Patent Publication Number: US-2022213757-A1

Title: Blowout preventer with multiple application ram blades

Description:
CONTINUATION STATEMENT 
     This application claims priority to U.S. Provisional Application Ser. No. 62/836,699, filed Apr. 21, 2019. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to the field of drilling wells. More particularly, the invention concerns blowout preventers (BOPS) for shearing tubing string or tools and sealing wellbores. 
     BACKGROUND 
     This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. 
     Blowout preventers (BOPS) are used extensively throughout the oil and gas industry. Typical blowout preventers are used as a large specialized valve or similar mechanical device that seal, control, and monitor oil and gas wells. The two categories of blowout preventers that are most prevalent are ram blowout preventers and annular blowout preventers. Blowout preventer stacks frequently utilize both types, typically with at least one annular blowout preventer stacked above several ram blowout preventers. The ram units in ram blowout preventers allow for both the shearing of the drill pipe and the sealing of the blowout preventer. Typically, a blowout preventer stack may be secured to a wellhead and may provide a safe means for sealing the well in the event of a system failure. 
     In order to meet consumer and industrial demand for natural resources, companies invest significant amounts of time and money in finding and extracting oil, natural gas, and other subterranean resources from the earth. Particularly, once a desired subterranean resource such as oil or natural gas is discovered, drilling and production systems are employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly through which the resource is extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, fluid conduits, and the like, that control drilling or extraction operations. 
     More particularly, wellhead assemblies often include a blowout preventer to control pressure at the top of a well and prevent flow of formation fluids through the blowout preventer. Among the various types of blowout preventers, a shear ram blowout preventer achieves pressure control through the operation of rams (operated hydraulically or electrically) capable of shearing a tubular contained within a main bore of the blowout preventer (e.g., drill pipe, a liner, or a casing string). The rams are grouped in opposing pairs and are forced together as a result of the hydraulic or electric operation. Often, the rams are driven into and out of a main bore of a blowout preventer by operating pistons coupled to the ram blocks by connecting rods. 
     In a typical blowout preventer, a ram bonnet assembly may be bolted to the main body using a number of high tensile bolts or studs. These bolts are required to hold the bonnet in position to enable the sealing arrangements to work effectively. Typically an elastomeric sealing element is used between the ram bonnet and the main body. There are several configurations, but essentially they are all directed to preventing a leakage bypass between the mating faces of the ram bonnet and the main body. 
     During normal operation, the blowout preventers may be subject to pressures up to 20,000 psi, or even higher. To be able to operate against and to contain fluids at such pressures, blowout preventers are becoming larger and stronger. Blowout preventer stacks, including related devices, 30 feet or more in height are increasingly common. 
     As noted above, ram-type blowout preventers may be designed and constructed for use with drill pipe or other tubulars of specified diameter. A blowout preventer stack including rams for one size of pipe may be used with pipe of a different size by changing the pipe engaging rams or parts of the rams. Also, the ram operating mechanisms in a blowout preventer are comparatively complex and require inspection and servicing before the blowout preventer is put into service at a wellhead. Such activities, when performed in a large modern blowout preventer stack, may require the presence of personnel at locations that can be hazardous, if not impractical. 
     A blowout preventer may be used for shearing a tubular positioned in a bore extending through the blowout preventer, as disclosed in US2016/0258238, incorporated herein by reference in its entirety. The blowout preventer includes a first shear ram movable towards the tubular, the first shear ram including a first blade, and the first blade including an outer cutting profile and an inner cutting profile. The blowout preventer further includes a second shear ram positioned opposite the first shear ram with respect to the tubular and movable towards the tubular, the second shear ram including a second blade, and the second blade including the outer cutting profile and the inner cutting profile. The outer cutting profile includes blade portions on opposite sides of the inner cutting profile, and positioned between an angle of about 120 degrees and an angle of about 140 degrees from each other. 
     U.S. Pat. No. 4,537,250 discloses a ram-type shearing apparatus for a wellhead having a body with a vertical bore therethrough and aligned opposed ram guideways extending outward in the body from the bore, a ram assembly in each of the guideways, each of the ram assemblies having a ram body with a shearing blade on the face of the ram and means for moving the ram inward and outward in the guideway, the cutting edge of the upper shear blade and the face of the ram assembly below the upper shear blade being concave to support the string during shearing sufficiently to constrain the string below the upper shear blade as it is sheared to a shape suitable for receiving an overshot type of retrieving tool and to allow flow therein, the lower shear blade having at least one node extending toward the upper shear blade so that when a pipe is being sheared the node engages and penetrates the pipe prior to other shearing of the pipe to thereby reduce the force used for such shearing. 
     A unitary blade seal for a shearing blind ram of a ram-type blowout preventer is disclosed in U.S. Pat. No. 7,354,026. The blade seal includes an elongate member having a generally semi-circular cross section with a curved upper surface and a lower surface. The lower surface has a pair of laterally extending sides that taper outwardly and have a metal outer cap bonded thereto. The metal outer caps form an acute angle that engages a complementary groove formed in the upper ram of the shearing blind ram assembly. 
