Patent Application
20100296359
In many well applications, various well cementing operations are performed. To improve the integrity of the cement material, fiber products acting as fluid-loss reduction additives can be added to the cement slurry that is pumped downhole. The fiber products typically are added by hand or with toothed drums. However, such techniques can lead to uneven metering of the fiber products into the cement mix. Additionally, toothed drums and other field-improvised equipment can be inadequate due to insufficient delivery rate, lack of reliability, and lack of accuracy.
Additionally, any equipment used to deliver fiber material into the cement mixing tank can present a problem with respect to height of the equipment. When equipment is mounted on top of a portable well servicing unit, for example, the equipment is susceptible to extending beyond the legal height requirements that must be met when transporting equipment over a highway system.
In general, a system and methodology is provided that facilitate well servicing operations, such as cementing operations. A hopper system is designed to introduce an additive into a cement mixing tank. The hopper system comprises a feeder and a hopper that delivers the additive into the feeder. The feeder, in turn, enables introduction of the additive into the cement mixing tank in a controlled manner. When the hopper system is used on a transportable cementing unit, the hopper system may be mounted on a cement mixing tank. In this type of application, the hopper also may be expandable to accommodate a greater amount of additive and contractible to facilitate transport.
Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
The present disclosure relates to a system and methodology to facilitate well cementing operations. The system and methodology employ a hopper system that comprises a unique feeder to meter additives, e.g. dry additives, into a cement mixing tank. The additives are mixed into a cement slurry which can then be pumped downhole to perform a variety of well related cementing operations. The hopper system works well with additives having fibers, and other fibrous fluid-loss reduction agents. According to one embodiment, the feeder has a screw-type design of appropriate geometry and material selection to enable a precisely controlled metering rate and to improve reliability and accuracy with respect to the metering of fibrous fluid-loss reduction additives for well cementing work.
Additionally, the hopper system may be designed to facilitate ease of operation at a well site while allowing transport of the hopper system when mounted to a transportable cementing unit. For example, the hopper system may be part of a well servicing system having a transportable cementing unit mounted on a truck or trailer for transport over public highway systems. In some embodiments, the hopper system is mounted on top of a cement mixing tank which forms part of the transportable cementing unit. In this embodiment, the hopper system comprises a hopper positioned above the feeder, and the hopper can be selectively expanded in capacity to, for example, hold one sack of additive, e.g. fiber additive, or another desired quantity of additive. The hopper also can be selectively contracted to reduce the height of the overall transportable cementing unit to ensure the overall transportable unit meets legal road height limits. The hopper may be extended during a well cementing operation and retracted after the operation for transport.
Referring generally to
In the embodiment illustrated, transportable cementing unit 20 comprises a platform 22 that may be a trailer or truck bed designed to transport the cementing unit 20 over public highways and other types of roads. The transportable cementing unit 20 further comprises a cement mixing tank 24 and a hopper system 26 mounted on the cement mixing tank 24. The cement mixing tank 24 is designed to mix a desired cement slurry that may be pumped downhole into a wellbore via a pumping system mounted on platform 22 or on a separate transportable platform. The cement slurry is pumped into the wellbore and delivered to specific regions of the wellbore to accomplish the planned cementing operation.
The hopper system 26 may be used to deliver additives into cement mixing tank 24. For example, dry additives may be added to the cement slurry to provide the cement slurry with characteristics that improve the quality of the cementing job. In a variety of applications, the additive comprises a fibrous fluid-loss reduction additive that substantially improves the functionality of the cement downhole.
In the embodiment illustrated, hopper system 26 comprises a feeder 28 mounted, for example, directly above the cement mixing tank 24 to precisely meter additive into cement mixing tank 24. The illustrated hopper system 26 also comprises a hopper 30 mounted on feeder 28. For example, the hopper 30 may be mounted directly over feeder 28 to guide additive into an upper opening of the feeder 28. The additive, e.g. a fibrous fluid-loss reduction additive, can be poured into an upper hopper opening 32, and hopper 30 is designed to guide the additive to feeder 28.
Hopper 30 may be designed as an adjustable hopper that can be actuated between a contracted configuration, as illustrated in
The expansion and contraction, e.g. raising and lowering, of hopper 30 can be accomplished automatically with an actuation system 34. By way of example, actuation system 34 comprises a pressure system 36 that directs fluid under pressure to cylinders 38 which are mounted between a movable portion 40 of hopper 30 and a stationary portion 42. Fluid is delivered from pressure system 36 to cylinders 38 and returned from cylinders 38 via pressure lines 44. Additionally, a valve or valves 46 can be used to control the flow of pressure fluid and thus the actuation of cylinders 38. In the illustrated example, cylinders 38 are dual acting cylinders to enable both the controlled expansion and contraction of hopper 30. In a variety of specific applications, pressure system 36 comprises a pneumatic pressure system using air or other appropriate fluid to actuate pneumatic cylinders 38. However, pressure system 36 also may be formed as a hydraulic pressure system.
