This disclosure relates in general to oil and gas tools, and in particular, to systems and methods for shearing lines or pipes.
In oil and gas production, drilling and recovery may occur in high pressure environments where various tools may be utilized to control wellbore pressures. For example, a blowout preventer or the like may be arranged at an entrance to the wellbore. During operations, equipment may pass through the blowout preventer and, if necessary, the blowout preventer may be utilized to seal the wellbore to reduce the likelihood of uncontrolled releases from the wellbore. One component of the blowout preventer may be a shear ram. The shear ram may be a hydraulically driven component that drives cutting edges of two components toward one another to contact and shear the components between, such as wirelines or piping. However, the shear rams may be subject to excessive stresses during operation, and as a result, may wear out quickly. Repairs may be expensive or time consuming.
Applicants recognized the problems noted above herein and conceived and developed embodiments of systems and methods, according to the present disclosure, for shear rams.
In an embodiment, a shear ram system includes an upper block coupled to a first arm, the upper block positioned to transition from a first location outside a bore to a second location within the bore, the upper block including a blade control arm having a first contact surface extending along a first length. The shear ram system also includes a lower block coupled to a second arm, the lower block positioned to transition from the first location outside the bore to the second location within the bore, the lower block including a second contact surface positioned proximate the first contact surface. The shear ram system further includes a progressive gap between the first contact surface and the second contact surface, the progressive gap being larger at a first end than at a second end such that a first gap distance at the first end is greater than a second gap distance the second end.
In another embodiment, a blowout preventer includes a tubular fluidly coupled to a wellbore, the tubular having a bore; and a pressure control device positioned to extend into the bore. The pressure control device includes an upper block arranged proximate the bore in a first position and within the bore in a second position, the upper block including a blade control arm having a first contact surface. The pressure control device also includes a lower block arranged proximate the bore in a first position and within the bore in a second position, the lower block including a second contact surface that faces the first contact surface. The pressure control device further includes a progressive gap between the first contact surface and the second contact surface, the progressive gap being larger at a first end than at a second end such that a first gap distance at the first end is greater than a second gap distance the second end.
In an embodiment, a blowout preventer includes a tubular fluidly coupled to a wellbore, the tubular having a bore and a pressure control device positioned to extend into the bore. The pressure control device includes an upper block adapted to translate into the bore, the upper block including a first contact surface. The pressure control device also includes a lower block adapted to translate into the bore, the lower block including a second contact surface, wherein the first contact surface and the second contact surface are opposite facing. The pressure control device further includes a progressive gap between the first contact surface and the second contact surface, the progressive gap formed when the first contact surface and the second contact surface complete a shearing stroke, wherein a first gap distance at a first end of the first contact surface is greater than a second gap distance at a second end of the first contact surface.
The present technology will be better understood on reading the following detailed description of non-limiting embodiments thereof, and on examining the accompanying drawings, in which:
The foregoing aspects, features and advantages of the present technology will be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the preferred embodiments of the technology illustrated in the appended drawings, specific terminology will be used for the sake of clarity. The present technology, however, is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose.
When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Any examples of operating parameters and/or environmental conditions are not exclusive of other parameters/conditions of the disclosed embodiments. Additionally, it should be understood that references to “one embodiment”, “an embodiment”, “certain embodiments,” or “other embodiments” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, reference to terms such as “above,” “below,” “upper”, “lower”, “side”, “front,” “back,” or other terms regarding orientation are made with reference to the illustrated embodiments and are not intended to be limiting or exclude other orientations.
Embodiments of the present disclosure include systems and methods to keep the cutting edges of a wireline blind shear ram in close proximity to one another during a wireline (or submersible that includes wireline as a component) shearing operation.
For example, the design of the present technology can use high bending capacity arms on an upper carrier that interface with landing surfaces on a lower carrier. These control surfaces allow the lower carrier to be lifted upwards so that the blade edges on the lower and upper carriers are positioned by as few machined surfaces as possible (e.g., a limited number of machined surfaces). This arrangement helps to provide a close clearance between the blades of the upper and lower carriers. In addition, in some embodiments replaceable wear inserts can be located on the arms of the upper ram block. Such replaceable wear inserts can be composed of softer materials than the ram arms, and are intended to take the brunt of wear and damage during cycling and shearing. Recessed areas can be machined or otherwise introduced into the lower ram block to help the arms of the upper carrier disengage from the lower block after shearing has occurred and the rams are fully closed. Such a recess is advantageous because when the wellbore pressure deflects the rams upwards the arms of the upper carrier will not be in the load path. Although the present technology as shown and described herein includes arms attached to the upper carrier and recesses defined by the lower carrier, it is to be understood that other appropriate configurations can fall within the scope of the technology. For example, in some embodiments the arms can be associated with the lower carrier and the recess with the upper carrier.