     Over the past decade the drilling market has experienced an increase in governmental regulation and operational challenges that have impacted the requirements of drilling safety equipment. To meet these requirements operators and contractors have placed an increased focus on pressure controlling equipment and the enhancement of its capabilities. One such desired enhancement is the increased shear and seal capacity of shear rams. 
     During drilling activities contractors are limited in what they can shear based on the shear capacity of their deployed shear rams. This requires drillers to keep track of what is in front of their shear ram blades to successfully ensure a shear in the event of an emergency disconnect situation. 
     The increased competitive nature of the energy industry has driven the need for more efficient and capable blowout preventer designs within the drilling and completions industry. 
     SUMMARY 
     In accordance with the teachings of the present disclosure, the invention greatly enhances the shear capability of the shearing pressure control equipment (shear ram) utilized inside of drilling blow out preventers. The invention enhances the shear effectiveness of a shear ram&#39;s leading edge by reducing its contact area with an opposing pipe. The design incorporates a rounded edge terminating in two symmetric angles above and below the rounded point of contact with the pipe. This “bull nose” design allows the leading contour to dig into the pipe and impart a ripping action throughout the contact plane by placing the tubular into tension at the point of contact. Further, the symmetric angles ensure no bending is incorporated onto the blade edge as the vertical component of the reaction force of the pipe is equalized with the other symmetric angle. 
     One aspect of the invention is a blowout preventer for shearing structures positioned in a bore extending through the blowout preventer, the blowout preventer comprising: a body having a bore, a first guideway, and a second guideway; a first ram movably positioned relative the first guideway and movable toward the bore, the first ram comprising a first blade, the first blade comprising: a blunt leading contour, at least one upper inclined surface above the blunt leading contour, and at least one lower declined surface below the blunt leading contour, wherein the first blade is positioned and is movable above a first plane; a second ram movably positioned relative to the second guideway and movable toward the bore, the second ram comprising a second blade, the second blade comprising: a leading contour, and at least one lower declined surface, wherein the second blade is positioned and is movable below the first plane, wherein the blunt leading contour of the first blade is movable in a second plane, the first and second planes are parallel, and the at least one lower declined surface of the first blade is between the first and second planes. 
     According to one aspect of the invention, there is provided a ram blade of a blowout preventer for shearing structures positioned in a bore extending through the blowout preventer, the ram blade comprising: at least one flat side; a blunt leading contour at a distal end of the ram blade, at least one upper inclined surface above the blunt leading contour, wherein the at least one upper inclined surface forms an angle between about 120 and 160 degrees with the flat side, and at least one lower declined surface below the blunt leading contour, wherein the at least one lower declined surface forms an angle between about 60 and 100 degrees with the at least one upper inclined surface. 
     A further aspect of the invention provides a blowout preventer for shearing structures positioned in a bore extending through the blowout preventer, the blowout preventer comprising: a body having a bore, a first guideway, and a second guideway; a first ram movably positioned relative the first guideway and movable toward the bore, the first ram comprising a first blade, the first blade comprising: at least one flat side; a blunt leading contour, at least one upper inclined surface above the blunt leading contour, wherein the at least one upper inclined surface forms an angle between about 120 and 160 degrees with the flat side, and at least one lower declined surface below the blunt leading contour, wherein the at least one lower declined surface forms an angle between about 60 and 100 degrees with the at least one upper inclined surface; a second ram movably positioned relative to the second guideway and movable toward the bore, the second ram comprising a second blade, the second blade comprising: at least one flat side, a leading contour, and at least one lower declined surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present embodiments may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features. 
         FIG. 1A  illustrates a cross-sectional side view of a blowout preventer, wherein the rams are in an open position. 
         FIG. 1B  shows a cross-sectional top view of the blowout preventer shown in  FIG. 1A . 
         FIG. 1C  illustrates a cross-sectional side view of the blowout preventer shown in  FIGS. 1A-1B , wherein the rams are in a shearing or ripping position. 
         FIG. 1D  shows a perspective view of a blowout preventer body. 
         FIG. 2A  illustrates perspective views of first and second rams. 
         FIG. 2B  shows top views of the first and second rams of  FIG. 2A . 
         FIG. 3A  shows a top perspective view of a first ram. 
         FIG. 3B  illustrates a bottom perspective view of the first ram shown in  FIG. 3A . 
         FIG. 3C  shows a front view of the first ram shown in  FIGS. 3A-3B . 
         FIG. 3D  illustrates a top view of the first ram shown in  FIGS. 3A-3C . 
         FIG. 3E  shows a bottom view of the first ram shown in  FIGS. 3A-3D . 
         FIG. 3F  shows a side view of the first ram shown in  FIGS. 3A-3E . 
         FIG. 4A  shows a top perspective view of a second ram. 
