Abstract:
A method comprises rendering a hydrocarbon industry servicing fluid biologically inert without using chemical biocides. One method of rendering a hydrocarbon industry servicing fluid biologically inert comprises irradiating at least one constituent of the servicing fluid to produce an irradiated fluid. Another method comprises irradiating a used hydrocarbon industry servicing fluid to produce a remediated fluid that is biologically inert. A fluid treatment system comprises an irradiation apparatus, inlet piping directing an untreated fluid into the irradiation apparatus, outlet piping directing an irradiated fluid out of the irradiation apparatus, and a connection to a hydrocarbon industry application.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     None.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not applicable.  
       REFERENCE TO A MICROFICHE APPENDIX  
       [0003]     Not applicable.  
       FIELD OF THE INVENTION  
       [0004]     The present invention relates generally to the use of irradiation, such as ultraviolet light, to disinfect fluids, including water. More particularly, the present invention relates to hydrocarbon industry applications where irradiation may be used to disinfect fluids, instead of treating fluids with chemical biocides or using untreated fluids.  
       BACKGROUND  
       [0005]     In hydrocarbon industry applications, such as offshore pipeline pre-commissioning procedures and well fracturing operations, servicing fluids including seawater and fresh water may be left untreated or may be rendered biologically inert by treating the fluids using chemical biocides.  
         [0006]     In offshore pipeline applications, a water-based servicing fluid may be used to flood the pipeline during installation or to flood and hydrostatically test the pipeline once installed. During installation, the pipeline is laid on the seabed and then flooded with seawater, or in the case of alloy pipelines, fresh water. Once a pipeline is flooded, subsea connections can then be made. In particular, divers or remotely operated vehicles (ROVs) physically open the pipeline and connect it to a wellhead, subsea template, or riser system, for example. When making subsea connections to an alloy pipeline, it is undesirable for the seawater to contact the inner pipeline surfaces because seawater may corrode the pipeline. Therefore, the alloy pipeline is flooded with fresh water that includes a slug of gelled water at each end. As such, when the end of the pipeline is opened up for subsea connections to be made, the gel barrier prevents seawater from ingressing into the pipeline and mixing with the fresh water. After all subsea connections are made, additional water is pumped into the pipeline to hydrostatically test the structural integrity of the pipeline and any connected components. Once installation and testing are complete, the water contained within the pipeline is displaced and, in some cases, disposed of to sea.  
         [0007]     At any point where water is being introduced into the pipeline, whether in the flooding stage or in the hydrostatic test stage, this water is typically filtered and treated with a chemical biocide to disinfect the water. The purpose of such treatment is to prevent bacteria and biological growth from causing damage to the pipeline internal surface. However, due to environmental laws and regulations, seawater used for hydrostatic testing in a number of locations, such as the Gulf of Mexico, cannot be disposed of to sea if it contains any chemical biocides. Therefore, untreated seawater is used, which permits organic growth in the pipeline, which may constrict and/or corrode the pipeline. This can have a detrimental effect on the available flow rates of the pipeline once in service. Although discharge of water containing chemical biocides is still permitted in other parts of the world, many countries are beginning to follow the lead of the Gulf of Mexico by prohibiting the discharge of chemical biocide treated water to sea because such discharge may harm marine life. Therefore, a need exists for a fluid treatment method that complies with environmental requirements and is not harmful to marine life if discharged to the ocean.  
         [0008]     Chemical biocides are also used during pre-commissioning procedures for pipelines installed onshore. Disposal of water containing chemical biocides on land is also prohibited in some environmentally sensitive regions of the United States. In regions where no prohibitions exist, disposing of water containing chemical biocides is still undesirable in that it may harm wildlife and contaminate underground water. Therefore, a need exists for an alternative, environmentally friendly method of disinfecting fluid.  
         [0009]     Fluids treated with chemical biocides are also used in well bore servicing operations, such as fracturing a formation, for example. These operations are often conducted in remote locations where water is scarce and must be transported to the well site, which is costly. Typically, the water is filtered and treated with chemical biocides to prevent bacterial growth during transportation and/or storage. In a fracturing application, a gelling agent and other constituents are added to the water prior to injection into the well bore. However, gel may act as a food source for any bacteria present in the fluid. Thus, if bacteria is present in the base water, the bacteria will eventually destroy the gel and negatively impact the fracturing operation. Hence, the water is generally disinfected with chemical biocides before its use in the fracturing operation.  
