BACKGROUND

[0001] The field of the disclosure relates generally to a blowout preventer (BOP) for oil and gas wells, and more particularly, to a variable ram for a BOP.

[0002] Most known BOPs mount on top of a wellhead and provide a means to regulate the pressure of a wellbore. Variable bore rams typically include a pair of rams on opposing sides of a BOP stack that actuate to form a sealed arrangement with a drill pipe. When the variable bore rams are actuated radially inward, the inner most bore face contacts the outer surface of a drill pipe and forms a sealing arrangement. Some known variable rams include metallic inserts and elastomer packers that cooperate as a coherent unit to create a seal across drill pipes of different sizes.

[0003] Many known variable rams can only seal-off a range of pipe sizes ranging from L to L/2 (where L is the circumferential length of all inserts placed side by side). BOPs therefore require at least two variable bore rams in the BOP stack to cover the entire range of pipe sizes, which adds extra cost and complexity to the BOP design. Furthermore, the contact pressure between a typical variable ram and the pipe is limited to the force transmitted by the operator to the rubber on the sealing surface. The force transmitted may not be adequate for sealing high wellbore pressure or could cause excessive strain on the variable ram.

BRIEF DESCRIPTION

[0004] In one aspect, a variable ram packer for a blowout preventer (BOP) is provided. The variable ram packer includes a body with a bore contact region, at least one fluidic flexible matrix component (FFMC) tube, an inflation mechanism, and a fluid port. The FFMC tube is positioned inside the body next to the bore contact region. The fluid port is fluidly coupled with a connecting line, which is fluidly coupled with the inflation mechanism. The FFMC tube inflates in response to an increase in pressure from the inflation mechanism, which translates the bore contact region inward. [0005] In another aspect, a variable bore ram assembly for a BOP is provided. The variable bore ram assembly includes at least one ram block and at least one variable ram packer inside at least one ram block. The variable ram packer includes a body with a bore contact region, at least one FFMC tube, an inflation mechanism, and a fluid port. The FFMC tube is positioned inside the body next to the bore contact region. The fluid port is fluidly coupled with a connecting line, which is fluidly coupled with the inflation mechanism. The FFMC tube inflates in response to an increase in pressure from the inflation mechanism, which translates the bore contact region inward.

[0006] In yet another aspect, a method of using a variable ram packer for use within a blowout preventer is provided. The variable ram packer includes a body with a bore contact surface, a plurality of packer inserts designed to rotate radially inward, at least one FFMC tube inside the body adjacent to the bore contact region, and a fluid port inside the body. The fluid port is fluidly coupled with a connecting line, which is fluidly coupled with the inflation mechanism. The method includes translating a variable ram packer into a first closed position around a drill pipe. The method further includes rotating the plurality of packer inserts radially inward to a second closed position around the drill pipe. The method further includes translating the bore contact region to seal with the drill pipe by inflating the FFMC tube. The FFMC tube is inflated by activating the inflation mechanism to increase the pressure of a fluid inside the FFMC tube.

DRAWINGS

[0007] These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:

[0008] FIG. 1 is a schematic view of an exemplary blowout preventer

(BOP) stack;

[0009] FIG. 2 is an isometric view of an exemplary variable bore ram in an open position that is used with the BOP shown in FIG. 1 ; [0010] FIG. 3 is a top plan view of exemplary variable bore ram packers in a first closed position used with the variable bore ram shown in FIG. 2;

[0011] FIG. 4 is a perspective view of an exemplary fluidic flexible matrix composite (FFMC) tube used with the variable bore ram packer shown in FIG.

3;

[0012] FIG. 5 is a top plan view of the variable bore ram packers shown in FIG. 3 in a second closed position; and

[0013] FIG. 6 is a top plan view of the variable bore ram packers shown in FIG. 3 in a third closed position.

[0014] Unless otherwise indicated, the drawings provided herein are meant to illustrate features of embodiments of this disclosure. These features are believed to be applicable in a wide variety of systems comprising one or more embodiments of this disclosure. As such, the drawings are not meant to include all conventional features known by those of ordinary skill in the art to be required for the practice of the embodiments disclosed herein.

