Patent Description:
The invention relates generally to riser assemblies for use in drilling operations and, more particularly, but not by way of limitation, to riser assemblies that can be lowered through a rotary of an offshore platform for assembly of auxiliary components below the rotary.

Offshore drilling operations have been undertaken for many years. Traditionally, pressure within a drill string and riser pipe have been governed by the density of drilling mud alone. More recently, attempts have been made to control the pressure within a drill string and riser pipe using methods and characteristics to the density of drilling mud. Such attempts may be referred to in the art as managed pressure drilling (MPD). See, e.g., <NPL>.

<CIT> suggests a pump module for maintaining a select-ed wellbore pressure. The pump module is coupled to a segment of a riser and has a fluid inlet in fluid communication with an intake of the pump. The fluid inlet is configured to provide a fluid tight hydraulic connection to a fluid outlet of the riser segment when the frame is coupled thereto.

<CIT> discloses a diverter for diverting mud, cuttings and natural resources from coming through a riser. The diverter comprises blind pipe having lateral openings being connected via valves and a gooseneck connection to a drape hose.

MPD techniques generally require additional or different riser components relative to risers used in conventional drilling techniques. These new or different components may be larger than those used in conventional techniques. For example, riser segments used for MPD techniques may utilize large components that force auxiliary lines to be routed around those components, which can increase the overall diameter or transverse dimensions of riser segments relative to riser segments used in conventional drilling techniques. However, numerous drilling rigs are already in existence, and it is generally not economical to retrofit those existing drilling rigs to fit larger riser segments.

Currently, MPD riser segment assemblies and/or components with an overall diameter or other transverse dimension that is too large to fit through a rotary or rotary table of a drilling rig must be loaded onto the rig below the deck (e.g., on the mezzanine level) and moved laterally into position to be coupled to the riser stack below the rotary. This movement of oversize components is often more difficult than vertically lowering equipment through the rotary from above (e.g., with a crane).

The above outlined problems are addressed by the invention as defined by the independent claim <NUM>. Advantageous embodiments of the invention are subjects of the dependent claims.

At least some of the disclosed riser segment assemblies can address this issue for MPD-capable flow spool components by allowing a flow spool riser segment to be lowered through a rotary and having portions of the flow spool connected (e.g., without welding) below the rotary (e.g., portions that would prevent the flow spool segment from passing through the rotary if those portions were connected before the flow spool is passed through the rotary).

Some embodiments of the present riser segment assemblies comprise: a main tube defining a primary lumen; a collar defining a lateral opening in fluid communication with the primary lumen; and a valve coupled to the lateral opening, the valve having a longitudinal flow axis that is more parallel than perpendicular to a longitudinal axis of the main tube. Some embodiments further comprise: two flanges each coupled to a different end of the main tube, each flange comprising: a mating face configured to mate with a flange of an adjacent riser segment; and a central flange lumen configured to be in fluid communication with the primary lumen of the main tube. In some embodiments, the collar is unitary with one of the two flanges. In some embodiments, the lateral opening is not threaded. In some embodiments, the valve comprises a double ball valve.

Some embodiments of the present riser segment assemblies further comprise: a fitting coupled to the collar over the lateral opening and to the valve, the fitting defining a fitting lumen in fluid communication with the lateral opening. In some embodiments, a portion of the fitting that is closer to the valve than to the collar has a longitudinal axis that is substantially parallel to a longitudinal axis of the main tube. Some embodiments further comprise: a first connector secured to the fitting and to a first end of the valve, a second connector secured to a second end of the valve and having a protrusion, and a third connector configured to be coupled to the main tube and defining a recess configured to slidably receive the protrusion of the second connector to provide a sealed connection between the second connector and the third connector. In some embodiments, the third connector defines a lumen having an inlet through which fluid can enter the third connector in a first direction, and an outlet through which fluid can exit the third connector in a second direction that is different than the first direction. In some embodiments, the second direction is substantially opposite the first direction. In some embodiments, the third connector further defines a secondary lumen with a second exit sealed by a removable cover, the second exit configured such that if the cover is removed, fluid can exit the third connector in a third direction that is different than the first direction and the second direction. Some embodiments further comprise: a retainer coupled to the main tube and configured releasably engage the third connector without welding to secure the third connector in fixed relation to the main tube. In some embodiments, the retainer includes a body having a recess configured to receive a portion of the third connector to restrict lateral movement of the third connector relative to the main tube. In some embodiments, the retainer includes one or more movable members pivotally coupled to the body and movable between an open position in which the third connector is permitted to enter or exit the recess of the body, and a closed position in which the one or more movable members prevent the third connector from entering or exiting the recess of the body.