         [0010]     Once the fracturing operation is complete, flowback fluid recovered from the well bore may be stored in man-made tanks or lined pits, but it is not disposed of to land due to the chemical biocides. This flowback fluid containing chemical biocides is typically not remediated for re-use or disposal because such remediation of the fluid using chemical treatments, for example, is cost prohibitive. Instead, the flowback fluid is generally removed from the well site for proper treatment and disposal. Specifically, proper disposal of fluids containing biocides requires removal of the biocide before the fluid can be returned to the environment.  
         [0011]     Due to the scarcity of water in many remote locations, and the cost associated with transporting water to and from these well sites, it would be beneficial if formation fluid produced from the well could be used, or flowback fluid could be reused following a service operation. However, treatment of formation fluid and flowback fluid to remove bacteria is necessary for the success of many operations, such as fracturing. Hence, a need exists for a cost effective method of disinfecting produced fluid and flowback fluid for reuse in a well bore servicing operation, or for disposal to the environment.  
       SUMMARY OF THE INVENTION  
       [0012]     In one aspect, the present disclosure relates to a method of rendering a hydrocarbon industry servicing fluid biologically inert without using chemical biocides. In another aspect, the present disclosure relates to a method of rendering a hydrocarbon industry servicing fluid biologically inert comprising irradiating at least one constituent of the hydrocarbon industry servicing fluid to produce an irradiated fluid. The irradiating may comprise exposure to ultraviolet light. In various embodiments, the at least one constituent comprises a volume of fresh water, seawater, formation fluid, flowback fluid, or a combination thereof. The method may further comprise filtering at least one constituent either before or after irradiating, or injecting other constituents into the irradiated fluid. In an embodiment, the method further comprises performing a hydrocarbon industry service operation with the hydrocarbon industry servicing fluid. The hydrocarbon industry service operation may comprise filling, cleaning, hydrotesting, flushing, preserving, or a combination thereof; and may be conducted within a pipeline; or within a hydrocarbon processing, storage or transport facility; or within a well bore. The method may further comprise disposing of the hydrocarbon industry servicing fluid to the environment by releasing or injecting the fluid.  
         [0013]     In yet another aspect, the present disclosure relates to a method of irradiating a used hydrocarbon industry servicing fluid to produce a remediated fluid that is biologically inert. In various embodiments, the method may further comprise performing a hydrocarbon industry service operation with the remediated fluid; storing the remediated fluid; re-irradiating the remediated fluid; injecting other constituents into the remediated fluid; and/or disposing of the remediated fluid to the environment, which may be performed by releasing or injecting the fluid.  
         [0014]     In another aspect, the present disclosure relates to a fluid treatment system comprising an irradiation apparatus, inlet piping directing an untreated fluid into the irradiation apparatus, outlet piping directing an irradiated fluid out of the irradiation apparatus, and a connection to a hydrocarbon industry application. In various embodiments, the fluid treatment system may be portable, the irradiation apparatus may comprise an ultraviolet light device, and a filter may be disposed along the inlet piping or the outlet piping. In various embodiments, the fluid treatment system comprises at least one pump, at least one valve that directs the irradiated fluid into the hydrocarbon industry application or into a disposal line, and/or a re-treatment line that directs the irradiated fluid into the irradiation apparatus. In an embodiment, the hydrocarbon industry application comprises a pipeline, a processing facility component, a storage facility component, a transportation facility component, or a well. In another embodiment, a hydrocarbon industry application comprises the fluid treatment system. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]     For a more detailed description of the present invention, reference will now be made to the accompanying drawings, wherein:  
         [0016]      FIG. 1  is a flow schematic of a representative pipeline operation employing an irradiation system to disinfect seawater, fresh water or another fluid;  
         [0017]      FIG. 2  is a flow schematic of a representative well servicing operation employing an irradiation system to disinfect fluid to be used in a fracturing operation; and  
         [0018]      FIG. 3  is a flow schematic of a representative well servicing operation employing an irradiation system to remediate formation fluid or flowback fluid, either for re-use in another servicing operation or for disposal. 
     
    
     NOTATION AND NOMENCLATURE  
       [0019]     Certain terms are used throughout the following description and claims to refer to particular assembly components. This document does not intend to distinguish between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”.  
         [0020]     As used herein, each of the terms “disinfect” and “remediate” mean to render biologically inert. Hence, to disinfect or remediate water, for example, means to render the water biologically inert by killing the micro-organisms in the water.  
