Multi-point blade and pocket blade for a shear ram in a blow-out preventer

Abstract

A pair of blades in a shear ram of a blow-out preventer for cutting a tubular includes an upper blade and a lower blade. The lower blade shears the tubular in concert with the upper blade, the lower blade having a multi-point geometry to initiate shearing the tubular. The upper blade guides the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade. A blow-out preventor includes a blind ram, a shear ram, and a pipe ram, each including two ram blocks configured to extend into a bore to seal a bore. The shear ram includes an upper blade and a lower blade, where the lower blade shears the tubular in concert with the upper blade, the lower blade having a multi-point geometry to initiate shearing the tubular, the upper blade to guide the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade.

Description

BACKGROUND

[0001] In the oil and gas industry, hydrocarbons are located in porous rock formations beneath the Earth's surface. Wells are drilled into the formations to access and produce the hydrocarbons. As a well gets deeper, the pressure of downhole formations increases. As such, downhole pressures must be managed while drilling a well to prevent downhole pressures from overcoming the wellbore pressure-causing a kick or a blow-out. Blow-out preventers are used while drilling a well to provide a pressure barrier in situations where the downhole pressure is improperly managed and a kick occurs. Blow-out preventers include different sets of rams that serve different purposes, depending on what is located in the well at the time of the kick. It is important that the rams efficiently and successfully perform their desired functions or else the blow-out preventer may fail which can lead to an uncontrolled release of hydrocarbons-harming people and the environment.SUMMARY

[0002] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0003] This disclosure presents, in accordance with one or more embodiments, a pair of blades to be provided in a shear ram of a blow-out preventer for cutting a tubular. The pair of blades may include an upper blade and a lower blade. The lower blade may be configured to shear the tubular in concert with the upper blade, the lower blade having a multi-point geometry configured to initiate shearing of the tubular. The upper blade may be configured to guide the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade.

[0004] This disclosure presents, in accordance with further embodiments, a blow-out preventor. The blow-out preventor may include a blind ram, a shear ram, and a pipe ram. The blind ram, the shear ram, and the pipe ram may each include two ram blocks configured to extend into a bore to seal a bore. The shear ram may include an upper blade and a lower blade, where the lower blade is configured to shear the tubular in concert with the upper blade, the lower blade having a multi-point geometry configured to initiate shearing of the tubular. The upper blade may be configured to guide the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade.

[0005] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.BRIEF DESCRIPTION OF DRAWINGS

[0006] Specific embodiments of the disclosed technology will be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, particular shapes of elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.

[0007] FIG. 1 shows a blow-out preventer in accordance with one or more embodiment.

[0008] FIGS. 2-8 show various views of the upper block in accordance with one or more embodiments.

[0009] FIGS. 9-24 show various views of lower blocks in accordance with one or more embodiments.

[0010] FIG. 25 shows a top view of an upper block and a lower block used in combination in accordance with one or more embodiments.

[0011] FIG. 26 shows how the upper block and the lower block may be able to successfully shear a tubular no matter how the tubular is situated in the containment zone of the upper blade in accordance with one or more embodiments.

[0012] FIG. 27 shows how the upper guide arms of the upper block can retain and control the deformation of the tubular when the tubular is in the process of being sheared by the shear ram in accordance with one or more embodiments.DETAILED DESCRIPTION

[0013] In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art that the disclosure may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description.

[0014] Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before,”“after,”“single,” and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element may encompass more than one element and succeed (or precede) the second element in an ordering of elements.

[0015] FIG. 1 shows a blow-out preventer (BOP) (100) in accordance with one or more embodiments. The BOP (100) is capping a well (102) and is located below a rig floor (104). The rig floor (104) may be the surface of a land or offshore drilling rig where equipment is being staged to be lowered into the well (102). The BOP (100) has a bore (106) extending through the center of the BOP (100). In accordance with one or more embodiments, the bore (106) extends relatively along the same axis as the entrance to the well (102). A tubular (108) is shown being run into / out of the well (102) through the bore (106) of the BOP (100).

[0016] The BOP is shown having a blind ram (110), a shear ram (112), and a pipe ram (114). The BOP (100) is shown for example purposes only and a person skilled in the art will appreciate that the BOP (100) may have any type and configuration of rams without departing from the scope of the disclosure herein.

[0017] The blind ram (110), the shear ram (112), and the pipe ram (114) may each be made of two ram blocks that are actuated to extend out of the ram into the bore (106) of the BOP (100) to seal the bore (106) of the BOP (100). The ram blocks may be actuated using any actuation system known in the art, such as a hydraulic or electronic actuation system.

