Patent Description:
Typically, to produce hydrocarbon-containing fluids from a subsea reservoir, several oil and gas wells are often drilled in a pattern that spaces the wells apart from each other. Each of the wells typically comprises a Christmas or production tree that is mounted on a wellhead. The tree is coupled to a production conduit such as a flowline or a jumper at the sea floor. The production conduits from the trees are typically coupled to other components such as manifolds, pipeline end terminations (PLETs), or other subsea processing units that collect or re-distribute the hydrocarbon-containing fluids produced from the wells.

When initial plans are made to produce hydrocarbon-containing fluids from a subsea reservoir, field developers must make some judgments as to the future development of the reservoir or field. Such decisions may include the anticipated location of various wells to be drilled into the reservoir as well as the anticipated location of certain items of subsea equipment that will be positioned subsea, such as Christmas (production) trees, manifolds, PLETs, flowlines, jumpers, pipelines, umbilicals, etc. At the time many of the original decisions are made with respect to the location and placement of various items of subsea equipment, the developer's knowledge about the capabilities of the reservoir in terms of production is somewhat limited. As development of the reservoir continues, i.e., as additional wells are drilled into the reservoir, developers acquire more and better information as it relates to the potential and actual development of the reservoir. Unfortunately, as this additional information about the field becomes available, the original decisions regarding the location of various items of subsea equipment may, in retrospect, not be ideal in terms of the efficient and economical consumption of subsea plot space (i.e., footprints) and/or efficient and economical production of hydrocarbon-containing fluids from the reservoir.

Prior art includes <CIT> and <CIT>. <CIT> relates to a subsea flowline deployed onto the sea floor having tie-in points for interfacing other subsea facilities. Mudmats support hubs at the tie-in points. One embodiment has a cradle supporting flowline for relative rotative movement. Hydraulic jacks are connected to arms to position and maintain hub in a vertical orientation. Another embodiment has an outer swivel sleeve which is mounted on mudmat and receiving flowline for relative rotation. An annular fluid chamber or toroid provides fluid communication between flowline and hub connected to outer swivel sleeve. <CIT> relates to a standby means of a pipeline designed for deployment one the seabed, and a method for utilization of the standby means. The pipeline has at least one branch in the form of a flexible pipeline which is arranged for simultaneous or possible future extension to and connection to a connecting point, such as one located on a nearby subsea installation, e.g. a wellhead for an injection well. The flexible pipeline is connected to a main pipeline via a pipe stub. The pipe stub is designed with one of several possible types of connecting means (for standby purposes) and has in its extension a transition part to the flexible pipeline. The transition part includes a zone that constitutes a possible cutting-off point in case the flexible pipeline needs to be replaced by a new flexible pipeline during the service lifetime of the pipeline. The connecting means is intended to co-operate with one or more axially acting clamping means that must be used with the new flexible pipeline.

Typically, various utilities that are to be supplied to subsea production equipment, such as electrical power, communication lines, chemicals, etc., are supplied to the subsea equipment via relatively large and expensive bundled umbilicals that extend from a surface location, e.g., a platform to the subsea equipment. Such umbilicals may be relatively large in size and they can be very expensive to manufacture and install.

The present application is directed to various embodiments of a novel subsea pipeline system and utilities that comprise multiple pre-fabricated and pre-positioned access nodes or tie-in locations that may be accessed on an as-needed basis that may eliminate or at least minimize some of the problems noted above.

The following presents a simplified summary of the subject matter disclosed herein in order to provide a basic understanding of some aspects of the information set forth herein. This summary is not an exhaustive overview of the disclosed subject matter. It is not intended to identify key or critical elements of the disclosed subject matter or to delineate the scope of various embodiments disclosed herein. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.

The present application is generally directed to various embodiments of a novel subsea pipeline system that comprises multiple access nodes or tie-in locations that may be accessed on an as-needed basis. In one example, the system comprises a pipeline and a plurality of access node structures axially spaced apart from one another along the pipeline, wherein each of the plurality of access node structures comprises a substantially planar upper surface.

In another example, a method disclosed herein comprises deploying a pipeline that comprises a plurality of future access node structures, wherein, at the time the pipeline is deployed subsea, the future access node structures prevent access to an interior of the pipeline, and wherein the plurality of access node structures comprises at least one of a tapping structure, a pressure-barrier retaining structure that is adapted to receive a pressure-barrier device and a pressure-barrier retaining structure comprised of a recess with a scored pressure-retaining bottom.

Certain aspects of the presently disclosed subject matter will be described with reference to the accompanying drawings, which are representative and schematic in nature and are not be considered to be limiting in any respect as it relates to the scope of the subject matter disclosed herein:.

While the subject matter disclosed herein is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the disclosed subject matter to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosed subject matter as defined by the appended claims.

Various illustrative embodiments of the disclosed subject matter are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

The present subject matter will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present disclosure with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present disclosure. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.

<FIG> depicts one illustrative embodiment of a subsea pipeline system <NUM> disclosed herein that may be employed in performing a variety of operations as it relates to the general process of producing hydrocarbon-containing fluids <NUM> from a subsea reservoir <NUM>. In general, in one illustrative embodiment, the subsea pipeline system <NUM> generally comprises a pipeline <NUM> with a plurality of future access nodes <NUM> spaced along the pipeline <NUM>. In another embodiment, the system <NUM> may also comprise a plurality of utility lines <NUM> that are coupled, e.g., strapped to the pipeline <NUM>. The utility lines <NUM> may include a variety of different utilities, including but not limited to, electrical power lines, electrical heating lines, chemical or liquid flow lines, electrical communication lines, fiber optic lines, control lines (electrical and/or hydraulic), etc. As will be appreciated by those skilled in the art after a complete reading of the present application, in one illustrative embodiment, the pipeline <NUM> may be used to receive and transport production fluid from various wells positioned subsea to a production facility. In another embodiment, water may be introduced into the pipeline <NUM> and ultimately introduced into one or more of the wells drilled in the reservoir <NUM>. Thus, in the broadest sense, the pipeline <NUM> may be employed to receive any type of fluid (gas or liquid; single phase or multiple phase) from the reservoir <NUM> or from any equipment positioned subsea. Similarly, the pipeline <NUM> may be employed to introduce any type of fluid (gas or liquid; single phase or multiple phase) into the reservoir <NUM>. The utility lines <NUM> may be used to supply one or more utilities (e.g., any fluids, controls or electrical power) to one or more items of equipment positioned subsea. For example, various chemicals in one or more of the utility lines <NUM> may be introduced into the wells drilled in the reservoir <NUM> or into any equipment positioned subsea.

The discussion below will primarily focus on the situation where the pipeline <NUM> is employed to receive production fluid from the reservoir <NUM> and transmit the production fluid to a production facility. However, as noted above, the novel system disclosed herein is not to be considered to be limited to this illustrative example. Additionally, depending upon the particular application, the pipeline <NUM> may be accessed (via one of the access nodes <NUM>) when the pipeline <NUM> has a relatively high internal operating pressure, i.e., when the pipeline <NUM> is in operation, or when the pipeline <NUM> is non-operational, i.e., when the internal pressure within the pipeline <NUM> is at, above or below hydrostatic pressure.

The access nodes <NUM> may be accessed on an as needed basis (by performing various activities described more fully below) during the course of the development of the field. That is, in one example, as additional wells are drilled into the reservoir <NUM> over several years, one or more of the access nodes <NUM> may be accessed on an as-needed basis so as to permit production fluid from the additional wells to be introduced into the pipeline <NUM>. The number and spacing of the access nodes <NUM> along the pipeline <NUM> may vary depending upon the particular application and a variety of factors such as, for example, the overall physical size of the reservoir <NUM>. The access nodes <NUM> may be approximately equally spaced from one another along the pipeline <NUM> (as depicted in <FIG>) or they may be randomly and/or unequally spaced and positioned along the pipeline <NUM>. The position of the access nodes <NUM> along the pipeline <NUM> may be indicated by appropriate markings, e.g., painted lines and/or painted numbers on the outside of the pipeline <NUM> or the insulation positioned around the pipeline <NUM>. Ultimately, as noted above, the hydrocarbon-containing fluids <NUM> produced from the reservoir <NUM> will flow through the pipeline <NUM> to a production facility, such as for example, a floating production vessel (not shown), a production facility located on a platform (not shown), an on-shore production facility (not shown) or a subsea production facility or item of equipment (not shown).

