Abstract:
A method of providing a liner which can be rolled up on a reel for convenient transport and which can be unrolled into the bore of an oil or gas well and expanded to the approximate bore size of the casing size which the liner was run through and is collapsed in a way which allows sealing and stripping with a blowout preventer for well control protection during running and providing smooth surface support wedging without the need for marking the pipe with slip teeth.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
         [0001]    N/A  
         STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    N/A  
         INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK  
         [0003]    N/A  
         BACKGROUND OF THE INVENTION  
         [0004]    The field of this invention is that of liner hangers for the isolation of the well bore of oil and gas wells from the earth formations through which the oil or gas well is being drilled.  
           [0005]    As different producing formations which the drilled well will pass through must be isolated from each other, a casing string must be cemented in place to isolate each zone. An oil or gas well is typically drilled by first deciding the minimum bore of the production string of casing, or the last pipe to be cemented in place, and which will be continuous from the surface all the way down to the oil or gas producing formations. This production string of casing must be large enough to allow the production tubing landed inside it to flow enough oil or gas at sufficient volumes to make the well economic.  
           [0006]    Each casing set point requires that an additional concentric casing string be set. A typical set of casing strings in a subsea environment from the inside out would be 7″, 9.625″, 11.750″, 13.375″, and 16″ set within an 18.750″ bore blowout preventer stack, 20 and 30″ casing strings set before the 18.750″ bore blowout preventer stack is installed. Each casing string occupies a certain amount of radial space, requiring that the next string of pipe be progressively smaller. That program provides a maximum of 5 casing set points with blowout preventer protection during drilling.  
           [0007]    Typically, a casing string, i.e. 11.75″ outer diameter, is installed in a drill well bore suspended from the surface to a depth such as 10,000 foot depth. After cementing the 11.750″ casing in place, a hole is drilled with a bit through the 11.750″ casing, i.e. 10.50″ diameter hole to 12,000 feet deep. Into this hole a 9.625″ outside diameter casing can be landed and cemented in place. If the 9.625″ casing string is suspended from the surface and is therefore 12,000 feet long, it is called a casing string. If, however, the 9.625″ casing is only 2000′ long and is suspended by a hanger from the lower end of the 11.750″ casing string, it is called a liner. The use of a liner can save substantially on the cost of casing and cement, e.g. 10,000 feet of casing not purchased. The well program would be followed with a 7.000″ casing string continuous from the surface to the bottom of the well as the production casing string.  
           [0008]    The 9.625″ liner in the example above would have saved the operator the 10,000 feet of casing not purchased, with the cost of a conventional liner hanger being generally offset by the cost of the surface casing hanger. The liner still “costs” the drilling company the “radial space”, forcing the next string to be progressively larger.  
           [0009]    In this conventional scenario, if an unexpected pressured formation is encountered and requires that an extra casing string be set, it would probably be 5.500″ in outside diameter. With the 5.500″ size, the tubing string landed inside would be reduced from 3″ to 2″, substantially restricting the flow of production from the well. Flow from wells is especially important offshore where the high cost of drilling and producing wells demands a high flow rate to be economic. Cases have been seen of abandonment of wells when an extra pressurized reservoir zone was encountered and the driller realized that his final well bore size would be too small to be economic.  
           [0010]    Other methods, such as described in U.S. Pat. No. 6,435,281 provide for the ability to utilize liners which offer characteristics such as are listed in liners above, with the additional feature that they expand below the casing string they attach to. This means that the well bore will not be reduced a stage, making either the ultimate hole larger, or allowing one to start with a smaller string at the top. This style provides a feature that a substantial length of the liner could be rolled up on a reel and simply unrolled into the well bore for inflation. A disadvantage of this style was that during the unrolling and running operation, it was of a shape which could not be sealed on by blowout preventers to maintain well control. It depended upon having a “dead” well, or one in which the pressure head of the liquid mud column in the well bore exceeded the formation pressures. This can be of particular advantage when an actual application of the liner is to seal off an unexpected pressure zone in the formations.  
         SUMMARY OF THE INVENTION  
         [0011]    The object of this invention is to provide a liner which does not occupy “radial space” in the well bore and therefore does not force each previously set casing hanger to be a step larger in diameter.  