[0018] In accordance with one or more embodiments, the blind ram (110) is designed to seal the well (102) when there is no tubular (108) located in the bore (106) of the BOP (100). In accordance with one or more embodiments, the blind ram (110) may include two ram blocks that fully meet in the center of the bore (106) to seal the bore (106). That is, when the blocks meet in the center and successfully seal by pressing up against one another, fluid is unable to escape from the well (102) through the BOP (100) to the atmosphere.

[0019] In accordance with one or more embodiments, the pipe ram (114) is manufactured to close around and seal a particularly-sized tubular (108) that is being run through the bore (106) of the BOP (100). In other words, the pipe ram (114) is designed to seal the annulus located between the tubular (108) and the inner wall of the bore (106) of the BOP. Once the pipe ram (114) is actuated and seals around the tubular (108) located in the bore (106), hydrocarbons should not be able to travel up the annulus of the tubular (108) to the atmosphere.

[0020] In accordance with one or more embodiments, the pipe ram (114) has two ram blocks that are each machined with a half-circular hole so that when the two ram blocks have extended into the bore (106), the half-circle profiles line up to create a full circle with a diameter / circumference equal to the tubular (108) that is deployed in the bore (106) of the BOP (100).

[0021] In accordance with one or more embodiments, there may be multiple pipe rams in one BOP (100), each having different sizes of half-circular holes, based on the sizes of the various tubulars (108) that are planned to be run into the bore (106) of the BOP (100) for the drilling operation. For example, there may be one pipe ram that is sized to seal around drill pipe and there may be another pipe ram that is sized to seal around casing.

[0022] In accordance with one or more embodiments, the shear ram (112) is designed to cut through the tubular (108) that is deployed in the bore (106) of the BOP (100). Once the shear ram (112) has cut through the tubular (108), the shear ram (112) should also be able to seal the bore (106) of the BOP (100). That is, once the shear ram (112) has cut through the tubular (108) that is deployed in the bore (106) of the BOP (100), the shear ram (112) should seal the bore (106) such that hydrocarbons are unable to escape to the atmosphere from the well (102) through the bore (106) of the BOP (100).

[0023] In accordance with one or more embodiments, the shear ram (112) includes an upper block (200) and a lower block (300). The upper block (200) has an upper blade (202), and the lower block (300) has a lower blade (302). As shown in FIG. 1, the upper block (200) and the lower block (300) may be on the same horizontal axis (i.e., an axis perpendicular to the axis of the bore (106)), even though they are designated “upper” and “lower.” These designations come from the orientation of the blades located on each block.

[0024] As can be seen in FIG. 1, the upper blade (202), located on the upper block (200), extends along a first horizontal axis (116) and the lower blade (302), located on the lower block (300), extends along a second horizontal axis (118). The first horizontal axis (116) is located above the second horizontal axis (118). Herein, the terms “above” and “below” are in relation to the well (102). That is, the upper blade (202) on the first horizontal axis (116) is further from the well (102) and the lower blade (302) on the second horizontal axis (116) is closer to the well (102), in comparison.

[0025] Shear rams (112) are used as a last resort when neither the pipe ram (114) nor the blind ram (110) can be used. For example, the blind ram (110) may not usable due to the presence of a tubular (108) deployed in the well (102), as shown in FIG. 1. The pipe ram (114) may also not be usable because the tubular (108) deployed in the well (102) is too large or too small for the size of the pipe ram (114) installed in the BOP (100); because the pipe ram (114) is damaged and failed to seal; or because the flapper valve in the interior of the tubular (108) is non-existent or fails and fluid can travel up the interior of the tubular (108) to the atmosphere.

[0026] Because the shear ram (112) is the last resort, it is imperative that the shear ram (112) can successfully shear whatever kind of tubular (108) is located in the bore (106) and subsequently seal the bore (106). Conventional designs of the shear ram (112) may fail to shear and / or seal if the tubular (108) is not centered in the bore (106) or may fail when large diameter tubulars (108) are deployed in the well (102). The present disclosure outlines a specific configuration and geometry of blades (upper blade (202) and lower blade (302)), that drive controlled collapse of the tubular (108), prevent expansion of the tubular (108), and fold the tubular (108) sheared zones to ensure that the shear ram (112) can shear and seal across any sized or oriented tubular (108) deployed in the bore (106) of the BOP (100).

[0027] The geometrical design of the upper blade (202) and the lower blade (302) enable the shear ram (112) to apply localized or concentrated shear forces on the subject tubular (108) in order to decrease the total amount of force required to shear the tubular (108). These concentrated forces may result in localized tearing or deformation of the tubular (108), which starts the shearing action of the tubular (108) and reduces the remaining force needed to shear. On larger tubulars (108), such as casing, these concentrated loads allow the upper blade (202) and the lower blade (302) to “bite” the tubular (108) to prevent outward expansion, which is advantageous to the overall shear process.