The physical size of the pipeline <NUM> may also vary depending upon the particular application. The spatial positioning of the subsea pipeline system <NUM> relative to the reservoir <NUM> may also vary depending upon the particular application and a variety of factors such as, for example, the anticipated location of various wells that will be drilled into the reservoir <NUM>. In the example depicted in <FIG>, the subsea pipeline system <NUM> is positioned such that the centerline of the pipeline <NUM> is positioned in the approximate middle of the reservoir <NUM>. In other applications, the subsea pipeline system <NUM> may be positioned adjacent one side of the reservoir <NUM> or it may be positioned, in whole or part, completely outside of the area defined by the reservoir <NUM>. The pipeline <NUM> may be made of a variety of different materials that are commonly used in the production of hydrocarbon-containing fluids such as, for example, carbon steel.

As noted above, in the illustrative example depicted in <FIG>, the subsea pipeline system <NUM> also comprises illustrative and schematically depicted utility lines <NUM> that are coupled to the pipeline <NUM> by straps (not shown). As will be appreciated by those skilled in the art after a complete reading of the present application, the utility lines <NUM> are intended to be representative of any of a variety of different utilities that may be provided to equipment positioned subsea so as to allow operation, control and monitoring of the subsea equipment so as to produce hydrocarbon-containing fluids <NUM> from the reservoir <NUM> or introduce one or more fluids into the reservoir <NUM> and/or any subsea equipment. As noted above, the utility lines <NUM> may include, among other things, electrical power lines, electrical heating lines, chemical or liquid flow lines, electrical communication lines, fiber optic lines, control lines (electrical and/or hydraulic), etc. The number, size and location of such utility lines <NUM> that may be part of the overall subsea pipeline system <NUM> may vary depending upon the particular application. However, as will be appreciated by those skilled in the art after a complete reading of the present application, in some embodiments, the utility lines <NUM> may be omitted from the subsea pipeline system <NUM>, and the utilities needed by various items of subsea equipment to produce hydrocarbon-containing fluids <NUM> from the reservoir <NUM> may be supplied by one or more traditional bundled umbilical lines (not shown) that extend from a surface structure, such as a platform, to the equipment on the sea floor.

In one illustrative example, the subsea pipeline system <NUM> may be installed or positioned above the reservoir <NUM> at a very early point during the process of developing the reservoir <NUM>. In effect, the subsea pipeline system <NUM>, with the plurality of access nodes <NUM> positioned therein, may constitute a primary pipeline or production backbone for the overall reservoir <NUM>. In general, the development of the reservoir <NUM> will likely grow or increase over the years, i.e., additional wells will be drilled into the reservoir <NUM> and/or additional subsea processing equipment will be positioned above or adjacent the reservoir <NUM> to produce all of the hydrocarbon-containing fluids <NUM> from the various wells drilled into the reservoir <NUM>. The hydrocarbon-containing fluids <NUM> produced from these additional wells may be tied into the pipeline <NUM> by accessing (using one or more of the techniques and devices described more fully below) one or more of the access nodes <NUM> such that the produced hydrocarbon-containing fluids <NUM> will flow through the pipeline <NUM> to the final production facility. The utilities for these additional wells and/or additional subsea equipment may also be provided by coupling to or accessing one or more of the utility lines <NUM> (as described more fully below) that are coupled to the pipeline <NUM>.

Still referencing <FIG>, various items of subsea production equipment 16A-16F (generally referenced using the numeral <NUM>) that are schematically depicted in <FIG> may be positioned subsea and operatively coupled to the pipeline <NUM> at any desired point in time by accessing one or more of the access nodes <NUM> on an as-needed basis. The production equipment <NUM> should be understood to be representative of any type of equipment that may be positioned subsea and assist in at least some manner with the production of the hydrocarbon-containing fluids <NUM> from the reservoir <NUM>. For example, the production equipment <NUM> may comprise, among other things, a Christmas or production tree, a flow manifold, a subsea separator vessel, the outlet of a subsea pump, the inlet of a subsea pump, another pipeline (not shown), a PLET (inline or not inline), skid mounted equipment, etc. Each schematically depicted item of subsea production equipment 16A-16F should be understood to be representative of one or more items of subsea equipment.

In the example depicted in <FIG>, the production equipment 16A is the initial production equipment that was installed for the first well drilled in the reservoir <NUM>, and the subsea production equipment 16A was installed at or about the same time as the subsea pipeline system <NUM> was laid or positioned above the reservoir <NUM>. As indicated, the subsea production equipment 16A was directly coupled to the pipeline <NUM> by the schematically depicted flow line <NUM> via a plurality of mating flanges (not shown). That is, the initial subsea production equipment 16A was not operatively coupled to the pipeline <NUM> by accessing one of the access nodes <NUM>, although such a situation could occur in some applications.

As also depicted in <FIG>, one or more utilities were provided to the production equipment 16A by accessing the utility lines <NUM>, as indicated by the solid curved line <NUM>. After the installation of the initial subsea production equipment 16A, the additional items of subsea production equipment 16B-16F were sequentially positioned above the reservoir <NUM> over a period of time as the development of the reservoir <NUM> was continued, i.e., as additional wells were drilled into the reservoir <NUM>. The items of subsea production equipment 16B-16F are depicted in dashed lines so as to reflect the positioning of these additional items of subsea production equipment 16B-16F above the reservoir <NUM> over time. As each of these additional items of subsea production equipment 16B-16F are positioned subsea, they will be operatively coupled to the pipeline <NUM> by accessing the pipeline <NUM> via one or more of the access nodes <NUM>, as simplistically depicted by the dashed lines <NUM>. One or more utilities may be provided to each of these additional items of subsea production equipment 16B-16F by accessing the utility lines <NUM>, as indicated by the dashed curved line <NUM>.

In general, various techniques and devices may be employed to access the pipeline <NUM> at the access nodes <NUM>. Each of the access nodes <NUM> comprises an access node structure 14X that, in one embodiment, may be formed integral with the pipeline <NUM> prior to positioning the pipeline <NUM> subsea. The access node structure 14X may take a variety of different forms and may employ different techniques and devices to gain access to the pipeline <NUM> via one of the access nodes <NUM>. In one illustrative example, the access node structure 14X takes the form of a tapping structure <NUM> that is adapted to allow tapping (hot or cold) of the pipeline <NUM> by performing various machining activities.

<FIG> are, respectively, an end view and a cross-sectional side view of a portion of the pipeline <NUM> and an illustrative example of various structures associated with an illustrative tapping structure <NUM> that is positioned at one or more of the access nodes <NUM>. As indicated, in one illustrative embodiment, the tapping structure <NUM> is integrally formed with an access node section of pipe 12A (with a centerline 12B) of the pipeline <NUM>. The access node section of pipe 12A is adapted to be coupled to (e.g., welded to) other sections 12X, 12Y of the pipeline <NUM>. The other sections 12X, 12Y of the pipeline <NUM> may or may not comprise tapping structures <NUM>.

In some applications, the access node section of pipe 12A may be coupled to the other sections (e.g., 12X, 12Y) of the pipeline at an on-shore location so as to establish a substantially continuous pipeline <NUM> with several of the tapping structures <NUM> spaced apart along the continuous pipeline <NUM>. At that point, as described more fully below, the substantially continuous pipeline (with the tapping structures <NUM>) may be positioned on or wrapped around a reel of a pipe-laying vessel, as described more fully below. In other applications, the pipeline <NUM> may be substantially completely fabricated aboard a pipe-laying vessel by welding the access node sections of pipe 12A (with the tapping structure <NUM> attached thereto) into position between other sections of the pipeline <NUM> that may or may not comprise a tapping structure <NUM>. In either situation - the fabrication of a substantially continuous pipeline on-shore or the fabrication of the pipeline <NUM> on a section-by-section basis on board a pipe-laying vessel - the pipeline <NUM> will be deployed into the sea and positioned on the sea floor at the desired location relative to the reservoir <NUM> as the sea-going pipe-laying vessel moves above the reservoir <NUM>. In one particular application, and as described more fully below, at the same time the pipeline <NUM> is being deployed off of the pipe-laying vessel into the sea, one or more utility lines <NUM> may be strapped to the pipeline <NUM> and deployed into the sea along with the pipeline <NUM>. The axial length <NUM> of the access node section of pipe 12A may vary depending upon the application. In one illustrative embodiment the axial length <NUM> may be about <NUM>-<NUM>. The tapping structure <NUM> may be comprised of the same material as that of the pipeline <NUM> or it may be made of a different material than that of the pipeline <NUM>.

