pumping friction, to reduce or eliminate the fluid's reaction to the geological formation in which the well is formed, to operate as surfactants, and/or to serve other functions.

Pump and blender system50receives the fracturing fluid and combines it with other components, including proppant from proppant source40and/or additional fluid from the additives. The resulting mixture may be pumped down well60under a pressure sufficient to create or enhance one or more fractures in a subterranean zone, for example, to stimulate production of fluids from the zone. Notably, in certain instances, fracturing fluid producing apparatus20, fluid source30, and/or proppant source40may be equipped with a conveyor system (seeFIGS. 3-7) or multiple conveyor systems in series (seeFIG. 8) and one or more metering devices (seeFIG. 7) to control the flow of fluids, proppants, and/or other compositions to pumping and blender system50. Such metering devices may permit pumping and blender system50to receive from one, some or all of the different sources at a given time, and may facilitate the preparation of fracturing fluids in accordance with the present disclosure using continuous mixing or “on-the-fly” methods. Thus, for example, the pumping and blender system50can provide just fracturing fluid into the well at some times and at other times combinations of fracturing fluid and proppant.

FIG. 2shows well60during a fracturing operation in a portion of a subterranean formation of interest102surrounding a well bore104. Well bore104extends from the surface106, and a fracturing fluid108is applied to a portion of subterranean formation102surrounding the horizontal portion of the well bore. Although shown as vertical deviating to horizontal, well bore104may include horizontal, vertical, slanted, curved, and other types of well bore geometries and orientations, and the fracturing treatment may be applied to a subterranean zone surrounding any portion of the well bore. Well bore104can include a casing110that is cemented or otherwise secured to the well bore wall. Well bore104can be uncased or include uncased sections. Perforations can be formed in casing110to allow fracturing fluids and/or other materials to flow into subterranean formation102. In cased wells, perforations can be formed using shaped charges, a perforating gun, hydro jetting and/or other tools.

The well is shown with a work string112descending from surface106into well bore104. Pump and blender system50is coupled with a work string112to pump fracturing fluid108into well bore104. Working string112may include coiled tubing, jointed pipe, and/or other structures that allow fluid to flow into well bore104. Working string112can include flow control devices, bypass valves, ports, and or other tools or well devices that control a flow of fluid from the interior of working string112into subterranean zone102. For example, working string112may include ports adjacent the well bore wall to communicate fracturing fluid108directly into subterranean formation102, and/or working string112may include ports that are spaced apart from the well bore wall to communicate fracturing fluid108into an annulus in the well bore between working string112and the well bore wall.

Working string112and/or well bore104may include one or more sets of packers114that seal the annulus between working string112and well bore104to define an interval of well bore104into which fracturing fluid108will be pumped. For example purposes only,FIG. 2shows two packers114, one defining an up-hole boundary of the interval and one defining the down-hole end of the interval. It should be understood that other embodiments may use a greater or lesser number of packers. When fracturing fluid108is introduced into well bore104(e.g., inFIG. 2, the area of well bore104between packers114) at a sufficient hydraulic pressure, one or more fractures116may be created in subterranean zone102. The proppant particulates in fracturing fluid108may enter fractures116where they may remain after the fracturing fluid flows out of the well bore. These proppant particulates may “prop” fractures116such that fluids may flow more freely through fractures116.

The apparatuses and methods of this disclosure relate to a conveyor system that transfers a material from a first end to a second end of the conveyor system and may mechanically re-circulate a portion of the material from the second end to the first end of the conveyor system in order to prevent buildup in the conveyor system. The herein disclosed conveyor system provides the means of moving large amounts of material with little or no spillage and also providing a steady, even flow of material to a desired location.

As depicted inFIGS. 3-5, conveyor system200typically has a least a supply conveyor210for transferring the material from a first end202to a second end204and a return conveyor220to re-circulate at least a portion of the material from a second end204to a first end202.

As further depicted inFIGS. 3-5, supply conveyor210has an inlet212at first end202of the conveyor system to receive material232from a first source230, and an outlet214at second end204of the conveyor system to release a portion of the material (released material242) to a second source240.

