Abstract:
A chemical injection assembly with telemetric capacity and a single fluid injection line capable of reaching multiple downhole injection points. The assembly may take advantage of downhole power telemetry modules so as to intelligently power and direct actuator valves at any of a number of different injection points. So, for example, the need for cumbersome and expensive usage of different delivery lines dedicated to serve different delivery points with the same fluid may be avoided.

Description:
PRIORITY CLAIM/CROSS REFERENCE TO RELATED APPLICATION(S) 
       [0001]    This Patent Document is a Continuation-In-Part claiming priority under 35 U.S.C. §120 to U.S. application Ser. No. 13/364,785, entitled “Chemical Injection Regulation Mechanism”, filed Feb. 2, 2012, and which claims priority under 35 U.S.C. §119 to U.S. Provisional App. Ser. No. 61/438,995, filed on Feb. 3, 2011, and entitled, “Chemical Injection U-Tube Prevention System”, both of which are incorporated herein by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    Exploring, drilling and completing hydrocarbon wells are generally complicated, time consuming and ultimately very expensive endeavors. As a result, over the years increased attention has been paid to monitoring and maintaining the health of such wells. Significant premiums are placed on maximizing the total hydrocarbon recovery, recovery rate, and extending the overall life of the well as much as possible. Thus, logging applications for monitoring of well conditions play a significant role in the life of the well. Similarly, significant importance is placed on well intervention applications, such as clean-out techniques which may be utilized to remove debris from the well so as to ensure unobstructed hydrocarbon recovery. 
         [0003]    In addition to interventional applications, the well is often outfitted with chemical injection equipment to enhance ongoing recovery efforts without the requirement of intervention. For example, most of the well may be defined by a smooth steel casing that is configured for the rapid uphole transfer of hydrocarbons and other fluids from a formation. However, a buildup of irregular occlusive scale, wax and other debris may occur at the inner surface of the casing or tubing and other architecture so as to restrict flow. Such debris may even form over perforations in the casing, screen, or slotted pipe thereby also hampering hydrocarbon flow into the main borehole of the well from the surrounding formation. 
         [0004]    In order to address the potential for scale and other buildup as noted above, time consuming interventional applications may be avoided through use of a circulating chemical injection system. With such systems in place, a metered amount of chemical mixture, such as a hydrochloric acid mix, may be near continuously circulated downhole to help prevent such buildup. This equipment includes an injection line that may be run from surface and directed at different downhole points of interest such as within production tubing, at a production screen or into formation fluid prior to entering the noted tubing. Regardless, the need to halt production or run expensive interventions in order to address undesirable buildup may be largely eliminated. 
         [0005]    Unfortunately, unlike more interactive interventions, chemical injection faces a variety of limitations in terms of delivery. For example, the permanently installed hydraulic line generally terminates at a port below an area of concern such as the indicated production screen. However, this delivery is targeted at a single release point with the system relying on circulation of the delivered chemical mix in order to reach any other locations. Thus, even though a variety of locations may be of potential concern, only the target location is ensured of receiving the intended mix with a notable degree of precision. 
         [0006]    With the limitations of single port delivery in mind, there are circumstances in which the delivery line is outfitted with multiple delivery ports such that delivery to more than one location is not limited to sole reliance on circulation. However, in these situations, the versatility of the delivery nevertheless remains limited. For example, where delivery is directed at multiple production zones, there may be particular zones of concern at one point in time and other zones of interest at other times. Yet, with a single delivery line available, each port delivers a predetermined rate of chemical mix when directed from surface equipment. That is to say, different ports at different locations are generally unable to activated while others are left closed. Rather, by way of a single delivery line, all ports are generally on or all are turned off. 
         [0007]    Of course, it may be possible to provide a dedicated delivery line for each port which runs from surface equipment. In this manner, each line may be independently turned on or off at surface so as to allow for downhole ports to be independently activated. However, this type of system would require a dedicated delivery line for each and every port, thus, dramatically increasing completions equipment and installation expense. 
         [0008]    As an alternative to providing a dedicated line running to each port where multiple ports are utilized, isolation techniques may be employed. That is, as in the case of stimulation and other zonally directed applications, different downhole zones may be isolated for sake of targeted delivery. In such cases, packers or other isolating downhole features may be employed as a means of targeting chemical injection delivery from multiple ports. For example, one downhole region may be isolated in a manner that prevents chemical delivery thereto while allowing such delivery elsewhere. Of course, again, shutting down production for sake of attaining isolation results in applications that are no more cost-effective or time saving than the original types of interventions which chemical injection systems are configured to help avoid. 
         [0009]    Ultimately, dedicated delivery lines and isolation techniques are usually avoided. As a matter of time and cost, such options remain largely impractical. Thus, operators are generally left with reliance on single or multi-point chemical injection delivery which lacks any real measure of control over location specific delivery and/or adjustment thereto. 