Still referencing <FIG>, the tapping structure <NUM> may take a variety of different forms or configurations, and the physical size of the tapping structure <NUM> may vary depending upon the particular application. In the illustrative examples depicted herein, the tapping structure <NUM> has a generally rectangular configuration (when viewed from above) with a lateral width 20W and an axial length <NUM>. However, it is not required that all of the tapping structures <NUM> on the pipeline <NUM> be of the same size and configuration, although that may be the case in some applications. The tapping structure <NUM> may be sized such that it has a relatively small projection 20D above the outer surface of the pipeline <NUM>. In the depicted example, the tapping structure <NUM> comprises a substantially planar upper surface <NUM> and an alignment/coupling recess <NUM> defined in the body of the tapping structure <NUM>. In other embodiments, the alignment/coupling recess <NUM> may be omitted. In yet other embodiments, the tapping structure <NUM> may comprise a plurality of alignment/coupling recesses that are adapted to facilitate alignment of a machining tool that is to be coupled to the access node structure 14X, wherein the machining tool is adapted to be used to machine an opening that extends through the access node structure 14X and provides fluid access to the internal of the pipeline <NUM>. In one illustrative embodiment, the alignment/coupling recess <NUM> may have a generally circular configuration when viewed from above. The depth of the alignment/ coupling recess <NUM> may also vary depending upon the particular application. However, the depth of the alignment/coupling recess <NUM> should be controlled such that there is enough material <NUM> remaining below the bottom of the alignment/coupling recess <NUM> to withstand all anticipated forces (e.g., pressure and/or mechanical forces) to be applied to the tapping structure <NUM> during, for example, installation, commissioning, operation and abandonment of the pipeline <NUM>.

As indicated in <FIG>, the tapping structure <NUM> may be sized such that the substantially planar upper surface <NUM> is located a desired vertical distance <NUM> above the centerline 12B of the pipeline <NUM>. The tapping structure <NUM> may be forged with a machined inner surface <NUM> that matches the inner surface of the pipeline <NUM>, wherein the tapping structure <NUM> is welded into an opening cut in the pipeline <NUM>. In other applications, the tapping structure <NUM> may simply be welded into position on the outside surface of the pipeline <NUM>. In one embodiment, the lateral width 20W of the tapping structure <NUM> may be less than the outside diameter of the pipeline <NUM> to facilitate wrapping a continuous pipeline <NUM> of a reel of a pipe-laying vessel, as described more fully below. In general, as noted above, the physical dimensions of the tapping structure <NUM> may vary depending upon the particular application. However, in one illustrative embodiment, the lateral width 20W may be as small as about one-half the outside diameter of the pipe <NUM> but no greater than the outside diameter of the pipe <NUM>. In one illustrative example, the axial length <NUM> of the tapping structure <NUM> may be about <NUM>-<NUM>. In one illustrative embodiment, the projection 20D may be approximately equal to the wall thickness of the pipe <NUM> up to about double the outside diameter of the pipe <NUM>. With reference to <FIG>, when the pipeline <NUM> is positioned on the sea floor, the planar upper surface <NUM> will ideally be oriented substantially normal to the vertical. However, such exact precision in the orientation of the planar upper surface <NUM> is not required, i.e., in one illustrative embodiment, the pipeline <NUM> may be rotated plus or minus about <NUM> degrees (and preferably at most about <NUM> degrees) as represented by the arrows 12Z and still function as intended.

<FIG> are, respectively, an end view and a cross-sectional side view of another embodiment of a portion of a subsea pipeline system <NUM> disclosed herein. In this example, relative to the embodiment shown in <FIG>, thermal insulation material <NUM> has been positioned around the pipeline <NUM> and an illustrative tapping structure <NUM>. Also depicted are various utility lines <NUM> that have been strapped to the outside of the pipeline <NUM> as it was deployed into the sea. As noted above, the utility lines <NUM> may provide various utilities to the equipment positioned on the sea floor and/or perform various functions. For example, in the depicted example, electrical heating lines <NUM>, electrical power lines <NUM>, liquid (e.g., chemical) supply lines <NUM> and fiber optic communications lines <NUM> are strapped to the pipeline <NUM>. Note that, in the depicted example, there are redundant lines for the various utilities <NUM>. Of course, the number, size, location and functions of the various utility lines <NUM> strapped to the pipeline may vary depending upon the particular application. Additionally, in some embodiments, although one or more utility lines <NUM> are coupled to the pipeline <NUM>, additional utilities may be provided to subsea equipment positioned adjacent the pipeline <NUM> by one or more traditional umbilicals (not shown) on either a permanent or temporary basis.

<FIG> depicts an embodiment of a subsea pipeline system <NUM> wherein there is no insulation material <NUM> provided on the pipeline <NUM>. In this example, the utility lines <NUM> include the above-mentioned electrical power lines <NUM>, liquid (e.g., chemical) supply lines <NUM> and fiber optic communications lines <NUM> that have been strapped to the pipeline <NUM>. In this example, the electrical heating lines <NUM> have been omitted.

<FIG> is a cross-sectional view of a portion of the pipeline <NUM> taken across the diameter of the pipeline <NUM>. <FIG> is a partial cross-sectional side view (with the tapping structure <NUM> omitted) taken through the centerline 12B of the pipeline <NUM>. The figures will be referenced to generally describe one illustrative technique for attaching the utility lines <NUM> to the pipeline <NUM> and how the electrical power lines <NUM> may be accessed as equipment is periodically installed subsea so as to supply electrical power to the equipment. In this example, the subsea pipeline system <NUM> comprises the above-mentioned insulation material <NUM>, the electrical heating lines <NUM> and the electrical power lines <NUM> that were all attached to the pipeline <NUM> at the time the subsea pipeline system <NUM> was being lowered into the sea.

In one illustrative embodiment, at some point in time after the subsea pipeline system <NUM> was positioned subsea, additional equipment (not shown) was positioned subsea so as to continue the development of the reservoir <NUM>. For example, after the original subsea pipeline system <NUM> was first positioned subsea, a decision was made to drill another well into the reservoir and associated production equipment, such as a Christmas tree (i.e., a production tree) was positioned on the latest well. With reference to <FIG>, electrical power for such subsea equipment may be supplied by use of an induction coupling clamp <NUM> that is positioned around a portion of one of the electrical power lines <NUM>. The structure, function and operation of such induction coupling clamps are well known to those skilled in the art. The leads 36A, 36B may be coupled to the newly-added subsea equipment. To the extent that the portion of the electrical power line <NUM> that is to be accessed is covered by insulation material <NUM>, such insulation material <NUM> may be removed by use of an ROV. The installation of the induction coupling clamp <NUM> and the coupling of the leads 36A, 36B to the subsea equipment may also be accomplished by use of an ROV. Of course, a fiber tapping device (not shown) may be positioned around a portion of one of the fiber optic communications lines <NUM> (not shown in the <FIG> drawings) so as to provide a communications link with the newly-added subsea equipment.

<FIG> depict one illustrative example of a utilities support block <NUM> that may be used when coupling the utility lines <NUM> to the pipeline <NUM>. In this example, the utilities support block <NUM> comprises an open-ended slot 38A and a strap recess 38B. <FIG> includes a cross-sectional view of the utilities support block <NUM> taken through the center of the slot 38A in a direction parallel to the centerline 12B of the pipeline <NUM>. <FIG> is a cross-sectional view of the utilities support block <NUM> taken through the slot 38A in a direction that is transverse to the centerline 12B of the pipeline <NUM>. After the electrical power line <NUM> is positioned within the slot 38A, a band or strap <NUM> is wrapped about the pipeline <NUM> and positioned within the strap recess 38B. In this embodiment, the strap <NUM> insures that the electrical power line <NUM> remains positioned within the slot 38A. The strap recess <NUM> insures that the strap <NUM> remains in positon above the slot 38A. Of course, the utilities support block <NUM> may comprise any desired number of such slots 38A to accommodate the desired number and size of the various utility lines <NUM> that are coupled to the pipeline <NUM>.