         FIG. 4B  illustrates a bottom perspective view of the second ram shown in  FIG. 4A . 
         FIG. 4C  shows a front view of the second ram shown in  FIGS. 4A-4B . 
         FIG. 4D  illustrates a bottom view of the second ram shown in  FIGS. 4A-4C . 
         FIG. 4E  shows a top view of the second ram shown in  FIGS. 4A-4D . 
         FIG. 4F  shows a side view of the second ram shown in  FIGS. 4A-4E . 
         FIG. 4G  shows a side view of a portion of a blade of the second ram shown in  FIGS. 4A-4F . 
         FIG. 5A  illustrates a side view of first and second blades initially engaging a tubular in a blowout preventer. 
         FIG. 5B  shows a side view of the first and second blades of  FIG. 5A  fully engaging to shear or rip the tubular. 
         FIG. 6A  illustrates a side view of first and second blades initially engaging a wire in a blowout preventer. 
         FIG. 6B  shows a side view of the first and second blades of  FIG. 5A  fully engaging to cut the wireline. 
         FIG. 7A  illustrates perspective views of first and second rams. 
         FIG. 7B  shows top views of the first and second rams of  FIG. 7A . 
         FIG. 8A  shows a top perspective view of a first ram. 
         FIG. 8B  illustrates a bottom perspective view of the first ram shown in  FIG. 8A . 
         FIG. 8C  shows a front view of the first ram shown in  FIGS. 8A-8B . 
         FIG. 8D  illustrates a top view of the first ram shown in  FIGS. 8A-8C . 
         FIG. 8E  shows a bottom view of the first ram shown in  FIGS. 8A-8D . 
         FIG. 8F  shows a side view of the first ram shown in  FIGS. 8A-8E . 
         FIG. 9A  shows a top perspective view of a second ram. 
         FIG. 9B  illustrates a bottom perspective view of the second ram shown in  FIG. 9A . 
         FIG. 9C  shows a front view of the second ram shown in  FIGS. 9A-9B . 
         FIG. 9D  illustrates a bottom view of the second ram shown in  FIGS. 9A-9C . 
         FIG. 9E  shows a top view of the second ram shown in  FIGS. 9A-9D . 
         FIG. 9F  shows a side view of the second ram shown in  FIGS. 9A-9E . 
         FIGS. 10A-10E  are top views of first and second rams with a tubular in various positions between the ram blades. 
     
    
    
     DETAILED DESCRIPTION 
     The following discussion is directed to various embodiments of the present disclosure. The drawing figures are not necessarily to scale. Certain features of the embodiments may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment. 
     Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but are the same structure or function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     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 . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. In addition, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. The use of “top,” “bottom,” “above,” “below,” and variations of these terms is made for convenience, but does not require any particular orientation of the components. 
     Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present disclosure. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment. 
     Preferred embodiments are best understood by reference to  FIGS. 1A-10E  below in view of the following general discussion. The present disclosure may be more easily understood in the context of a high level description of certain embodiments. Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that embodiments may be practiced without these specific details. For example, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. 
     Referring now to  FIGS. 1A-1C , multiple views of a blowout preventer  10  for shearing a tubular D in accordance with one or more embodiments of the present disclosure are shown. The blowout preventer  10 , which may be referred to as a ram blowout preventer, includes a body  12  with a vertical bore  14  formed and/or extending through the body  12 . As shown, the body  12  may include a lower flange  16  and/or an upper flange  18 , such as to facilitate connecting the blowout preventer  10  to other blowout preventers and/or other components. Cavities and/or guideways  20  and  22  may be formed within the body  12  of the blowout preventer  10 , in which the guideways  20  and  22  may extend outwardly from the bore  14  and/or be formed on opposite sides of the bore  14 . 
     The blowout preventer  10  may then include one or more ram assemblies, such as a first ram  24  and a second ram  26 . The first ram  24  may be positioned and movable within the first guideway  20  and a second ram  26  positioned and movable within the second guideway  22 , such as by having the first ram  24  and/or the second ram  26  movable towards and away from the tubular D, One or more actuators  28  may be provided to move the first ram  24  and/or the second ram  26 , such as for moving the first ram  24  and/or the second ram  26  into the bore  14  to shear the portion of the tubular D extending through the bore  14  of the blowout preventer  10 . In this embodiment, a hydraulic actuator is shown, though any type of actuator (e.g., pneumatic, electrical, mechanical) may be used in accordance with the present disclosure. As such, the actuators  28  shown in this embodiment may include a piston  30  positioned within a cylinder  32  and a rod  34  connecting the piston  30  to each respective ram  24  and  26 . Further, pressurized fluid may be introduced and fluidly communicated on opposite sides of the piston  30  through ports  35 , thereby enabling the actuator  28  to move the rams  24  and  26  in response to fluid pressure. 
