Patent Application
20110220371
None.
Not applicable.
Not applicable.
This invention relates to systems and methods of treating fluids associated with wellbores.
Suitable fluid supplies are sometimes required to perform wellbore servicing operations and to produce wellbore servicing fluids. However, a fluid supply local to a wellbore may be abundant but nonetheless unusable due to the presence of bacteria, non-beneficial microorganisms, and an undesirable organic composition of the fluid supply. For example, fluids such as produced water and flowback water, each of which may be extracted from a wellbore, may be unusable for wellbore servicing operations and production of wellbore servicing fluids due to their undesirable bacteria, microorganism, and organic composition. Further, the fluids may need to be treated prior to disposal due to their undesirable composition. Accordingly, there is a need for transforming the sometimes abundantly available but unusable fluids into fluids that are usable for wellbore servicing operations and for producing wellbore servicing fluids. Further, there is a need for at least partial remediation of such fluid prior to disposal of the fluid to the environment.
Disclosed herein is a method of treating a fluid, comprising treating a fluid by adding ozone to the fluid and exposing the fluid to ultraviolet radiation, and producing a wellbore servicing fluid using the treated fluid. Further, the wellbore servicing fluid may comprise a gelling agent, the wellbore servicing fluid may be an aqueous fracturing fluid, the fluid may comprise produced water obtained from the wellbore during production of hydrocarbons from the wellbore, the fluid may comprise flowback water that was introduced into the wellbore as part of a previous or ongoing wellbore servicing operation, and/or the fluid may be introduced into the wellbore at substantially the same fluid flow rate as the fluid flow rate at which the fluid may be treated.
Also disclosed herein is a mobile apparatus for treating a wellbore servicing fluid, comprising a fluid flow path comprising an upstream end and a downstream end, the fluid flow path being configured to allow passage of the fluid therethrough, an ozone inlet configured to allow introduction of ozone into the fluid flow path, a source of ultraviolet radiation associated with the fluid flow path so that ultraviolet radiation generated by the source of ultraviolet radiation is introduced into the fluid flow path, and wherein the fluid flow path is configured to treat a fluid at a rate of at least about 25 to about 100 barrels per minute. The source of ultraviolet radiation may be electrically powered. The apparatus may further comprise a fluid mixer configured to promote turbulence of the fluid within the fluid flow path, and/or the apparatus may be carried by at least one of a truck, a trailer, and a skid. The apparatus may further comprise an electrically powered ozone generator configured to produce ozone from air or oxygen. The fluid flow path may be configured to allow passage of between about 10 barrels per minute of fluid to about 250 barrels per minute of fluid from the upstream end to the downstream end. The apparatus may be configured to introduce ozone and ultraviolet radiation in sufficient quantities relative to a flowrate of the fluid through the fluid flow path so that the fluid may be transformed from a fluid that may not be suitable for at least one of disposal to the environment and use in producing a wellbore treatment fluid into a fluid that may be suitable for at least one of disposal to the environment and use in producing a wellbore treatment fluid, and/or the fluid flow path may be disposed in a fluid circuit that may deliver fluid to the apparatus from the wellbore and may deliver fluid from the apparatus to the wellbore.
Further disclosed herein is a method of servicing a wellbore, comprising transporting a fluid treatment system to a location near the wellbore, receiving fluid into the fluid treatment system, adding ozone to the fluid, irradiating the fluid with ultraviolet radiation, passing the fluid treated with the ozone and the ultraviolet radiation out of the fluid treatment system, and delivering the treated fluid into the wellbore. The transporting the fluid treatment system may comprise carrying the fluid treatment system by truck, aircraft, boat, or other mobile craft. The method may further comprise after treating the fluid, transporting the fluid treatment system away from the location near the wellbore, and/or adjusting at least one of the oxidation dosing rate and a rate of the fluid flow through the fluid treatment system in response to results of the comparison of the at least one of a chemical oxygen demand (COD) and an oxygen consumption count (OCC), and determining at least one of a COD and an OCC of the treated fluid.
Further disclosed herein is a method of producing a wellbore servicing fluid, comprising extracting a fluid from a wellbore, and treating the fluid by adding ozone to the fluid and exposing the fluid to ultraviolet radiation, and producing a wellbore servicing fluid using the treated fluid. Further, the fluid may be treated at a fluid flow rate of between about 10 barrels per minute and about 250 barrels per minute and at least one of a COD and an OCC of the treated fluid may be suitable to produce a wellbore servicing fluid using the treated water, and/or the treated fluid may be used to produce a wellbore servicing fluid at substantially the same rate at which the fluid may be treated.