DETAILED DESCRIPTION

[0015] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings.

[0016] The singular forms "a", "an", and "the" include plural references unless the context clearly dictates otherwise.

[0017] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0018] "Variable bore ram" and "variable ram" are used interchangeably, unless the context clearly dictates otherwise. [0019] Pipe sizes "L" and "L/2" are used herein to denote the diameter of the pipe that the variable bore ram can seal against. Many known variable bore rams specify an upper limit, L, of the largest diameter pipe they can seal against. These known variable bore rams have a lower limit of about one-half the diameter of L, i.e., L/2, which indicates the smallest diameter pipe they can seal against.

[0020] Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about", "approximately", and "substantially", are not to be limited to the precise value specified. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range limitations may be combined and/or interchanged; such ranges are identified and include all the sub-ranges contained therein unless context or language indicates otherwise.

[0021] The variable bore ram for a blowout preventer (BOP) described herein facilitates increasing the variety of drill pipe sizes that the variable bore ram can engage. Many known variable bore rams can seal a pipe of size L/2 in diameter. Specifically, adding a fluidic flexible matrix composite (FFMC) tube behind the bore contact region facilitates translating the bore contact region into a sealed arrangement with the drill pipe once the FFMC tube is inflated by pressurized fluid. The FFMC tube pressurizes to seal pipes of smaller diameters than L/2. The increased sealing effect of the pressurized FFMC tube potentially eliminates the need of one or more additional variable bore rams in the BOP stack. By eliminating additional variable bore rams in the BOP stack, the infrastructure surrounding the BOP is simplified, reducing the plumbing and controls necessary to run an additional variable bore ram.

[0022] FIG. 1 is a schematic view of an exemplary blowout preventer (BOP) stack 100. BOP stack 100 surrounds a drill pipe 101 and mounts on top of a wellhead connector 102 that includes both a wellhead and a tree (not shown). Known BOP stacks, such as BOP stack 100, typically include a test ram 103, a plurality of variable bore rams 104, a plurality of shear rams 105, a plurality of annular rams 106, and a plurality of control pods 107.

[0023] FIG. 2 is an isometric view of an exemplary variable bore ram 104 in an open position that is used with BOP 100 (shown in FIG. 1). Variable bore ram 104 includes two opposed variable ram packers 110, 112, each housed with a respective ram block 1 14, 1 16. Variable ram packers 1 10, 112 are replaced when sufficiently worn and are therefore removed and replaced by inserting a new set of variable ram packers 1 10, 1 12 into ram block 114, 116. When variable bore ram 104 is in use, ram blocks 114, 116 are actuated or translated toward each other, typically through piston or hydraulic means, such that ram blocks 1 14, 1 16 couple together and packers 110, 1 12 couple together to define a substantially circular bore 118. Bore 1 18 is configured to receive drill pipe 101, around which variable ram packers 110, 1 12 form a sealing arrangement as described herein.

[0024] Although variable bore ram 104 is shown in an open position in this view, the embodiments disclosed below show variable bore ram 104 in a variety of closed positions. Ram blocks 114, 116 are piston-actuated or translated into a first closed position (shown in FIG. 3), where a bore 118 is configured to receive pipe 101 of diameter L. Alternatively, ram blocks 1 14, 116 are hydraulically actuated or translated into a first closed position, or actuated or translated by any other suitable means to couple packers 110, 112 to define bore 118. If variable bore ram 104 needs to seal a smaller pipe 101 with a diameter as small as L/2, variable ram packers 110, 1 12 are piston actuated or translated or hydraulically actuated or translated to a second closed position (shown in FIG. 5). If variable bore ram 104 needs to seal a pipe 101 with a diameter smaller than L/2, variable ram packers 110, 1 12 are inflated, as described herein, to a third closed position (shown in FIG. 6).

