Patent Application
20110030951
The present invention relates to self-contained, mobile, fluid filtration systems, and more particularly, to an integrated fluid filtration and recirculation system and method especially adapted for filtration and recycling of cleaning fluids used to clean the bore of a well.
A number of systems have been developed for evacuating accumulations of blockages in wellbores to include oil and gas producing wells. The blockages may include accumulations of sediments and other solids generated from the well. A well is typically lined at the upper portion with a casing, and the down-hole portion is lined with metallic, plastic, or other liners, sometimes referred to as “well tubulars”. The tubulars may be in the form of production tubing, and slotted or wire-wrapped liners. The well tubulars may be particularly susceptible to corrosion, and deposits may develop on the tubulars such as silicates, sulfates, sulfides, carbonates, calcium and organic growth.
One solution for performing well cleaning operations is to utilize a cleaning implement placed down-hole that also carries a cleaning solution. The cleaning implement forms the distal end of a tubular member placed down-hole, referred to as coiled tubing. The coiled tubing is placed into the well to perform the cleaning operation to include the injection of treating and cleaning fluids, which remove blockages and otherwise clean the well tubulars. The circulation and cleaning fluid may include water, acid, foam, chemical cleaning solutions, and corrosion inhibitors.
It is desirable to perform an efficient well cleaning operation in which the coiled tubing is advanced into the well as quickly as possible, and then the fluid is injected into the well. The cleaning implement in conjunction with the cleaning fluid provides both mechanical and fluid/chemical cleaning which under most circumstances adequately cleans the wellbore.
Depending upon the depth and number of wells to be cleaned, a significant amount of cleaning fluids may be required to adequately clean the targeted wells. Because of environmental concerns in most locations, the cleaning fluids cannot be disposed of by allowing the fluid to be dumped onto the surrounding land. Therefore, there is an operational requirement to prevent the cleaning fluids from contacting the ground. Significant measures are taken to retrieve the used cleaning fluids in order to dispose of the fluids in an environmentally responsible manner.
One system disclosed for cleaning a well is found in U.S. Pat. No. 4,919,204. This reference more specifically discloses a cleaning apparatus for pressurized cleaning of well flow conductors. The apparatus provides cleaning of the conductors by use of the apparatus in combination with high pressure directed fluid jets that flow through the apparatus. Rotation of the cleaning apparatus can also be used for combined mechanical and hydraulic drilling to remove deposits from within the well flow conductors. The reference discloses coiled tubing mounted on a reel, and the reel itself is mounted on a vehicle. A manifold is connected to the coiled tubing. The manifold includes the necessary pumps, valves, and fluid reservoirs to discharge high pressure cleaning fluid through the coiled tubing into the wellbore.
Another example of a system for cleaning a well is disclosed in the U.S. Pat. No. 7,549,468. Specifically, the reference discloses a coiled tubing injector system which includes transport trailer components for separate transfer to and from a drilling site. Each component is taken to the site with its own transport tractor, a first component including a coil storage reel and a second component including a tubing injector carried on a mast which is raised from a horizontal transport position, through a stabbing and unstabbing position to a raised working position. When the components are arranged together in an end-to-end with the mast in a stabbing position, a tube gripping member is positioned between the storage reel and tubing injector for controlling the handling of a free end of the stored tubing for stabbing and unstabbing of the tubing injector
Other examples of wellbore cleaning devices include the U.S. Pat. Nos. 4,744,420 and 7,377,283.
As environmental regulations become more stringent, particularly in areas such as the Arctic, extreme measures have to be taken to prevent the inadvertent spillage of any cleaning fluid. The cleaning fluid cannot be permanently stored and treated at the well location and, therefore, once the cleaning fluid is spent, the cleaning fluid must be trucked offsite to a treatment facility. Often times, the treatment facility is many hundreds of miles from the well locations. Thus, one significant problem with well cleaning operations is the time and expense involved with trucking the needed cleaning fluid to and from the well locations.
Therefore, there is a need to provide a well cleaning system in which the logistics associated with use of the cleaning fluid are simplified and made more efficient. Furthermore, there is also a need to greatly conserve the use of the cleaning fluid, not only for purposes of addressing the logistical concerns, but also to reduce the risk that a significant amount of cleaning fluid could be inadvertently spilled.