In some embodiments of the present riser segment assemblies, the maximum transverse dimension of the assembly is less than <NUM> (<NUM> inches). In some embodiments, the maximum transverse dimension of the assembly is greater than <NUM> (<NUM> inches) if the second connector is coupled to main tube, and is less than <NUM> (<NUM> inches) if the second connector is not coupled to the fitting. In some embodiments, the fitting and the collar are configured to form a substantially gapless connection comprising: a female flange having an inward-facing conically tapered sealing surface; a male flange having an outward-facing conically tapered sealing surface; and a seal ring having an outward-facing conically tapered surface complementary to the sealing surface of the female flange; and an inward-facing conically tapered surface complementary to the sealing surface of the male flange; where the seal ring is positioned between the male and female flanges with the conically tapered surfaces of the seal ring in contact with the complementary sealing surfaces of the male and female flanges and the male and female flanges are coupled together to form a connection between the primary lumen of the main tube and the fitting lumen of the fitting; where one of the collar and the fitting defines the female flange, and the other of the collar and the first defines the male flange; and where an interface between male flange and the female flange is substantially free of gaps.

In some embodiments of the present riser segment assemblies, the collar defines a second lateral opening in fluid communication with the primary lumen of the main tube, and the assembly further comprises: a second valve coupled to the second lateral opening, the second valve having a longitudinal flow axis that is more parallel than perpendicular to a longitudinal axis of the main tube. Some embodiments further comprise: a second fitting coupled to the collar over the second lateral opening and to the second valve, the second fitting defining a fitting lumen in fluid communication with the second lateral opening. In some embodiments, the present riser segment assemblies are located in a riser stack between an isolation unit and a formation.

Some embodiments of the present riser segment assemblies comprise: a main tube defining a primary lumen; a collar defining a lateral opening in fluid communication with the primary lumen; and a fitting coupled to the collar over the lateral opening and configured to be removably coupled to a valve assembly, the fitting defining a fitting lumen in fluid communication with the lateral opening. Some embodiments further comprise: two flanges each coupled to a different end of the main tube, each flange comprising: a mating face configured to mate with a flange of an adjacent riser segment; and a central flange lumen configured to be in fluid communication with the primary lumen of the main tube. In some embodiments, the collar is unitary with one of the two flanges. In some embodiments, the lateral opening is not threaded. In some embodiments, the fitting includes a recess configured to receive a portion of the valve assembly without threads or welding to permit fluid communication between the fitting lumen and the valve assembly. In some embodiments, the recess of the fitting that is configured to receive the portion of the valve assembly has a longitudinal axis that is substantially parallel to a longitudinal axis of the main tube.