Further disclosed herein is a method of treating a wellbore servicing fluid, comprising extracting a fluid from a wellbore, treating the fluid by adding ozone to the fluid and exposing the fluid to ultraviolet radiation, and disposing of the treated fluid to the environment.
In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals, respectively. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness.
Disclosed herein are systems and methods for transforming a fluid including fluid extracted from a wellbore from an unusable state into a usable state for wellbore servicing operations and/or production of wellbore servicing fluids. In an embodiment, the methods and systems described herein are utilized to reduce a chemical oxygen demand (COD) of the fluid, which is related to impurities in water that consume oxygen. These COD impurities may include material derived from natural sources and material introduced to the wellbore in the form of organic chemicals. These can be dissolved organic compounds, materials that have easily oxidizable groups or inorganic materials with redox metal centers that are in their reduced state. Alternatively, the methods and systems described herein are utilized to reduce an oxygen consumption count (OCC). The OCC content of the fluid also arises from easily oxidizable groups in the organic content in the fluid, and is basically a reflection of the chemical oxygen demand (COD) of the fluid system. Their difference basically arises from the reagents and procedures of the tests designed to measure each of them. While COD is more of a laboratory methodology, OCC is more applicable to the field operations. However, both methods may be amendable to laboratory or field use. Hereinafter, all materials that contribute to the oxygen consumption are collectively referred to as oxidizable organic contaminants. As will be understood by one of ordinary skill in the art, a fluid that contains oxidizable organic contaminants may adversely affect the intended function of the fluid and/or render the fluid unusable for use in wellbore servicing operations and/or for use in producing a wellbore servicing fluid. A greater understanding of some of the problems posed by the presence of organic contaminants in fluids for use in wellbore servicing operations may be found in U.S. Pat. No. 7,332,094 which is hereby incorporated by reference in its entirety. The systems and methods disclosed herein are directed toward treating fluids including extracted fluid with both ozone and ultraviolet radiation to alter the organic composition of the fluid such that its COD and/or OCC are reduced and the problematic oxidizable organic contaminants are likewise significantly reduced. The systems and methods disclosed herein may similarly be used to remediate the fluid and/or otherwise alter an organic composition of the fluid into a form more suitable for disposal to the environment. Further, different constituents of the oxidizable organic contaminants may react to exposure to the ozone and ultraviolet radiation differently. Accordingly, treatment of the extracted fluid may result in more effectively reducing some constituents of the organic contaminants while other constituents may be less effectively reduced and/or not reduced at all. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art with the aid of this disclosure upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings.
As used herein, the term “organic composition” is intended to broadly encompass the full mixture of organic contaminants of a fluid. The organic contaminants described herein include all organic materials, whether introduced to the fluid through natural processes and/or wellbore servicing operations. The organic composition may be described as comprising, but not being limited to, biological elements such as bacteria and other microorganisms, dissolved and/or entrained organic materials, various classes of compounds such as paraffins, aromatics, resins, asphaltenes, and organic components of treatment fluids such as gelling agents, friction reducers, and/or surfactants. Further, as used herein, the phrase “treating a fluid” and other similar phrases are intended to mean that at least by introducing the fluid to ozone and ultraviolet radiation, the fluid is handled, altered, managed, and/or manipulated physically and/or chemically to reduce bacteria and biological growth as well as to reduce and/or alter the organic contaminants of the fluid and/or to otherwise alter an organic composition of the fluid to a state that is more amenable to being used in a wellbore servicing operation and/or being used to produce a wellbore servicing fluid.
Most generally, system 100 is configured so that as fluid is flowed from the upstream end 104 to the downstream end 106, ozone may be added to the fluid through ozone inlets 108, the fluid may be irradiated with ultraviolet radiation emanating from ultraviolet radiation sources 114 while the fluid is in irradiation chambers 110, and the fluid may become more turbulent in response to interaction with mixers 112. The above-described actions serve to provide a powerful oxidizing effect on the contents of the fluid within the fluid flow path 102. In particular, components of an organic composition may be at least partially oxidized and/or reduced to reduce and/or alter the COD and/or OCC of the fluid. Further, while the ultraviolet irradiation may be limited to increasing an oxidization effect while the fluid is located within the radiation chambers 110, the ozone introduced through the ozone inlets 108 may continue to provide an oxidization effect to the fluid and fluid conduits conducting the fluid even after the fluid has exited the fluid treatment system 100.