[0028] The individual blade designs of the upper blade (202) and the lower blade (302) may include a combination of vertical or angled faces near the cutting edge, with a steeper angle moving away from the cutting edge to ensure forces are concentrated at the cutting edge and to apply some force in the vertical direction to separate the tubular (108) as the shearing action progresses.

[0029] The system may incorporate interface control of the upper block (200) and the lower block (300) to the shear ram (112) to control shearing of large diameter tubulars (108). The features are modular in nature and may be added or removed as needed. These provide moment and twisting control of the upper block (200) and the lower block (300) within the cavity of the BOP (100) and lead to control of the sheared tubular (108) during the shear operation. In accordance with one or more embodiments, the interface control may be provided using the upper guide arms (220, described below), which may contact an inner profile of the BOP (100) cavity during the shearing operation. In this case, expansion of larger tubulars (108) during shearing will be resisted by the upper guide arms (220), which is further supported by the BOP cavity to prevent movement of the upper guide arms (220) under high loading.

[0030] FIGS. 2-8 show various views of an upper block in accordance with one or more embodiments. FIGS. 2 and 3 show a side angle view of the upper block (200). FIG. 4 shows a top view of the upper block (200). FIG. 5 shows an underneath view of the upper block (200). FIG. 6 shows an angled view of the underneath portion of the upper block (200). FIG. 7 shows a side view of the upper blade (202) and the upper block (200). FIG. 8 shows another example of an upper block (400) in accordance with embodiments disclosed here.

[0031] In accordance with one or more embodiments, the upper block (200) is located inside the shear ram (112) housing and is configured to move towards the bore (106) whenever the upper block (200) is actuated. The upper block (200) includes an upper blade (202). The upper blade (202) is the portion of the upper block (200) that is directed into the bore (106) and contacts the tubular (108). In accordance with one or more embodiments, the upper blade (202) is made of, for example, high strength steel.

[0032] In accordance with one or more embodiments, the upper block (200) may also include a first upper flat surface (204), a second upper flat surface (206), a first lower flat surface (208), and a second lower flat surface (210). A gap (214) may be located between the first upper flat surface (204) and the second upper flat surface (206). The gap (214) may be used to house an elastomeric seal, which functions to seal the well (102) when the shear ram (112) is fully closed. The first lower flat surface (208) and the second lower flat surface (210) are shown in FIGS. 5 and 6.

[0033] The first lower flat surface (208) may be located on a lower, yet parallel, plane to the plane on which the second lower flat surface (210) sits. As such, the first lower flat surface (208) and the second lower flat surface (210) may be connected to one another by a wall (218). In accordance with one or more embodiments, the second lower flat surface (210), in conjunction with a corresponding flat surface on the lower block (300) (e.g., upper flat surface (304)), creates a clearance region where the tubular (108) gets pushed into during the shearing process.

[0034] In accordance with one or more embodiments, the upper block (200) further includes two upper guide arms (220). The upper guide arms (220) are located opposite one another on the upper block (200) and are located on a plane parallel-to and below the plane on which the upper blade (202) sits. The upper guide arms (220) may be used to assist in tubular (108) centralization and counteract tubular (108) expansion by pushing the tubular (108) away from the outer boundaries of the upper block (200) (see FIGS. 26 and 27).

[0035] The upper blade (202) has a working / cutting end formed into a pocket geometry. In accordance with one or more embodiments, the working end of the upper blade (202) includes a flat leading surface (222), two jutting edges (224), a cutting edge (226), an upper primary blade face (228), and a lower chamfer (230). The two jutting edges (224) each have a sharp corner (232) that may bite into the tubular (108) as it deforms outward during the shearing action. The flat leading surface (222) runs along the upper blade (202) between the two jutting edges (224), along the blade's width dimension. The two jutting edges (224), along with the depressed shape of the flat leading surface (222) makes the upper blade (202) have, and is how the upper blade (202) is formed in the “pocket” shape.

[0036] The flat leading surface (222) is flat in that its face does not curve outward (convex) or inward (concave) along its thickness between an upper edge and a lower edge. Specifically, the face of the flat leading surface (222) may be a flat surface with an upper edge and a lower edge. In one or more embodiments, the flat leading surface (222) may be a flat / planar surface extending along a vertical plane running along the blade's thickness dimension, e.g., perpendicular to the plane of the blade lower flat surface (236). In some embodiments, the flat leading surface (222) may be angled with respect to the vertical plane. The upper edge and the lower edge follow the same path along the upper blade's width dimension as the flat leading surface (222).