Some embodiments of the present riser segment assemblies further comprise: a valve assembly comprising a first connector configured to be inserted into the recess of the fitting, a second connector configured to be coupled to the main tube, and a valve disposed between the first connector and the second connector. In some embodiments, the valve comprises a double-ball valve. In some embodiments, the second connector defines a lumen having an inlet through which fluid can enter the second connector in a first direction, and an outlet through which fluid can exit the second connector in a second direction that is different than the first direction. In some embodiments, the second direction is substantially opposite the first direction. In some embodiments, the second connector further comprises a secondary lumen with a second exit sealed by a removable cover, the second exit configured such that if the cover is removed, fluid can exit the connector in a third direction that is different than the first direction and the second direction. Some embodiments further comprise: a retainer coupled to the main tube and configured releasably engage the second connector without welding to secure the second connector in fixed relation to the first fitting and the main tube. In some embodiments, the retainer includes a body having a recess configured to receive a portion of the second connector to restrict lateral movement of the second connector relative to the main tube. In some embodiments, the retainer includes one or more movable members pivotally coupled to the body and movable between an open position in which the second connector is permitted to enter or exit the recess of the body, and a closed position in which the one or more movable members prevent the second connector from entering or exiting the recess of the body.

In some embodiments of the present riser segment assemblies, the maximum transverse dimension of the assembly is less than <NUM> (<NUM> inches). In some embodiments, the maximum transverse dimension of the assembly is greater than <NUM> (<NUM> inches) if the valve assembly is coupled to the fitting, and is less than <NUM> (<NUM> inches) if the valve assembly is not coupled to the fitting. In some embodiments, the first fitting and the collar are configured to form a substantially gapless connection comprising: a female flange having an inward-facing conically tapered sealing surface; a male flange having an outward-facing conically tapered sealing surface; and a seal ring having an outward-facing conically tapered surface complementary to the sealing surface of the female flange; and an inward-facing conically tapered surface complementary to the sealing surface of the male flange; where the seal ring is positioned between the male and female flanges with the conically tapered surfaces of the seal ring in contact with the complementary sealing surfaces of the male and female flanges and the male and female flanges are coupled together to form a connection between the primary lumen of the main tube and the fitting lumen of the first fitting; where one of the collar and the first fitting defines the female flange, and the other of the collar and the first defines the male flange; and where an interface between male flange and the female flange is substantially free of gaps.

In some embodiments of the present riser segment assemblies, the collar defines a second lateral opening in fluid communication with the primary lumen of the main tube, and the assembly further comprises: a second fitting coupled to the collar over the second lateral opening and configured to be removably coupled to a valve assembly, the fitting defining a fitting lumen in fluid communication with the lateral opening. In some embodiments, the second fitting is substantially similar to the first fitting. In some embodiments, the present riser segment assemblies are located in a riser stack between an isolation unit and a formation.

Some embodiments of the present methods comprise: lowering an embodiment of the present riser segment assemblies through a rotary of a drilling rig. Some embodiments further comprise: connecting, below the rotary, one of the present second connectors to the riser segment assembly without welding; and/or connecting, below the rotary, one of the present valve assemblies to the riser segment assembly without welding.

The term "coupled" is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are "coupled" may be unitary with each other. The terms "a" and "an" are defined as one or more unless this disclosure explicitly requires otherwise. The term "substantially" is defined as largely but not necessarily wholly what is specified (and includes what is specified; e.g., substantially <NUM> degrees includes <NUM> degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. In any disclosed embodiment, the terms "substantially," "approximately," and "about" may be substituted with "within [a percentage] of" what is specified, where the percentage includes. <NUM>, <NUM>, <NUM>, and <NUM> percent.

The terms "comprise" (and any form of comprise, such as "comprises" and "comprising"), "have" (and any form of have, such as "has" and "having"), "include" (and any form of include, such as "includes" and "including") and "contain" (and any form of contain, such as "contains" and "containing") are open-ended linking verbs. As a result, an apparatus that "comprises," "has," "includes" or "contains" one or more elements possesses those one or more elements, but is not limited to possessing only those elements. Likewise, a method that "comprises," "has," "includes" or "contains" one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

Any embodiment of any of the apparatuses, systems, and methods can consist of or consist essentially of - rather than comprise/include/contain/have - any of the described steps, elements, and/or features. Thus, in any of the claims, the term "consisting of" or "consisting essentially of" can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb.