In operation of some embodiments, a portable fluid treatment system 100 may be transported to a location of a fluid source to be treated. Once located near the fluid source to be treated, the fluid treatment system 100 may be coupled to the fluid source. In some embodiments flowback fluid (such as flowback water) and/or a produced fluid (such as produced water) stored at the location may be drawn into the conduit 122 by operation of the pump 118 or by other pumping means (e.g., well circulation or flowback loops). The pump 118 may deliver the fluid into the fluid flow path 102 of the fluid treatment system 100. At various locations along the fluid flow path 102, ozone and ultraviolet radiation may be introduced into the fluid flow path 102, thereby treating the fluid within the fluid flow path 102. Optionally, turbulence of the fluid may be increased by mixers 112 to further enhance the fluid treatment. It will be appreciated that any number and/or combinations of ozone inlets 108, radiation chambers 110, and mixers 112 may be disposed along the fluid flow path 102. Further, in an alternative embodiment, a recirculation conduit may be provided to direct some fluid from a first location within the fluid flow path 102 to a second relatively further upstream location within the fluid flow path 102. Such recirculation may increase turbulence and/or may be controlled to increase a level of treatment of the fluid. In an embodiment, the flowback fluid (such as flowback water) and/or a produced fluid (such as produced water) stored at the location in container 130 may also contain water from other sources such as surface water, well water, run-off water, and municipal water.
In some embodiments, the fluid treatment system may be used to effectively treat fluids at the above-described rates even though the fluid enters the fluid treatment system 100 having a turbidity of about between about 0 to 2,000 Nephelometric Turbidity Units (NTUs), alternatively between about 0 to about 300 NTUs, alternatively between about 100 to about 200 NTUs, alternatively about 150 NTUs. In some embodiments, a fluid may be treated to reduce the COD and/or OCC of the fluid for disposal into the environment. In such cases, repetitive and/or looping treatment (i.e., recirculating already treated fluid back through the fluid treatment system 100 multiple times) of a fluid may eventually completely or nearly completely remediate the fluid for disposal to the environment. In other embodiments, a fluid may be considered effectively treated when the COD and/or OCC of the fluid is reduced to at least 30% of its original value. An example where such a value of the COD or OCC may provide an appropriate measure of treatment success for the fluid may arise where the fluid is to be subsequently used to produce a wellbore servicing fluid. For example, if the fluid treatment system 100 is to treat a fluid that will be used to create a gelling fluid, it may be desirable for the treated fluid to comprise a COD and/or OCC that will not substantially adversely affect the ingredients used to generate or break the gelling fluid. By lowering the COD and/or OCC of the treated fluid, predictability in the performance of the gelling fluid and/or the breakers used to oxidize (break) the gelled fluid may be maintained because the organic composition of the treated fluid will not inadvertently degrade, interact, or otherwise inhibit the intended function of the gelling fluid and/or breakers. In other embodiments, the COD and/or OCC of the treated fluid may be reduced only enough to prevent a substantial degradation in performance of the resulting wellbore servicing fluid generated using the treated fluid.
In other embodiments, the fluid treatment system 100 may be described as configured to treat a fluid using so-called “oxidation dosing.” In this embodiment, oxidation dosing may be accomplished by administering an “oxidation dose” that generally comprises the above-described added ozone as an “ozone dose” to the fluid and the above-described administered ultraviolet radiation as a “radiation dose” to the fluid. The oxidation dosing, in some embodiments, may comprise intermittent administration of ozone and ultraviolet radiation to the fluid. In other embodiments, the oxidation dosing may be accomplished by administering the ozone and the ultraviolet radiation at an “oxidation dose rate.” In some embodiments, the oxidation dose rate may be provided in a manner independent of the rate of fluid passing through the fluid treatment system 100. In other embodiments, the oxidation dose rate may be administered in response to or to account for a rate of fluid passing through the fluid treatment system 100. For example, the oxidation dose rate may be proportionally, linearly, or non-linearly adjusted in response to a change in the rate of fluid passing through the fluid treatment system 100. In an embodiment, the oxidation dose rate may be tuned to the COD and/or OCC of the water to be treated. Water with higher COD and/or OCC levels may be treated with higher oxidation dose rates. Using the above-described oxidation dosing, a strength of the treatment may be controlled and/or adjusted to selectively treat the fluid. In some embodiments, oxidation dosing may be accomplished by administering ozone only.
In some embodiments, the effectiveness of the treatment of the fluid may be measured and/or otherwise quantified by testing the fluid both before and after treatment. For example, each of a sample of untreated fluid and a sample of treated fluid may be analyzed for their total organic carbon (TOC) content. In response to a change in TOC content, the oxidation dosing rate, a rate of fluid passing through the fluid treatment system 100, and/or both may be adjusted and/or controlled to achieve a desired change in the TOC content. In some embodiments, a fluid may be considered successfully treated when a treated fluid is determined to have a TOC content at or below a threshold level. Alternatively, a fluid may be considered successfully treated when a treated fluid comprises a TOC of about a desired percent reduction from a TOC content of the fluid prior to treatment.