The present technology provides many advantages of known systems. For instance, in known systems cutting small diameter wire typically requires adjustment or tightening of the gap between the upper and lower carrier blades. The present technology reduces or eliminates the need to adjust or tighten the blades because the geometry of the upper carrier arms and the landing surfaces on the lower carry maintains a tight gap between the blades without the need for such adjustment.
Another advantage over known systems is that the present technology does not require an interference fit between components, and therefore does not wear down as quickly as known systems in the field. This allows for relatively inexpensive and efficient field replacements to be made to maintain the equipment.
In addition, known systems include small guide pins that connect into holes in the lower block. These pins remain in the load path during pressurization, and can incur damage from deflection of the components under pressure. In contrast, the design of the present technology may engage the controlling arms only during the shearing sequence. However, it should be appreciated that engagement of the controlling arms may also occur at other times. Once shearing is completed, the arms are released and remain out of the load path during pressurization. This helps to ensure that no damage or accelerated wear occurs.
Another advantage to the present technology is that it uses intentional wear items to control the service life of more expensive components. For example, there is a phased sequence of controlling surfaces that allow for a tight blade fit up during shear and then a subsequent release of those surfaces during pressurization to prevent unnecessary damage and/or wear to the critical components. The design advantageously does not rely on interference fit between components like other known systems. Such known interference fits reduce life of the components.
Embodiments may also include one or more features that enable centralization of a wellbore component, such as a wireline, and also a reduction in stress. Blades used on shearing rams may not cover the full wellbore diameter because of an interface dilemma with the sealing system. Normally, this is of little to no consequence because almost all drillpipe is large enough to be centered by the blade alone. However, when wireline is being sheared, it is small enough to fall outside of the blade range, and as a result, a centralizer may be used to bring it back into position. Moreover, ram block stress is generally derived from bearing stress loads on the surfaces between the upper and lower block. Problems can occur when the high bearing stresses are adjacent to critical surfaces such as seal surfaces, hardfacing, and stress concentrations. This centralizing feature also serves as a bearing surface between the upper and lower blocks. The surface is located far away from any critical surfaces and therefore helps to guard those sensitive areas from damage.
Embodiments of the present disclosure include a shear ram system that includes a progressive gap between contact surfaces of an upper block and a lower block. The progressive gap is narrower proximate a body of the upper block and larger at an end of a blade control arm. In various embodiments, the progressive gap is particularly selected and sized to accommodate pressures, such as wellbore pressures, which may deflect the blade control arm toward the lower block, which could potentially damage or wear the components. By maintaining the progressive gap, or a substantially constant gap when pressure is within the system, frictional forces between various contact surfaces may be reduced, which may increase the life of components of the system. Additionally, the progressive gap provides efficient use of the available material. For example, if excessive material is used (e.g., more than a threshold or baseline amount), the design may be compromised in regard to stress. The progressive contour is particularly selected to strike a balance between the gap to disconnect the arms when desired and maintaining material enough for proper safety factors and product service life. Furthermore, in embodiments, one or both of the upper block and the lower block may include a centralizer feature to position wellbore components for shearing via the shear ram system, as well as to reduce stresses as various locations.
The wellbore system 100 includes a wellhead assembly 112, shown at an opening of the wellbore 104, to provide pressure control of the wellbore 104 and allow for passage of equipment into the wellbore 104, such as the cable 110 and the tool 102. In this example, the cable 110 is a wireline being spooled from a service truck 114. The wellhead assembly 112 may include a blowout preventer (BOP) 116 (e.g., pressure control device) that comprises shear rams that may be utilized to shear components extending through BOP 116. As will be described below, in various embodiments the shear rams may be energized to move from a position outside of a bore of the BOP 116 to a position within the bore of the BOP 116. The shear rams may cut the cable 110 in the illustrated embodiment to thereby facilitate closure of the wellbore 104. Furthermore, it should be appreciated that the seal rams may also shear and seal across drill pipe, casing, shear subs or combinations of pipe, control lines, tubing, hoses, and/or wireline. Accordingly, while embodiments herein may be described with respect to shearing the cable 110, it should be appreciated that various other downhole components may be sheared that features of the present disclosure may facilitate and improve those shearing operations as well.
The illustrated shear ram system 300 includes an upper block 302 and a lower block 304, which may also be referred to as rams. In the illustrated embodiment, the upper block 302 and the lower block 304 are blind rams. As would be appreciated by one skilled in the art, a blind shear ram may operate to seal a wellbore, even when the wellbore is occupied by an object, such as a wireline or drilling string. While embodiments described herein may refer to a blind shear ram, it should be appreciated that other rams, such as a ripe ram or dual offset ram, may also be utilized.