The feature or features of one embodiment may be applied to other embodiments, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of the embodiments.

Details associated with the embodiments described above and others are described below.

The following drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate an identical structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers. The figures are drawn to scale for at least the embodiments shown.

Referring now to the drawings, and more particularly to <FIG>, shown there and designated by the reference numeral <NUM> is one embodiment of a riser assembly or stack that includes multiple riser segments. In the embodiment shown, assembly <NUM> includes a rotating control device (RCD) body segment <NUM>, an isolation unit segment <NUM>, a flow spool segment <NUM>, and two crossover segments <NUM> (one at either end of assembly <NUM>). In this embodiment, crossover segments <NUM> each has a first type of flange <NUM> at an inner end (facing segments <NUM>, <NUM>, <NUM>) a second type of flange <NUM> at an outer end (facing away from segments <NUM>, <NUM>, <NUM>). Flanges <NUM> can, for example, include a proprietary flange design and flanges <NUM> can, for example, include a generic flange design, such that crossover segments <NUM> can act as adapters to couple segments <NUM>, <NUM>, <NUM> to generic riser segments with others types of flanges. Crossover segments <NUM> are optional, and may be omitted where riser segments above and below segments <NUM>, <NUM>, <NUM> have the same type of flanges as segments <NUM>, <NUM>, <NUM>.

<FIG> show the depicted embodiment of flow spool segment assembly <NUM> in more detail. In this embodiment, assembly <NUM> comprises: a main tube <NUM> having a first end <NUM> and a second end <NUM> and defining a primary lumen <NUM>; and two flanges 112a and 112b each coupled to a different end of the main tube. In this embodiment, each flange 112a, 112b includes a mating face <NUM> configured to mate with a flange of an adjacent riser segment (e.g., via bolts extending through bolt holes <NUM>); a central lumen <NUM> configured to be in fluid communication with main tube <NUM>; and at least one auxiliary hole <NUM> configured to receive an auxiliary line <NUM>. In the embodiment shown, assembly <NUM> includes a plurality of auxiliary lines <NUM> and each flange 112a, 112b includes a plurality of auxiliary holes <NUM>, each configured to receive a different one of the auxiliary lines. One example of a flange design (for flanges 112a and 112b) that is suitable for at least some embodiments is described in <CIT>. In the embodiment shown, each auxiliary line <NUM> extends between a female fitting <NUM> sized to fit within the corresponding one of auxiliary holes <NUM> of flange 112a, and a male fitting <NUM> sized to fit within the corresponding one of auxiliary holes <NUM> of flange 112b. Fittings <NUM> and <NUM> can be coupled to the respective flanges 112a and 112b via welds, threads, and/or the like (e.g., via external threads on fittings <NUM> and <NUM> that correspond to internal threads of the respective flange 112a or 112b in the corresponding auxiliary hole (<NUM>). Female fitting <NUM> is configured to slidably receive a corresponding male fitting (e.g., <NUM>) in an adjacent riser segment to provide a connection between the corresponding auxiliary lines of adjacent riser segments. Likewise, male fitting <NUM> is configured to be slidably received in a corresponding female fitting (e.g., <NUM>) of an adjacent riser segment to provide a connection between the corresponding auxiliary lines of adjacent riser segments. Female fitting <NUM> can include, for example, internal grooves configured to receive sealing and/or lubricating components (e.g., O-rings, rigid washers, grease, and/or the like) to facilitate insertion of a male fitting into the female fitting and/or improve the seal between the male and female fittings of adjacent riser segments. For clarity and brevity, auxiliary lines are omitted from <FIG>.

In the embodiment shown, assembly <NUM> also comprises a collar <NUM> defining a lateral opening <NUM> in fluid communication with primary lumen <NUM>. Collar <NUM> includes a mating surface around lateral opening <NUM> to which fitting <NUM> is coupled, as described below. In the embodiment shown, collar <NUM> is welded to an end of a pipe <NUM> such that the collar and the pipe cooperate to form main tube <NUM> and primary lumen <NUM>. In other embodiments, the collar may be disposed (e.g., concentrically) around the pipe, or the collar may be unitary with flange (e.g., 112b).