There is also a need to provide an integrated cleaning solution in which the system can be easily transported to remote locations where vehicle access is limited to off-road type vehicles or vehicles that otherwise can travel on unimproved roads.
There is also a need to provide a cleaning solution that is self contained and automated which reduces manpower requirements and allows remote control of the system which may be installed at remote geographical locations.
In accordance with the present invention, a system and method are provided for an integrated fluid filtration and recirculation system that is especially adapted for filtering and re-circulating well cleaning and treatment fluid (referred to hereinafter collectively as “cleaning fluid”). With the method and system of the present invention, well cleaning fluid may be conserved by filtering and re-circulating used cleaning fluid back to the well for further cleaning operations. Thus, the cleaning fluid may be recycled a number of times before having to be evacuated from the site. The filtering and recycling of the cleaning fluid greatly conserves the amount of cleaning fluid required, and provides great economic savings and logistical savings with respect to the effort otherwise necessary to truck the cleaning fluid to and from the well locations.
The integrated fluid filtration and recirculation system of the present invention is characterized by a self-contained, automated, mobile/transportable, and efficiently sized system in which the cleaning fluid can be filtered and treated to a degree so that it may be reused in a number of subsequent cleaning cycles.
The system of the present invention includes a power generation capability for powering a pump which is capable of circulating the fluid from an intake where spent/used cleaning fluid arrives from the wellbore. The used fluid or contaminant fluid stream passes through a series of filtration elements which effectively filter the cleaning fluid so that the cleaning fluid may be reintroduced into the coiled tubing for subsequent cleaning operations.
The filtration assembly includes a primary or coarse filter that removes larger sized solids, and a secondary filtration group that provides filtration for finer particles, as well as removable of other unwanted chemical and organic contaminates in the fluid stream. The power generation capability is in the form of a generator unit that is co-mounted along with the filtration assembly within a common enclosure.
The enclosure can be insulated depending upon the environment in which the enclosure is used. The enclosure may have integral heating and cooling capabilities, such as an electric heater and an electrical air conditioning unit powered by the generator. Thus, the enclosure can be habitable, even in the most extreme climate conditions.
The enclosure itself is mounted upon a skid or base which is sized to be conveniently mounted on a standard sized hauling platform. The generator and filtration assembly are arranged so that they provide an elongated, linear configuration that is adapted for mounting on the skid/base that can be mounted upon a surface/platform that is not oversized and is capable of being transported without any size restrictions according to highway requirements. For example, the surface may be a flat bed trailer, or the system may be mounted to a hauler truck. More specifically, the generator and the filter assembly are linearly aligned and spaced from one another so that the generator and filtration assembly may be mounted for transport, yet maximum room is provided for operators to move within the enclosure that houses the generator and filtration assembly.
The enclosure itself has a number of features that allow it to be used in different climatic conditions from freezing Arctic weather, to tropical areas.
The fuel that powers the generator can be drawn directly from another vehicle by an auxiliary fuel line which interconnects the fuel system of the vehicle to the generator. Alternatively, a smaller fuel storage tank may be incorporated on the enclosure such as an exposed fuel tank mounted to the end of the enclosure closest to the generator or the fuel tank may be stored beneath the generator.
The system can be monitored and operated by a master electronic controller that can control a number of functions to include the operation of the generator, the operation of the filtration assembly, the heating/cooling of the enclosure, and various alarm conditions that can be used to shut the system down or to otherwise manipulate the system based on the volumetric and flow rate needs of the particular well being serviced.
The cleaned fluid or filtrate stream may be further treated by the introduction of additives into the filtrate stream. A dosing pump is used to convey the additives to the filtrate stream prior to the filtrate stream being conveyed back to the coiled tubing.
The present invention provides a method for cleaning, treating and re-circulating fluid for purposes of maintenance of a well. The system is self contained, transportable, and adaptable for use in varying climatic conditions.
In sub-combination, the invention also provides a functional and unique filtration assembly that is especially adapted to be trailer mounted.
In another aspect, the invention can be considered in combination with a coiled tubing system to provide a complete solution for well cleaning operations.