[0025] FIG. 3 is a top plan view of exemplary variable bore ram packers 110, 112 in a first closed position used with variable bore ram 104 (shown in FIG. 2). Packer 1 10 is substantially symmetrical to packer 1 12, such that packer 110 receives packer 1 12 when in a sealed arrangement. Ram blocks 1 14, 1 16 (shown in FIG. 2) and the corresponding variable ram packers 110, 1 12 are piston-actuated or translated into a first closed position, where a bore 118 is configured to receive pipe 101 of diameter L. Alternatively, packers 1 10, 112 are hydraulically actuated or translated into a first closed position, or actuated or translated by any other suitable means to couple packers 1 10, 1 12 to define bore 1 18. The parts of packer 110 disclosed herein describe the same or similar parts on packer 112.

[0026] Packer 1 10 includes body 120, including a contact region 130 and a non-contact region 131. The remaining portion of body 120 of packer 110 that is not contact region 130 is non-contact region 131 of packer 110. Contact region 130 includes both a bore contact region 132 and a packer contact region 134. Bore contact region 132 is adjacent to packer contact region 134 laterally on both sides of bore contact region 132. Bore contact region 132 is at least partially arcuate, i.e. semicircular or arcual, to receive drill pipe 101 when in a sealed position. Bore contact region 132, as described herein, is also known as a tubular contact region or a bore-face region, and includes the extent of contact region 130 that seals with drill pipe 101.

[0027] Packer 1 10 includes one or more packer pins 142 coupled to body 120 that enable packer 1 10 to couple to ram block 1 14. Packer pins 142 provide a means to couple packer 1 10 to ram block 1 14. Body 120 further includes packer inserts 144, which are triangular-shaped members arranged around bore 1 18 and are positioned axially juxtaposed above and below bore contact region 132. Packer inserts 144 are configured to rotate radially inward towards bore 118 to provide support for bore contact region 132. Packer inserts 144 extend radially outward from bore 1 18 to non-contact region 131. Body 120 also includes a fluidic flexible matrix composite (FFMC) tube 150 disposed within body 120 and extending semi-circularly inside body 120, recessed from bore contact region 132, but circumferentially extending around bore contact region 132 to define a channel 152. In the embodiment, shown in the first closed position, FFMC tube 150 is in a deflated position, as described herein. FFMC tube 150 is fluidly coupled to fluid port 156, which is fluidly coupled to connecting line 157, which fluidly couples to inflation mechanism 158.

[0028] FIG. 4 is a perspective view of an exemplary fluidic flexible matrix composite (FFMC) tube 150 used with the variable bore ram packer shown in FIG. 3. In one embodiment, FFMC tube 150 includes an inner liner 162 and an outer tube 164. Inner liner 162 is disposed substantially entirely inside outer tube 164. Outer tube 164 includes a plurality of interwoven fibers 166. At rest, interwoven fibers 166 are positioned at substantially equal and opposite angles 167, 168 above and below longitudinal axis 169. Inner liner 162 defines an inner volume 172 of FFMC tube 150. As fluid is applied to inner liner 162, and the pressure within inner volume 172 increases, radially outward pressure is applied to outer tube 164, causing outer tube 164 to expand radially, i.e., inflating FFMC tube 150. As the pressure increases, interwoven fibers 166 displace from their resting angles 167, 168 and interlock at a predetermined weave angle 174, preventing FFMC tube 150 from further inflation. In one embodiment weave angle 174 is between about 40 degrees and about 60 degrees, and more specifically between about 45 degrees and about 54 degrees. Interwoven fibers 166 can be made of a polymer based material including, but not limited to, nylon, rayon, or metal such as steel or Inconel. Inner liner 162 can be made of materials including, but not limited to, fluorocarbon elastomer material (FKM), perfluoro-elastomers (FFKM), tetrafluoro ethylene propylene rubber (FEPM), hydrogenated nitrile butadiene rubber (HNBR), carboxylated nitrile butadiene rubber (XNBR), or any suitable material that enables an operator to inflate FFMC tube 150.