         [0021]     As used herein, the term “pipeline” includes any line in which fluid is moved, including any onshore or offshore flow system, such as mainline systems, risers, flow lines used to transport untreated fluid between a wellhead and a processing facility, and flow lines used to transport treated fluids.  
         [0022]     In the drawings, the arrows indicate the direction of fluid flow through the system in a sequential operation.  
       DETAILED DESCRIPTION  
       [0023]     Various embodiments of apparatus and methods for treating a fluid for use in hydrocarbon industry applications will now be described with reference to the accompanying drawings, wherein like reference numerals are used for like features throughout the several views. There are shown in the drawings, and herein will be described in detail, specific embodiments of irradiation systems and methods of using such systems to disinfect fluid, with the understanding that this disclosure is representative only and is not intended to limit the invention to those embodiments illustrated and described herein. The embodiments of fluid treatment methods and irradiation systems disclosed herein may be utilized in any type of hydrocarbon industry application, operation, or process where it is desired to disinfect fluid, including, but not limited to, pipeline operations; well servicing operations; upstream exploration and production applications; and downstream refining, processing, storage and transportation applications. It is to be fully recognized that the different teachings of the embodiments disclosed herein may be employed separately or in any suitable combination to produce desired results.  
         [0024]      FIG. 1  schematically depicts a representative pipeline operation  100  utilizing an irradiation system  110 , such as an ultraviolet light treatment apparatus, to render the fluid  120  biologically inert. The fluid  120  may be seawater, fresh water, or another fluid, and preferably comes from a readily available source, such as a river or the ocean. In one embodiment, the pipeline operation  100  comprises a lift pump  150 , an irradiation system  110 , filters  130 , a pipeline fill pump  160 , and a pipeline  140 . The filters  130  may comprise any type of filtering apparatus to remove particles from the fluid  120 , such as a sock type filter where the fluid  120  flows through a filtering insert that collects particles or any other filter as described herein. The lift pump  150  and the pipeline fill pump  160  may be any type of pump suitable for moving the fluid  120  through the irradiation system  110 , filters  130  and pipeline  140 . The pipeline  140  may be constructed of carbon steel, an alloy, or any other material suitable for the pipeline pre-commissioning operation  100 . The pumps  150 ,  160 , the irradiation system  110 , and the filters  130  may be containerized with other flow equipment and regulation instrumentation and mounted on a skid, thereby making the entire apparatus portable. In an embodiment, the skid mounted equipment is electrically powered and may be operated using generators in remote locations.  
         [0025]     As represented by the flow arrows, the lift pump  150  transports the fluid  120  through the filters  130 , into line  180 , and then into the irradiation system  110 , where the filtered fluid is disinfected. The purpose of disinfection is to kill micro-organisms in the fluid  120 . In an embodiment, the irradiation system  110  comprises an ultraviolet light apparatus, such as a UV-disinfection system available from HOH Water Technology A/S of Denmark, for example. The irradiation system  110  causes the deactivation of micro-organisms, thereby effectively disinfecting the fluid  120 . In an embodiment, the filters  130  remove a significant quantity of debris and biological material from the fluid  120  upstream of the irradiation system  110 , thereby enhancing the treatment process. In particular, the ultraviolet light source within the irradiation system  110  should penetrate through a filtered fluid more effectively than through a debris-laden fluid, and some removal of biological material upstream of the irradiation system  110  should enhance the efficiency of the irradiation treatment. In contrast to untreated fluids, such as water, irradiated fluids do not as readily corrode the wall of the pipeline  140 . Further, as compared to using chemical biocides, disinfection by irradiation is more cost effective and also produces an environmentally safe fluid for disposal to the environment. After exiting the irradiation system  110 , the irradiated and filtered fluid in line  185  is then transferred by the pipeline fill pump  160  through line  190  and into the pipeline  140  for use in pipeline operations, such as filling and testing procedures, for example. Once the pipeline operations are complete, the fluid exits the pipeline  140  through line  195  where the fluid may be disposed of to the environment  170  without harm thereto.  
         [0026]     One of ordinary skill in the art will readily appreciate that the representative pipeline operation  100  of  FIG. 1  may be performed offshore or onshore, and may include different components than the ones shown in  FIG. 1 . The pipeline operation  100  may involve pre-commissioning the pipeline  140 , such as during installation and testing, or post-commissioning operations, such as a repair or replacement procedure. Although  FIG. 1  shows the fluid  120  passing first through the filters  130  and then through the irradiation system  110 , the relative position of these treatment devices may be reversed. For example, the fluid  120  may be first irradiated and then filtered.  