     A first (e.g., upper) blade  36  (any blade according to the present disclosure) may be included with or connected to the first ram  24 , and a second (e.g., lower) blade  38  (any blade according to the present disclosure) may be included with or connected to the second ram  26 . The first and second blades  36  and  38  may be formed and positioned such that the second blade  38  passes below the first blade  36  in shearing of a section of a tubular D. The shearing action of first and second blades  36  and  38  may shear the tubular D. The lower portion of the tubular D may then drop into the well bore (not shown) below the blowout preventer  10 , or the tubular D may hung off a lower set of rams (not shown). 
     Accordingly, disclosed herein are a system, blowout preventer, and/or a blade for a blowout preventer for shearing a tubular. The tubular may be positioned within the bore extending through the blowout preventer, in which the blowout preventer may be actuated to move one or more blades to engage and shear the tubular. A blade of a blowout preventer in accordance with the present disclosure may be used for shearing one or more different types of tubulars that may have different shapes, sizes, thicknesses, and other dimensions and properties. For example, a tubular may include a drill pipe joint, a casing joint, and/or a tool joint, in which a blowout preventer in accordance with the present disclosure may be used to shear each of these different types of tubulars. These tubulars may be sheared with or without replacement of any blade of the blowout preventer. 
       FIG. 1D  shows a perspective view of an embodiment of the body  12  of the blowout preventer  10  shown in  FIGS. 1A-1C . Rather, than an upper flange  18 , this embodiment has studs  19  to make up a studded connection. The guideway  22  has a cross-sectional shape that is linear on the top and the bottom and semi-circular on the left and the right sides. 
     Referring to  FIG. 2A , a perspective view of an embodiment of a first ram  24  and a second ram  26  are shown. The rams are positioned opposite each other as they would be if positioned within the guideways  20  and  22  of the body  12  of the blowout preventer  10 . The first ram  24  has a first seal  37  extending from a right side, over the top, and to the left side. The first ram  24  also has first side seals  40 , one on each side. The second ram  26  similarly has a second seal  39  extending from a right side, over the top, and to the left side. The second ram  26  also has second side seals  41 , one on each side. The seals engage with the sides and tops of the guideways  20  and  22  to seal the vertical bore  14  when the rams are fully extended to the closed position by the actuators  28 . A ram seal is positioned in a seal channel  42  in the bottom side of the first ram  24  so as to seal between the rams when they are in a closed position. (See  FIG. 3B ). The first ram  24  has upper guides  44  and lower guides  46  for guiding the first ram  24  in guideway  20  (see  FIG. 1A ). As shown, one upper guide  44  and one lower guide  46  are on the left side of the ram and another upper guide  44  and another lower guide  46  are on the right side of the first ram  24 . The upper and lower guides  44  and  46  define guide channels  48  of the first ram  24  for receiving and guiding the second lower blade  38  and the second side seals  41  of the second ram  26 . 
       FIG. 2B  is a top view of the embodiment of the first ram  24  and the second ram  26  shown in  FIG. 2A , except that the seals are removed from the rams. The first ram  24  has a first upper blade  36 , which has a blunt leading contour  58 . The second ram  26  has a second lower blade  38 , which has a blunt leading contour  88 . 
     Referring to  FIGS. 3A and 3B , top and bottom perspective views of an embodiment of a first ram  24  are shown. The first ram  24  comprises a first upper blade  36  having a blunt leading contour  58  that extends between the upper guides  44  at the front of the blade  36 . The first upper blade  36  has upper inclined surfaces  60  extending from the blunt leading contour  58  to the top side  52 . At the leading most portions of the bottom side  50 , the blade  36  has a cutting edge  64 . The first upper blade  36  also has lower inclined surfaces  62  extending from the blunt leading contour  58  to the cutting edge  64 . The cutting edge  64  is a very short substantially vertical front side of the blade  36  that meets the bottom side  50 . The first upper blade  36  also has lower declined surfaces  62  extending from the blunt leading contour  58  to the cutting edge  64 . In the middle of the blunt leading contour  58 , the first upper blade  36  has a point  66 . 
       FIG. 3C  shows a front view of the first ram  24 . As clearly shown in this view, the first upper blade  36  is flat and horizontal on its bottom side  50 . The top side  52  of the first upper blade  36  is also flat and horizontal, except that in the mid-section of the blade the top side is pitched to a ridge  54 . Ridge planes  56  extend from the flat and horizontal portions of the top side  52  to the ridge  54 . The blunt leading contour  58  extends between the upper guides  44  at the front of the blade  36 . 