In this embodiment, the assembly also comprises a valve <NUM> coupled to lateral opening <NUM> and having a longitudinal flow axis <NUM> that is more parallel than perpendicular to a longitudinal axis <NUM> of the main tube. For example, in the embodiment shown, valve <NUM> comprises a double ball valve having an elongated body <NUM>, as shown. While certain details of the double ball valve are omitted from the figures for clarity and brevity, various valves are commercially available that may be used in the present embodiments. One example of a double ball valve that is suitable for at least some of the present embodiments is part number JB503 offered by Piper Valves, an Oil States Company. The embodiment shown includes two substantially similar (e.g., identical) valves <NUM> and corresponding structures. As such, while only one valve and corresponding structure will generally be described below, it should be understood that the description is provided below is accurate for the corresponding second set of structures shown in the figures. Other embodiments may include only a single valve and corresponding structures (e.g., only a single lateral opening <NUM>).

In the embodiment shown, lateral opening <NUM> is not threaded and need not be threaded to connect valve <NUM> to lateral opening <NUM>. Instead, assembly <NUM> comprises a fitting <NUM> coupled to collar <NUM> over lateral opening <NUM> and coupled to valve <NUM> (e.g., via bolts <NUM>). In the embodiment shown, fitting <NUM> defines a fitting lumen <NUM> in fluid communication with lateral opening <NUM>. In this embodiment, fitting lumen <NUM> defines an elbow (e.g., a <NUM>-degree bend) that includes a first portion <NUM> that is substantially perpendicular to axis <NUM>, and a second portion <NUM> that is substantially parallel to axis <NUM>. In the embodiment shown, fitting <NUM> and collar <NUM> are configured to include a TaperLok. RTM connection, as described in <CIT>. In particular, in this embodiment, collar <NUM> includes a female flange or mating surface <NUM> having an inward-facing conically tapered sealing surface <NUM>; and fitting <NUM> includes a male flange or mating surface <NUM> having an outward-facing conically tapered sealing surface <NUM>. In this embodiment, a seal ring (not shown here but illustrated in the figures of <CIT>) having an outward-facing conically tapered surface complementary to surface <NUM> and an inward-facing conically tapered surface complementary to surface <NUM> is positioned between male and female flanges <NUM> and <NUM> with the conically tapered surfaces of the seal ring in contact with the complementary sealing surfaces <NUM> and <NUM>. Fitting <NUM> (and surface <NUM>) is coupled to collar <NUM> (and surface <NUM>) to form a connection between primary lumen <NUM> of the main tube and fitting lumen <NUM> of the fitting, and such that the interface between male flange <NUM> and female flange <NUM> is configured to be substantially free of gaps. In this embodiment, a connector <NUM> is secured (e.g., by bolts <NUM>) to fitting <NUM> and secured (e.g., by bolts <NUM>) to a first end <NUM> of valve body <NUM> to provide a sealed connection between valve <NUM> and fitting <NUM>.