       SUMMARY 
       [0010]    A “smart” chemical injection assembly utilizing telemetry is provided. The assembly includes a mandrel housing coupled to a downhole tubular with an electric line that runs from an oilfield surface to the mandrel in a land well or offshore well. A fluid injection line is provided that also runs from the oilfield surface to the mandrel in a land well or offshore well. Further, a power telemetry module is coupled to the electric line. Thus, an electric actuator that is coupled to the injection line may be provided for governing fluid injection. Additionally, one or both of the module and the actuator may be secured within the mandrel housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  is a side cross-sectional view of an embodiment of a telemetric chemical injection assembly disposed in a well. 
           [0012]      FIG. 2A  is an enlarged view of an embodiment of an injection sub of the assembly of  FIG. 1  and corresponding downhole fluid flow. 
           [0013]      FIG. 2B  is an enlarged view of an alternate embodiment of an injection sub of the assembly with alternate corresponding downhole fluid flow. 
           [0014]      FIG. 3  is an overview of an oilfield employing an embodiment of the assembly of  FIG. 1  for tailored regulation of injection fluids at multiple well zones. 
           [0015]      FIG. 4A  is an alternate embodiment of the injection sub of  FIG. 2B , equipped to accommodate a secondary injection line. 
           [0016]      FIG. 4B  is another alternate embodiment of the injection sub, outfitted with multiple injection valves. 
           [0017]      FIG. 5  is a flow-chart summarizing an embodiment of employing a telemetric chemical injection assembly within a well. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    Embodiments are described with reference to certain configurations of completions hardware that make use of chemical injection assemblies. In particular, completions are depicted and described which utilize a chemical injection assembly to help prevent scale and other buildup in a manner that may be telemetrically directed. For example, different injection points in different well locations may be independently directed from an oilfield surface even though a common injection line may be utilized. Of course, a variety of different completion architectures may benefit from utilization of such an injection assembly. For example, even a system utilizing a single injection point may benefit from telemetrically directed injection. Regardless, an injection sub (or mandrel housing) is provided that is equipped to accommodate either, or both, of an actuator valve to govern injection and a power module. Thus, the valve may be directly and independently powered and controlled via telemetric and fluid injection lines running thereto from surface. 
         [0019]    Referring now to  FIG. 1 , a side cross-sectional view of an embodiment of a telemetric chemical injection assembly  100  is depicted within a well  180 . In the embodiment shown, the assembly  100  makes up a portion of completions hardware that is disposed below casing  185  and a production packer  110 . Further, the assembly  100  is positioned across multiple production regions  190 ,  195 . More specifically, a zonal isolation packer  120  is provided about a production tubular  107 . Thus, separate annular spaces  105 ,  106  adjacent the tubular  107  may be zonally isolated from one another whereas a common fluid channel  103  is defined within the tubular  107 . 
         [0020]    Zonal isolation at production regions  190 ,  195  as described above may allow for tailored recovery of production fluids. For example, the tubular  107  may be outfitted with a separate flow control valve  115 ,  116 , exposed to the isolated annular space  105 ,  106 . Thus, a hydraulic or other suitable control line  117  may be utilized to independently open or close the valves  115 ,  116 . As such, production through a slotted liner  187 , screen, perforated liner or similar hardware where utilized, at either formation region  190 ,  195  may be regulated via the open or closed valve  115 ,  116 . 
         [0021]    Continuing with reference to  FIG. 1 , each zonally isolated annular space  105 ,  106  is equipped with its own mandrel housing or injection sub  101 ,  102 . As such, a chemical injection fluid mix may be directed at each space  105 ,  106 , the liner  187  or other downhole hardware so as to impede production inhibiting buildup. In one embodiment, the mix may even be directed internally at the tubular channel  103  (see  FIG. 2B ). Regardless, while separate injection points  161 ,  163  are provided, independent control over the separate valves  160 ,  162  at each point  161 ,  163  is a different matter. That is, in the embodiment shown, the valves  160 ,  162  may be an electrically powered actuator of plunger, gas lift, solenoid valve, electric motor or other metering variety. Thus, rather than opening or closing alone, more precise delivery of chemical injection mix may be achieved. So, for example, the valves may include fully opened, fully closed and variable choke positions. 
         [0022]    Further, while it might be possible to supply each valve  160 ,  162  with its own dedicated fluid line which may be controlled from the oilfield surface  300 , this may be extremely cost prohibitive (see  FIG. 3 ). Therefore, the embodiment of  FIG. 1  reveals the use of a single injection line  150  routed to each valve  160 ,  162  in combination with a telemetric line  155  so as to more fully and practically take advantage of such tailored delivery. 