<FIG> are, respectively, perspective, plan and cross-sectional side views of embodiments of the illustrative utilities support blocks <NUM> (with various utility lines <NUM> positioned therein) that may be strapped to the pipeline <NUM> using the depicted strap or band <NUM>. <FIG> depicts one illustrative utilities attachment location <NUM> along the pipeline <NUM> where three illustrative utilities support blocks <NUM> have been strapped to the pipeline <NUM> using the band or strap <NUM>. Of course, any desired number of such utilities support blocks <NUM> may be employed at each utilities attachment location <NUM>. The number and spacing of the utilities attachment locations <NUM> along the pipeline <NUM> may vary depending upon the particular application and a variety of factors. The utilities attachment locations <NUM> may be equally spaced from one another along the pipeline <NUM> or they may be randomly and/or unequally spaced and positioned along the pipeline <NUM>. The position of the utilities attachment location <NUM> along the pipeline <NUM> may be indicated by appropriate markings, e.g., painted lines and/or painted numbers on the outside of the pipeline <NUM> or the insulation positioned around the pipeline <NUM>. In this example, each of the utilities support blocks <NUM> comprises a plurality of open-ended slots 38A and an above-described strap recess 38B. Any of the above-mentioned utility lines <NUM>, e.g., the lines <NUM>, <NUM>, <NUM>, etc., may be positioned in the slots 38A. In the case wherein heating elements <NUM> are employed, the heating elements <NUM> may be positioned so as to contact the outer surface of the pipeline <NUM> for more effective heat transfer. In such a situation, the heating elements <NUM> may be positioned in downward facing open-ended slots (not shown) formed in the utilities support blocks <NUM>. As best seen in <FIG>, in this example, a hinge <NUM> is provided between adjacent utilities support blocks <NUM> so as to couple the utilities support blocks <NUM> to one another and to allow the group of the three utilities support blocks <NUM> to approximately conform to the outer surface of the pipeline <NUM>.

<FIG> are, respectively, plan and cross-sectional side views of illustrative embodiments of a plurality of fluid tapping support blocks <NUM> that are also adapted to be coupled or strapped to the pipeline <NUM> at various fluid tapping attachment locations <NUM> along the pipeline <NUM>. The fluid tapping support blocks <NUM> may comprise one or more openings <NUM> that are adapted to receive a liquid-carrying utility line <NUM>, e.g., the above-mentioned liquid (e.g., chemical) supply line <NUM>. The illustrative fluid tapping support blocks <NUM> (with various liquid-carrying utility lines <NUM> positioned therein) may be strapped to the pipeline <NUM> using a strap or band (not shown in the <FIG> drawings) such as the above-depicted strap or band <NUM>. Strap recesses (not shown in the <FIG> drawings) similar to the above-described strap recesses <NUM> may also be formed in the fluid tapping support blocks <NUM>.

<FIG> depict illustrative fluid tapping attachment locations <NUM> along the pipeline <NUM> where three illustrative fluid tapping support blocks <NUM> have been strapped to the pipeline <NUM>. Of course, any desired number of such fluid tapping support blocks <NUM> may be employed at each fluid tapping attachment location <NUM>. The number and spacing of the fluid tapping attachment locations <NUM> along the pipeline <NUM> may vary depending upon the particular application and a variety of factors. The fluid tapping attachment locations <NUM> may be equally spaced from one another along the pipeline <NUM> or they may be randomly and/or unequally spaced and positioned along the pipeline <NUM>. The position of the fluid tapping attachment locations <NUM> along the pipeline <NUM> may be indicated by appropriate markings, e.g., painted lines and/or painted numbers on the outside of the pipeline <NUM> or the insulation positioned around the pipeline <NUM>. In this example, each of the fluid tapping support blocks <NUM> comprises only a single opening <NUM> that is drilled through the block <NUM>. In practice, each of the fluid tapping support blocks <NUM> may comprise any desired number of such openings <NUM>. In the depicted example, each of the fluid tapping support blocks <NUM> comprises a drilled and tapped opening <NUM> that is positioned so as to expose and provide access to a portion of the liquid-carrying utility line <NUM> positioned within the opening <NUM>. As best seen in <FIG>, in this example, a hinge <NUM> is provided between adjacent fluid tapping support blocks <NUM> so as to couple the fluid tapping support blocks <NUM> to one another and to allow the group of the three fluid tapping support blocks <NUM> to approximately conform to the outer surface of the pipeline <NUM>.

In one illustrative example, a liquid-carrying utility line <NUM> is positioned within the opening <NUM> in the fluid tapping support blocks <NUM>. A seal may be formed between the liquid-carrying utility line <NUM> and the fluid tapping support blocks <NUM> at the ends of the opening <NUM>. Such a seal may be effectuated in a variety of different ways, e.g., by welding, swaging, heat-expansion, threading, etc..

In one illustrative embodiment, as shown in <FIG>, the tapped opening <NUM> is adapted to threadingly receive an externally threaded tapping structure <NUM> (the external threads being indicated by the reference numeral <NUM>). In one illustrative embodiment, the tapping structure <NUM> comprises a plurality of wrench flats <NUM> and a fluid passageway <NUM> that extends through the body of the tapping structure <NUM>. A pointed end <NUM> is provided at one end of the fluid passageway while a fluid outlet <NUM> is provided at the opposite end of the fluid passageway <NUM>.

In one illustrative process, when the combination of the fluid tapping support blocks <NUM> with the liquid-carrying utility line <NUM> positioned therein is initially strapped to the pipeline <NUM>, the tapping structure <NUM> is partially threaded into the opening <NUM> such that a seal is established between the tapping structure <NUM> and the opening <NUM> due to the interactions of the threads. In this initially installed position, the tapping structure <NUM> does not extend into the opening <NUM> a sufficient depth such that the pointed end <NUM> of the tapping structure <NUM> engages and penetrates the liquid-carrying utility line <NUM>. The combination of the pipeline <NUM> with the attached fluid tapping support blocks <NUM> is then lowered into the sea with the tapping structure <NUM> in this initial, non-penetrating position within the opening <NUM> in the fluid tapping support blocks <NUM>.

At some point later in time it may be desirable to tap the liquid-carrying utility line <NUM> so as to provide a fluid, e.g., a chemical, in the liquid-carrying utility line <NUM> to an item of subsea equipment (either recently installed or previously installed) positioned near the pipeline <NUM>. At that time, an ROV may be used to turn the tapping structure <NUM> so as to force it further into the opening <NUM> in the fluid tapping support blocks <NUM>. This process continues until such time as the pointed end <NUM> of the tapping structure <NUM> engages and penetrates the liquid-carrying utility line <NUM> thereby allowing fluid (as represented by the arrow <NUM>) from within the liquid-carrying utility line <NUM> to flow into the passageway <NUM> and out of the fluid outlet <NUM>. A suitable conduit (not shown) may be provided between the fluid outlet <NUM> and the subsea equipment. An illustrative seal <NUM> is provided between the tapping structure <NUM> and the fluid tapping support block <NUM> such that a fluid tight seal is established when the tapping structure <NUM> is in this fully-inserted and line-penetrating position. Of course, the illustrative example of the tapping structure <NUM> is provided by way of example only and other forms of tapping structures may be employed such as, for example, a push-fit hydraulic snap-in connector, a banjo type fitting, etc..

In other embodiments, the liquid-carrying utility line <NUM> may be penetrated on board the pipe-laying vessel after the liquid-carrying utility line <NUM> has been positioned in the fluid tapping support block <NUM> and sealed therein. Thereafter, a simple threaded plug (not shown) may be positioned in the tapped opening <NUM>. The plug may be removed at a later date when access to the liquid-carrying utility line <NUM> is needed.

As indicated above, in one illustrative embodiment, the pipeline disclosed herein may take the form of a continuous pipeline <NUM> with several of the access nodes <NUM> spaced apart along the continuous pipeline <NUM> that is adapted to be positioned on or wrapped around a pipeline reel <NUM> of a pipe-laying vessel <NUM>. <FIG> simplistically depicts an illustrative pipe-laying vessel <NUM> that is positioned above a body of water <NUM>. The vessel <NUM> comprises an opening <NUM> through which the pipeline <NUM> (that includes a plurality of illustrative access node structures 14X, such as the illustrative tapping structures <NUM>) may be deployed into the water. In some embodiments, the pipeline system <NUM> may also comprise a plurality of utility lines <NUM> that are attached to the pipeline <NUM> as the pipeline is un-reeled from the pipeline reel <NUM> wherein the combination of the pipeline <NUM> (that includes a plurality of access node structures 14X) and the utility lines <NUM> attached to the pipeline <NUM> are deployed into the water <NUM> at the same time via the opening <NUM>.