In some embodiments, the effectiveness of the treatment of the fluid may be measured and/or otherwise quantified by testing the fluid both before and after treatment. For example, each of a sample of untreated fluid and a sample of treated fluid may be analyzed for their COD, OCC, and/or TOC. In response to a change in COD, OCC, and/or TOC, the oxidation dosing rate, a rate of fluid passing through the fluid treatment system 100, and/or both may be adjusted and/or controlled to achieve a desired change in the COD, OCC, and/or TOC. In some embodiments, a fluid may be considered successfully treated when a treated fluid is determined to have a COD, OCC, and/or TOC content at or below a threshold level. Alternatively, a fluid may be considered successfully treated when a treated fluid comprises a COD, OCC, and/or TOC of about a desired percent reduction from a COD, OCC, and/or TOC content of the fluid prior to treatment.
Further, a fluid may be considered successfully treated and considered useable for wellbore servicing operations and/or for use in producing a wellbore servicing fluid when, after exposure to a predetermined oxidation dose and/or at a predetermined oxidation dosing rate, the amount of reduction of COD, OCC, and/or TOC content is less than a threshold amount of reduction. In such an embodiment, the failure of a COD, OCC, and/or TOC content of a fluid to be reduced in response to a known oxidation dosing and/or oxidation dosing rate may serve to indicate that the remaining organic contaminants are of such composition that the remaining organic contaminants are not so harmful to a wellbore servicing operation or to the production of wellbore servicing fluid as to consider the treated fluid unusable. In other words, by measuring a COD, OCC, and/or TOC content of the fluid before and after treatment, it may be determined that while organic contaminants remain in the treated fluid, the remaining organic contaminants may be (as indicated by their resistance to oxidation) unlikely to easily cause undesirable oxidation reactions while performing a wellbore servicing operation and/or producing a wellbore servicing fluid using the treated fluid.
The procedure for determination of the chemical oxygen demand (COD) has been described by Andrea M. Jirka and Mark J. Carter (“Micro Semi-Automated Analysis of Surface and Wastewaters for Chemical Oxygen Demand”, Analytical Chemistry, Vol. 47, No. 8 (1975), 1397. Additionally, a modified COD method for waters with high chloride concentrations may be found in “Dichromate Reflux A Proposed Method for Chemical Oxygen Demand Chloride Correction in Highly Saline Wastes” by Frank J. Baumann in Analytical Chemistry, Vol. 46, No. 9 (1974) 1337. Oxygen consumption count (OCC) is a parameter that reflects the amount of oxidizable content in the water. It is defined as the excess ammonium persulfate required to break a 40 lb/1000 gal guar gel in a fluid, e.g., in produced water, to a viscosity of less than 10 cps in a 2-hour time period at 120° F., compared to the amount of ammonium persulfate required reduce the viscosity to less than 10 cps using a solution of 40 lb/1000 guar in purified water at the same reaction conditions.
OCC or oxygen consumption count may be mathematically represented as follows:
OCC=X−Y
Where:
Y=amount of ammonium persulphate needed to break 40 lb guar gel in sample water to less than 10 cps under reaction conditions;
X=amount of ammonium persulphate needed to break 40 lb guar gel in purified water, to less than 10 cps under reaction conditions; and
Reaction conditions for OCC may be: Temperature=120° F., Pressure=Atmospheric, and Time=2 hours.
In an embodiment, the method involved in treating and using a fluid may comprise: testing the untreated input fluid to measure its OCC; determining a treatment dosage for ozone and/or UV irradiation that is based on the OCC readings taken in the earlier step; and treating the fluid using at least one of the estimated ozone and UV irradiation dosages; and optionally testing the fluid again to measure its OCC after treatment. In an embodiment, a subsequent a treatment dosage of ozone and/or UV irradiation may be estimated and the fluid may be treated according to the estimated dosage. In an embodiment, a final OCC may be used to appropriately increase the amount of breaker materials added to the final fluid formulation.