         [0023]    The telemetric line  155  of  FIG. 1  may be a conventional electric line or other suitable communication line for downhole use. In the embodiment shown, the line  155  is routed through a power telemetry module  170 ,  171  in order to supply the power for independently opening or closing each valve  160 ,  162  as directed. These modules  170 ,  171  are shown disposed within the subs  101 ,  102 . However, in other embodiments, alternative locations may be utilized. Further, such modules  170 ,  171  may be made available for sake of monitoring and communicating downhole conditions such as pressure and/or temperature. Thus, an added feature of such modules  170 ,  171  may now be to advantageously serve as a supportive platform for independent powerable control over each valve  160 ,  162  in a “smart” fashion. 
         [0024]    Referring now to  FIG. 2A , an enlarged view of an embodiment of one of the injection subs  102  of the assembly of  FIG. 1  is shown. In this depiction, fluid flow in the area is apparent. More specifically, production fluid  250  is shown moving uphole within the channel  103  of the production tubular  107  whereas injection fluid  200  is shown released from the valve  162  at the injection point  163 . So, for example, the injection fluid  200  may serve to prevent occlusive buildup at the well formation interface of the slotted liner  187  and the depicted production region  195 . Thus, when the flow control valve  116  is opened, production fluid  250  may flow substantially freely into the noted channel  103 . Further, in one embodiment, an operator or control unit  310  may ensure that the flow control valve  116  is in an open or ‘choked’ position whenever the injection valve  162  is in an open position (see  FIG. 3 ). 
         [0025]    Continuing with reference to  FIG. 2A , with added reference to  FIG. 1 , a shiftable member  216  of the flow control valve  116  may be directed to open the valve  116  by a conventional control line  117 . For example, a conventional power/data cable may be utilized. However, opening of the injection valve  162  for sake of chemical injection delivery is two-fold. That is, the valve  162  may be supplied with the noted injection fluid  200  by way of the noted injection line  150 . Further, tailored control over opening and/or the degree of opening of the valve  162  may be directed by another line (i.e. the telemetric line  155 ). While the injection and telemetry functions are split between two separate lines  150 ,  155 , this type of layout allows for the use of a single injection line  150  across multiple subs  101 ,  102 . That is, a tailored opening and/or closing of valves such as the injection valve  162  may be independently controlled. Therefore, even though only a single injection line  150  is utilized, the operator is not limited to an unintelligent injection of either all injection points  161 ,  163  open or all closed. 
         [0026]    As described above, the independent control over chemical injection delivery is directed through a telemetric line  155 . This may be a conventional electronic or other suitable cable. Once more, the line  155  may be routed from surface to a power telemetry module  171  as detailed above. That is, the module  171  may serve a function of acquiring and relaying data relative to temperature, pressure and perhaps other location-based well characteristics (note the exposed outlet to the tubular channel  103 ). However, the module  171  may also advantageously serve the added function providing power and communicative relay to the injection valve  162  (note the electrical branch  255  of the line  155  routed to the valve  162 ). Thus, independent control over the valve  162  may be exercised from the oilfield surface  300 . Indeed, with multiple modules  170 ,  171  available, this same type of telemetric layout may be repeated at multiple downhole subs  101 ,  102  (see  FIG. 1 ). As such, independent “intelligent” control over each valve  160 ,  162  by way of a single main telemetric line  155  may be provided (see  FIG. 3 ). 
         [0027]    Referring now to  FIG. 2B , an enlarged view of an alternate embodiment of the injection sub  102  is depicted. In this embodiment, the injection valve  162  and injection point  163  are reoriented so as to deliver injection fluid  200  within the channel  103  of the production tubing  107  as opposed to at the surrounding annular space  106 . For example, this may be advantageous where the sub  102  is located further uphole adjacent well casing  185 . That is, the fluid  200  may be directed at impeding buildup at internal tubular components as opposed to the slotted liner  187  as shown in  FIG. 2A . Regardless, the same intelligent, independently controllable manner of injection may be directed from the oilfield surface  300  of  FIG. 3 . 
         [0028]    Continuing now with reference to  FIG. 3 , an overview of an oilfield  300  is shown, whereat an embodiment of the assembly  100  of  FIG. 1  is disposed within a well  180 . More specifically, a more schematic view of the assembly  100  is shown allowing for tailored regulation of injection fluid  200  at different downhole production regions  190 ,  195 . More specifically, production and chemical injection are both closed off relative the more downhole region  195 . For example, where water is being produced or for any number of other reasons, a determination may be made to effectively shut off the region  195 . Nevertheless, a determination to continue recovery of production fluids from points below the region  195  may also be made. Further, and perhaps more significantly in terms of the depicted figure, a determination may similarly be made to continue recovery and chemical injection at the other region  190 . 