         [0027]     In another hydrocarbon industry application, the irradiation apparatus  110  may be used to remediate produced fluid, which includes formation fluid or flowback fluid produced during well fracturing or other servicing operations. Such remediated fluid may be reused as a well bore servicing fluid, or may be disposed of to the environment. While the following discussion of  FIG. 2  and  FIG. 3  focuses on well fracturing, it should be understood that the present disclosure may be used to treat water for use in any well bore servicing fluid, or to treat such fluids themselves as needed to disinfect same.  
         [0028]      FIG. 2  schematically depicts a representative well bore servicing operation  200  utilizing the irradiation apparatus  110  to disinfect or remediate fluid supplied from a readily available source as an alternative to using trucked-in water treated with chemical biocides. The water  210  from a readily available source may be fresh water, seawater, or formation water. Formation water includes water produced from a well on site, which may be the same or different well from that being serviced. In an embodiment, this water  210  could even comprise trucked-in water that has not been treated with chemical biocides. The well bore servicing operation  200  comprises a lift pump  150 , filters  230 , the irradiation apparatus  110 , a valve  260 , storage  290  for gel and other fracturing fluid components, an injection pump  295 , a service pump  285 , and a well bore  280  within which a servicing operation is being conducted, such as fracturing, for example.  
         [0029]     The filters  230  may comprise a variety of different types of filters, depending upon the requirements of the operation, including sock type filters, boron removal filters, micron particle filters, activated charcoal filters, and/or another type of filter to make the fluid  120  suitable for a well fracturing operation. In one embodiment, the filters  230  comprise the filtering system depicted and described in U.S. patent application Ser. Nos. 11/062,963 and 11/063,307, both filed on Feb. 22, 2005, and both entitled “Devices and Processes for Removal of Impurities from a Fluid Recovered from a Subterranean Environment”, assigned to Halliburton Energy Services, Inc., also the assignee of the present application. Pumps  150 ,  285 , and  295  may be any type of pump suitable for moving the fluid  210 . Valve  260  may be any type that is operable to direct fluid flow and that is compatible with the fluids in the well bore servicing operation  200 . As in the pipeline operations  100  shown in  FIG. 1 , the pumps  150 ,  285 ,  295 ; the filters  230 ; the irradiation apparatus  110 ; and the valve  260  may be containerized with the connecting piping and other flow regulation equipment and instrumentation and mounted on a skid, thereby making the entire apparatus portable. In an embodiment, the skid mounted equipment is electrically powered and may be operated using generators in remote locations.  
         [0030]     As depicted, the water  210  from a readily available source is conveyed through the filters  230  by the lift pump  150 . The filtered water in line  240  then passes through the irradiation apparatus  110 , where it is disinfected. The filtered and irradiated fluid in line  250  then passes through a valve  260  where it may be diverted into a retreatment line  255  or continue on through line  265  to the fracturing operation in the well bore  280 . The filtered and irradiated fluid in line  265  is injected with gel and other fracturing fluid components from storage  290  via injection pump  295 , resulting in a fracturing fluid entering line  270 . The service pump  285  then injects the fracturing fluid from line  270  into the well bore  280  to conduct the fracturing operation. It should be understood that other servicing fluids can be made in a like manner, and the additives injected via pump  295  may be selected accordingly.  
         [0031]     Because water is often scarce at remote well site locations, it may also be desirable to re-use the flowback water produced by the well fracturing or other servicing operation.  FIG. 3  schematically depicts a representative remediation operation  300  utilizing the irradiation apparatus  110  to disinfect flowback fluid with the option to re-use the remediated fluid or dispose of it. The remediation operation  300  comprises a lift pump  150 , filters  230 , an irradiation apparatus  110 , a first valve  380 , a storage tank  310 , a second valve  330 , an injection pump  295 , storage  290  for gel and other fracturing fluid components, and a service pump  285 .  
         [0032]     The filters  230  may be of the same type, or a different type, as those used in the pipeline operation  100  or the well servicing operation  200  shown in  FIGS. 1 and 2 , respectively. The storage tank  310  may be replaced by a lined pit or other fluid storage reservoir. Pumps  150 ,  285 , and  295  may be of any type suitable for moving fluid and compatible with fluids in the remediation operation  300 . Valves  330  and  380  may be any type of valve used to direct fluid flow and compatible with fluids in the remediation operation  300 . Again, all or some of the components shown in  FIG. 3  may be containerized with other flow regulation equipment and instrumentation and mounted on a skid, thereby making the entire apparatus portable. In an embodiment, the skid mounted equipment is electrically powered, and may be operated using generators in remote locations.  
