Abstract:
The invention is related in general to wellbore-telemetry technology. In particular, the invention relates to improved equipment and methods for deploying line in a wellbore. A continuous line is dispensed from two apparatuses. One apparatus is attached to a device such as a wiper plug that travels through a tubular body such as casing. The other apparatus is fixed either inside or outside a wellhead. As a process fluid is pumped into the tubular body, forcing the first apparatus and the device through the tubular body, line may unfurl from the first apparatus, the second apparatus, or both. In this way, stress on the line during deployment is minimized.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
         [0002]    The invention is related in general to wellbore-telemetry technology. In particular, the invention relates to improved equipment and methods for deploying line in a wellbore. Those skilled in the art will appreciate that the term “line” is applicable to fiber, wire, rope and the like. In addition, a line may comprise one or more strands of material. 
         [0003]    In recent years, the deployment of fiber lines in subterranean wellbores has become increasingly frequent. The most common application is to install optical fiber as a conduit through which various downhole measurements may be performed. Such measurements include temperature, pressure, pH, density, resistivity, conductivity, salinity, carbon dioxide concentration, asphalene concentration, etc. Today, optical fiber technologies may be employed throughout the lifetime of a well—drilling, completion, stimulation, production surveillance and even after abandonment. 
         [0004]    Optical fibers are deployed in several ways. For example, the fiber line may be preinstalled in equipment and tools and lowered into the well, it may be pumped downhole such that it unfurls as it follows the fluid down the well, and it may be lowered into the wellbore in the same manner as wireline. It might be desirable to perform some of the aforementioned measurements during well cementing operations. 
         [0005]    After a well is drilled, the conventional practice in the oil and gas industry consists of lining the well with a metal casing. An annular area is thus formed between the casing and the subterranean formation. A cementing operation is then conducted with the goal of filling the annular area with cement slurry. After the cement sets, the combination of casing and set cement strengthens the wellbore and provides hydraulic isolation between producing zones through which the well penetrates. 
         [0006]    It is common to employ more than one string of casing in the wellbore. In this respect, a first string of casing is set in the wellbore when the well is drilled to a first designated depth. The first string of casing is hung from the surface, and then cement is circulated into the annulus behind the casing. The well is then drilled to a second designated depth, and a second string of casing, or a liner, is run into the well. The second string is set at a depth such that the upper portion of the second string of casing overlaps the lower portion of the first string of casing. The second liner string is then fixed or hung off of the existing casing. Afterwards, the second casing string is also cemented. This process is typically repeated with additional liner strings until the well has been drilled to total depth. In this manner, wells are typically formed with two or more strings of casing of an ever-decreasing diameter. 
         [0007]    The well cementing process typically involves the use of wiper plugs. Wiper plugs are elongated elastomeric bodies that are used to separate fluids as they travel through the casing interior. This practice prevents performance difficulties that may occur if the various fluids commingle. Usually the cementing operation requires two wiper plugs. When the cement slurry is ready to be dispensed, a first plug is released into the casing. The cement slurry is pumped behind the plug, thereby moving the plug downhole. At the bottom of the casing string, the first plug seats against a float valve, thereby closing off flow through the float valve. Hydraulic pressure builds above the first plug until it is sufficient to cause a membrane in the first plug to rupture. Thereafter, cement slurry flows through the first plug and the float valve, and up into the annular space between the wellbore and the casing string. 
         [0008]    After a sufficient amount of cement slurry has been placed into the wellbore, a second wiper plug is deployed. A displacement fluid is pumped behind the second plug to move the second plug down the casing string, whereupon it lands upon the first plug. Unlike the first plug, the second plug does not have a membrane; therefore, the second plug seals the interior of the casing from the annular space between the wellbore and the casing string. 
         [0009]    In this application, fluids such as drilling fluid, cement slurry, spacer fluid, chemical wash, displacement fluid, acidizing fluid, completion fluid, fracturing fluid and gravel-pack fluid will be referred to as “process fluid.” 
         [0010]    A thorough discussion of the primary cementing process may be found in the following publication: Piot B. and Cuvillier G.: “Primary Cementing,” in Nelson E. B. and Guillot D. (eds.):  Well Cementing -2 nd  Edition, Houston: Schlumberger (2006): 459-501. 
         [0011]    Optical fiber line may be deployed during primary cementing by attaching it to a wiper plug. A number of methods have been described. One method involves a spool of fiber line, with one end of the fiber connected to the wiper plug. The spool remains at the top of the well, either inside or outside the wellhead. The spool dispenses fiber line as the wiper plug travels through the casing string. A second method attaches the fiber-line spool to the wiper plug, with one end of the fiber attached to the wellhead. The spool unfurls fiber as the plug travels through the casing string. 