       FIG. 3D  shows a top view of the first ram  24 . In this view, the profile of the blunt leading contour  58  is shown extending between the upper guides  44 . The point  66  extends from the mid-section of the blunt leading contour  58 , with flanks  68  on opposite sides. The flanks  68  merge into concave arcs  70 . Each of the concave arcs  70  in the blunt leading contour  58  merge into forward angled sections  72 . Each of the forward angled sections  72  merge into convex arcs  74  located adjacent the upper guides  44 . Relative to the forward advancing direction of the first ram  24 , which is upward in  FIG. 3D , the convex arcs  74  are more forward than the point  66 . The ridge  54  is on the centerline  76  of the first ram  24 . The flanks  68  sweep backwardly from the point  66  at an angle of about 65 degrees from the centerline  76 . Said another way, the flanks  68  form an angle of about 130 degrees at the point  66 . In some embodiments, the flanks  68  form an angle between about 110 to 150 degrees at the point  66 . The forward angled sections  72  sweep forwardly at an angle of about 52 degrees from the centerline  76 . The concave arcs  70  have radii about 8% the width of the first upper blade  36  between the upper guides  44 . 
     Referring to  FIG. 3E , a bottom view is shown of the embodiment of the first ram  24  of  FIGS. 3A-3D . In this view, the bottom side of the first upper blade  36  is visible between the lower guides  46 . A seal channel  42  is located in the bottom side  50 . A seal may be positioned in the seal channel  42  for sealing engagement between the first upper blade  36  and the second lower blade  38  (see  FIG. 2 ) when the rams are closed. The profile of the blunt leading contour  58  is also visible in  FIG. 3E . Further, from this perspective, the cutting edge  64  is also visible. The cutting edge  64  has a profile similar to the blunt leading contour  58 . Lower decline surfaces  62  extend between the blunt leading contour  58  and the cutting edge  64 . 
       FIG. 3F  shows a right side view of the first ram  24 . An upper guide  44  is at the top of the first ram  24  and a lower guide  46  is at the bottom of the first ram  24 . A guide channel  48  is bounded between the upper and lower guides  44  and  46 . The blunt leading contour  58  extends slightly beyond the distal end of the upper guide  44 . In this view, the depth and width of the seal channel  42  are clearly visible. In one embodiment, the inclination angle of the upper inclined surfaces  60  and the declination angle of the lower declined surfaces  62  of the first upper blade  36  may be about 40 degrees from horizontal. (See  FIG. 3C ). 
     Referring to  FIGS. 4A and 4B , top and bottom perspective views of an embodiment of a second ram  26  are shown. The second ram  26  comprises a second lower blade  38  having a top side  92 , a bottom side  90 , and a blunt leading contour  88  at the front of the blade  38 . At the leading most portions of the top side  92 , the blade  38  has a cutting edge  94 . The cutting edge  94  is a very short substantially vertical front side of the blade  38  that meets the top side  92  at a substantially 90 degree corner. The second lower blade  38  has upper inclined surfaces  80  extending from the blunt leading contour  88  to the cutting edge  94  at the leading boundary of the top side  92 . The second lower blade  38  also has lower declined surfaces  82  extending from the blunt leading contour  88  to the bottom side  90 . The blunt leading contour  88  of the second lower blade  38  has two points  96 . 
       FIG. 4C  shows a front view of the second ram  26 . As clearly shown in this view, the second lower blade  38  is flat and horizontal on its top side  92 . The bottom side  90  of the second lower blade  38  is also flat and horizontal, except that first and second thirds of the width of the blade  38  the bottom side  90  is pitched to two ridges  84 . Ridge planes  86  extend from the flat and horizontal portions of the bottom side  90  to the ridges  84 . The blunt leading contour  88  extends across front of the blade  39  between the upper inclined surfaces  80  and the lower declined surfaces  82 . Two pointes  96  are at about the first and second thirds of the width of the blade  38 . 
       FIG. 4D  shows a bottom view of the second ram  26 . In this view, the profile of the blunt leading contour  88  is shown at the leading portion of the second lower blade  38 . The blunt leading contour  88  is symmetrical about the centerline  76 . Two points  96  extend from the first and second thirds of the width of the blunt leading contour  88 , with flanks  98  on opposite sides of each point  96 . The flanks  98  merge into concave arcs  100  toward the ends of the blade  38  and merge into a common concave arc  101  at the mid-section. Each of the concave arcs  100  in the blunt leading contour  88  merge into forward sections  102 , which are substantially parallel to the centerline  76 . Each of the forward sections  102  merge into forward angled sections  104 . The forward angled sections  104  finally merge into transverse sections  106 , which are substantially transverse to the centerline  76 . Relative to the forward advancing direction of the first ram  24 , which is upward in  FIG. 4D , the transverse sections  106  are more forward than the points  96 . The ridges  84  are colinear with the points  96 . The flanks  98  sweep backwardly from the points  96  at angle of about 60 degrees from the centerline  76 . The forward angled sections  104  sweep forwardly at an angle of about 75 degrees from the centerline  76 . The concave arcs  100  have radii about 3% the width of the second lower blade  38 . The common concave arc  101  has a radius about 10% the width of the second lower blade  38 . 
