The present invention relates to water reclamation, and in particular, to a portable and scalable water reclamation system and method.
Fresh water and affordable energy are two of the most valuable resources on the planet for sustaining economic growth and development. As the demand for oil and gas continues to increase, the consumption of fresh water by exploration and production activities is skyrocketing. Competition for fresh water is becoming an industry-limiting factor in some geography. To ensure that the fresh water needed by the oil and gas industry is available in the future, better water resource management practices must by implemented.
Currently, the drilling, completion, and stimulation of each horizontal shale well consumes up to 10 million gallons of fresh water, roughly equal to daily water usage of 144,000 people. Once fresh water becomes oilfield waste, the water is typically disposed of into reservoirs below the fresh water table, permanently removing it from the fresh water cycle. Reusing the water is desirable but often presents technical problems with water quality, water management logistics, and cost.
Water for use in the oil and gas industry is most commonly acquired from surface waters (lakes, ponds, and streams), aquifers (on-site water well), or through the local municipal water supplies. Fresh water is used throughout the process of drilling and completing a well. Once the water has been used in exploration and production activities, the water becomes one of three types of oilfield waste water: drilling waste, completion flow back, or production (geological) saltwater.
During the drilling phase, fresh water is used as the solute and suspension medium for the drilling mud, which draws the cuttings away from the drill bit, stabilizes the well bore, and cools the bit while drilling. In a typical open-loop system, the mud is circulated by pumps on the drilling rig and the waste water, cuttings, and mud are discharged into the reserve pit, typically a 5,000-25,000 barrel earthen pit adjacent to the drilling rig. Occasionally, the waste fluids in one reserve pit are reused on another drilling location or allowed to settle and discharged onto the land surrounding the well (permitted in limited situations only). Both of these waste disposal practices are currently under tight scrutiny and are becoming less of an option for oil drilling companies. When surface discharge or transfer to another pit is not an option, the waste water must be either injected into the well bore or hauled to a disposal well. Like surface discharge, down hole injection is being tightly regulated, and hauling the waste for disposal is expensive. While injecting the water below the freshwater aquifer protects the ground water from contamination from the exploration and production waste, deep well injection permanently removes the waste water from the fresh water cycle. Further, injecting the water below the freshwater aquifer creates added pressure on underground formations. Although the total dissolved solutes (TDS) in water-based drilling waste is typically less than 5,000 ppm, the primary contaminants in drilling waste that are undesirable to carry forward into reclaimed water for reuse are colloidal suspended solids, hydrocarbons, and heavy metals. For example, the typical drilling rig on a gas well in north Louisiana and east Texas consumes approximately 800,000 gallons of fresh water and produces approximately the same amount of waste water.
Once the well-bore is drilled, the completion phase of the well begins. The completion phase involves setting pipe in the well bore, connecting the well bore to the hydrocarbon producing geological formations, and stimulating and/or fracturing the formations to facilitate the production of gas and/or oil. Each facet of completion requires fresh water as a lubricant, chemical delivery medium, and hydraulic fracture medium. The waste water from the completion phase is called flow-back, which consists of water mixed with various chemicals, suspended solids, and formation (geological) saltwater. Unlike reserve pit water, which can occasionally be returned to the fresh water cycle through surface disposal (where permitted), flow back water must be treated for reuse or disposed of via deep well injection due to the higher concentrations of salt, minerals, and chemical additives. Reuse requires storage and treatment of the flow-back, which poses logistical, economical, and environmental concerns. For example, a gas well in north Louisiana—east Texas uses approximately 500,000 gallons per completion and produces 20-80% of that amount of flow back water, depending on the specific completion technique and geological formation. Since each horizontal well may have 12 or more completion stages, an additional 6,000,000 gallons of water can be permanently withdrawn from the fresh water cycle.
After the well has been completed, the production phase begins. Most gas wells produce geological saltwater that naturally flows with the oil and gas as the well is producing. Early during the production stage, the water being co-produced with the gas resembles flow back and as the well reaches a steady production state, the water being produced is primarily geological saltwater. Typically, very little fresh water is consumed while a well is in production. Due to the high salt, mineral, and hydrocarbon content, the produced wastewater is almost always disposed of into an injection well. Thus, the production waste water did not originate from the freshwater cycle, and it is not introduced to the freshwater cycle. Some research groups and service companies are exploring the use of production water from an existing well as the source of saltwater for use during the completion phase of a new well. Utilizing geological saltwater as base fluid for exploration and production activities represents a gain on an operator's water balance sheet. The amount of produced waste water varies dramatically from well to well but typically ranges between 1,000 and 40,000 gallons per week. Treating production water for reuse requires removal of hydrocarbons, well-bore treatment chemicals, undesirable minerals, and in rare cases—desalination. Two hurdles to overcome in the course of reusing production wastewater are volume and transportation. Some geological formations make relatively large amounts of water and others very little production water. Storing, treating, and moving production water can pose a significant cost and logistical challenge.