         [0033]     When a fracturing operation is conducted in the well bore  280 , flowback fluid  370  is produced comprising a mixture of formation fluid and fracturing fluid. The flowback fluid  370  is lifted out of the well bore  280  and conveyed through the filters  230  by the lift pump  150 . Filtered fluid in line  240  then passes through the irradiation apparatus  110 , where it is disinfected. The filtered and irradiated fluid in line  250  is then diverted by valve  380  to the storage tank  310  via line  390  or towards a second valve  330  via line  360 . Fluid stored in the tank  310  may later be circulated through re-treatment line  320  and through the irradiation apparatus  110 . The fluid diverted into line  360  is directed towards valve  330 , where the filtered and irradiated fluid may be diverted through line  340  for disposal to the environment  350  or through return line  265  for re-use in the fracturing operation. Alternatively, instead of re-using the filtered and irradiated fluid at the same well site, this fluid may be hauled by truck or transported by another means for re-use at a remote well site. If diverted through line  340  for disposal, the filtered and irradiated fluid will be tested to ensure that it is environmentally safe before it is released to the environment  350 , which may be a water source, e.g. river or lake; a land surface; or injected into a disposal well. If diverted through return line  265  for re-use, gel and other frac fluid components from storage  290  may be added to the irradiated and filtered fluid in line  265  by the injection pump  295  to produce the frac fluid in line  270 . The frac fluid is then injected by the service pump  285  to conduct the fracturing operation in the well bore  280 .  
         [0034]     Thus, where fluids treated with chemical biocides or untreated fluids previously may have been used in a hydrocarbon industry application, such as pipeline pre-commissioning or well fracturing, for example, an irradiated servicing fluid may be used instead. Irradiation may be performed using a portable system comprising an irradiation apparatus  110 . These portable systems may also be used at sites where fluids must be disinfected, but the use of fluids treated with chemical biocides is prohibited, either due to environmental concerns or cost or both. Therefore, the irradiation apparatus may be sent to the location for any type of hydrocarbon industry application where it is desirable to disinfect fluid.  
         [0035]     The foregoing descriptions of specific embodiments of hydrocarbon industry systems and applications utilizing an irradiation apparatus to disinfect fluids have been presented for purposes of illustration and description and are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously many other modifications and variations of these hydrocarbon industry systems and applications are possible. In particular, the position of the irradiation system  110  could be varied. For example, the irradiation could be performed prior to the fluid entering the filtering stage, or the fluid may not require filtering at all. Also, the ultraviolet light treatment could be performed more than once, if necessary, with the use of additional piping. The systems  100 ,  200 ,  300  could be arranged differently, and have more or less components.  
         [0036]     Moreover, other hydrocarbon industry applications are possible. In particular, one of ordinary skill in the art will readily appreciate that the fluid treatment systems disclosed herein are equally suitable for disinfecting servicing fluids, or constituents thereof, for use in applications such as refining and processing vessels, reactors and pipelines; production platform vessels and pipelines; storage applications, including land-based storage tanks and tanks provided on floating production storage and offloading facilities; and pipeline transportation stations and facilities, as well as other applications. Such disinfected servicing fluids may be used for a wide variety of purposes, such as flushing out product and/or cleaning hydrocarbons from the walls of a vessel or pipeline, preserving a vessel or pipeline after cleaning, or filling a storage tank, for example.  
         [0037]     While various embodiments of hydrocarbon industry applications utilizing irradiation to disinfect fluid, as a substitute for fluids treated with chemical biocides, or untreated fluids, have been shown and described herein, modifications may be made by one skilled in the art without departing from the spirit and the teachings of the invention. The embodiments described herein are representative only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. 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.). Use of the term “optionally” with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required. Both alternatives are intended to be within the scope of the claim. Use of broader terms such as comprises, includes, having, etc. should be understood to provide support for narrower terms such as consisting of, consisting essentially of, comprised substantially of, etc.  
         [0038]     Accordingly, the scope of protection is not limited by the description set out above but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of the present invention. Thus, the claims are a further description and are an addition to the preferred embodiments of the present invention. The discussion of any reference in the Background section is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent that they provide representative, procedural or other details supplementary to those set forth herein.