     Referring to  FIG. 4E , a top view is shown of the embodiment of the second ram  26  of  FIGS. 4A-4D . In this view, the top side  92  of the second lower blade  38  is visible. The profile of the blunt leading contour  88  is also visible in  FIG. 4E . Further, from this perspective, the cutting edge  94  is also visible. The cutting edge  94  has a profile similar to the blunt leading contour  88 . Upper incline surfaces  80  extend between the blunt leading contour  88  and the cutting edge  94 . 
       FIG. 4F  shows a left side view of the second ram  26 . The blunt leading contour  88  is located at the distal end of the second lower blade  38 . The top side  92  is opposite the bottom side  90 . A ridge  84  is at the bottom most portion of the blade  38 . A ridge plane  86  extends between the ridge  84  and the bottom side  90  of the blade  38 . An upper inclined surface  80  extends between the blunt leading contour  88  and the cutting edge  94 . In this embodiment, the top side  92  is flat. A reference horizontal plane  116  cuts through the middle of the blunt leading contour  88  and is parallel to the top side  92 . The upper inclined surface  80  has an inclination angle  112  of about 40 degrees relative to the reference horizontal plane  11 . Said another way, the upper inclined surface forms an angle of about 140 degrees with the top side  92 . In some embodiments, the upper inclined surface forms an angle between about 120 and 160 degrees with the top side  92 . A lower decline surface  82  extends between the blunt leading contour  88  and the bottom side  90  of the blade  38 . In this embodiment, the lower decline surface  82  has a declination angle  114  of about 40 degrees from reference horizontal plane  116 . Said another way, the lower declined surface  82  forms an angle of about 80 degrees with the upper inclined surface  80 . In some embodiments, the lower declined surface  82  forms an angle between about 60 and 100 degrees with the upper inclined surface  80 . Further, lower decline surfaces  82  extend from various portions of the blunt leading contour  88  to the ridge plane  86 . 
     A further aspect of the invention is that the first upper blade  36  functions to rip tubular, tools, or whatever else is located in the vertical bore of the blowout preventer body  12 . The first and second blades  36  and  38  may be formed and positioned such that the second blade  38  passes below the first blade  36  in shearing of a section of a tubular D. (See  FIG. 1C ). The shearing action of first and second blades  36  and  38  may shear whatever structures are located in the vertical bore  14  of the blowout preventer  10 . The blades may shear: (1) tubulars D of any diameter that may be inserted into the vertical bore  14 ; (2) tool joint; (3) drill collar; (4) production tubular; (5) hard banded tubular; (6) casing tubular; (7) tubular pin/box connections of any diameter; (8) coil tubing of any diameter; (9) tools, such as wireline tools, perforating guns, drill bits; fishing tools, etc.; (10) wireline; and (11) any other objects that may find their way into the vertical bore  14  of the blowout preventer  10 . Referring again to  FIG. 2B , relatively larger diameter tubular may become positioned at the centerline  76  where it may be initially engaged by the point  66  of the first upper blade  36  and the common concave arc  101  of the second lower blade  38 . Relatively smaller diameter tubular may similarly become positioned at the centerline  76 , or it may become position away from the centerline  76  wherein it may be initially engaged by one of the points  96  of the second lower blade  38  and a concave arc  70  of the first upper blade  36 . Still smaller diameter tubulars may be positioned in either of these locations, or may be positioned still further away from the centerline  76  and be initially engaged by a forward angled section  72  of the first upper blade  36  and an outside flank  98  of the second lower blade  38 . 
     The rams  24  and  26  may consists of blunt leading contours  58  and  88  running horizontally across the blades  36  and  38 . The rounded blunt leading contours  58  and  88  may terminate in two symmetric angled surfaces (upper inclined surface  60  and  80  and lower declined surface  62  and  82 ), where the angle between the surfaces is less than 90 degrees (inclination angle  112 +declination angle  114  shown in  FIG. 4F ). Once contact is initiated with the pipe tubular D, the rounded blunt leading contour  58  will indent the pipe tubular D at which time the upper inclined surface  60  and  80  and lower declined surface  62  and  82  will begin to force the contact region open as the ram  24  and  26  continues its forward motion, thereby imparting a tensile load at the point of contact. The blade  36  and  38  may cause the pipe tubular D to fail in a ripping manner, rather than a traditional shear manner. 
     For example,  FIG. 4G  shows a cross-sectional side view of a second lower blade  38 , the upper inclined surface  80  and lower declined surface  82  surrounding the bull nose or rounded blunt leading contour  88  reduce the propensity of the blade  38  to bend during emergency disconnect operations. The rounded blunt leading contour  88  is substantially symmetric causing reaction forces in the vertical direction RF 1 Y and RF 2 Y to be balanced during closing operations. Thus, the “bull nose design” enhances the structural integrity of the blade during well control operations. 
       FIG. 5A  shows cross-sectional side views of the first upper blade  36  and the second lower blade  38  at positions of initial engagement with a tubular D. Because the blades have inclined and declined surfaces, the blunt leading contour  58  of the first upper blade  36  and the blunt leading contour  88  of the second lower blade  38  are vertically offset from each other by an offset distance  100 . Rather than a sharp leading edge, the blades  36  and  38  present blunt leading contours  58  and  88 . 