           [0012]    A second object of the present invention is to provide the capability of installing multiple liners in a drilling program to compensate for unforeseen well control situations.  
           [0013]    A third object of the present invention is to provide a liner that can be rolled up for compact storage and shipment.  
           [0014]    Another object of the present invention is to provide a liner assembly that is compact enough to be airlifted out to an offshore drilling vessel.  
           [0015]    Another object of the present invention is to provide an expandable liner that is metallic in construction and impervious to fluid flow.  
           [0016]    Another object of the present invention is to provide an expandable liner which can be sealed upon with a blowout preventer to provide well control during the running operations.  
           [0017]    Another object of the present invention is to provide an expandable liner which can be supported by smooth face wedge slips which eliminate the need for marking the liner with sharp slip teeth. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    [0018]FIG. 1 is a section through the oil or gas well with a liner of the present invention unrolled into the well.  
         [0019]    [0019]FIG. 2 is a section through the oil or gas well which eliminates the blowout preventer equipment of FIG. 1 to allow for easier viewing.  
         [0020]    [0020]FIG. 3 is a section through the oil or gas well showing the liner inflated.  
         [0021]    [0021]FIG. 4 is a section through the oil or gas well showing the expander in the running tool expanded.  
         [0022]    [0022]FIG. 5 is a section through the oil or gas well showing that the running tool has been removed and a rolling expander approaching the top of the liner.  
         [0023]    [0023]FIG. 6 is a section through the oil or gas well showing the rolling expander has expanded the liner and the lower section of the casing.  
         [0024]    [0024]FIG. 7 is a section through the lower end of the expandable liner.  
         [0025]    [0025]FIG. 8 is a section through the oil or gas well along lines “ 8 - 8 ” of FIG. 2  
         [0026]    [0026]FIG. 9 is a section through a blowout preventer as shown in FIG. 1 showing the rams sealing on the liner as it is being run.  
         [0027]    [0027]FIG. 10 is a section through a portion of reeled liner showing the stacking method.  
         [0028]    [0028]FIG. 11 is a section through the support slip assembly taken along lines “ 11 - 11 ” of FIG. 14.  
         [0029]    [0029]FIG. 12 is an end view of a reel holding the liner of this invention.  
         [0030]    [0030]FIG. 13 is a side view of a reel holding the liner of this invention and sitting on a skid to assist in the deployment of the liner into a well bore.  
         [0031]    [0031]FIG. 14 is a side view of a reel holding the liner of this invention with the liner being deployed thru a slip assembly and into the well bore. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0032]    Referring now to FIG. 1, the collapsed liner  2  is shown in a bore  4  in the formations  6  and is supported by a running tool  8 . The running tool  8  is supported by a running string  10  which is inside a casing string  12 , which is supported by a casing hanger  14  inside a housing  16 . A connector  18  is attached to housing  16  and supports two ram type blowout preventers  20  and  22 , an annular type blowout preventer  24 , and a flex joint  26 . Riser  28  extends to the surface on a subsea well, but would not exist on a land well.  
         [0033]    Referring now to FIG. 2, an enlarged view is shown of a portion of FIG. 1 for clarity.  
         [0034]    Referring now to FIG. 3, area  50  shows that pressure has been pumped down running string to inflate the liner and to push the central portion  52  of the shoe  54  to shear a pin. After inflation, spring  56  pushes the central portion  52  up to allow an opening through the shoe  54 . This allows cement to be circulated down to cement the lower portion of the liner in place.  
         [0035]    Referring now to FIG. 4, a sealing dart  60  is dropped into the running tool  8  and the running string  10  is pressured to inflate the rubber element  62  to expand the portion of the liner  64 . As the liner is of a relatively soft metal, it will be yielded into the casing string and will retain contact with the casing string when the pressure is removed.  
         [0036]    Referring now to FIG. 5, the running tool  8  (from FIG. 4) is removed by right hand rotation and a rolling expander  70  is approaching the top of the liner. As the eccentric rolls  72 ,  74 ,  76 , and  78  on the rolling expander  70  move into the top of the liner with a rotary motion, the non-expanded portions of the liner are expanded to the I.D. of the casing string.  