Referring to
The wellbore servicing system 1100 comprises a blender 1114 that is coupled to a wellbore services manifold trailer 1118 via flowline 1116. As used herein, the term “wellbore services manifold trailer” includes a truck and/or trailer comprising one or more manifolds for receiving, organizing, and/or distributing wellbore servicing fluids during wellbore servicing operations. In this embodiment, the wellbore services manifold trailer 1118 is coupled to eight high pressure (HP) pumps 1120 via outlet flowlines 1122 and inlet flowlines 1124. In alternative embodiments, however, there may be more or fewer HP pumps used in a wellbore servicing operation. Outlet flowlines 1122 are outlet lines from the wellbore services manifold trailer 1118 that supply fluid to the HP pumps 1120. Inlet flowlines 1124 are inlet lines from the HP pumps 1120 that supply fluid to the wellbore services manifold trailer 1118.
The blender 1114 mixes solid and fluid components to achieve a well-blended wellbore servicing fluid. As depicted, sand or proppant 1102, water 1106, and additives 1110 are fed into the blender 1114 via feedlines 1104, 1108, and 1112, respectively. The water 1106 may be potable, non-potable, untreated, partially treated, or treated water. In an embodiment, the water 1106 may be produced water that has been extracted from the wellbore while producing hydrocarbons form the wellbore. The produced water may comprise dissolved and/or entrained organic materials, salts, minerals, paraffins, aromatics, resins, asphaltenes, and/or other natural or synthetic constituents that are displaced from a hydrocarbon formation during the production of the hydrocarbons. In an embodiment, the water 1106 may be flowback water that has previously been introduced into the wellbore during wellbore servicing operation. The flowback water may comprise some hydrocarbons, gelling agents, friction reducers, surfactants and/or remnants of wellbore servicing fluids previously introduced into the wellbore during wellbore servicing operations.
The water 1106 may further comprise local surface water contained in natural and/or manmade water features (such as ditches, ponds, rivers, lakes, oceans, etc.). Further, the water 1106 may comprise water obtained from water wells. Still further, the water 1106 may comprise water stored in local or remote containers. The water 1106 may be water that originated from near the wellbore and/or may be water that has been transported to an area near the wellbore from any distance. In some embodiments, the water 1106 may comprise any combination of produced water, flowback water, local surface water, and/or container stored water.
In this embodiment, the blender 1114 is an Advanced Dry Polymer (ADP) blender and the additives 1110 are dry blended and dry fed into the blender 1114. In alternative embodiments, however, additives may be pre-blended with water using a GEL PRO blender, which is a commercially available preblender trailer from Halliburton Energy Services, Inc., to form a liquid gel concentrate that may be fed into the blender 1114. The mixing conditions of the blender 1114, including time period, agitation method, pressure, and temperature of the blender 1114, may be chosen by one of ordinary skill in the art with the aid of this disclosure to produce a homogeneous blend having a desirable composition, density, and viscosity. In alternative embodiments, however, sand or proppant, water, and additives may be premixed and/or stored in a storage tank before entering a wellbore services manifold trailer 1118.
The HP pumps 1120 pressurize the wellbore servicing fluid to a pressure suitable for delivery into the wellhead 1128. For example, the HP pumps 1120 may increase the pressure of the wellbore servicing fluid to a pressure of up to about 20,000 psi or higher. The HP pumps 1120 may comprise any suitable type of high pressure pump, such as positive displacement pumps.
From the HP pumps 1120, the wellbore servicing fluid may reenter the wellbore services manifold trailer 1118 via inlet flowlines 1124 and be combined so that the wellbore servicing fluid may have a total fluid flow rate that exits from the wellbore services manifold trailer 1118 through flowline 1126 to the flow connector wellbore 1128 of between about 1 BPM to about 200 BPM, alternatively from between about 50 BPM to about 150 BPM, alternatively about 100 BPM. Persons of ordinary skill in the art with the aid of this disclosure will appreciate that the flowlines described herein are piping that are connected together for example via flanges, collars, welds, etc. These flowlines may include various configurations of pipe tees, elbows, and the like. These flowlines connect together the various wellbore servicing fluid process equipment described herein.
In this embodiment, the wellbore servicing system 1100 further comprises a fluid treatment system 100 of the type described above. The fluid treatment system 100 is integrated into the wellbore servicing system 1100 in a fluid circuit between the fluid storage container 130 and the water 1106. As such, the fluid treatment system 100 is configured to accept fluids from fluid storage and treat the fluids as the fluids pass through the fluid treatment system 100, and subsequently pass the treated fluids to the supply of water 1106. In this embodiment, the water storage contain may comprise fluids from any number of water sources such as water produced from wellbores (produced water), surface water, or potable water. Accordingly,
At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R1, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R1=k*(Ru−R1), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. The discussion of a reference in the disclosure is not an admission that it is prior art, especially any reference that has a publication date after the priority date of this application. The disclosure of all patents, patent applications, and publications cited in the disclosure are hereby incorporated by reference in their entireties.