As shown, the upper block 302 includes a blade control arm 306 at a lower portion thereof and a blade 308 opposite the blade control arm 306. In operation, the upper block 302 is driven in the first direction 210 toward the lower block 304 such that the blade control arm 306 is nested within a pocket 310 formed in the lower block 304. The lower block 304 further includes a second blade 312, which may be utilized to sever the wireline and/or pipe arranged within the bore 214.
In the illustrated embodiment, the upper block 302 includes a wear insert 314 arranged within a recess 316 formed within the blade control arm 306. The wear insert 314 may be formed from a material that is softer than other components of the upper block 302, such as the wear control 306, blade 308, a lower block contact surface, the second blade 312, or the like. As will be described below, in operation at least a portion of the blade control arm 306, such as the wear insert 314, may contact at least a portion of the lower block 304. The wear insert 314 may be utilized to accept any wear and/or degradation from the contact and, thereafter, serve as a replaceable component that may be easily repaired.
The embodiment of
In the illustrated embodiment, the blade control arm 306 includes a downwardly sloped surface 706 extending for a second length 708, which is less than the length 602 of the blade control arm 306. The slope of the surface 706 may be particularly selected based on a variety of factors, such as anticipated operating conditions, material forming the upper block 302, and the like. The illustrated downwardly sloped surface 706 terminates at a step 710, but it should be appreciated that a more gradual ending may be included toward the recess 316 that receives the wear insert 314. In the illustrated embodiment, a wear insert height 712 is larger than an ending height 714 of the downwardly sloped surface 706, but less than a starting height 716. However, in various embodiments, the respective heights may be adjusted.
The pocket 310 of the lower block 304 is shaped to receive the blade control arm 306 and includes a second downwardly sloped surface 718 arranged proximate the downwardly sloped surface 706. In the illustrated embodiments, an angle 720 of the downwardly sloped surface 706 is different than an angle 722 of the second downwardly sloped surface 718. As described above, this difference in angle may enable the progressive gap 720. The second downwardly sloped surface 718 has a third length 724, which is shorter than the second length 708. The second downwardly sloped surface 718 is connected to a transition 726, which is upwardly sloped, and further extends to a substantially planar surface 728. As illustrated, a portion of the transition 726 and planar surface 728 are aligned with the wear insert 314. Because the transition 726 is upwardly sloped, a greater gap distance 700 is enabled. As noted above with respect to the upper block 302, in various embodiments the components, dimensions, and the like of the lower block 304 may also be particularly selected based on operating conditions.
In various embodiments, the various gap distances 700, 702, and 704 may be particularly selected in order to maintain a substantially uniform gap distance between the blade control arm 306 and the lower block 304 (e.g., at least a portion of the lower contact surface 320). That is, after deflection, it may be desirable for the progressive gap 600 to be substantially equal along the length 602 of the blade control arm 306, as well as at the wear insert 314. However, it should be appreciated that maintaining the progressive gap 600 may also be desirable, as including any gap may reduce the likelihood of deformation and/or wear between at least a portion of the upper contact surface 318 and the lower contact surface 320. Additionally, the progressive gap 600 may be designed to enable efficient use of the available material. For example, if excessive material is used (e.g., more than a threshold or baseline amount), the design may be compromised in regard to stress. The progressive contour is particularly selected to strike a balance between the gap to disconnect the arms when desired and maintaining material enough for proper safety factors and product service life.
While the above-described progressive gap 600 and wear insert 314 may be helpful to reduce wear between components of the shear ram system 300, in various embodiments it may be challenging to position small diameter components, such as the cable 110, within a region of the shear ram system 300 to enable the blades 308, 312 to shear the line. Accordingly, in various embodiments, one or more centralizing features may further be positioned proximate the above-described blade control arm 306.
As shown, the centralizer 802 is arranged below (relative to a direction of flow into the wellbore) the blade 312. Furthermore, the centralizer 802 illustrated in
In the illustrated embodiment, the centralizer 802 includes a height 910, which may be particularly selected based on various factors, such as a size of the BOP. The height 910 may be selected, as least in part, as a ratio of other components of the lower block 304, such as the blade 312, but in other embodiments the height 910 may be designed separately. As will be described below, in operation the centralizer 802 may engage a slot formed in the upper block 302.
Although the technology herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present technology. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present technology as defined by the appended claims.
This application claims priority to U.S. Provisional Application No. 62/655,485 filed Apr. 10, 2018 titled “WIRELINE BLIND SHEAR RAM,” the disclosure of which is incorporated herein by reference in its entirety.
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Number | Date | Country | |
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Number | Date | Country | |
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