These and other aspects and advantages of the present invention will become clearer in a review of the following drawings, taken in conjunction with the detailed description.
The coiled tubing 110 is paid-out from a dispensing reel 122 which may be, for example, mounted on a vehicle 120. The vehicle 120 may include a manifold (not shown) for receiving filtered/treated cleaning fluid through line 76, which thereby reintroduces the filtered/treated cleaning fluid for subsequent cleaning operations.
Referring also to
With respect to the construction of the enclosure 160, it provides a convenient, economical, and adaptable solution for cleaning/treating a fluid circulated through the filtration assembly. The enclosure is characterized by a roof 162, sidewalls 164, and an internal firewall 166 that separates two rooms, one room which houses the generator 176, and the other room which houses the filtration assembly. Respective doors (not shown) are used to access each of the rooms. The enclosure may be completely enclosed by sidewalls, or one or more of the sidewalls may incorporate removable panels (not shown), thereby exposing the generator and filtration assembly. In temperate climates, the removable panels may be advantageous, while providing a completely closed enclosure may be an optimal solution for extreme climate conditions, such as Arctic or desert conditions. As shown, two side openings 168 are provided, and these may be closed or may receive the removable panels. The
A main control panel 174 can be mounted on the internal firewall as shown. The control panel 174 houses the main controller 200. The functions of the main controller 200 are discussed further below. Optionally, the generator 176 may have its own generator control panel 178 that allows local operation and monitoring of the generator 176. Two operators O1 and O2 are shown attending to the system. The enclosure is sized so that the operators have adequate room to access system components for repair, operation, and preventative maintenance. Although two operators are shown for purposes of illustrating the relative size of a person as compared to the size of the enclosed space provided by the enclosure, it shall be understood that one main objective of the main controller 200 is to provide an automatically controlled system which minimizes the necessity for operators to attend to the system. Of course, some preventative maintenance has to occur over time, but the system does not require monitoring by an operator on a continual basis.
The generator and filtration assemblies are both mounted on a common pallet or skid 182. This pallet 182 is sized to fit within the dimensions of the trailer or haul vehicle carrying the system. For example, a standard trailer of a tractor-trailer rig may have a dimension of approximately 52 feet in length and 8.5 feet in width. The pallet 182 is sized to fit within this profile or a smaller length. A pair of hoisting bars 184 is disposed at opposite ends of the pallet, which enables the pallet to be lifted and moved from the trailer/vehicle that carries the system.
The lower portion of the enclosure includes raised edges constituting a spill containment lip that prevents fluids leaking from the generator or filtration assembly from spilling out of the enclosure onto the surrounding ground. The spill containment lip may be sized in height to accommodate a worst case scenario, i.e., a scenario in which substantially all of the fluids in the filtration assembly at any particular time were spilled to include the fluid being filtered as well as operating fluids such as hydraulic fluid and fuel. Thus, the height of the spill containment lip would be sized as a function of the volume necessary in the filtration assembly room to capture the fluid.
Each of the rooms also includes respective heating/cooling vents 188 which communicate with integral heating elements (not shown) and/or air conditioning elements (not shown). These heating/cooling units could be mounted to the ceiling or the sidewalls.
A bulkhead support 180 is located on both opposite sides of the walls of the enclosure. The supports 180 include one or more openings that receive the inlet/discharge lines from the filtration assembly.
Referring to
Primary filter 36 can be selected to provide the necessary coarse filtration. One example of a range of pore sizes for the filter 36 could be in the range of 10-25 microns. This range may provide adequate coarse filtration for many oil well applications however the particular range can be adjusted for the particular application. The primary filter 36 may also have an automatic backwash feature to periodically clean the filter. The construction of the filter element(s) within the filter 36 can also be chosen to maximize filtration results, and one example of a filter construction is one that has a woven wire mesh filter arrangement. In a backwash cycle, the filter is cleaned to remove the arrested contaminant particles, and primary filter backwash valve 40 is actuated to enable the backwash fluid containing the loosened particles from the filter to travel through primary waste line 52. Primary waste line 52 may also have its own dedicated discharge valve 84. The downstream side of the discharge valve communicates with a receptacle (not shown) which captures the waste concentrate.