         [0029]    In the embodiment of  FIG. 3 , chemical injection fluid  200  is delivered in the vicinity of one region  190  so as to inhibit buildup at the slotted liner or screen or perforated liner  187  as described above. This same fluid  200  is recovered within the tubular  107  along with production fluids  250  for transport uphole. The ability of the assembly  100  to efficiently recover these fluids  200 ,  250  at one region  190  while keeping injection and recovery closed off from another region  195  is rendered practical and effective by the availability of cooperative valves  160 ,  162  and modules  170 ,  171  as detailed hereinabove (see  FIG. 1 ). Indeed, an electrically actuated plunger type valve  160 ,  162  in conjunction with a readily available power telemetry module  170 ,  171  may be particularly beneficial in allowing for the construction of such an assembly  100 . 
         [0030]    Continuing with reference to  FIG. 3 , an operator may intelligently direct chemical injection as detailed above through the use of surface equipment. More specifically, a control unit  310  may be provided for sake of directing operations, including the exercise of control over the telemetric line  155  and downhole valves as detailed above. Further, a chemical mix tank  320  may be provided for supplying of injection fluid  200  to the injection line  150 . Thus, later recovery of injection  200  and production  250  fluids may ultimately be routed through the well head  330  and a production line  340  for processing. 
         [0031]    Referring now to  FIG. 4A , an alternate embodiment of the injection sub  102  and assembly  100  of  FIG. 2B  is shown. In this embodiment, a secondary line  400  is routed to the location of the injection valve  162 . In this manner, a fluid other than the chemical injection fluid  200  may also be delivered through the valve  162 . That is, while fluid of any practical type may be directed through the injection line  150 , there may be circumstances in which different fluid types are segregated from one another. For example, an acid injection type of stimulation fluid may be delivered through the secondary line  400  at certain targeted points in time whereas the noted injection fluid  200  is delivered through the injection line  150  on a more regular or continuous basis. 
         [0032]    Keeping fluids separated from one another may be desirable where the different fluids serve different applications, for example, different chemical injection and stimulation applications as noted above. However, it is worth noting that the added secondary line  400  is not required for sake of delivery to different injection points  161 ,  163  (see  FIG. 1 ). Indeed, as depicted in  FIG. 4A , even though separate fluid types and lines  150 ,  400  are provided, the same injection point  163  is ultimately utilized. 
         [0033]    Referring now to  FIG. 4B , another alternate embodiment of the injection sub  102  is depicted. In this case, the sub  102  is outfitted with multiple injection valves  162 ,  462 ,  463  all drawing actuation from the same power telemetry module  171 . For example, note the electrical branch  255  running to the primary injection valve  162  as detailed above, as well as a secondary branch  455  splitting off to other secondary injection valves  462 ,  463 . 
         [0034]    In the embodiment of  FIG. 4B , the availability of multiple valves  162 ,  462 ,  463  allows for targeting of different delivery locations. That is, embodiments such as that depicted in  FIG. 1  reveal different subs  101 ,  102  at different depths being independently serviceable via a single injection line  150 . However, in  FIG. 4B  another embodiment is shown that reveals the possibility of also servicing different locations at roughly the same depth of the same sub  102 . More specifically, the primary injection valve  162  is shown servicing the channel  103  at the interior of the production tubular  107  similar to the configuration of  FIG. 2B . Further, the secondary valves  462 ,  463  are shown simultaneously servicing the annular space  106  similar to the configuration of  FIG. 2A . 
         [0035]    Referring now to  FIG. 5 , a flow-chart is shown summarizing an embodiment of employing a telemetric chemical injection assembly within a well. Namely, with the assembly installed as indicated at  510 , a chemical injection fluid may be selectively delivered through a line to any one of many injection points downhole (see  530 ). Subsequently, over the same line, the fluid may be delivered to another of the points as indicated at  550 . Once more, as noted at  570 , these same injection points may be serviced by a secondary line for delivery of another fluid such as an acid-based stimulation fluid. Ultimately, over the course of such fluid delivery applications, the fluids may be recovered with production up to an oilfield surface as indicated at  590 . 
         [0036]    Embodiments described hereinabove include a telemetric or “smart” chemical injection assembly which is able to provide targeted chemical injection at multiple downhole depths or locations in a tailored manner. That is, without the requirement of a multitude of individually dedicated chemical injection lines, multiple delivery locations may be independently regulated for delivery from an oilfield surface. Further, no intervening isolations are required in order to achieve such targeted or tailored delivery. Indeed, one downhole location may be opened and serviced while another remains turned off and vice versa. This may be achieved in a cost-effective manner through the use of available power telemetry modules. 
         [0037]    The preceding description has been presented with reference to presently preferred embodiments. Persons skilled in the art and technology to which these embodiments pertain will appreciate that alterations and changes in the described structures and methods of operation may be practiced without meaningfully departing from the principle, and scope of these embodiments. Regardless, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.