Transportable cementing unit 20 also may comprise a canopy system 48 to provide a covering during operation of hopper system 26 and cement mixing tank 24. By way of example, canopy system 48 comprises a movable canopy 50 that can be raised to a working configuration, as illustrated in
In an embodiment, pressure system 36 is a pneumatic pressure system coupled to hopper 30 via pressure lines 44 and to cylinders 52 of canopy system 48 via pressure lines 54. The pressure lines 44 and 54 can be connected to a common valve 46 that enables actuation of both canopy system 48 and hopper system 26 by adjusting a single valve. For example, when the transportable cementing unit 20 is deployed at a well site and set up for a cementing operation, valve 46 can be opened to both raise canopy 50 and expand hopper 30. Upon completion of the cementing operation, valve 46 can be reversed to move hopper 30 into the contracted configuration and canopy 50 into the lowered position for transport. The actuation may be timed so that the canopy rises before the hopper and lowers after the hopper is moved to its contracted configuration.
Referring generally to
In the embodiment illustrated and in other embodiments of hopper 30, a variety of alternate or additional components can be incorporated into the design. For example, one or more pressure gauges 60 may be deployed along the lines 44 to monitor pressure applied to cylinders 38. Additionally, the hopper opening 32 may incorporate a grate 62 or other structure to break up the additive material as it is poured into hopper 30 through opening 32. Additionally, hopper 30 may be formed from a variety of materials that provide suitable longevity and consistent actuation when used with the desired additive in a variety of well site environments. In an embodiment, movable portion 40 and stationary portion 42 are formed from stainless steel, however other materials and combinations of materials may be employed.
As further illustrated in
In the embodiment illustrated, feeder 28 comprises a feeder body 66 containing at least one screw 68 for moving additive along feeder body 26 before discharging it into cement mixing tank 24, as further illustrated in
The screws 68 are rotated by a gearbox 76 which may be mounted adjacent one of the end plates 72 and coupled with shafts 70. The gearbox 76 may be powered by a suitable motor 78, such as a hydraulic motor or an electric motor. In one example, gearbox 76 has a high gearbox drive ratio, and motor 78 comprises a small volumetric displacement hydraulic motor that provides great control at low speeds.
Each of the feeder components is designed to function well with the desired additive. For example, the dual screws 68 and open inlet 64 may be arranged in a compact, low-profile design and used in cooperation with hopper 30 to provide a functionally effective construction for use with fiber products, such as fibrous fluid-loss reduction additives, such as those recited in U.S. Pat. Nos. 7,267,173 and 7,331,391, the entire disclosures of each of which are incorporated by reference in their entirety. Component materials also can be selected to facilitate the controlled and consistent movement of additive through both hopper 30 and feeder 28. In various applications, feeder body 66 may be formed from stainless steel, for example, to reduce friction and to discharge any build up of static electricity. Additionally, gearbox 76, motor 78, hopper 30, screws 68, and feeder body 66 (including end plates 72) can be constructed as modular components held together by a variety of fasteners 80. This high degree of modularity provides ease of assembly and disassembly when desired for initial construction, cleaning, repair, or other related operations.
Referring to
The feeder 28 may be constructed in a variety of sizes and configurations with various components to facilitate metering of additive material. For example, one or more flow control inserts 88 can be mounted in feeder body 66 to facilitate flow from hopper 30 into screws 68, as illustrated in
Motor 78 and gearbox 76 also may have a variety of forms and configurations. In the embodiment illustrated in
The system 20 is useful in a variety of cementing operations including, but not limited to, foamed cementing operations and a variety of well environments. The system 20 may be utilized for providing an additive to a variety of well servicing fluid including, but not limited to, drilling mud or drilling fluid, a foamed cement mixture, an acidizing mixture, a proppant additive, such as a coating additive, or other well servicing fluids for delivery into a wellbore, as will be appreciated by those skilled in the art. In one example of a methodology for using transportable cementing unit 20 and hopper system 26, the transportable cementing unit 20 is driven to a well site for performance of a servicing operation. Once properly located at the well site, the hopper 30 is actuated to its expanded position to accommodate a desired amount of fibrous fluid-loss reduction additive. The additive is placed into hopper 30, and feeder 28 is operated to meter a controlled amount of the fibrous fluid-loss reduction additive into cement mixing tank 24 of the transportable cementing unit 20. The cement mixing tank is operated to mix in the additive and to form a desired cement slurry for a well cementing operation. Subsequently, the cement slurry is delivered downhole to a desired region of the wellbore to complete performance of the cementing operation. Once the cementing operation is completed, hopper system 26 can be converted to its contracted configuration and, if applicable, canopy 50 can be lowered to facilitate transport of the transportable cementing unit.
The actual configuration of hopper system 26 and the overall transportable cementing unit 28 may vary depending on the additive or additives involved, the goals of the servicing operation, and the environment in which the operation is conducted. For example, the size and type of components used to construct hopper system 26 may vary depending on the specific application. Additionally, the materials used to form the various components may be different from one application to another, depending on the environment, the additive, and other factors affecting the cementing operation. The methodology of operating the hopper system and the cementing unit, as well as the methodology for mixing materials to form the cement slurry, can be adjusted and varied for different applications.
Accordingly, although only a few embodiments have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Such modifications are intended to be included within the scope of this invention as defined in the claims.