Without costly and energy-intensive processing, most exploration and production waste water is not clean enough for release into the environment via land farming (surface discharge) and is therefore typically disposed of via deep well injection. In order to deep well inject the waste water, the fluids must be trucked or piped to a secondary location where the water is stored in tanks and pumped into a deep formation (below the lowest freshwater aquifer) where the water will never return to the freshwater cycle. Much of the cost for disposal of the waste water comes from hauling the water from the well site to the injection point. As shale gas plays continue to flourish around the United States, the industry's fresh water demands are continually increasing. Experts and regulatory agencies agree that a key factor in sustaining domestic on-shore oil and gas activity will be developing water conservation strategies for the industry. Several states have implemented regulations and incentives for exploration and production companies to reuse their waste water. In regions such as the Permian Basin and Eagleford Shale of west and south Texas, where exploration and production activities continue to increase, but water resources are already limited, and in densely populated areas where cities and exploration and production operators must share the water (such as the Barnett Shale in the Dallas-Fort Worth area), industry leaders have already begun to develop exploration and waste water reclamation processes. Currently, the public and private agencies developing these processes are focused primarily on adapting technologies and processes that are being effectively used to for waste water treatment in other industries, such as reverse osmosis (RO), evaporation/distillation, electro-coagulation (EC), chemical oxidation, chemical precipitation, serial filtration, and combinations thereof, but the systems developed to employ the technology lack portability, scalability, and versatility.
Since the waste streams in the oilfield change significantly and rapidly over short periods of time (in both volume and chemical composition), developers have struggled to design a single portable water treatment system that can handle the various waste streams.
Applicant has recognized a need for a single portable and scalable water reclamation system that can handle various waste streams.
An embodiment of the water reclamation system of this invention includes at least one water filtration module mounted on a transport vehicle. The water filtration module comprises a bulk container and a plurality of treatment vessels positioned therein. Each treatment vessel has an upper fluid reservoir, a lower fluid reservoir, and a waste water treatment media positioned therebetween. A waste water distribution line is connected to and extends from a waste water inlet header into each of the treatment vessels for distributing waste water into the treatment vessels. A produced water line is connected to and extends from each of the treatment vessels and into a produced water collection header for collecting produced water from each of the treatment vessels. At least one waste water outlet line is connected to and extends from the bulk container and into a waste water outlet header for collecting waste water from the treatment vessels.
An embodiment of the water reclamation system of this invention includes a plurality of water filtration modules mounted on a transport vehicle. The plurality of water filtration modules each comprises a bulk container and a plurality of treatment vessels positioned therein. Each treatment vessel has an upper fluid reservoir, a lower fluid reservoir, and a waste water treatment media positioned therebetween. A waste water distribution manifold is connected to a waste water inlet header for controlling the distribution of waste water into each of the treatment vessels. A waste water distribution line is connected to and extends from the waste water distribution manifold into each of the treatment vessels for distributing waste water into the treatment vessels. A chemical treatment header is connected to a chemical treatment reservoir. A chemical treatment manifold is connected to the chemical treatment header for controlling the distribution of chemical treatment to each of the treatment vessels. A chemical treatment feed line is connected to and extends from the chemical treatment manifold and into the treatment vessels. A produced water line is connected to and extends from the treatment vessels and into a produced water collection header for collecting produced water from each of the treatment vessels. At least one waste water outlet line is connected to and extends from the bulk container and into a waste water outlet header for collecting waste water from the treatment vessels.
An embodiment of this invention is directed to a method of reclaiming waste water. The method comprises mounting at least one filtration module on a transport vehicle. The at least one filtration module has a bulk container, a plurality of treatment vessels positioned within the container, and is connected to a waste water inlet header, a produced water collection header, and a waste water outlet header. Each of the treatment vessels has a treatment media positioned therein. The transport vehicle is moved to a water reclamation site. Waste water is flowed into the waste water inlet header, thereby distributing the waste water into the treatment vessels. The waste water is engaged with the treatment media in the treatment vessels, thereby filtering the waste water. The produced water is collected from each of the treatment vessels in a produced water collection header. The waste water is collected from each of the treatment vessels in a waste water outlet header.