         [0012]    Both methods described above pose difficulties. If the fiber line is fixed at the top of the well, fluids pumped into the well at the wellhead may exert a drag force that can break the fiber. The drag force may be exacerbated by the high velocity of fluids falling in vacuum inside the casing due to for example a U-tubing effect. If the fiber is fixed on the wiper plug and deployed from surface, the fiber may touch the interior casing surface and break, or it may not have sufficient tensile strength to withstand high plug velocities. These problems are magnified as the length of the casing string increases. 
         [0013]    It remains desirable to develop equipment and methods by which fiber line, as well as other types of line, may be deployed more reliably. 
       SUMMARY OF THE INVENTION 
       [0014]    The present invention solves the problems mentioned herein. 
         [0015]    The first aspect of the invention is a system for deploying line in a subterranean wellbore. It preferably comprises three principal elements. The first element is a device that travels down a tubular body inside the subterranean wellbore. In the present application, the first element is presented as a wiper plug; however, those skilled in the art will appreciate that other devices such as sondes, darts, balls, canisters, bombs and the like would be equally appropriate. The second element is a first apparatus for dispensing line, comprising a first reel of line. The line is preferably attached to the wiper plug, and is able to be unwound from the first reel of the first apparatus as process fluid is pumped into the tubular body and the wiper plug travels through the tubular body. The third element is a second apparatus for dispensing line, comprising a second reel of line. The line wound around both the first and second apparatuses is preferably one continuous line. The second apparatus is installed at a location away from the device; however, line from the second reel may also be unwound as the device travels through the tubular body. In this way, stress on the line is minimized during deployment. Those skilled in the art will recognize that the line may comprise a bundle of individual strands, each strand having the ability to operate independently. For example, one or more strands may transmit measurement data, while other strands may transmit power to operate devices located downhole. 
         [0016]    The first aspect of the invention comprises two embodiments. In one embodiment, both the first and second apparatuses for dispensing line are located inside a wellhead and tubular body. The first apparatus is attached to the wiper plug, and the second apparatus is fixed inside the wellhead such that the line may be unfurled from the first apparatus, the second apparatus or both as the wiper plug travels through the tubular body. In another embodiment, the first apparatus is attached to the wiper plug, and the second apparatus is located outside the wellhead. Line preferably passes from the first apparatus, through a hollow tube that extends from inside the wellhead to the outside, and then to the second apparatus. 
         [0017]    In both of the above embodiments, the wiper plug may contain a chemical substance that may be released at some point during its displacement through the tubular body. 
         [0018]    In both of the above embodiments, one or more instruments may be attached to the wiper plug, the instruments measuring one or more parameters in the list comprising: temperature, pressure, distance, pH, density, resistivity, conductivity, salinity, carbon dioxide concentration and asphaltene concentration. 
         [0019]    The second aspect of the invention is a method for deploying line in a subterranean wellbore. The method comprises several steps. First, a continuous line is selected. The line may comprise one or more individual strands, each strand having the ability to operate independently. Second, a portion of the line is wound around a first reel in a first apparatus for dispensing line. Next, the other portion of the line is wound around a second reel in a second apparatus for dispensing line. The first apparatus is attached to a wiper plug that travels through a tubular body, and the combination is inserted into the tubular body connected to a wellhead. The second apparatus is fixed inside the wellhead such that the first apparatus may travel away in the tubular body when the wiper plug is released. Process fluid is pumped into the wellhead, releasing the wiper plug and forcing the wiper plug to begin traveling through the tubular body. Continued pumping of process fluid allows the line to unwind from the first apparatus, the second apparatus or both as the wiper plug travels through the tubular body. The line-deployment process is complete when the wiper plug lands on float equipment at the end of the tubular body. 
         [0020]    The third aspect of the invention is a method for deploying line in a subterranean wellbore. The method comprises several steps. First, a continuous line is selected. The line may comprise one or more individual strands, each strand having the ability to operate independently. Second, a portion of the line is wound around a first reel in a first apparatus for dispensing line. Third, the other end of the line is threaded through a hollow tube that extends from the inside of a wellhead to the outside. Third, after passing through a hollow tube, the other portion of line is wound around a second reel in a second apparatus for dispensing line. The second apparatus is located outside the wellhead. The first apparatus is then attached to a wiper plug that travels through a tubular body, and the combination is inserted into the tubular body connected to the wellhead. Process fluid is pumped into the wellhead, releasing the wiper plug and forcing the wiper plug to begin traveling through the tubular body. Continued pumping of process fluid allows the line to unwind from the first apparatus, the second apparatus or both as the wiper plug travels through the tubular body. The line-deployment process is complete when the wiper plug lands on float equipment at the end of the tubular body. 