[0029] FIG. 5 is a top plan view of variable bore ram packers 110, 112 (shown in FIG. 3) in a second closed position. Ram blocks 114, 116 are actuated or translated into a first closed position (shown in FIG. 3), where bore 118 is configured to receive pipe 101 of diameter L. If variable bore ram 104 needs to seal a smaller pipe 101 with a diameter as small as L/2, variable ram packers 110, 112 are actuated or translated to a second closed position (shown in FIG. 5) by rotating packer inserts 144 radially inward towards bore 118. Many known variable bore rams are limited by the ability to seal around a pipe size of only L/2.

[0030] FIG. 6 is a top plan view of variable bore ram packers 110, 112 (shown in FIG. 3) in a third closed position. After packers 110, 112 are actuated or translated to a second closed position, if variable bore ram 104 needs to seal a pipe 101 with a diameter smaller than L/2, variable ram packers 110, 112 are inflated to a third closed position. As such, FFMC tube 150 is not solely a seal or a packer element, but inflates to tighten bore contact region 132 around smaller pipe sizes than L/2. Inflation mechanism 158 pumps fluid into FFMC tube 150 causing FFMC tube 150 to expand radially, thereby translating bore contact region 132 radially inward to seal against pipe 101 smaller than L/2. Inflation mechanism 158 fluidly coupled with connecting line 157 fluidly coupled with fluid port 156 fluidly coupled with FFMC tube 150. Inflation mechanism 158 is any mechanism suitable for inflating FFMC tube 150. In one embodiment, inflation mechanism 150 is a hydraulic mechanism. In another embodiment, inflation mechanism 158 is a pneumatic mechanism. In one embodiment, fluid port 156 is fluidly coupled with FFMC tube 150 and extends radially outward from FFMC tube 150 such that connecting line 157 extends out of the back of packer 110. In another embodiment, fluid port 156 is coupled with FFMC tube 150 and extends axially upward, such that connecting line 157 extends through the top of packer 110. Any suitable fluid is used to apply pressure to the inner walls of inner liner 162 and therefore inflate FFMC tube 150. In one embodiment, a fluid with a bulk modulus of greater than 2.0 gigapascals (GPa) is used, such as, and without limitation, water.

[0031] The above-described variable bore ram described herein overcomes several deficiencies associated with known blowout preventers (BOP). Many known variable bore rams can seal a pipe of size L/2 in diameter. Specifically, adding a fluidic flexible matrix composite (FFMC) tube behind the bore contact region facilitates translating the bore contact region into a sealed arrangement with the drill pipe once the FFMC tube is inflated by pressurized fluid. The FFMC tube pressurizes to seal pipes of smaller diameters than L/2. The increased sealing effect of the pressurized FFMC tube potentially eliminates the need of one or more additional variable bore rams in the BOP stack. By potentially eliminating additional variable bore rams in the BOP stack, the infrastructure surrounding the BOP is simplified, reducing the plumbing and controls necessary to run an additional variable bore ram.

[0032] An exemplary technical effect of the methods, systems, and apparatus described herein includes at least one of: (a) potentially eliminating the need of one or more additional variable bore rams on the BOP stack by increasing the contact pressure between the variable bore ram and the drill pipe by inflating the FFMC tube; (b) eliminating the need for surrounding infrastructure, such as plumbing and controls, for the one or more additional variable bore rams on the BOP stack; (c) sealing against a large wellbore pressure without excessive strain along the bore contact region; and (d) increasing the variety of drill pipe sizes that the variable bore ram can engage over many known variable bore rams that can only seal against a drill pipe between L and L/2 in diameter.

[0033] Exemplary embodiments of a variable bore ram are described above in detail. The variable bore ram and methods of manufacturing or operating such a system and device are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein. For example, the systems, apparatus, and methods may also be used in combination with other types of rams for BOPs, such as fixed bore rams or annular rams, and are not limited to practice with only the devices, systems and methods as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other applications, equipment, and systems that may benefit from using an FFMC tube for inflating around a pipe or regulating pressure of a pipe.

[0034] Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the disclosure, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

[0035] This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.