So that the mariner in which the features and benefits of the invention, as well as others which will become apparent, may be understood in more detail, a more particular description of the invention briefly summarized above may be had by reference to the embodiments thereof which are illustrated in the appended drawings, which form a part of this specification. It is also to be noted, however, that the drawings illustrate only various embodiments of the invention and are therefore not to be considered limiting of the invention's scope as it may include other effective embodiments as well.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different foams and should not be construed as limited to the embodiment set forth herein; rather, this embodiment is provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.
Referring to
The downstream connection from chemical treatment header 27 is connected to a chemical treatment manifold 47. A plurality of chemical treatment feed lines 49 extend from the chemical treatment manifold 47. Each chemical treatment feed line 49 extends from the chemical treatment manifold 47 into a chemical treatment feed line chase 51 (
The upstream connection from the produced water collection header 29 is connected to a produced water collection manifold 53. The upstream connection from the produced water collection manifold 53 is connected to a plurality of produced water lines 55. In this embodiment, each produced water line 55 extends from the downstream (treated) outlet of the treatment media 54 of each corresponding treatment vessel 33 to the produced water collection manifold 53 (
The upstream connection from the waste water outlet header 31 is connected to a waste water collection manifold 59 via a valve and union. The upstream connection from the waste water collection manifold 59 is connected to either a singular and common or multiple waste water outlet lines 61. Each waste water outlet line 61 collects the unreclaimed waste water into the waste water collection manifold 59 via the lower portion 62 of a corresponding treatment vessel 33 (
Referring to
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In this embodiment, a second motor and pump assembly 73 are connected upstream of the chemical treatment header 27. A chemical treatment tank or reservoir 75 is located upstream of the motor and pump assembly 73. For example, the chemical treatment tank 75 may be a tank of sodium chloride or another chemical necessary for chemical treatment of the waste water including, but not limited to pH adjusting chemicals, flocculants, polymers, resin activators, emulsifiers, de-emulsifies, detergents, solvents, catalysts, and/or specialized reactants. The motor and pump assembly 73, when activated, will draw the contents of the chemical treatment tank 75 from the tank 75 and into the chemical treatment header 27 and the chemical treatment manifold 47. The motor and pump assemblies 69, 73 are powered by a power source, for example, a generator.
In operation, the waste water inlet header 25 is connected to the waste water source 71 via the quick connect cam-lock coupling or union 39. The chemical treatment header 27 is connected to the chemical treatment tank 75 via the quick connect cam-lock coupling or union 41. The waste water outlet header 31 is connected to a waste water tank 77 via the quick connect cam-lock coupling or union 63. In this embodiment, the waste water is continuously recirculated through the water reclamation system 21 until the desired amount of waste water is reclaimed. In alternate embodiments, the waste water may pass through the reclamation system once 21 and be subsequently stored in a waste water tank for disposal. The motor and pump assemblies 69, 73 are activated. Waste water is drawn from the waste water source 71 via the pump and motor assembly 69, pumped through the waste water inlet header 25, and into the waste water distribution manifold 43. In this embodiment, chemical treatment of the waste water is desired. As a result, chemical solution, for example, concentrated sodium chloride, is drawn from the chemical treatment source 75 via the pump and motor assembly 73, pumped through the chemical treatment header 27, and into the chemical treatment manifold 47.
In this embodiment, when the waste water reaches the upper reservoir 54 of each treatment vessel 33 (via the waste water distribution manifold 43 and water distribution lines 45), gravity feeds the waste water through the treatment media 37 (
In this particular embodiment, pressure differences on each side of the treatment media 37 and the differences in hydrostatic pressure between the upper 54 and lower 60 reservoirs causes the waste water to be pulled through the treatment media 37 in each treatment vessel 33, where it becomes produced (i.e., reclaimed) water. In alternate embodiments, hydrostatic pressure, capillary action, differential surface tension, and/or selectively permeability may result in transition of waste water to reclaimed water, depending on the treatment media and the chemical additives. In this embodiment, the produced water is pushed through the produced water lines 55 connected to each of the treatment vessels 33 via gravitational forces on the fluid in the reservoirs 54, 60. In an alternate embodiment, the produced water may not merely be gravity fed, for example, a pump may be connected to draw the produced water through the produced water lines 55. The produced water travels through the produced water lines 55, into the produced water collection manifold 53, and into the produced water collection header 29. The produced water then travels through the produced water collection header 29, through the quick cam-lock coupling or union 57, and into a produced water collection tank 79.