[0037] In accordance with one or more embodiments, the cutting edge (226) is the lower edge of the flat leading surface (222). The cutting edge (226) is the portion of the upper blade (202) that initiates the cut in the tubular (108). The upper primary blade face (228) extends at an angle away from the flat leading surface (222) towards an upper inclined surface (234). The upper primary blade face (228) acts to distribute load on the tubular (108) during the shearing action. In this way, the shearing load will remain concentrated at the cutting edge (226) and the upper primary blade face (228) will apply a vertical force component to aid in separating the tubular (108) at the shearing plane. The lower chamfer (230) extends at an angle away from the flat leading surface (222) towards a blade lower flat surface (236). The blade lower chamfer (230) aids in distributing the load that is concentrated at the cutting edge (226) so that the cutting edge (226) does not become mechanically overloaded and deformed during the shearing process. As the cutting edge (226) shears into the tubular (108), the blade lower flat surface (236) provides separation between the upper and lower sections of the tubular (108).

[0038] FIG. 8 shows another example of an upper block according to embodiments disclosed herein, showing the side angle view of the upper block (400). As in FIG. 3, the upper block (400) is located inside the shear ram (112) housing and is configured to move towards the bore (106) whenever the upper block (400) is actuated. The upper block (400) includes an upper blade (402). The upper blade (402) is the portion of the upper block (400) that is directed into the bore (106) and contacts the tubular (108). In accordance with one or more embodiments, the upper blade (402) is made of, for example, high strength steel.

[0039] In accordance with one or more embodiments, the upper block (400) may also include a first upper flat surface (404) and a second upper flat surface (406). A gap (414) may be located between the first upper flat surface (404) and the second upper flat surface (406). The gap (414) may be used to house an elastomeric seal, which functions to seal the well (102) when the shear ram (112) is fully closed. The upper block (400) may further include a first lower flat surface and a second lower flat surface, similar to the first lower flat surface (208) and the second lower flat surface (210) shown in FIGS. 6 and 7.

[0040] In accordance with one or more embodiments, the upper block (400) further includes two upper guide arms (420). The upper guide arms (420) are located opposite one another on the upper block (400) and are located on a plane parallel-to and below the plane on which the upper blade (402) sits. The upper guide arms (420) may be used to assist in tubular (108) centralization and counteract tubular (108) expansion by pushing the tubular (108) away from the outer boundaries of the upper block (400) (similar to upper block (200) shown in FIGS. 26 and 27).

[0041] The upper blade (402) has a working / cutting end formed into a pocket geometry. In accordance with one or more embodiments, the working end of the upper blade (402) includes a flat leading surface (422), two jutting edges (424), a cutting edge (426), an upper primary blade face (428), and a lower chamfer (430). The two jutting edges (424) each have a sharp corner (432) that may bite into the tubular (108) as it deforms outward during the shearing action. The flat leading surface (422) runs along the upper blade (402) between the two jutting edges (424), along the blade's width dimension. The two jutting edges (424), along with the depressed profile of the flat leading surface (422) makes the upper blade (402) have, and is how the upper blade (402) is formed in the “pocket” shape.

[0042] The flat leading surface (422) is flat in that its face does not curve outward (convex) or inward (concave) along its thickness between an upper edge and a lower edge. Specifically, the face of the flat leading surface (422) may be a flat surface with an upper edge and a lower edge. In one or more embodiments, the flat leading surface (422) may be a flat / planar surface extending along a vertical plane running along the blade's thickness dimension, e.g., perpendicular to the plane of the blade lower flat surface (236). In some embodiments, the flat leading surface (422) may be angled with respect to the vertical plane. The upper edge and the lower edge follow the same path along the upper blade's width dimension as the flat leading surface (422).

[0043] In accordance with one or more embodiments, the cutting edge (426) is the lower edge of the flat leading surface (422). The cutting edge (426) is the portion of the upper blade (402) that initiates the cut in the tubular (108). In some embodiments, the cutting edge (426) may be formed by a chamfer along the lower edge of the flat leading surface (422). For example, in FIG. 8, a lower chamfer (430) extends at an angle away from the flat leading surface (422) towards a blade lower flat surface (236). The blade lower chamfer (430) aids in distributing the load that is concentrated at the cutting edge (426) so that the cutting edge (426) does not become mechanically overloaded and deformed during the shearing process. As the cutting edge (426) shears into the tubular (108), the blade lower flat surface (236) provides separation between the upper and lower sections of the tubular (108).

[0044] Further, as shown in FIG. 8, the upper primary blade face (428) extends at an angle away from the flat leading surface (422). In accordance with one or more embodiments, an upper primary blade face may extend from the flat leading surface (422) to the first upper flat surface (404). The upper primary blade face (428) acts to distribute load on the tubular (108) during the shearing action. In this way, the shearing load will remain concentrated at the cutting edge (426) and the upper primary blade face (228) will apply a vertical force component to aid in separating the tubular (108) at the shearing plane.