In this embodiment, and as shown in greater detail in <FIG>, a second connector <NUM> is secured (e.g., by bolts <NUM>) to a second end <NUM> of valve body <NUM> and has a protrusion <NUM> (e.g., having a circular cross-sectional shape as shown). In the embodiment shown, assembly <NUM> also includes a third connector <NUM> configured to be coupled to the main tube (<NUM>) and defining a recess <NUM> configured to slidably receive protrusion <NUM> of second connector <NUM> to provide a sealed connection between second connector <NUM> and third connector <NUM>. In the embodiment shown, third connector <NUM> includes internal grooves <NUM> around recess <NUM> that are configured to receive sealing and/or lubricating components (e.g., O-rings, rigid washers, grease, and/or the like) to facilitate insertion of protrusion <NUM> into the recess <NUM> and/or improve the seal between second connector <NUM> and third connector <NUM>. In this embodiment, third connector <NUM> defines a lumen <NUM> having an inlet <NUM> through which fluid can enter the third connector in a first direction <NUM>, and an outlet <NUM> through which fluid can exit the third connector in a second direction <NUM> that is different than (e.g., substantially opposite to) first direction <NUM>. For example, in the embodiment shown, lumen <NUM> is U-shaped such that first direction <NUM> is substantially opposite to second direction <NUM>. In the embodiment shown, third connector <NUM> further defines a secondary lumen <NUM> with a second exit <NUM> sealed by a removable cover <NUM> (e.g., secured by bolts <NUM>), and second exit <NUM> is configured such that if cover <NUM> is removed, fluid can exit third connector <NUM> in a third direction <NUM> that is different than (e.g., substantially perpendicular to) first direction <NUM> and second direction <NUM>.

In the embodiment shown, third connector <NUM> includes an elbow fitting <NUM>, a tee fitting <NUM>, cover <NUM> bolted to tee fitting, a nozzle or connection <NUM> welded to tee fitting, a conduit <NUM> extending between and welded to fittings <NUM> and <NUM>, and a brace <NUM> extending along the length of conduit <NUM> and welded to fittings <NUM>, <NUM> and to conduit <NUM>. In other embodiments, connector <NUM> can have any suitable components or construction that permits assembly <NUM> to function as described in this disclosure.

In the embodiment shown, the connection (protrusion <NUM> of second connector <NUM> and recess <NUM> of third connecter <NUM>) enables removal of third connector <NUM> from second connector <NUM> by simply moving third connector <NUM> in direction <NUM> away from second connector <NUM>. As such, third connector <NUM> can be readily removed from the remainder of assembly <NUM> to permit the remainder of assembly <NUM> to be lowered through a rotary of a drilling rig, as described in more detail below. Likewise, if assembly <NUM> is included in a riser stack that is used for conventional drilling operations, there may be no need to attach third connector <NUM> to assembly <NUM> and valve <NUM> can be kept closed and third connector <NUM> can simply be omitted during use (e.g., but available for later MPD operations using the same riser stack).

However, during shipping and/or use during MPD operations (e.g., after assembly <NUM> has been lowered through a rotary), it is generally desirable to prevent removal of third connector <NUM>. In the embodiment shown, and as shown in detail in <FIG> and <FIG> (in which flange 112a, including its neck portion, is omitted for clarity), assembly <NUM> includes a retainer <NUM> coupled to main tube <NUM> and configured releasably engage third connector <NUM> without welding to secure the third connector in fixed relation to the main tube. In particular, retainer <NUM> includes a body <NUM> having a recess <NUM> configured to receive a portion of third connector <NUM> (fitting <NUM>) to restrict lateral movement of the third connector relative to main tube <NUM>. In this embodiment, fitting <NUM> includes a T-shaped cross-section with lateral protrusions <NUM>, and recess <NUM> includes lateral grooves or slots <NUM> configured to receive protrusions <NUM> to prevent fitting <NUM> (and third connector <NUM>) from moving radially outward relative to retainer <NUM> (and main tube <NUM>). Additionally, the T-shaped cross-section of fitting <NUM> (and the corresponding T-shaped cross-section of recess <NUM>) tapers from a larger top to a smaller bottom ('top' and 'bottom' in the depicted orientation of assembly <NUM>) facilitate insertion of fitting <NUM> into recess <NUM> and restrain downward vertical freedom of third connector <NUM> relative to retainer <NUM>. In other embodiments, fitting <NUM> and recess <NUM> can have any cross-sectional shape(s) that enable assembly <NUM> to function as described in this disclosure. In this embodiment, retainer <NUM> includes two identical body members that are bolted together around main tube <NUM> as shown.