The waste water that was not reclaimed passes through an opening in the lower reservoir 60 of each of the treatment vessels 33, where it enters the waste water outlet line 61. The waste water then drains into the waste water outlet manifold 59, and into the waste water outlet header 31. The waste water continues through the waste water outlet header 31, through the quick cam-lock coupling or union 63, and into a waste water tank 81. As previously indicated, the waste water may be recirculated through the reclamation system 21 until the desired results are achieved.
In an alternate embodiment, the module 23 may further comprise an overflow/volume control header. The overflow/volume control header would either be connected to an overflow/volume control manifold or directly to overflow/volume control lines. The overflow/volume control lines would be connected to an overflow/volume control port or ports in an upper surface portion of the bulk container 32. In the event that the fluid level in the bulk container 32 reached the port or ports, the excess fluid would travel through the overflow/volume control lines and the overflow/volume control manifold and/or header. The excess fluid could be captured for future reclamation or could be re-circulated back into the current reclamation cycle.
Depending upon the desired method of filtration and the desired level of treatment, each of the treatment vessels 33 in a treatment module 23 can be connected in various ways to facilitate a particular reclamation process. For example, as illustrated in
The water reclamation system 21 as comprised by the present invention is both scalable and portable. Referring to
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Sleeves 103 are rotatably connected to an outer surface portion of the second 97 and third 99 legs of the frame 91, near the ends of the legs 97, 99 that are connected to the fourth leg 101. The sleeves 103 are capable of rotation about an axis parallel to the axis of the fourth leg 101. In this embodiment, the sleeves 103 are rectangular in shape. First cylindrical sleeves 105 are connected to upper surface portions of the fourth leg 101 near the ends of the leg 101 connected to the second 97 and third 99 legs. The cylindrical sleeves 105 extend axially along a length of the fourth leg 101 parallel to the axis of the fourth leg 101. Second cylindrical sleeves 107 are connected to outer surface portions of the fourth leg 101 near the ends of the leg 101 connected to the second 97 and third 99 legs. The cylindrical sleeves 107 extend axially along a length of the fourth leg 101, parallel to the axis of the fourth leg 101.
In this embodiment, the hand rail 89 is comprised of a substantially rectangular frame 109. In this embodiment, the frame 109 is comprised of rectangular members, but may be shaped differently in alternate embodiments. The frame 109 comprises first 111 and second 113 legs positioned spaced apart from and parallel to one another, each having first and second ends. A third leg 115 is connected to and extends between the first ends of the first 111 and second legs 113, substantially perpendicular to the first 111 and second 113 legs. A fourth leg 117 is connected to and extends between the first 111 and second 113 legs, substantially perpendicular to the first 11 and second 113 legs, a select distance from and parallel to the third leg 115. A first hole or aperture 119 is located in and extends through a medial portion of the first 111 and second legs 113, parallel to the third 115 and fourth 117 legs. A second hole or aperture 121 is located in and extends through the second end portion of the first 111 and second legs 113, a select distance from the first holes 119, and parallel to the third 115 and fourth 117 legs.
The second ends of the first 111 and second 113 legs of the hand rail 89 are positioned within the sleeves 103, which are rotatably connected to the cat walk 97. In the position illustrated in
As illustrated in
Referring to
Referring to
As the individual treatment vessels in a module may be connected in various ways to achieve a desired treatment method and result, the modules in a multi-module system, similar to that illustrated in
The invention has significant advantages. The portable and scalable water filtration system uses low pressure (primarily gravity) and differences in hydrostatic head height to control the flow rates through the system. The system can be scaled up and down for various reclamation projects. The water reclamation system has various applications for oil and gas exploration and production, environmental remediation, industrial hygiene, agriculture, and other wastewater producing decentralized or centralized industries.
In the drawings and specification, there have been disclosed a typical preferred embodiment of the invention, and although specific terms are employed, the terms are used in a descriptive sense only and not for purposes of limitation. The invention has been described in considerable detail with specific reference to these illustrated embodiments. It will be apparent, however, that various modifications and changes can be made within the spirit and scope of the invention as described in the foregoing specification and as set forth in the following claims.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/223,128, filed on Jul. 6, 2009, and herein incorporated by reference in its entirety.
Number | Date | Country | |
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61223128 | Jul 2009 | US |