[0045] According to embodiments of the present disclosure, an upper blade having a working end with a pocket geometry, e.g., as shown in FIGS. 2-8, may be paired with a lower blade may have a working end with a multi-point geometry, e.g., as described below. According to embodiments of the present disclosure, a multi-point geometry may include multiple points spaced apart (along a blade width dimension) and positioned between jutting edges. In one or more embodiments, a multi-point geometry may include a central point and two peripheral points on opposite sides of the central point, where the central and peripheral points are positioned between and spaced apart along the blade's width dimension.

[0046] FIGS. 9-24 show various views of examples of lower blocks and lower blades having a working end with multi-point geometries in accordance with one or more embodiments. FIGS. 9-14 show a first geometry for the lower blade (302) of the lower block (300) and FIGS. 15-18 show a second geometry for the lower blade (302) of the lower block (300). The difference between the two geometries is the configuration of the points (342), as will be explained in further detail below. FIGS. 19-24 show a third multi-point geometry for a lower blade (502) of a lower block (500).

[0047] FIGS. 9 and 10 show a side angle view of the lower block (300) with the lower blade (302) having the first geometry. FIG. 11 shows a top view of the lower block (300) with the lower blade (302) having the first geometry. FIG. 12 shows an underneath view of the lower block (300) with the lower blade (302) having the first geometry. FIG. 13 shows an angled view of the underneath portion of the lower block (300) with the lower blade (302) having the first geometry. FIG. 14 shows a side view of the first geometry of the lower blade (302) of the lower block (300). FIG. 15 shows a top view of the second geometry of the lower blade (302).FIG. 16 shows a side angle view of the second geometry of the lower blade (302). FIG. 17 shows a side view of the second geometry of the lower blade (302). FIG. 18 shows an angled view of the underneath portion of the second geometry of the lower blade (302).

[0048] In accordance with one or more embodiments, the lower block (300) is located inside the shear ram (112) housing and is configured to move towards the bore (106) whenever the lower block (300) is actuated. The lower block (300) includes the lower blade (302). The lower blade (302) is the portion of the lower block (300) that is directed into the bore (106) and contacts the tubular (108). In accordance with one or more embodiments, the lower blade (302) is made of, for example, high strength steel.

[0049] In accordance with one or more embodiments, the lower block (300) may also include a body that has a first portion (338), a second portion (340), an upper flat surface (304), and a lower flat surface (308). The first portion (338) and the second portion (340) are elevated from the upper flat surface (304) via a wall (318). The first portion (338) and the second portion (340) have a gap (314) located between them. The gap (314) may be used to house an elastomeric seal, which functions to seal the bore (106) once the shear rams (11) are fully closed and shearing is completed. The first portion (338), the second portion (340), and the upper flat surface (304) are located on the upper surface of the lower block (300). The lower flat surface (308) is located on the lower surface of the lower block (300).

[0050] In accordance with one or more embodiments, engagement between the upper and lower blades upon actuation of the blocks may shear the tubular (108) and seal the bore (106) of the BOP (100) if there is a kick.

[0051] In accordance with one or more embodiments, the lower block (300) further includes two lower guide arms (320). The lower guide arms (320) are located opposite one another on the lower block (300) and are located on a plane parallel-to and below the plane on which the lower blade (302) sits. The lower guide arms (320) may be used to assist in tubular (108) centralization and counteract tubular (108) expansion by pushing the tubular (108) away from the outer boundaries of the lower block (300) (see FIGS. 19 and 20).

[0052] The lower blade (302) is formed into a multi-point geometry, which may include two or more points (342). Each point (342) is formed in a rounded-triangular-like shape. The example multi-point geometries shown in the FIGS. 9-18 have three points (342) but this disclosure is meant to encompass any blade that has two or more points (342). The design of the points (342) enable the concentration of shear force and localized shearing of the tubular (108).

[0053] In accordance with one or more embodiments, the lower blade (302) includes a flat leading surface (322), two jutting edges (324), a cutting edge (326), an upper chamfer (328), and a lower primary blade face (330). The flat leading surface (322) runs generally along the lower blade's width dimension between the two jutting edges (324), and protrudes / recedes along the blade's depth dimension as part of the points (342). The points (342) are partially created by the shape in which the flat leading surface (322) follows the lower blade (302). The jutting edges (324) of the lower blade (302) each have inward facing surfaces that descend from the jutting edges (324) into the remainder of the lower blade (302) to form a V-like shape before the lower blade (302) extends back outwards to create one of the points (342). These jutting edges (324) and their inward facing surfaces help to provide an inward reaction force which helps to contain the tubular (108) during the shearing action. In accordance with one or more embodiments, the flat leading surface (322) begins and ends at these inward facing surfaces.