In one illustrative embodiment, the pipe-laying vessel <NUM> comprises a structural support mechanism <NUM>, a pipeline straightener mechanism <NUM>, a pipeline tensioner mechanism <NUM> and a pipeline aligner mechanism <NUM>. As depicted, in one illustrative embodiment, the pipeline <NUM> (that includes a plurality of access node structures 14X) is wrapped around the pipeline reel <NUM> prior to being deployed in the water <NUM>. In general, and as will be appreciated by those skilled in the art after a complete reading of the present application, when the pipeline <NUM> is initially wrapped around the pipeline reel <NUM>, the pipeline <NUM> undergoes plastic deformation such that it maintains its generally circular "as-reeled" configuration when it is positioned on the pipeline reel <NUM>. When the pipeline <NUM> is deployed or "un-wrapped" from the pipeline reel <NUM>, the pipeline <NUM> will again be plastically deformed into a substantially linear configuration as it is un-wound from the pipeline reel <NUM> and passes through the pipeline aligner <NUM>, the pipeline straightener <NUM> and the pipeline tensioner <NUM> in route to the opening <NUM> in the pipe-laying vessel <NUM>.

As noted above, in one illustrative embodiment, the pipeline system <NUM> may also comprise one or more of the above-described utility lines <NUM> that are positioned on or wrapped around a separate utilities reel <NUM>. The utilities reel <NUM> is also mechanically supported on the vessel <NUM> by various support structures (not shown). In the illustrative example where the utility lines <NUM> comprises one or more of the liquid (e.g., chemical) supply lines <NUM> with the associated fluid tapping support blocks <NUM>, the utility lines <NUM> may be wrapped around the utilities reel <NUM> in a manner similar to that described below with respect to the wrapping of the pipeline <NUM> around the pipeline reel <NUM>. In one particularly illustrative embodiment, all of the utility lines <NUM> (including those with the associated fluid tapping support blocks <NUM>) that will be attached or coupled to the pipeline <NUM> (via strapping) are wrapped around a single utilities reel <NUM>. In other applications, a separate fluid-carrying utilities reel (not shown) may be provided so as to allow the wrapping of any or all of the fluid-carrying utility lines <NUM> (with the associated fluid tapping support blocks <NUM>) around this separate fluid-carrying utilities reel. Of course, as will be understood by those skilled in the art after a complete reading of the present application, any number of loaded pipeline reels <NUM> (with the pipeline <NUM> that includes a plurality of access node structures 14X) may be positioned on the pipe-laying vessel <NUM>. After a first of the loaded pipeline reels <NUM> is "emptied" by deploying the pipeline <NUM> (that includes a plurality of access node structures 14X) into the water <NUM>, additional pipeline <NUM> (that includes a plurality of access node structures 14X) from a second loaded pipeline reel <NUM> may be welded to the end of the previously deployed pipeline <NUM> so as to permit substantially continuous introduction of the pipeline <NUM> into the water <NUM> via the opening <NUM>.

As noted above, in one illustrative example, the pipeline system <NUM> may comprise one or more utility lines <NUM> that are adapted to be coupled to the pipeline <NUM> (that includes a plurality of access node structures 14X) prior to deploying the combination of the pipeline <NUM> and the one or more utility lines <NUM> into the water <NUM> via the opening <NUM> in the vessel <NUM>. In one illustrative embodiment, after the pipeline <NUM> (that includes a plurality of access node structures 14X) exits the pipeline tensioner <NUM>, workers on board the pipe-laying vessel <NUM> position or guide one or more of the utility lines <NUM> from the separate utilities reel <NUM> into the openings or slots 38A in one or more of the above-described utilities support blocks <NUM> that have been positioned around or adjacent an exterior surface of the pipeline <NUM>. After positioning the utility lines <NUM> in the slots 38A, workers on board the vessel <NUM> strap the utilities support blocks <NUM> into position at one of the utilities attachment locations <NUM> along the pipeline <NUM> by wrapping the above-described strap <NUM> around the utilities support blocks <NUM> so as to insure that the utility lines <NUM> are "trapped" or maintained within the open-ended slots 38A within the utilities support blocks <NUM>.

In another illustrative embodiment wherein the utility lines <NUM> that are to be attached to the pipeline <NUM> comprise one or more liquid-carrying utility lines <NUM> (such as the chemical line <NUM>), workers on board the vessel <NUM> may also attach the above-described fluid tapping support blocks <NUM> to the pipeline <NUM> at fluid tapping attachment locations <NUM> by strapping the fluid tapping support blocks <NUM> (with the liquid-carrying utility line <NUM> welded into position therein) around the pipeline <NUM>. In one embodiment, all of the utility lines <NUM> (including the liquid-carrying utility line <NUM>) are positioned on the same utilities reel <NUM>. In other applications, due to the presence of the fluid tapping support blocks <NUM> on the liquid-carrying utility line <NUM>, the liquid-carrying utility line <NUM> may be wrapped around a separate reel (not shown). In one illustrative embodiment, after the pipeline <NUM> (that includes a plurality of access node structures 14X) exits the pipeline tensioner <NUM>, workers on board the pipe-laying vessel <NUM> position or guide one or more of the liquid-carrying utility lines <NUM> (such as the chemical line <NUM>) from the separate utilities reel <NUM> (or another separate reel) adjacent an exterior surface of the pipeline <NUM> and thereafter strap or secure the fluid tapping support blocks <NUM> into position at one of the fluid tapping attachment locations <NUM> along the pipeline <NUM> by wrapping the above-described strap <NUM> around the fluid tapping support blocks <NUM>. At that point, workers on board the pipe-laying vessel <NUM> may install the above-described externally threaded tapping structure <NUM> in its initial, non-penetrating position within the tapped opening <NUM> in the fluid tapping support block <NUM>. At that point, in this illustrative embodiment, the illustrative pipeline system <NUM> comprised of the combination of the pipeline <NUM> (that includes a plurality of access node structures 14X), the utility lines <NUM> installed in the utilities support blocks <NUM> (as strapped to the pipeline <NUM>) and the liquid-carrying utility line <NUM> positioned within the fluid tapping support blocks <NUM> (as strapped to the pipeline <NUM>) are deployed as a single unit into the water <NUM> via the opening <NUM> in the pipe-laying vessel <NUM>.

Of course, as will be appreciated by those skilled in the art after a complete reading of the present application, in another illustrative embodiment, the access node structures 14X may be omitted from the pipeline system <NUM>, and only the utility lines <NUM> may be attached to the pipeline <NUM> as it is deployed subsea.

<FIG> depict various illustrative examples of how the continuous pipeline <NUM> (that includes a plurality of illustrative access node structures 14X, such as the illustrative tapping structures <NUM>) may be wrapped around the pipeline reel <NUM>. The pipeline reel <NUM> comprises flanges 64A and the reel has a diameter of about <NUM>. <FIG> depicts the pipeline system <NUM> at a point in time wherein an initial section <NUM>-<NUM> of the pipeline <NUM>, a section without the access node structures 14X, i.e., a "clean" section of the pipeline <NUM>, has been wrapped around the pipeline reel <NUM> so as to define a first layer of the pipeline <NUM>. As depicted, the first layer <NUM>-<NUM> of the pipeline <NUM> is substantially uniformly positioned around the reel <NUM> both in terms of lateral spacing (if any) between the laterally adjacent portion of the wrapped pipeline <NUM> as well as the height 12H1 (or radial distance) of the outermost surfaces of the portions of the pipeline <NUM> in this first layer <NUM>-<NUM> of wrapped pipeline <NUM> relative to a centerline 64B of the pipeline reel <NUM>.

<FIG> depicts the pipeline system <NUM> at a point in time wherein another section of the pipeline, a section that includes a plurality of the illustrative tapping structures <NUM>, has been wrapped around the pipeline reel <NUM> so as to define a second layer <NUM>-<NUM> of the pipeline <NUM>. As depicted, the second layer <NUM>-<NUM> of the pipeline <NUM> is substantially uniformly positioned around the reel <NUM> in terms of lateral spacing (if any) between the laterally adjacent portions of the wrapped pipeline section <NUM>-<NUM>. The outer surfaces of the portions of the second layer <NUM>-<NUM> of the pipeline <NUM> that do not include any of the tapping structures <NUM> are also located a substantially uniform height or radial distance 12H2 from the centerline 64B of the pipeline reel <NUM>. As depicted, in this illustrative example, the centerlines of the tapping structures <NUM> on adjacent wraps of the second layer <NUM>-<NUM> of the pipeline <NUM> are laterally offset from one another (as indicated by the dimension <NUM>) and vertically offset from one another on adjacent wraps of the pipeline section <NUM>-<NUM> (as indicated by the dimension 12V). The magnitude of the dimensions <NUM>, 12V may vary depending upon the particular application. In one illustrative example, where the nominal diameter of the pipe of the pipeline <NUM> has a diameter of about <NUM>-<NUM>, the second layer <NUM>-<NUM> of the pipeline <NUM> comprises eighteen of the tapping structures <NUM> that are axially spaced apart from one another along the pipeline <NUM> by about <NUM>. Additional sections of pipeline <NUM> (not shown) that comprise the tapping structures <NUM> may be wrapped around the reel <NUM> on top of the section <NUM>-<NUM>. If needed, a steel cover (not shown) may be provided between the wrapped layers of the pipeline <NUM> that comprise the tapping structures <NUM> to smooth out the "bumps" in the reeled pipeline <NUM> due to the presence of the tapping structures <NUM>. In some cases, the very outermost sections of the pipeline <NUM> wrapped on the reel may be clean portions of the pipeline that do not include any tapping structures <NUM>.