Supply conveyor210has a first carrier system for transferring material from first end202to second end204of conveyor system200. First carrier system may be a screw system, drag chain system, a belt system, a pneumatic system, or some other system capable of transferring material232from first end202to second end204of conveyor system200. As shown inFIGS. 3-5, the first carrier system is a supply screw211for the transfer of the material232. The return conveyor220has an inlet222at second end204of the conveyor system to receive an unreleased material244, and an outlet224at first end202of the conveyor system to re-circulate the unreleased material244to supply conveyor inlet212. The return conveyor has a second carrier system for transferring unreleased material244from second end204to first end202of conveyor system200. Second carrier system may be a screw system, drag chain system, a belt system, a pneumatic system, or some other system capable of transferring unreleased material244from second end204to first end202of conveyor system200. As shown inFIGS. 3-5second carrier system is a return screw221for the transfer of unreleased material244.

Material232may be a proppant made of virtually any generally solid particle that has sufficient particle strength, sphericity and size. Examples of proppants include silica-containing material, like sand, and ceramic materials have proved to be especially suitable for use in hydraulic fracturing.

In any embodiment herein disclosed, first source230consists of a proppant source such as a silo or some other storage unit, and second source240covers a companion conveyor system (seeFIG. 8), a metering device, a hopper, a pump and blender system50(seeFIGS. 1-2) or some combination.

A drive motor system270, comprising at least one drive motor, may be configured to engage the first carrier system and the second carrier system. As depicted inFIG. 3, drive motor system270is configured to rotate at least one of supply screw211and return screw221. Drive motor system270may be configured in such a way to rotate supply screw211to transfer material232from first end202to second end204of the conveyor and to rotate return screw221to re-circulate a portion of the material from second end204to first end202of the conveyor system. As shown, drive motor system270is located at first end202of the conveyor system. In the alternative, drive motor system270may be located elsewhere, such as at second end204, or as an independent system apart from conveyor system200. A drive motor suitable to rotate either supply screw211or return screw221may include any suitable hydraulic motor, electric motor or direct drive system. One suitable drive motor is the Dowmax 600B hydraulic motor marketed by Eaton Hydraulics.

Generally, screw conveyors are available in many configurations and are designed based on industry needs. The diameter of supply screw211may depend on the capacity of supply conveyor210and the amount of material to be conveyed. Supply screw211conveys material232at a volumetric rate from first end202to second end204. Similarly, the diameter of return screw221may depend on the capacity of return conveyor220and the amount of material re-circulated. Return screw221conveys unreleased material232at a volumetric rate from second end202to first end204. For example, supply screw211and return screw221may have a diameter of 18 inches and configured with drive motor system270capable of rotating at a first rate sufficient to transfer material at 200 cubic feet per minute (CFM).

As further shown inFIG. 3, first end202of the conveyor system may mount to a collection hopper250wherein supply screw211accepts gravity fed material232from first source230. At second end204of the conveyor system, supply conveyor210directs material (released material242) to second source240. Supply screw211runs at a preset rate to maintain a volumetric flow of material to second source240. If second source240accepts released material242at a volumetric flow rate less than supplied by the supply conveyor210, buildup of unreleased material244occurs (seeFIG. 4). The unreleased material244gravity feeds into return conveyor220materially connected to the supply conveyor210at second end204of conveyor system200. Return conveyor220re-circulates unreleased material244back to collection hopper250at first end202. This arrangement requires no human interaction, electronic or hydraulic control systems to maintain a consistent volumetric flow of material to the metering device.

As shown inFIG. 4, outlet214of the supply conveyor may also comprise a first outlet216and a second outlet218. As supply screw211of supply conveyor210transfers material232from first end202to second end204of conveyor200, first outlet216may release released portion of material (released material242) to second source240. If the volumetric flow rate of the material transferred from first end202to second end204is greater than the volumetric flow rate of released material242at first outlet216then a buildup of unreleased material244occurs. Supply screw211continues to run at a preset rate until eventually the buildup of unreleased material244gravity feeds from second outlet218of the supply conveyor210to inlet222of the return conveyor220. Return screw221then re-circulates unreleased material244to inlet212of supply conveyor210at first end202. Inlet212of supply conveyor210and outlet224of return conveyor220may be in material communication through collection hopper250, which can facilitate the distribution and collection of material received (seeFIG. 3).