       FIG. 5B  shows cross-sectional side views of the first upper blade  36  and the second lower blade  38  of  FIG. 5A  at positions of full engagement with the tubular D. The blades engage the tubular D in opposite horizontal inward directions to induce horizontal shear forces in the tubular D. Further, the offset distance  110  between the leading contours enables the blades to induce vertical tensile and shear forces in the tubular D. These forces combine to rip and tear the tubular D, rather than slice or cut. 
       FIG. 6A  shows cross-sectional side views of the first upper blade  36  and the second lower blade  38  at positions of initial engagement with a wireline  120 . Because the blades have inclined and declined surfaces, the blunt leading contour  58  of the first upper blade  36  and the blunt leading contour  88  of the second lower blade  38  are vertically offset from each other by an offset distance  100 . Rather than a sharp leading edge, the blades  36  and  38  present blunt leading contours  58  and  88 . Cutting edge  64  and cutting edge  94  present sharper edges capable of cutting wireline  120 . 
       FIG. 6B  shows cross-sectional side views of the first upper blade  36  and the second lower blade  38  of  FIG. 6A  at positions of full engagement with the wireline  120 . The blades engage the tubular D in opposite horizontal inward directions so that the wireline  120  simply deforms around the blunt leading contours  58  and  88  in an S-shape. Further inward movement of the blades  36  and  38  causes the cutting edges  64  and  94  to engage and cut the wireline  120 . 
     Referring to  FIG. 7A , a perspective view of an embodiment of a first ram  124  and a second ram  126  are shown. The rams are positioned opposite each other as they would be if positioned within the guideways  20  and  22  of the body  12  of the blowout preventer  10  (see  FIGS. 1A-1D ). The rams also have seals similar to the embodiment shown in  FIGS. 2A-2B . The first ram  124  has upper guides  144  and lower guides  146  for guiding the first ram  124  in guideway  20  (see  FIG. 1A ). As shown, one upper guide  144  and one lower guide  146  are on the left side of the ram and another upper guide  144  and another lower guide  146  are on the right side of the first ram  124 . The upper and lower guides  144  and  146  define guide channels  148  of the first ram  124  for receiving and guiding the second lower blade  138  of the second ram  26 . 
       FIG. 7B  is a top view of the embodiment of the first ram  124  and the second ram  126  shown in  FIG. 7A . The first ram  124  has a first upper blade  136 , which has a blunt leading contour  158 . The second ram  126  has a second lower blade  138 , which has a cutting edge  194 . 
     Referring to  FIGS. 8A and 8B , top and bottom perspective views of an embodiment of a first ram  124  are shown. The first ram  124  comprises a first upper blade  136  having a blunt leading contour  158  that extends between the upper guides  144  at the front of the blade  136 . The first upper blade  136  has upper primary inclined surfaces  160  extending from the blunt leading contour  158  to upper secondary inclined surfaces  161 . At the leading most portions of the bottom side  150 , the blade  136  has a cutting edge  164 . The first upper blade  136  also has lower inclined surfaces  162  extending from the blunt leading contour  158  to the cutting edge  164 . The cutting edge  164  is a very short substantially vertical front side of the blade  136  that meets the bottom side  150 . The first upper blade  136  also has lower declined surfaces  162  extending from the blunt leading contour  158  to the cutting edge  164 . In the middle of the blunt leading contour  158 , the first upper blade  136  has a concave arc  170  and the left and right sides have forward angled sections  172 . 
       FIG. 8C  shows a front view of the first ram  124 . As clearly shown in this view, the first upper blade  136  is flat and horizontal on its bottom side  150 . The top side  152  of the first upper blade  136  is also flat and horizontal so as to fit within a guideway  20 . The blunt leading contour  158  extends between the upper guides  144  at the front of the blade  136 . 
       FIG. 8D  shows a top view of the first ram  124 . In this view, the profile of the blunt leading contour  158  is shown extending between the upper guides  44 . In the middle of the blunt leading contour  158 , the first upper blade  136  has a concave arc  170  and the left and right sides have forward angled sections  172 . The first upper blade  136  has upper primary inclined surfaces  160  extending from the blunt leading contour  158  to upper secondary inclined surfaces  161 . In one embodiment, the inclination angle of the upper primary inclined surfaces  160  of the first upper blade  136  may be about 75 degrees from horizontal and the inclination angle of the upper secondary inclined surfaces  161  of the first upper blade  136  may be about 60 degrees from horizontal. (See  FIG. 8C ). 