<FIG> and <FIG> depict an embodiment wherein the axial spacing of the access node structures 14X, such as the illustrative tapping structures <NUM>, along the pipeline <NUM> is approximately the same as the reeling diameter, e.g., the outer diameter of all of the previous sections of pipeline wrapped around the reel <NUM>. As shown in <FIG>, by taking this approach, the tapping structures <NUM> are positioned in a substantially continuous line or battery that is approximately parallel to the axis of the pipeline reel <NUM>. More specifically, <FIG> depicts an embodiment wherein second layer <NUM>-<NUM> of the pipeline <NUM> includes a plurality of the tapping structures <NUM> that have an axial spacing along the pipeline of about <NUM>. The first section of pipeline (not shown in <FIG>) is free of the tapping structures <NUM>. <FIG> is a side view of the wrapped pipeline <NUM> with the flanges 64A on the reel <NUM> removed after the reel <NUM> has been completely filled. The wrapped pipeline <NUM> comprises six wrapped sections <NUM>-<NUM>(the innermost section), <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> (the outermost section). The sections <NUM>-<NUM> and <NUM>-<NUM> are clean sections of the pipeline <NUM> that are free of the tapping structures <NUM>. Each of the pipeline sections <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> comprise a plurality of the tapping structures <NUM>. The plurality of the tapping structures <NUM> in the sections <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> define lines <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM>, respectively, of tapping structures <NUM> that are oriented substantially parallel to the centerline 64B of the pipeline reel <NUM>. As indicated, the lines <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> of tapping structures <NUM> are positioned at increasing larger radial distances R2, R3, R4 and R5, respectively, from the centerline <NUM>. Also note that the lines <NUM>-<NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> of tapping structures <NUM> are angularly spaced from one another around the reel <NUM> by approximately <NUM> degrees. In one illustrative example, where the nominal diameter of the pipe of the pipeline <NUM> has a diameter of about <NUM>-<NUM>, the second section <NUM>-<NUM> of the pipeline <NUM> comprises eighteen of the tapping structures <NUM> that are axially spaced apart from one another along the pipeline <NUM> by about <NUM>; , the third section <NUM>-<NUM> comprises eighteen of the tapping structures <NUM> with an axial spacing along the pipeline of about <NUM>; the fourth section <NUM>-<NUM> comprises eighteen of the tapping structures <NUM> with an axial spacing along the pipeline of about <NUM>; and the fifth section <NUM>-<NUM> comprises eighteen of the tapping structures <NUM> with an axial spacing along the pipeline of about <NUM>.

<FIG> depict one illustrative method disclosed herein wherein the access node structure 14X is comprised of the above-described tapping structure <NUM> that is adapted for tapping (hot or cold) the pipeline <NUM> via one of the access nodes <NUM> on the pipeline <NUM> after the pipeline <NUM> was deployed subsea. In this example, the pipeline is wrapped with the thermal insulation material <NUM>. Also note that various utility lines <NUM> that may, in some embodiments, also have been strapped to the pipeline <NUM> at the time of deployment are not depicted in these drawings.

<FIG> depicts the use of a cutting tool <NUM> to remove a portion of the insulating material from above the tapping structure <NUM> at this particular access node <NUM>. The cutting tool <NUM> may be positioned subsea and operated by use of an ROV (not shown). This process operation exposes at least the planar upper surface <NUM> of the tapping structure <NUM>. Any residual insulation material <NUM> within the alignment/coupling recess <NUM> is also removed at this time.

<FIG> depicts the pipeline <NUM> after a CNC machine tool <NUM> has been landed on the tapping structure <NUM> and secured in place. The tool <NUM> may be positioned subsea by use of one or more downlines with visual observation being provided by an ROV. The tool <NUM> comprises an alignment/clamping structure <NUM> that is adapted to be aligned with and positioned at least partially within the alignment/coupling recess <NUM> defined in the tapping structure <NUM>. Once the tool <NUM> is properly positioned, expandable portions (not shown) of the alignment/clamping structure <NUM> are expanded outward so as to secure the CNC machine tool <NUM> to the tapping structure <NUM>. Also depicted in <FIG> are tools <NUM>, <NUM> that are adapted to drill and tap openings in the upper surface <NUM> of the tapping structure <NUM> so as to facilitate the later attachment of a valve (not shown in <FIG>) as described more fully below. The tools <NUM>, <NUM> are intended to be representative in nature of any kind of tooling necessary to drill and tap openings. Of course, the number and pattern of any such openings may vary depending upon the particular application. Also depicted in <FIG> is a tool <NUM> that is adapted to cut a seal recess into the upper surface <NUM>. Note that the debris from performing these various machining operations may be readily cleaned from above the upper surface <NUM> as machining progresses. An ROV may be used to supervise and/or control all of the operations performed by the CNC machine tool <NUM>.

<FIG> depicts the pipeline <NUM> after the CNC machine tool <NUM> was operated to form simplistically depicted drilled and tapped openings <NUM> and a seal recess <NUM> in the tapping structure <NUM>. At that point, the CNC machine tool <NUM> was retrieved to the surface.

<FIG> depicts the pipeline <NUM> after a schematically depicted valve <NUM> and a schematically depicted pressure-containing tapping CNC machine tool <NUM> was attached to the tapping structure <NUM>. The combination of the valve <NUM> and the tool <NUM> may be coupled together and run to the pipeline at the same time using a running tool (not shown) or by use of one or more downlines (not shown). Also depicted in <FIG> is an illustrative seal <NUM> positioned between the valve <NUM> and the tapping structure <NUM>. The seal <NUM> is positioned in the previously formed seal recess <NUM>. Also depicted is another seal <NUM> positioned between the CNC tool <NUM> and the valve <NUM>. A plurality of simplistically depicted bolts <NUM> are adapted to engage the drilled and tapped openings <NUM> so as to secure the combination of the valve <NUM> and the tool <NUM> to the tapping structure <NUM>. The valve <NUM> may be any type of valve that may, when opened, provide sufficient room to perform the machining process described below. In one illustrative example, the valve <NUM> may be a gate or a ball valve. <FIG> indicates the valve <NUM> in the open condition by virtue of the valve element 116A being non-shaded.

In <FIG> the valve element 116A has been omitted so as not to overly complicate the drawing. As shown in <FIG>, a cutting tool 122A (e.g., a drill) of the tapping CNC machine tool <NUM> was extended through the open valve <NUM> until such time as it engaged the bottom of the alignment/coupling recess <NUM>. At that time, the CNC machine tool <NUM> was operated to as to begin drilling through the tapping structure <NUM>.

<FIG> depicts the pipeline <NUM> after several operations were performed. First, the CNC tool <NUM> continued drilling until such time as an opening <NUM> was defined in the tapping structure <NUM> and or the pipeline itself. The opening <NUM> provides fluid communication between the inside of the pipeline <NUM> and the valve <NUM>. Thereafter, the cutting tool 122A was retracted through the open valve <NUM> and into the tool <NUM>.

<FIG> depicts the pipeline <NUM> after the valve <NUM> was closed, as indicated by virtue of the valve element 116A being shaded.

<FIG> depicts the pipeline <NUM> after the CNC tool <NUM> has been decoupled from the closed valve <NUM> and is in the process of being retrieved to the surface.

<FIG> depicts the pipeline <NUM> after an illustrative flowline <NUM> has been coupled to the closed valve <NUM>.