Additionally, supply conveyor210and return conveyor220are in material flow communication allowing for the recirculation of unreleased material244to prevent buildup. Inlet222of return conveyor220can accept at least a portion of unreleased material244from outlet214of supply conveyor210. Inlet212of supply conveyor210can re-circulate at least a portion of unreleased material244from outlet224of return conveyor220. In certain embodiments, inlet222of return conveyor220may accept material from second source240instead of directly from outlet218of supply conveyor.

In another embodiment, first source230may release material232to collection hopper250. Collection hopper250, having material flow communication with at least inlet212of the supply conveyor210, facilitates the distribution and transportation of material232to inlet212of the supply conveyor210. Supply conveyor210then transfers the material to second end204of conveyor system200. Outlet214of supply conveyor210releases a portion (released material242) to a metering device310(seeFIG. 7). Metering device310delivers released material242to a blender of a pump and blender system50(seeFIGS. 1-2). The blender mixes the released material242with a fracturing fluid to produce a fracturing mixture. The fracturing mixture is introduced into well60for use in a fracturing operations using one or more pumps from the pump and blender system50(seeFIGS. 1-2).

FIG. 5depicts supply conveyor210and return conveyor220isolated and separately housed from one another. As shown, material flow communication occurs only between supply conveyor210and return conveyor220at first end202and second end204of conveyor system200. Thus, inlet212of supply conveyor210at first end202of conveyor system200receives material232from first source230. Supply screw211transfers at least a portion of the material to second end204of conveyor system200. At second end204, first outlet216releases a released portion of material (released material242) to second source240. Material not released (unreleased material244) is transferred by supply screw211to second outlet218of supply conveyor210. Unreleased material244is gravity fed to inlet222of return conveyor at second end204. Return screw221re-circulates unreleased material244to inlet212of supply conveyor210at first end202.

In another embodiment, conveyor system200may be transportable by any means known to one of ordinary skill in the art. As shown inFIGS. 3-5, the conveyor system200secures to a transportation device260comprising a wheelbase having a platform for affixing a plurality of wheels to said wheelbase.

FIG. 6depicts the orientation of supply conveyor210and return conveyor220in relation to the conveyor system200. Supply conveyor210is depicted having a first direction vector270and a corresponding first angle γ measured from a first horizontal plane272. Return conveyor220is shown having a second directional vector280and a second angle β measured from a second horizontal plane282. First horizontal plane272and second horizontal plane282are parallel to one another. First angle γ and second angle β may be equal to one another. Alternatively, at the second end204of the conveyor system200, first angle γ may be greater than second angle at β. First angle γ may be between 0 degrees and about 45 degrees measured from the first horizontal plane272. Second angle β may be between 0 degrees and 45 degrees measured from the second horizontal plane282. Typically, first angle γ and second angle β are from 0 to 20 degrees with first angle γ being at least 1 degree greater than second angle α. More typically, first angle γ and second angle β are from 5 to 15 degrees, with first angle γ being at least 5 degrees greater than second angle β. Thus, the relative angle between directional vector280and directional vector270is generally greater than 1 degree and can be greater than 2 degrees or 5 degrees. Typically, the relative angle will be less than about 15 degrees, and more typically less than about 10 degrees or less than 7 degrees.

The embodiment disclosed shows second angle less than first angle γ. This configuration allows gravity to facilitate the releasing of unreleased material244from supply conveyor210to return conveyor220at second end204of conveyor system200. In a similar manner, gravity facilitates recirculation of unreleased material244from return conveyor220to supply conveyor210at first end202of conveyor system200.

Conveyor system200may have an angular position α fixed relative to ground292. Alternatively, angular position α may be adjustable. Angular position α of conveyor system200is measured from ground292to a third directional vector290. Third directional vector bisects first directional vector270and second directional vector280. Adjusting angular position α can be accomplished with at least one or more hydraulic cylinders controlling the adjustment of the conveyor's angular position α. When the hydraulic cylinders are retracted, the conveyor's angular position is less than the angular position when the hydraulic cylinders are extended. A hydraulic power pack, or some other power supply for hydraulic units, supplies the required hydraulic pressure to the hydraulic cylinders. Angular position α of conveyor system may range between 5 degrees and 25 degrees. More preferably, angular position α ranges between 10 degrees and 20 degrees or angular position α is 15 degrees.