[0054] The flat leading surface (322) is flat in that it's face does not curve outward (convex) or inward (concave) along its thickness between an upper edge and a lower edge. Specifically, the face of the flat leading surface (322) may be a flat surface with an upper edge and a lower edge. In one or more embodiments, the flat leading surface (322) may be a flat surface extending along the blade's thickness dimension perpendicular to the plane along the blade's upper flat surface (336). The upper edge and the lower edge follow the same path along the lower blade (302) as the flat leading surface (322).

[0055] In accordance with one or more embodiments, the cutting edge (326) is the upper edge of the lower blade's flat leading surface (322). The cutting edge (326) is the portion of the lower blade (302) that initiates the cut in the tubular (108). The upper chamfer (328) extends at an angle away from the flat leading surface (322) towards the blade upper flat surface (336). The upper chamfer (328) aids in distributing the load that is concentrated at the cutting edge (326) so that the cutting edge (326) does not become mechanically overloaded and deformed during the shearing process. As the cutting edge (326) shears through the tubular (108), the blade upper flat surface (336) will provide support and separating forces for the upper section of sheared tubular (108). The lower primary blade face (330) extends at an angle away from the flat leading surface (322) towards a ledge (344). The lower primary blade face (330) acts to distribute load on the tubular (108) during the shearing action. In this way, the shearing load will remain concentrated at the cutting edge (326) and the lower primary blade face (330) will apply a vertical force component to aid in separating the tubular (108) at the shearing plane.

[0056] In accordance with one or more embodiments, when the shearing action is completed and the lower block (300) has been pushed into / engaged with the upper block (200), a seal is created between the blade lower flat surface (236) and the blade upper flat surface (336). In accordance with one or more embodiments, an elastomeric seal is located proximate to the blade lower flat surface (236) (e.g., in a groove (240) between the blade lower flat surface (236) and the second lower flat surface (210)). Upon engagement, this elastomeric seal seals between the blade lower flat surface (236) and the blade upper flat surface (336) thus completing the seal across the bore (106) of the BOP (100).

[0057] In accordance with one or more embodiments, the points (342) in the first geometry of the lower blade (302) shown in FIGS. 9-14 extend the same protruding distance (343) away from the remainder of the lower blade (302). This configuration may be beneficial because having central and off-centered points (342) at the same distance away from the remainder of the lower blade (302) means at least one point will engage the tubular (108) no matter the position of the tubular (108) in the containment zone (238) of the upper blade (202). In other embodiments, the points (342) in the second geometry of the lower blade (302) shown in FIGS. 15-18 extend to different protruding distances (343) away from the remainder of the lower blade (302). In accordance with one or more embodiments, the two peripheral points (342) extend a further protruding distance away from the remainder of the lower blade (302) than the central point (342). This configuration may be beneficial because the three points (342) may hit the tubular (108) and distribute the force at the same time.

[0058] According to embodiments of the present disclosure, points in a multi-point geometry may be defined along their sides by curved surfaces, curved relative to the blade's depth and / or width dimensions. For example, as shown in FIG. 11, a point (342) may be defined by curved sides (345) (which may include the flat leading surface (322)) which meet at a rounded tip 346. Further, in one or more embodiments, the curved sides (345) of adjacent points (342) may have curved transitions (347) therebetween, which are curved relative to the blade's depth and width dimensions. In such embodiments, a flat leading surface (322) may be curved relative to the blade's depth and / or width dimensions but flat / planar along the blade's thickness dimension.

[0059] FIGS. 19-24 show another example of a multi-point geometry for the lower blade (502) of the lower block (500) according to embodiments of the present disclosure. FIGS. 19 and 20 show a side angle view of the lower block (500) with the lower blade (502) having the third geometry. FIG. 21 shows a top view of the lower block (500) with the lower blade (502) having the third geometry. FIG. 22 shows an underneath view of the lower block (500) with the lower blade (502) having the third geometry. FIG. 23 shows an angled view of the underneath portion of the lower block (500) with the lower blade (502) having the multi-point geometry. FIG. 24 shows a side view of the multi-point geometry of the lower blade (502) of the lower block (500).

[0060] In accordance with one or more embodiments, the lower block (500) is located inside the shear ram (112) housing and is configured to move towards the bore (106) whenever the lower block (500) is actuated. The lower block (500) includes the lower blade (502). The lower blade (502) is the portion of the lower block (500) that is directed into the bore (106) and contacts the tubular (108). In accordance with one or more embodiments, the lower blade (502) is made of, for example, high strength steel.

[0061] In accordance with one or more embodiments, the lower block (500) may also include a body that has a first portion (538), a second portion (540), an upper flat surface (504), and a lower flat surface (508). The first portion (538) and the second portion (540) are elevated from the upper flat surface (504) via a wall (518). The first portion (538) and the second portion (540) have a gap (514) located between them. The gap (514) may be used to house an elastomeric seal, which functions to seal the bore (106) once the shear rams (11) are fully closed and shearing is completed. The first portion (538), the second portion (540), and the upper flat surface (504) are located on the upper surface of the lower block (500). The lower flat surface (508) is located on the lower surface of the lower block (500).