         [0037]    Referring now to FIG. 6, a fully opened well bore is shown ready to be drilled out. The casing shoe  54  will be drilled up as drilling proceeds.  
         [0038]    Referring now to FIG. 7, a section of the casing shoe is shown, with the collapsed liner  2  at the top going into a transition section  80 . Central portion  52  is supported by shear pin  82  and is sealed by seal  84 . During the initial pressure cycle of inflating the liner, the shear pin  82  is sheared and the central portion  52  moves down to land on shoulder  86 . After the pressure of inflation is removed, the spring  56  pushes the central portion out and allows cement to be passed through the shoe to the annular area outside of the now inflated liner.  
         [0039]    Referring now to FIG. 8, a cross section of the collapsed liner  2  of this invention is shown with various bends to make the rolling of the liner on a reel practical. Circle  90  shows the internal diameter of the casing being run through and circle  92  shows the external diameter of the casing. Circle  94  shows the internal diameter of the liner after it is expanded and circle  96  shows the external diameter of the liner after it is expanded.  
         [0040]    Referring now to FIG. 9, the liner of this invention is shown going through the bore  100  of a ram type blowout preventer with blowout preventer ram  102  having front personality  104  to engage one side of the liner and blowout preventer ram  106  having a front personality  108  to engage the opposite side of the liner. It should be noted that the entire external surface of the liner  2  is engaged by seals on the relative faces of the blowout preventer rams to allow for full well protection during the running operations except for a couple of feet at each end. The interface  110  between the blowout preventer rams shows the parts of the rams which separate to allow full passage of components.  
         [0041]    Referring now to FIG. 10, several sections of the liner are engaged as they would be when rolled layer on layer on a reel, as will be discussed in later figures.  
         [0042]    Referring now to FIG. 11, a section through a support slip assembly as will be seen in FIG. 14 is shown. Slip segment  120  engages the collapsed liner  2  with personality  122  which matches the collapsed liner on one side. The back  124  of slip segment  120  engages surface  126  of bowl half  128 . Likewise, slip segment  130  engages the collapsed liner  2  with personality  132  which matches the collapsed liner on one side. The back  134  of slip segment  130  engages surface  136  of bowl half  138 . As the bowl surfaces  126  and  136  of conventional slip assemblies are normally tapered at angles from 8 degrees to 15 degrees with respect to vertical, the contact between the front personalities  122  and  132  require sharp teeth to effectively increase the coefficient of friction and ensure support of the pipe being supported. In this case, the angles of the personality  122  and  132  of the front of the slip segments  120  and  130  tend to wedge or amplify the force in comparison to the forces on the backs of the slip segments. Due to this amplification, a smooth surface can be utilized on the personalities  122  and  132  to eliminate cutting and stress concentrations on the collapsed liner.  
         [0043]    Referring now to FIG. 12, a roll  150  of the liner  2  is shown. Shoe  54  is shown on the free end of the roll and running tool  8  is shown on the first end of the liner which was wrapped on the reel, and is offset to make the reeling practical. Motor  152  is provided to drive chain  154  and the reel of liner through appropriate sprockets. Frame  156  supports the liner for transportation.  
         [0044]    Referring now to FIG. 13, a side view of the roll of liner  150  is shown within frame  156 . Subframe  160  is shown with cylinder  162  which can move the frame  156 . Subframe  160  is setting on the drilling rig floor  164  in the area of the rotary table  166 .  
         [0045]    Referring now to FIG. 14, liner  2  is shown being lowered into the well bore through slip assembly  170 . As liner  2  is reeled off the roll of liner  150  and the radius of the liner on the reel is reduced, cylinder  162  is used to keep the liner  2  centralized in the well bore. As running tool  8  is in the final rotation and moves to the vertical position, the slip assembly  170  is set to support the liner. Frame  156  and subframe  160  are removed and a running string is added to the top of the liner  2 . At this time the liner  2  is run as shown in FIGS. 2 through 6.  
         [0046]    Other applications of this expandable pipe concept exist, such as sending a liner into a leaking water pipe to reestablish the pressure competence of the pipe or to seal a bare hole which has no other pipe associated with the hole.  
         [0047]    The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.  
       SEQUENCE LISTING  
       [0048]    N/A