Another embodiment covers a method directed to the transfer of material232and recirculation of unreleased material244. As shown inFIG. 7, first source230stores material232. First source230may be silo300or some other storage unit. Silos300gravity feed material232through outlet conduits302to conveyor system200, as described above. Conveyor system200may operate at an inclined angular position α (seeFIG. 6) such that material232can be gravity fed from first source230to first end202of supply conveyor210. An operable angular a position depends on the height of outlet conduit302of silo300. The height is such that material communication occurs between first end202of supply conveyor210and collection hopper250. Such configuration allows silos300to gravity feed material232to collection hopper250. InFIG. 7, first source230comprises two silos300each having an outlet conduit302to direct material.FIG. 8shows more than two silos300.

As further depicted inFIG. 7, collection hopper250facilitates distribution of material232to first end202of supply conveyor210. Inlet212of supply conveyor accepts material232from collection hopper250. Supply conveyor210has a first carrier system for transferring material232from the first end202to the second end204of supply conveyor210. The first carrier system may be a screw system, drag chain system, a belt system, a pneumatic system, or some other system capable of transferring material232from the first end202to the second end204of supply conveyor210. As shown inFIG. 7the first carrier system is a supply screw211that rotates at a present speed to elevate material232to second end204of supply conveyor210at a first rate. The first rate should be a volumetric rate sufficient to transfer material232from first end202to second end204of supply conveyor211. For example, the first rate may be 200 cubic feet per minute (CFM).

Second end204of supply conveyor210releases a released portion242of the material to second source240through outlet214at a second rate. In some instances, the first rate and the second rate may be equal. In other instances, buildup of unreleased material244may occur at second end204of supply conveyor210when second rate of material released (released material242) to second source240is less than first rate of material232transferred from first end202to second end204of supply conveyor210.

Second source240may be a companion conveyor system (seeFIG. 8), metering device, a hopper (not shown), a pump and blender system50(seeFIGS. 1-2) or some combination. As shown inFIG. 7, the second source is a metering device310accepting released portion242of the material at second rate. From metering device310, released material enters a blender of pump and blender system50(seeFIGS. 1-2).

AnotherFIG. 7depicts that at second end204of supply conveyor (first end223of return conveyor220), supply conveyor210and return conveyor220are in material flow communication such that inlet222of return conveyor220can accept the buildup of unreleased material244from second outlet218of supply conveyor210. Return conveyor210has a second carrier system for transferring unreleased material244from the first end223to the second end225of return conveyor220. The second carrier system may be a screw system, drag chain system, a belt system, a pneumatic system, or some other system capable of transferring unreleased material244from the first end223to the second end225of return conveyor220. As shown inFIG. 7the second carrier system is a return screw221that conveys unreleased material244to a second end225of return conveyor220. At second end225of the return conveyor220(first end202of supply conveyor210), return conveyor220and supply conveyor210are in material flow communication such that inlet212of supply conveyor210can accept unreleased material244from outlet224of return conveyor220.

InFIG. 7, collection hopper250facilitates the distribution of unreleased material244to inlet212of the supply conveyor210. In addition to receiving unreleased material244, collection hopper250may simultaneously receive additional material232from silos300. Supply screw211elevates the combination of unreleased material244and additional material232to second end204of supply conveyor210. At second end204, a portion of such material is either directed to metering device310or to inlet222of return screw220. The portion directed to metering device310is then delivered to a blender of pump and blender system50(seeFIGS. 1-2). The portion directed to inlet222of return conveyor220is redistributed to inlet212of the supply screw210.

In another embodiment material232may be a proppant and second source240may be a blender from a pump and blender system50(seeFIGS. 1-2). The blender mixes the proppant with a fracturing fluid to produce a fracturing mixture. The fracturing mixture is introduced into a well for use in fracturing operations using one or more pumps from the pump and blender system.

FIG. 8depicts second source240as a companion conveyor system500. This configuration increases the amount of material stored and transported. Silos300may directly gravity feed material to first end202of conveyor system200. Silos300may also directly gravity feed material to a first end513of companion conveyor system500. Material flow communication occurs between first end513of companion conveyor system500and second end204of conveyor system200. Multiple companion conveyor systems may be aligned in series. As shown inFIG. 8, six silos300are depicted releasing material232to the conveyor systems. In this configuration, up to eight silos300may gravity feed material to conveyor systems for use in fracturing operations.