<FIG> depicts the pipeline <NUM> after the valve <NUM> was opened thereby allowing establishing a fluid flow path, as indicated by the double arrow <NUM> between the flowline <NUM> and the pipeline <NUM>. Fluids, such a production fluids, may flow from an item of subsea equipment, such as a production tree (not shown), into the flowline <NUM> and ultimately into the pipeline <NUM> and ultimately to a surface production facility.

<FIG> depict one illustrative method of plugging the opening <NUM> on a permanent or temporary basis. Such plugging of the opening <NUM> may be required in several scenarios, e.g., the failure of the valve <NUM> during the initial installation process or for later repair of the valve <NUM>. A plug may also be installed in the opening <NUM> as part of a permanent abandonment process operation.

<FIG> depicts the pipeline <NUM> after the valve <NUM> was closed so as to isolate the flowline <NUM>.

<FIG> depicts the pipeline <NUM> after the flowline <NUM> was disconnected from the valve <NUM>.

<FIG> depicts the pipeline <NUM> after a plug installation tool <NUM> was coupled to the closed valve <NUM>. A variety of known plug installation tools may be employed for this process operation. Also depicted in <FIG> is a simplistically depicted plug <NUM>.

<FIG> depicts the pipeline <NUM> after the valve <NUM> was opened so as to isolate the flowline <NUM>.

<FIG> depicts the pipeline after an arm 138A of the plug installation tool <NUM> was extended through the open valve <NUM> so as to position the plug <NUM> in its final sealed position within the portion of the opening <NUM> that extends through the tapping structure <NUM>. The plug <NUM> comprises one or more seals <NUM> on its outer surface that are adapted to sealingly engage the inner surface of the portion of the opening <NUM> that extends through the tapping structure <NUM>. At the time the CNC tool <NUM> was used to cut the opening <NUM> through the tapping structure <NUM>, the tool <NUM> was also used to form a recess 20Z in the tapping structure <NUM>. The recess 20Z is adapted to receive locking lugs <NUM> on the plug that may be actuated by the plug installation tool <NUM> so as to lock the plug <NUM> in its final sealed position within the tapping structure <NUM>.

<FIG> depicts the pipeline <NUM> after the arm 138A of the plug installation tool <NUM> was retracted through the open valve <NUM> and into the tool <NUM>.

<FIG> depicts the pipeline <NUM> after the valve <NUM> was decoupled from the tapping structure <NUM> and the combination of the valve <NUM> and the tool <NUM> is in the process of being retrieved to the surface.

<FIG> depicts the pipeline <NUM> after additional insulation material <NUM> has been positioned on the pipeline above the tapping structure <NUM> with the plug positioned therein. To the extent access is ever again needed to the pipeline <NUM> via the opening <NUM>, the valve <NUM> and the plug installation tool <NUM> may be re-attached to the tapping structure <NUM>. The plug installation tool <NUM> may then be operated so as to retract the locking lugs <NUM> from engagement with the tapping structure <NUM> and the plug may be retrieved from the opening <NUM> within the tapping structure <NUM>.

In another illustrative method disclosed herein, in the case where a plug has been previously installed in one of the access node structures 14X, the steps shown in <FIG> could be performed in reverse order to remove the previously installed plug so as to provide fluid flow access to the pipeline <NUM> via the access node structure 14X.

<FIG> depict another illustrative embodiment of an access node structure 14X disclosed herein. More specifically, in this example, the access node structure 14X takes the form of a pressure-barrier retaining structure <NUM> that is adapted to receive a simplistically depicted removable pressure-barrier device <NUM>. In general, the pressure barrier retaining structure <NUM> comprises an opening <NUM> that is exposed to the interior of the pipeline <NUM>. As was the case with the previously described tapping structure <NUM>, the pressure barrier retaining structure <NUM> may be formed integral with the pipeline <NUM>. The pressure-barrier retaining structure <NUM> may be attached to the access node section of pipe 12A at an on-shore facility or it may be attached to the access node section of pipe 12A on a pipe-laying vessel as the pipeline <NUM> is being deployed. In one illustrative embodiment, the pressure-barrier retaining structure <NUM> may have approximately the same dimensions as that of the illustrative tapping structure <NUM> discussed above. In other applications, the pressure-barrier retaining structure <NUM> may be significantly smaller than the tapping structure <NUM> described above. The size of the opening <NUM> may vary depending upon the particular application. In the example depicted, only a single pressure-barrier device <NUM> will be positioned in the opening <NUM>. However, if desired, the pressure-barrier retaining structure <NUM> could be made of sufficient size such that multiple pressure-barrier devices <NUM> could be positioned within the opening <NUM> to provide redundant pressure barriers. As will be appreciated by those skilled in the art after a complete reading of the present application, the pressure-barrier device <NUM> is intended to be representative of any type of pressure retaining device that may be positioned in an opening. With reference to <FIG>, in one illustrative embodiment, the pressure-barrier device <NUM> may be a simplistically depicted removable plug that comprises one or more elastomeric sealing elements (not separately shown) and a plurality of anchor slips <NUM>. Such plugs are commonly employed in various downhole operations such as, for example, fracturing operations. These types of plugs may be mechanically set in the opening <NUM>. <FIG> depicts the plug <NUM> in the un-set condition, while <FIG> depicts the plug <NUM> in the set condition wherein the sealing elements of the plug <NUM> have been expanded to seal against the inner surface of the opening <NUM> and the anchor slips <NUM> have been extended so as to engage the inner surface of the opening <NUM>. In other embodiments, the pressure-barrier device <NUM> may be what is generally known as a disappearing tubing hanger (or glass) plug. In this illustrative example, the pressure-barrier device <NUM> will be positioned in the opening <NUM> of the pressure-barrier retaining structure <NUM> and set so as to seal the opening <NUM> prior to the pipeline <NUM> being deployed into the sea. As noted above, at some point later in time, the pressure-barrier device <NUM> may be removed by using a device such as the above-mentioned plug installation/retrieval tool <NUM> and the valve <NUM>. In the case where the need for access to the pipeline <NUM> is only temporary, another pressure-barrier device <NUM> may be re-installed in the opening <NUM> at the completion of the temporary process operation.

<FIG> depict yet another illustrative embodiment of an access node structure 14X disclosed herein. More specifically, this example depicts one or more pressure barriers adapted to be positioned in the opening <NUM> of the pressure-barrier retaining structure <NUM>. In the depicted example, the pressure barrier is a single bursting pressure-retaining device <NUM> positioned in the opening <NUM> of the pressure-barrier retaining structure <NUM>. The device <NUM> comprise a membrane (or disc) <NUM> that is capable of being ruptured by increasing the pressure applied to the membrane <NUM> so as to gain fluid access to the interior of the pipeline <NUM>. As noted above, if desired, the pressure-barrier retaining structure <NUM> could be made of sufficient size such that multiple pressure barriers, e.g., multiple bursting pressure-retaining devices <NUM>, could be positioned within the opening <NUM> to provide redundant pressure barriers. In such a situation, access would be provided to the space between such multiple pressure barriers so as to monitor the pressure within the space between the multiple pressure barriers. <FIG> depicts the bursting pressure-retaining device <NUM> with the membrane <NUM> intact and the opening <NUM> sealed. <FIG> depicts the bursting pressure-retaining device <NUM> wherein the membrane <NUM> has been ruptured, thereby creating an opening <NUM> in the membrane <NUM> that allows access to the interior of the pipeline <NUM>. In this illustrative example, the bursting pressure-retaining device <NUM> will be positioned in the opening <NUM> of the pressure-barrier retaining structure <NUM> so as to seal the opening <NUM> prior to the pipeline <NUM> being deployed into the sea. At some point later in time, the membrane <NUM> of the bursting pressure-retaining device <NUM> may be removed by attaching the valve <NUM> to the pressure-barrier retaining structure <NUM> and coupling the valve <NUM> to a source of fluid, typically a liquid. At that point, the valve may be opened and the pressure of the fluid may be increased until such time as the membrane <NUM> ruptures, thereby providing access to the pipeline <NUM>. After the membrane <NUM> is ruptured, the bursting pressure-retaining device <NUM> may or may not be removed from the opening <NUM>.