         [0021]    In all aspects of the invention, process fluid may comprise (but not be limited to) drilling fluid, cement slurry, spacer fluid, chemical wash, completion fluid, acidizing fluid, fracturing fluid, gravel-pack fluid and displacement fluid. 
         [0022]    In both the second and third aspects of the invention, the first element may contain a chemical substance that may be released at some point during its displacement through the tubular body. 
         [0023]    In both the second and third aspects of the invention, the first element may contain one or more instruments that measure one or more parameters in the list comprising: temperature, pressure, distance, pH, density, resistivity, conductivity, salinity, carbon dioxide concentration and asphaltene concentration. 
         [0024]    In all aspects of the invention, the line may comprise an electrical conductor, allowing the line to supply power to downhole devices that deliver energy in the form of one or more in the list comprising: electricity, heat, acoustic waves, magnetic fields, microwaves, gamma rays, x-rays and neutrons. 
         [0025]    In all aspects of the invention, the line may comprise one or more strands, each strand able to operate independently. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0026]      FIG. 1  is an illustration of an embodiment of the invention, wherein the first and second line dispensing apparatuses are located inside the wellhead and tubular body. 
           [0027]      FIG. 2  is an illustration of an embodiment of the invention, wherein the first line dispensing apparatus is located inside the wellhead and tubular body, and the second line dispensing apparatus is located outside the wellhead. 
       
    
    
     DETAILED DESCRIPTION 
       [0028]    The invention may be described in terms of treatment of vertical wells, but is equally applicable to wells of any orientation. The invention may be described for hydrocarbon production wells, but it is to be understood that the invention may be used for wells for production of other fluids, such as water or carbon dioxide or, for example, for injection or storage wells. This invention may be described for offshore and land wells. It should also be understood that throughout this specification, when a concentration or amount range is described as being useful, or suitable, or the like, it is intended that any and every concentration or amount within the range, including the end points, is to be considered as having been stated. Furthermore, each numerical value should be read once as modified by the term “about” (unless already expressly so modified) and then read again as not to be so modified unless otherwise stated in context. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. In other words, when a certain range is expressed, even if only a few specific data points are explicitly identified or referred to within the range, or even when no data points are referred to within the range, it is to be understood that the inventor appreciates and understands that any and all data points within the range are to be considered to have been specified, and that the inventor has possession of the entire range and all points within the range. 
         [0029]    The first aspect of the invention is a system for deploying line in a subterranean wellbore. There are preferably three principal elements. The first element is a device that travels down a tubular body inside the subterranean wellbore. In this application, the first element is presented as a wiper plug; however, those skilled in the art will appreciate that other devices such as sondes, darts, balls, canisters, bombs and the like would be equally appropriate. The second element is a first apparatus for dispensing line, comprising a first reel of line. The line is attached to the wiper plug, and is able to be unwound from the first reel of the first apparatus as the wiper plug travels through the tubular body. The third element is a second apparatus for dispensing line, comprising a second reel of line. The line wound around both the first and second apparatuses is one continuous line. The second apparatus is installed at a location away from the device; however, line from the second reel may also be unwound as the device travels through the tubular body. In this way, stress on the line is minimized during deployment. Those skilled in the art will recognize that the line may comprise a bundle of individual strands, each strand having the ability to operate independently. For example, one or more strands may transmit measurement data, while other strands may transmit power to operate devices located downhole. 
         [0030]    One embodiment of the first aspect of the invention is shown in  FIG. 1 . The first element, in this case a wiper plug  1 , is installed in a tubular body  2 . The second element, a first apparatus  3  for dispensing line, is attached to the wiper plug  1 . The line  4  is continuous between the first device  3  and the third element—the second apparatus  5  for dispensing line. In this embodiment, the third element is fixed inside a wellhead  6 . As process fluid  7  is pumped into the wellhead, the wiper plug  1  and second element  3  travel through the tubular body  2 , away from the third element. Each dispensing device ( 3  and  5 ) may deploy line simultaneously as the wiper plug  1  travels through the tubular body; therefore, because the path of least resistance will be followed, stress on the line during deployment is minimized. 
         [0031]    Another embodiment of the first aspect of the invention is shown in  FIG. 2 . The first element, in the case a wiper plug  1 , is installed in a tubular body  2 . The second element, the first device  3  for dispensing line, is attached to the wiper plug  1 . The line  4  is continuous between the first device  3  and the third element—the second apparatus  5  for dispensing line. In this embodiment, the third element is located outside a wellhead  6 . The line  4  extends from the first apparatus  3 , through a hollow tube  8  located between the first and second apparatus, and continues into the second apparatus  5 . As process fluid  7  is pumped into the wellhead, the wiper plug  1  and second element  3  travel through the tubular body  2 , away from the third element. Each dispensing device ( 3  and  5 ) may deploy line simultaneously as the wiper plug  1  travels through the tubular body; therefore, because the path of least resistance will be followed, stress on the line during deployment is minimized. 