The present disclosure also covers the following embodiments of the present disclosure. All the embodiments include a conveyor system having a first end and second end. The conveyor system has a supply conveyor and a return conveyor. The supply conveyor has an inlet at the first end of the conveyor system, an outlet at the second end of the conveyor system and a first carrier system. The return conveyor has an inlet at the second end of the conveyor system and an outlet at the first end of the conveyor system and a second carrier system. The supply conveyor and the return conveyor are in material flow communication such that at the first end, the inlet of the supply conveyor can accept at least a portion of a material from the outlet of the return conveyor. At the second end, the inlet of the return conveyor can accept at least a portion of the material from the outlet of the supply conveyor.

In one embodiment, a storage unit releases the material to a collection hopper at the first end of the conveyor system. The collection hopper distributes at least a portion of the material to the inlet of the supply conveyor. On the second end, the outlet of the supply conveyor releases a second portion of material to a metering device. The metering device releases a third portion of material to a pump and blender system.

In another embodiment, the first carrier system may be a supply screw and the second carrier system may be a return screw.

In the above embodiments, the supply conveyor and return conveyor can be isolated from each other so that material flow communication occurs only between the supply conveyor and return conveyor at the first end and second end of the conveyor system.

Additionally, in the above embodiments, the conveyor system can be transportable.

Also, in the above embodiments the conveyor system has an adjustable angular position.

In one or more of the above embodiments, the supply conveyor can have a first directional vector with a corresponding first angle. The return conveyor can have a second directional vector with a corresponding second angle. The supply conveyor and return conveyor are configured such that at the first end of the conveyor system the second angle is less than or equal to the first angle.

In other embodiments, the above conveyor systems have at least one drive motor configured to rotate at least one of the supply screw and the return screw. The conveyor system may also have at least one drive motor configured to rotate at least one supply screw and at least one drive motor configured to rotate at least one return screw.

In still other embodiments of the above conveyor systems, the inlet of the supply conveyor accepts the material from a first source and the outlet of the supply conveyor releases a portion of the material to a second source.

In one or more of the above embodiments, the outlet of the supply conveyor can comprise a first outlet and a second outlet such that the first outlet can release at least a portion of the material to the second source, and the inlet of the return conveyor can accept at least a portion of the material from the second outlet. The first source may be a storage unit, and the second source may be a metering device. The inlet of the supply conveyor accepts the material from a collection hopper. The collection hopper receives the material from the storage unit. The outlet of the supply conveyor releases a released portion of material to the metering device and the metering device delivers the released portion of material to a pump and blender system.

Another embodiment covers a method of transferring a material from a first source to a first end of a supply conveyor. The material is conveyed to a second end of the supply conveyor at a first rate. At the second of the supply conveyor, a released portion of the material is released to a second source at a second rate. When the second rate is less than the first rate, buildup occurs of an unreleased material at the second end of the supply conveyor. The unreleased material is introduced to a first end of a return conveyor. The return conveyor conveys the unreleased material to a second end of the return conveyor. At the second end of the return conveyor, the unreleased material is re-circulated to the first end of the supply conveyor.

In some embodiments, the second source is a companion conveyor system having a first end, a second end, a supply conveyor and a return conveyor. The supply conveyor has an inlet at the first end, an outlet at the second end and a first carrier system. The return conveyor has an inlet at the second end and an outlet at the first end and a second carrier system. The supply conveyor and the return conveyor are in material flow communication such that the inlet of the supply conveyor can accept at least a portion of a material from the outlet of the return conveyor and the inlet of the return conveyor can accept at least a portion of the material from the outlet of the supply conveyor.

In another embodiment, a second portion of the material is introduced from the second end of the supply conveyor to the first end of the return conveyor and the second portion is at least part of the unreleased material. In the above embodiments, the material can be transferred from one or more storage units to the first source. The released material can be transferred from the second source to a pump and blender system. In the aforementioned embodiments, the material can be a proppant and a blender of the pump and blender system which mixes the proppant with a fracturing fluid to produce a fracturing mixture. The fracturing mixture can be introduced into a well for use in a fracturing operation. The fracturing mixture can be introduced into the well using one or more pumps.