[0062] In accordance with one or more embodiments, engagement between the upper and lower blades upon actuation of the blocks may shear the tubular (108) and seal the bore (106) of the BOP (100) if there is a kick.

[0063] In accordance with one or more embodiments, the lower block (500) further includes two lower guide arms (520). The lower guide arms (520) are located opposite one another on the lower block (500) and are located on a plane parallel-to and below the plane on which the lower blade (502) sits. The lower guide arms (520) may be used to assist in tubular (108) centralization and counteract tubular (108) expansion by pushing the tubular (108) away from the outer boundaries of the lower block (500) (similar to lower block (300) as in FIGS. 19 and 20).

[0064] The lower blade (502) is formed into a multi-point geometry, which may include two or more points (542). Each point (542) is formed in a rounded-triangular-like shape. The example multi-point geometries shown in the FIGS. 19-24 have two points (542) but this disclosure is meant to encompass any blade that has two or more points. The design of the points (542) enable the concentration of shear force and localized shearing of the tubular (108).

[0065] In accordance with one or more embodiments, the lower blade (502) includes a flat leading surface (522), two jutting edges (524), a cutting edge (526), an upper chamfer (528), and a lower primary blade face (530). The flat leading surface (522) runs generally along the lower blade's width dimension between the two jutting edges (524), and protrudes / recedes along the blade's depth dimension as part of the points (542). The points (542) are partially created by the shape in which the flat leading surface (522) follows the lower blade (502). The jutting edges (524) of the lower blade (502) each have inward facing surfaces that descend from the jutting edges (524) into the remainder of the lower blade (502) to form a V-like shape before the lower blade (502) extends back outwards to create one of the points (542). These jutting edges (524) and their inward facing surfaces help to provide an inward reaction force which helps to contain the tubular (108) during the shearing action. In accordance with one or more embodiments, the flat leading surface (522) begins and ends at these inward facing surfaces.

[0066] The flat leading surface (522) is flat in that its face does not curve outward (convex) or inward (concave) along its thickness between an upper edge and a lower edge. Specifically, the face of the flat leading surface (522) may be a flat surface with an upper edge and a lower edge. In one or more embodiments, the flat leading surface (522) may be a flat surface extending along the blade's thickness dimension perpendicular to the plane along the blade's upper flat surface (536). The upper edge and the lower edge follow the same path along the lower blade (502) as the flat leading surface (522).

[0067] In accordance with one or more embodiments, the cutting edge (526) is the upper edge of the lower blade's flat leading surface (522). The cutting edge (526) is the portion of the lower blade (502) that initiates the cut in the tubular (108). The upper chamfer (528) extends at an angle away from the flat leading surface (522) towards the blade upper flat surface (536). The upper chamfer (528) aids in distributing the load that is concentrated at the cutting edge (526) so that the cutting edge (526) does not become mechanically overloaded and deformed during the shearing process. As the cutting edge (526) shears through the tubular (108), the blade upper flat surface (536) will provide support and separating forces for the upper section of sheared tubular (108). The lower primary blade face (530) extends at an angle away from the flat leading surface (522) towards a ledge (544). The lower primary blade face (530) acts to distribute load on the tubular (108) during the shearing action. In this way, the shearing load will remain concentrated at the cutting edge (526) and the lower primary blade face (530) will apply a vertical force component to aid in separating the tubular (108) at the shearing plane.

[0068] In accordance with one or more embodiments, when the shearing action is completed and the lower block (500) has been pushed into / engaged with the upper block (200), a seal is created between the blade lower flat surface (236) and the blade upper flat surface (536). In accordance with one or more embodiments, an elastomeric seal is located proximate to the blade lower flat surface (236) (e.g., in a groove (240) between the blade lower flat surface (236) and the second lower flat surface (210)). Upon engagement, this elastomeric seal seals between the blade lower flat surface (236) and the blade upper flat surface (536) thus completing the seal across the bore (106) of the BOP (100).

[0069] In accordance with one or more embodiments, the points (542) in the multi-point geometry of the lower blade (502) shown in FIGS. 19-24 extend the same protruding distance (543) away from the remainder of the lower blade (502). This configuration may be beneficial because having off-centered points (542) at the same distance away from the remainder of the lower blade (502) means at least one point will engage the tubular (108) no matter the position of the tubular (108) in the containment zone (238) of the upper blade (202). In other embodiments, the points in the multi-point geometry of the lower blade may extend to different protruding distances away from the remainder of the lower blade.