     Referring to  FIG. 8E , a bottom view is shown of the embodiment of the first ram  124  of  FIGS. 8A-8D . In this view, the bottom side of the first upper blade  136  is visible between the lower guides  146 . A seal channel  142  is located in the bottom side  150 . A seal may be positioned in the seal channel  142  for sealing engagement between the first upper blade  136  and the second lower blade  138  (see  FIG. 2 ) when the rams are closed. The profile of the blunt leading contour  158  is also visible in  FIG. 8E . Further, from this perspective, the cutting edge  164  is also visible. The cutting edge  164  has a profile similar to the blunt leading contour  158 . Lower decline surfaces  162  extend between the blunt leading contour  158  and the cutting edge  164 . 
       FIG. 8F  shows a right side view of the first ram  124 . An upper guide  144  is at the top of the first ram  124  and a lower guide  146  is at the bottom of the first ram  124 . A guide channel  148  is bounded between the upper and lower guides  144  and  146 . In this view, the depth and width of the seal channel  142  are clearly visible. In one embodiment, the declination angle of the lower declined surfaces  162  of the first upper blade  136  may be about 45 degrees from horizontal. (See  FIG. 8C ). 
     Referring to  FIGS. 9A and 9B , top and bottom perspective views of an embodiment of a second ram  126  are shown. The second ram  126  comprises a second lower blade  138  having a top side  192 , and a bottom side  190 . At the leading most portions of the top side  192 , the blade  138  has a cutting edge  194 . The cutting edge  194  is a very short substantially vertical front side of the blade  138  that meets the top side  192  at a substantially 90 degree corner. The second lower blade  138  has lower primary declined surfaces  182  extending from the cutting edge  194  to lower secondary declined surfaces  183 , which extend to the bottom side  190 . 
       FIG. 9C  shows a front view of the second ram  126 . The top side  192  is substantially flat and horizontal. The bottom side  190  is also substantially flat, but it is slightly declined from its leading end toward its trailing end. 
       FIG. 9D  shows a bottom view of the second ram  126 . In this view, the profile of the cutting edge  194  is shown at the leading portion of the second lower blade  138 . The cutting edge  194  is symmetrical about the centerline  176 . A concave arc  200  is at the mid-section and a forward angled section  172  is on each side. The concave arc  200  merges into the forward angled sections  172 . The concave arc  200  has a radius about 50% the width of the second lower blade  138 . The forward angled sections  172  sweep forwardly at an angle of about 80 degrees from the centerline  76 . 
     Referring to  FIG. 9E , a top view is shown of the embodiment of the second ram  126  of  FIGS. 9A-9D . In this view, the top side  192  of the second lower blade  138  is visible. The profile of the cutting edge  194  is also visible in  FIG. 9E . 
       FIG. 9F  shows a left side view of the second ram  126 . The cutting edge  194  is located at the distal end of the second lower blade  138 . The top side  192  is opposite the bottom side  190 . A lower primary declined surface  182  extends between the cutting edge  194  and a secondary declined surface  183 , which extends to a bottom side  190  of the blade  138 . In this embodiment, the lower primary declined surface  182  has a declination angle  214  of about 83 degrees from horizontal  216 . In this embodiment, the lower secondary declined surface  183  has a declination angle  215  of about 60 degrees from horizontal  216 . 
     As represented on  FIGS. 10A through 10E , in embodiments of the disclosure, the forward angled sections  72  of the first upper blade  36  and the forward angled sections  104  of the second lower blade  38  are such that the resulting blade geometries can induce or drive motion on the drill pipe or tubular D, pushing it into a position designed to impart maximum force onto such tubular. The design of the rams are not intended to centralize the pipe or tubular D with the rams&#39; central axis, but rather induce motion of the pipe or tubular D into one of a plurality (here shown are three different) of locations designed to impart maximum load onto the tubular in order to successfully shear or rip it. In embodiments, the forward angled sections and other portions of the profiles are designed in such a manner that the pipe or tubular D will be pushed into one of these locations regardless of its original starting position. In embodiments as shown on  FIGS. 10A and 10B , the pipe is excentered on a far side of the rams ( FIG. 10A ) and the profiles of the leading contours of the blades enables, when the rams are moved towards a closed position, the pipe or tubular D to be driven to the preferred immediately following location ( FIG. 10B ) where optimum shearing or ripping can occur. Similarly, as shown on  FIG. 10D , the pipe is excentered on the other far side of the ram ( FIG. 10D ) and the profiles of the leading contours of the blades of the rams enable, when the rams are moved towards a closed position, the pipe or tubular D to be driven to the preferred immediately following location ( FIG. 10E ) where optimum shearing or ripping can occur. In  FIG. 10C , the pipe or tubular D is shown in a location appropriate for optimum shearing or ripping, and thus, the profiles of the leading contours of the blades do not induce movement of the pipe or tubular D when rams are closing. 
     Although the disclosed embodiments are described in detail in the present disclosure, it should be understood that various changes, substitutions and alterations can be made to the embodiments without departing from their spirit and scope. 
     INDUSTRIAL APPLICABILITY 
     Blowout preventer systems and methods of the present invention have many industrial applications including but not limited to preventing blowouts in drilled well bores for the oil and gas industry.