In the embodiment shown, retainer <NUM> also includes one or more (e.g., two, as shown) movable members <NUM> pivotally coupled (e.g., via bolts <NUM>) to the body and movable between an open position (<FIG>) in which third connector <NUM> is permitted to enter or exit recess <NUM> of body <NUM>, and a closed position (<FIG>, <FIG>) in which movable members <NUM> prevent the third connector from entering or exiting the recess of the body. More particularly, in the embodiment shown, each member <NUM> includes a hole through a first end and a slot in an opposing end, such that bolts <NUM> can be loosened and members <NUM> pivoted laterally outward as shown in <FIG> to permit fitting <NUM> to be vertically removed from or inserted into recess <NUM> of retainer <NUM>, and such that members <NUM> can be pivoted laterally inward such that the slots of the members fit over the shanks of bolts <NUM> and bolts <NUM> can be tightened to secure members <NUM> in their closed position of <FIG> and <FIG>.

In the embodiment shown, assembly <NUM> further includes a stabilizer <NUM> configured to stabilize valve <NUM> and second connector <NUM> relative to main tube <NUM>. In this embodiment, stabilizer extends around main tube <NUM> and second connector <NUM> to rigidly fix the position of second connector <NUM> (and valve <NUM>) relative to the main tube. In this embodiment, stabilizer <NUM> includes two identical body members that are bolted together around main tube <NUM> as shown.

As discussed above, assembly <NUM> is configured to be lowerable through a rotary of a drill rig when third connectors <NUM> are removed. For example, <FIG> show assembly <NUM> in a partially disassembled state in which third connectors <NUM> are removed. In this state, the maximum transverse dimension of assembly <NUM> (e.g., defined by stabilizer <NUM> for the embodiment shown) is less than <NUM> (<NUM> inches), which is a common diameter for a rotary on various drilling rigs (often referred to as a <NUM>-inch rotary). Other embodiments of assembly <NUM> can have a different maximum transverse dimension (e.g., greater than <NUM> (<NUM> inches)). For example, some rotaries have diameters greater than <NUM> (<NUM> inches) (e.g., <NUM> (<NUM> inches)). In this state, and in accordance with some of the present methods, the majority of assembly <NUM> (without third connectors <NUM>) can be passed through a rotary <NUM> (e.g., in an upper deck <NUM>) of a drilling rig <NUM>, and third connectors <NUM> can be connected (e.g., without welding) below rotary <NUM>, such as, for example, by a person standing in a mezzanine level <NUM> of the drilling rig. In particular, each sliding fitting <NUM> can be inserted into recess <NUM> of retainer <NUM> while protrusion <NUM> of second connector <NUM> is simultaneously received in recess <NUM> of fitting <NUM>. Once fittings <NUM> are disposed in recess <NUM> (and connectors <NUM> are secured as shown in <FIG>, members <NUM> can be pivoted inward and secured by bolts <NUM> to prevent removal of third connectors <NUM>. In this fully assembled state, the maximum transverse dimension of the depicted assembly <NUM> is greater than <NUM> (<NUM> inches) such that ability to remove connectors <NUM> facilitates lowering assembly <NUM> through a rotary in way that would otherwise not be possible.