<FIG> and <FIG> depict yet another illustrative embodiment of an access node structure 14X disclosed herein. More specifically, in this example, the access node structure 14X takes the form of a pressure-barrier retaining structure <NUM> having a scored or notched bottom <NUM> with various grooves or notches that function as stress risers so as to permit all or portions of the bottom <NUM> to be removed so as to gain access to the pipeline <NUM>. <FIG> is a side view of this embodiment of the access node structure 14X with the bottom <NUM> intact. <FIG> is a cross-sectional view of the pressure-barrier retaining structure <NUM> wherein portions of the bottom <NUM> have been mechanically removed, thereby forming an opening <NUM> that allows access to the pipeline <NUM>. <FIG> is a plan view showing the bottom <NUM>. <FIG> also indicates where the cross-sectional view of the bottom <NUM> shown in <FIG> is taken (the portion of the cross-sectional view in <FIG> that passes through bottom <NUM> is laterally from the centerline 12B of the pipe 12A). As shown in <FIG> and <FIG>, a plurality of grooves 173X and 173Y are formed in the bottom <NUM>. The grooves 173X, 173Y may be of any desired shape or configuration. As noted above, these grooves 173X, 173Y are formed in the bottom <NUM> so that they act as stress risers that enable the removal of all or a portion of the bottom <NUM> by mechanical means so as to gain access to the interior of the pipeline <NUM>. In general, the pressure barrier retaining structure <NUM> comprises recess <NUM> and the bottom <NUM>. The thickness of the bottom <NUM> as well as the depth of the grooves 173X, 173Y are designed such that the bottom <NUM> can withstand all loads applied to the bottom <NUM> during installation, commissioning, operation and abandonment of the pipeline <NUM>. As was the case with the previously described tapping structure <NUM>, the pressure barrier retaining structure <NUM> may be formed integral with the pipeline <NUM>. The pressure-barrier retaining structure <NUM> may be attached to the access node section of pipe 12A at an on-shore facility or it may be attached to the access node section of pipe 12A on a pipe-laying vessel as the pipeline <NUM> is being deployed. In one illustrative embodiment, the pressure-barrier retaining structure <NUM> may have approximately the same dimensions as that of the pressure-barrier retaining structure <NUM> or the tapping structure <NUM>. The size of the opening <NUM> may vary depending upon the particular application In this illustrative example, access node section of pipe 12A that contains the pressure-barrier retaining structure <NUM>, with the notched bottom surface <NUM>, will be positioned in the pipeline prior to the pipeline <NUM> being deployed into the sea. At some point later in time, all or part of the bottom <NUM> may be removed by using a hydraulic tearing device. This hydraulic tearing device could use hydraulic power to effectively push or pull on the notched or scored section to apply sufficient force to tear the material at the stress risers. In one illustrative embodiment, the hydraulic tearing device may comprise a hydraulic cylinder (similar to the hydraulic cylinder shown in <FIG>) that is adapted to be extended so as to push on the notched bottom surface <NUM>. In such an embodiment, a sloped face at the end of the piston rod may be provided so as to apply more force to one side of the notched bottom surface <NUM> to initiate the tear. As the rod continues to extend, the sloped face substantially completes the tear around the whole circumference of the notched bottom surface <NUM>. In another embodiment, a pilot hole (not shown) may be drilled through the bottom surface and a pull-out device (not shown) would be positioned in or through the pilot hole such that it is securely attached to or cannot be readily withdrawn from the pilot hole. In one embodiment, the pull out device may be part of or an attachment to a rod of a hydraulic cylinder, wherein the rod is in an extended position. At that time, the hydraulic cylinder may be actuated so as to retract the rod, thereby mechanically tearing the bottom surface <NUM>. In one particular embodiment, such a pilot hole may be drilled off-center so as to initiate the tear in an edge region of the bottom surface. After the initial tearing of the bottom surface <NUM>, the hydraulic cylinder would be further retracted to complete the tearing around the entire circumference of the bottom surface <NUM>. The hydraulic tearing device may be used in much the same manner as described above with respect to the tapping operations with the exception that a plug would not be set in the opening <NUM> after portions of the bottom <NUM> were removed.

As will be appreciated by those skilled in the art after a complete reading of the present application, any combination of the various access node structures 14X disclosed herein may be employed in a single pipeline <NUM>. For example, a single pipeline may comprise a plurality of the tapping structures <NUM>, a plurality of the pressure-barrier retaining structures <NUM> and/or a plurality of the pressure-barrier retaining structures <NUM>. Of course, if desired, a single pipeline may only contain a plurality of the tapping structures <NUM>. Thus, the presently disclosed subject matter provides great flexibility as it relates to ongoing field development activities and the manner in which access may be had to the pipeline via the access nodes <NUM>.

<FIG> depict one illustrative example of the flexibility provided by use of various embodiments of the pipeline system disclosed herein. In some applications, it may be desirable or necessary to expand the functionality of the subsea production equipment that was previously installed above a reservoir. For example, in the early stages of the development of a reservoir <NUM>, the production of hydrocarbon-containing fluid under the natural production forces of a well may be sufficient to make such a well commercially viable over a certain period of time. However, over time, the produced fluids from such a well may require the addition of extra energy to boost the flowrate of hydrocarbons. The hydrocarbon streams may be single phase, or a multiphase stream of hydrocarbon-containing fluids, i.e., a production stream that includes significant quantities of both liquid and gas hydrocarbon-containing materials. In that situation, it may be desirable to boost the energy of the fluids through the addition of further subsea processing equipment, which might include the addition of one or a combination of: a single phase pump, a multiphase pump, a separator, a compressor, etc. This is typically accomplished by adding the additional subsea processing equipment through a "tie-in" that provides fluid communication between the newly-added equipment and the pre-existing equipment, such as a subsea manifold. As the development of the reservoir <NUM> continues over time, it may be necessary to add further subsea equipment that serves to separate liquid and gas components of the overall produced fluid and pump the liquid portions of the produced fluid to further processing units. Such additional subsea equipment may need to be tied in to the preexisting items of equipment positioned subsea. At a further stage of the development of the reservoir <NUM>, existing production equipment and/or newly added production equipment may be tasked with performing the additional function of reinjecting some of the separated liquid portions of the produced fluid back into a well drilled into the reservoir. All of these modified production processes that occur over the useful life of the reservoir <NUM> typically involve adding additional valves, flowlines and equipment so as to provide the necessary functionality for producing hydrocarbon-containing fluids from the reservoir <NUM> in commercially viable quantities.

<FIG> depicts an embodiment of an illustrative pipeline <NUM> disclosed herein that comprises previously un-tapped access nodes <NUM> spaced along the pipeline <NUM>. As indicated, the original as-deployed pipeline <NUM> comprises an originally-installed valve <NUM>. At some point in time after the initial deployment of the pipeline <NUM> into the sea, additional equipment subsea must be added so as to provide additional subsea process capabilities.

With reference to <FIG>, using the illustrative tapping method disclosed herein, an opening <NUM> may be formed at previously un-tapped access nodes <NUM> on opposite sides of the valve <NUM>. Thereafter, a flow line <NUM> may be coupled to each of the valves <NUM> so as to provide the desired fluid communication between the pipeline <NUM> and the newly added subsea equipment (not shown). The flow lines <NUM> provide a fluid circulation path (to and from) between the pipeline <NUM> and the newly added subsea equipment.

Accordingly, as will be appreciated by those skilled in the art after a complete reading of the present application, the provision of the un-tapped access nodes <NUM> in the pipeline <NUM> at the time the pipeline <NUM> is deployed into the sea provides engineers with much more flexibility as it relates to the development of the reservoir <NUM> and the positioning of subsea equipment above the reservoir <NUM> over the life of the reservoir. Additionally, in the embodiments where the utility lines <NUM> are strapped or coupled to the pipeline <NUM> at the time the overall pipeline system <NUM> is deployed into the sea, the use of some or all of traditional subsea umbilicals to provide various utilities, e.g., power, communication, chemicals, etc., may be eliminated.

Claim 1:
A system, comprising:
a pipeline (<NUM>); and
a plurality of future access node structures (14X) axially spaced apart from one another along the pipeline (<NUM>), wherein of the plurality of future access node structures (14X) comprises a substantially planar upper surface, wherein the future access node structures (14X) are formed integral with the pipeline (<NUM>) and are configured to initially prevent access to an interior of the pipeline (<NUM>), wherein the system comprising the pipeline (<NUM>) and the integrally formed future access node structures (14X) is adapted to be deployed subsea, and wherein the plurality of future access node structures (14X) comprises at least one of: a tapping structure (<NUM>); a pressure-barrier retaining structure (<NUM>) and a pressure-barrier device (<NUM>) received therein; and a pressure-barrier retaining structure (<NUM>) comprised of a recess (<NUM>) with a scored pressure-retaining bottom (<NUM>), such that the plurality of future access node structures (14X) subsequently can be opened to provide fluid access to an interior of the pipeline (<NUM>).