[0070] According to embodiments of the present disclosure, points in a multi-point geometry may be defined along their sides by curved surfaces, curved relative to the blade's depth and / or width dimensions. For example, as shown in FIG. 21, a point (542) may be defined by curved sides (545) (which may include the flat leading surface (522)) which meet at a rounded tip 546. Further, in one or more embodiments, the curved sides (545) of adjacent points (542) may have curved transitions (547) therebetween, which are curved relative to the blade's depth and width dimensions. In such embodiments, a flat leading surface (522) may be curved relative to the blade's depth and / or width dimensions but flat / planar along the blade's thickness dimension.

[0071] FIG. 25 shows a top view of the upper block (202) and the lower block (300) in accordance with one or more embodiments. This figure shows how the upper block (202) and the lower block (300) may be situated in relation to one another in the shear ram (112). As can be seen in FIG. 25, the tubular (108) is located between the upper blade (202) and the lower blade (302), and, as the upper block (200) and the lower block (300) are actuated and move towards one another, the tubular (108) becomes trapped within a containment zone (238) in the pocket-like geometry of the upper blade (202) and the multi-point geometry of the lower blade (302) enables concentration of shear force and localized shearing on the tubular (108) as the points (342) are pushed into the tubular (108).

[0072] FIG. 26 shows how the upper block (202) and the lower block (300) may be able to successfully shear a tubular (108) no matter how the tubular (108) is situated in the containment zone (238) of the upper blade (202). FIG. 27 shows how the upper guide arms (220) of the upper block (202) can retain and control the deformation of the tubular (108) when the tubular (108) is in the process of being sheared by the shear ram (112).

[0073] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

1. A pair of blades to be provided in a shear ram of a blow-out preventer for cutting a tubular, the pair of blades comprising:an upper blade; anda lower blade configured to shear the tubular in concert with the upper blade, the lower blade having a multi-point geometry configured to initiate shearing of the tubular,wherein the upper blade is configured to guide the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade.

2. The pair of blades as in claim 1, wherein the multi-point geometry of the lower blade comprises two or more points.

3. The pair of blades as in claim 2, wherein the multi-point geometry of the lower blade has two points.

4. The pair of blades as in claim 2, wherein the two or more points are created by inward facing surfaces that descend from one or more jutting edges into the lower blade to form a V-like shape.

5. The pair of blades as in claim 1, wherein the pocket-like geometry of the upper blade comprises two jutting edges with a flat leading surface located between the two jutting edges.

6. The pair of blades as in claim 1, wherein the upper blade is housed in an upper block with two upper guide arms opposite one another on the upper block and located on a plane parallel-to and below the plane of the upper blade, wherein the two upper guide arms are configured to assist in tubular centralization and counteract tubular expansion.

7. The pair of blades as in claim 1, wherein the lower blade is housed in a lower block with two lower guide arms opposite one another on the lower block and located on a plane parallel-to and below the plane of the lower blade, wherein the two lower guide arms are configured to assist in tubular centralization and counteract tubular expansion.

8. A blow-out preventer comprising:a blind ram;a shear ram; anda pipe ram, wherein the blind ram, the shear ram, and the pipe ram each comprise two ram blocks configured to extend into a bore to seal the bore; andwherein the shear ram comprises:an upper blade; anda lower blade configured to shear the tubular in concert with the upper blade, the lower blade having a multi-point geometry configured to initiate shearing of a tubular,wherein the upper blade is configured to guide the tubular into a pocket-like geometry opposite the multi-point geometry of the lower blade.

9. The blow-out preventer as in claim 8, wherein the multi-point geometry of the lower blade comprises two or more points.

10. The blow-out preventer as in claim 9, wherein the multi-point geometry of the lower blade has two points.

11. The blow-out preventer as in claim 9, wherein the two or more points are created by inward facing surfaces that descend from one or more jutting edges into the lower blade to form a V-like shape.

12. The blow-out preventer as in claim 8, wherein the pocket-like geometry of the upper blade comprises two jutting edges with a flat leading surface located between the two jutting edges.

13. A method of shearing a tubular, comprising:positioning the tubular in a cavity of a blow-out preventer, within a shear ram, between an upper blade and a lower blade,wherein the lower blade has a multi-point geometry, andwherein the upper blade has a pocket-like geometry opposite the multi-point geometry of the lower blade,actuating the shear ram, the actuating comprising moving the lower blade to shear the tubular in concert with the upper blade,wherein the pocket-like geometry holds the tubular within a containment zone within the pocket-like geometry, andwherein, while the tubular is held within the containment zone, at least one point in the multi-point geometry contacts and initiates the shearing of the tubular by concentrating forces at the at least one point to locally tear the tubular at the at least one point.

14. The method of 13, further comprising containing the tubular within an inner profile of the cavity using guide arms positioned on opposite sides of the pocket-like geometry, wherein the guide arms prevent expansion of the tubular out of the pocket-like geometry during shearing.

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