A primary filter bypass line 48 is provided to enable fluid to bypass the primary filter 36. Primary filter bypass valve 46 is opened to receive the bypass fluid when primary filter intake valve 34 is closed to thereby facilitate the bypass. A check valve 50 is provided to prevent backflow through the bypass line 48. The bypass line 48 connects to the primary filtered fluid line allowing the fluid to flow directly to the secondary filtration station 14. This bypass function may be desirable when, for example, the used fluid does not require primary filtration to remove larger particles.
A diversion line 42 is also provided to divert a desired flow of fluid in order to flush the primary waste line 52, or to prevent freezing of the primary waste line 52 in the event the filtration assembly was inadvertently exposed to conditions which otherwise could freeze the lines. As shown, diversion line 42 connects to the primary waste line 52 downstream of diversion valve 44. Diversion valve 44 is opened to allow a desired amount of flow through diversion line 42 into the primary waste line 52. Thus, the diversion line 42 provides additional conveying fluid so that the concentrated waste does not obstruct line 52, since primary waste line 52 does not typically have a steady stream of fluid passing therethrough and the waste line is therefore more susceptible to becoming clogged by solids buildup.
From the primary filtered line 54, the primary filtered fluid then passes through the secondary filter inlet valves 56 into the secondary filtration station 14. The station 14 as shown comprises a plurality of secondary/fine filters 60. Within the plurality of fine filters 60, the final or secondary filtration occurs. One example of a range of pore sizes for the secondary filters 60 could be in the range of 3-5 microns. This range may provide adequate fine filtration for many oil well applications however this particular range can also be adjusted for the particular application. The finely filtered or secondary filtered fluid then passes through secondary filtrate discharge valves 62 and into the secondary filtrate line 64. Secondary filtrate line 64 then communicates with discharge valve 74, and the secondary filtered fluid is discharged through discharge line 76 and/or discharged through alternate discharge line 78. Final discharge valves 82 may be placed downstream from the discharge lines.
As also shown in the
If it is desired to bypass the secondary filtration station and deliver the primary filtered fluid for re-use at the well cleaning operation, and then the secondary filter inlet valves 56 are closed. The coarsely or primary filtered fluid passing through line 54 then passes through bypass line 66 and secondary bypass valve 68 is opened, enabling the fluid to then pass through the secondary filtrate line 64.
If it is desired to use the primary filtered fluid to flush the primary waste line 52, then the secondary filter inlet valves 56 are closed, secondary waste valve 70 is opened, and the fluid flows through secondary waste line 51. Secondary waste line 51 connects to primary waste line 52.
The secondary filters also have a backwash capability in which the filters may be cleaned, and the concentrated contaminants can be evacuated for waste disposal. More specifically, when a backwash cycle occurs, the backwash liquid is discharged from the secondary filters 60 back through the three way secondary filter inlet valves 56 into the secondary waste line 51 thereby allowing the concentrated waste to be finally evacuated.
The filtration assembly 10 is preferably mounted on the piping skid or base 80 that allows the assembly to be easily manipulated as a single unit. Thus, the intention of the filtration assembly design is to provide a modular, integral unit that can be more easily installed, removed, repaired, and transported.
The advantages of the present invention are quite apparent. A compact, automated, transportable, and self-sufficient re-circulation and filtration system is provided. The system is automated and allows the system to run unattended for significant periods of time. This system can be mounted to a trailer or hauling vehicle platform that is not over-sized, which greatly eases transporting requirements by not requiring any special transportation permits. The enclosure provides a habitable space for operators to efficiently inspect, troubleshoot, and repair the system. The enclosure can be insulated for use in severe climatic conditions. Selected addition of chemicals/conditioners allows the system to not only handle removal of contaminants, but to also treat the cleaning fluid for a desired application. The enclosure can be towed, for example, by a vehicle which includes a coiled tubing dispenser. Thus, the system can also be considered in combination with a coiled tubing dispenser and therefore in another aspect of the invention, it includes the integrated fluid filtration and recirculation system along with a coiled tubing dispenser.
Although the system and method of the present invention have been provided in preferred embodiments, it shall be understood that various other changes and modifications can be made to the invention commensurate with the scope of the claims appended hereto.