<FIG> depict a second embodiment 22a of flow spool riser segment assembly that can be included in assembly <NUM> of <FIG> (e.g., additional or alternative to isolation flow spool segment assembly <NUM>). Assembly 22a is similar in many respects to assembly <NUM> and the differences are therefore primarily described here. For example, assembly 22a differs from assembly <NUM> in that assembly 22a does not include auxiliary lines or a stabilizer (e.g., <NUM>), includes generic flanges 112c and 112d, and collar 140a is unitary with flange 112d (e.g., with the neck portion of flange 112d). Assembly 22a also differs from assembly <NUM> in that assembly 22a includes removable valve assemblies <NUM> in which valves <NUM> are included and therefore also removable. More particularly, in this embodiment, fitting 164a includes a recess <NUM> configured to receive a portion of valve assembly <NUM> without threads or welding to permit fluid communication between fitting lumen <NUM> and the valve assembly. In this embodiment, first connector 180a includes a protrusion <NUM> configured to extend into recess <NUM> to connect valve <NUM> and fitting lumen <NUM>. In some embodiments, such as the one shown, fitting 164a includes internal grooves <NUM> around recess <NUM> that are configured to receive sealing and/or lubricating components (e.g., O-rings, rigid washers, grease, and/or the like) to facilitate insertion of a protrusion <NUM> into the recess <NUM> and/or improve the seal between second connector <NUM> and third connector <NUM>. In this embodiment, recess <NUM> has a longitudinal axis <NUM> that is substantially parallel to longitudinal axis <NUM> of the main tube. As such, the connection between first connector 180a and fitting 164a provides a slidable, removable connection similar to the one between second connector <NUM> and third connector <NUM> in assembly <NUM>.

In the embodiment shown, second connector 196a is welded to third connector 212a, and are collectively referred to as second connector <NUM> for purposes of describing certain features of assembly 22a. For example, in this embodiment, each valve assembly <NUM> includes first connector 180a, valve <NUM>, and second connector <NUM>. Assembly 22a is configured such that valve assemblies <NUM> are removable (as shown in <FIG>) to permit the remainder of assembly 22a to be lowered through a rotary of a drilling rig as shown in <FIG>, and the valve assemblies <NUM> connected below the rotary. More particularly, in this embodiment, fitting 264a is lowered into recess <NUM> of retainer <NUM> while protrusion <NUM> of first connector 180a is simultaneously inserted into recess <NUM> of fitting 164a, after which members <NUM> can be secured to prevent removal of fitting 260a from recess <NUM>. In the embodiment shown, the maximum transverse dimension (defined between fittings 164a) of assembly 22a without valve assemblies <NUM> is less than <NUM> (<NUM> inches), and the maximum transverse dimension (defined by covers <NUM>) is greater than <NUM> (<NUM> inches) with the valve assemblies <NUM> connected to the remainder of assembly 22a.

Claim 1:
A riser segment assembly (<NUM>, 22a) comprising:
(i) a main tube (<NUM>) defining a primary lumen (<NUM>)
(ii) a collar (<NUM>, 140a) defining a first lateral opening (<NUM>), in fluid communication with the primary lumen (<NUM>);
(iii)a first valve (<NUM>) coupled to the first lateral opening (<NUM>), the first valve (<NUM>) having a longitudinal flow axis (<NUM>) that is parallel to a longitudinal axis of the main tube (<NUM>); and characterized in that the riser assembly (<NUM>, 22a) further comprises:
(iv) a removable valve assembly (<NUM>) having
a. the valve (<NUM>);
b. a first connector (180a) secured to a first end of the valve (<NUM>), wherein the first connector (180a) includes a protrusion (<NUM>);
c. a second connector (<NUM>) secured to a second end of the valve (<NUM>) and comprising a first fitting (<NUM>) having lateral protrusions (<NUM>);
(v) a second fitting (164a) coupled to the collar (140a), where the second fitting (164a) defines a fitting lumen (<NUM>) in fluid communication with the first lateral opening (<NUM>) and includes a recess (<NUM>) configured to receive the protrusion (<NUM>) of the first connector (180a) to connect the valve (<NUM>) and the fitting lumen (<NUM>), wherein the connection between first connector (180a) and second fitting (164a) is a slidable, removable connection,
(vi)a retainer (<NUM>) coupled to the main tube (<NUM>) and having a body (<NUM>) comprising a recess (<NUM>) having lateral grooves or slots (<NUM>), wherein the lateral grooves or slots (<NUM>) are configured to receive the lateral protrusions (<NUM>) of the first fitting (<NUM>) to prevent the second connector (<NUM>) from moving radially outward relative to the main tube (<NUM>).