         [0032]    In both of the above embodiments, process fluid  7  may comprise (but not be limited to) drilling fluid, cement slurry, spacer fluid, chemical wash, completion fluid, acidizing fluid, fracturing fluid, gravel-pack fluid and displacement fluid. 
         [0033]    In both of the above embodiments, the wiper plug  1  may contain a chemical substance that may be released at some point during its displacement through the tubular body  2 . 
         [0034]    In both of the above embodiments, one or more instruments may be attached to the wiper plug  1 , the instruments measuring one or more parameters in the list comprising: temperature, pressure, distance, pH, density, resistivity, conductivity, salinity, carbon dioxide concentration and asphaltene concentration. 
         [0035]    In both of the above embodiments, the line  4  may comprise an electrical conductor, allowing the line to supply power to downhole devices that deliver energy in the form of one or more in the list comprising: electricity, heat, acoustic waves, magnetic fields, microwaves, gamma rays, x-rays and neutrons. 
         [0036]    In both of the above embodiments, the line  4  may comprise one or more strands, each strand able to operate independently. 
         [0037]    The second aspect of the invention is a method for deploying line in a subterranean wellbore. Referring to  FIG. 1 , the method comprises several steps. First, a continuous line  4  is selected. The line may comprise one or more individual strands, each strand having the ability to operate independently. Second, a portion of the line is wound around a first reel in a first apparatus  3  for dispensing line. Next, the other portion of the line is wound around a second reel in a second apparatus  5  for dispensing line. The first apparatus  3  is attached to a wiper plug  1  that travels through a tubular body  2 , and the combination is inserted into the tubular body  2  connected to a wellhead  6 . The second apparatus  5  is fixed inside the wellhead  6  such that the first apparatus  3  may travel away in the tubular body  2  when the wiper plug  1  is released. Process fluid  7  is pumped into the wellhead  6 , releasing the wiper plug  1  and forcing the wiper plug to begin traveling through the tubular body  2 . Continued pumping of process fluid  7  allows the line  4  to unwind from the first apparatus  3 , the second apparatus  5  or both as the wiper plug  1  travels through the tubular body  2 . The line-deployment process is complete when the wiper plug  1  lands on float equipment at the end of the tubular body  2 . 
         [0038]    The third aspect of the invention is a method for deploying line in a subterranean wellbore. Referring to  FIG. 2 , the method comprises several steps. First, a continuous line  4  is selected. The line may comprise one or more individual strands, each strand having the ability to operate independently. Second, a portion of the line is wound around a first reel in a first apparatus  3  for dispensing line. Third, the other end of the line  4  is threaded through a hollow tube  8  that extends preferably from the inside of a wellhead  6  to the outside. Third, after passing through the hollow tube  8 , the other portion of line is wound around a second reel in a second apparatus  5  for dispensing line. The second apparatus  5  is located outside the wellhead  6 . The first apparatus  3  is then attached to a wiper plug  1  that travels through a tubular body  2 , and the combination is inserted into the tubular body  2  connected to the wellhead  6 . Process fluid  7  is pumped into the wellhead  6 , releasing the wiper plug  1  and forcing the wiper plug to begin traveling through the tubular body  2 . Continued pumping of process fluid  7  allows the line  4  to unwind from the first apparatus  3 , the second apparatus  5  or both as the wiper plug  1  travels through the tubular body  2 . The line-deployment process is complete when the wiper plug  1  lands on float equipment at the end of the tubular body  2 . 
         [0039]    In both the second and third aspects of the invention, process fluid  7  may comprise (but not be limited to) drilling fluid, cement slurry, spacer fluid, chemical wash, completion fluid, acidizing fluid, fracturing fluid, gravel-pack fluid and displacement fluid. 
         [0040]    In both the second and third aspects of the invention, the first element  1  may contain a chemical substance that may be released at some point during its displacement through the tubular body  2 . 
         [0041]    In both the second and third aspects of the invention, the first element  1  may contain one or more instruments that measure one or more parameters in the list comprising: temperature, pressure, distance, pH, density, resistivity, conductivity, salinity, carbon dioxide concentration and asphaltene concentration. 
         [0042]    In both the second and third aspects of the invention, the line  4  may comprise an electrical conductor, allowing the line to supply power to downhole devices that deliver energy in the form of one or more in the list comprising: electricity, heat, acoustic waves, magnetic fields, microwaves, gamma rays, x-rays and neutrons. 
         [0043]    In both the second and third aspects of the invention, the line  4  may comprise one or more strands, each strand able to operate independently. 
         [0044]    The preceding description has been presented with reference to presently preferred embodiments of the invention. Persons skilled in the art and technology to which this invention pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, and scope of this invention. Accordingly, 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.