Well flow control systems and methods

Flow control systems and methods for use in hydrocarbon well operations include a tubular and a flow control apparatus. The tubular defines a well annulus and includes an outer member defining a flow conduit. Fluid communication between the well annulus and the flow conduit is provided by permeable portion(s) of the outer member. The flow control apparatus is disposed within the flow conduit and comprises conduit-defining and chamber-defining structural members. The conduit-defining structural member(s) is configured to divide the flow conduit into at least two flow control conduits. The chamber-defining structural member(s) is configured to divide at least one of the at least two flow control conduits into at least two flow control chambers. Each of the flow control chambers has at least one inlet and one outlet, each of which is adapted to allow fluid flow therethrough and to retain particles larger than a predetermined size.

FIELD

The present disclosure relates generally to systems and methods for recovering hydrocarbons from subsurface reservoirs. More particularly, the present disclosure relates to systems and methods for controlling the flow of undesired particulates from subsurface reservoirs through well equipment to the surface.

BACKGROUND

This section is intended to introduce the reader to various aspects of art, which may be associated with embodiments of the present invention. This discussion is believed to be helpful in providing the reader with information to facilitate a better understanding of particular techniques of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not necessarily as admissions of prior art.

Hydrocarbon production from subterranean reservoirs commonly includes a well completed in either a cased-hole or an open-hole condition. In cased-hole applications, a well casing is placed in the well and the annulus between the casing and the well is filled with cement. Perforations are made through the casing and the cement into the production zones to allow formation fluids (such as, hydrocarbons) to flow from the production zones into the conduit within the casing. Additionally or alternatively, the fluid flow may be from the conduit within the casing into the subterranean formation, such as during injection operations. While the discussion herein will generally refer to production operations and fluid flow in the production direction, the principles and technologies described herein apply by analogy to fluid flow in the injection direction. A production string (or, an injection string), consisting primarily of one or more tubulars, is then placed inside the casing, creating an annulus between the casing and the production string. Formation fluids flow into the annulus and then into the production string to the surface through tubulars associated with the production string. In open-hole applications, the production string is directly placed inside the well without casing or cement. Formation fluids flow into the annulus between the formation and the production string and then into the production string to surface.

Modern hydrocarbon wells generally pass through or into multiple subterranean formation types and are continually reaching ever greater depths and/or lengths (such as for extended reach horizontal wells). Additionally, it is common for hydrocarbon wells to extend through multiple reservoirs over the life of the well. In some implementations, the well may extend through multiple reservoirs during any given production operation. Additionally or alternatively, a well may extend though a single reservoir that operates more like multiple reservoirs due to the variations of formation properties within the reservoir and/or the size of the reservoir.

The ever increasing complexity of modern hydrocarbon production operations often necessitates increasingly complex well constructions and completions. The construction of a hydrocarbon well typically includes modeling the subsurface to estimate the formation and reservoir properties. The modeling typically includes inputs from geologic and seismic data as well as data from test wells and/or adjacent wells in the field. These modeling efforts enable the scientists and engineers to identify a preferred location for the well and preferred drilling parameters for the drilling of the well. For example, the rate of penetration, the mud weight, and several parameters related to the drilling operation can affect the long-term operation of the well. While the models and the technology underlying the models are continually evolving, the scientists and engineers are left with an approximation based on previously collected data. The drilling operation is a dynamic, multi-parameter operation where changes in any one parameter could impact any of several parameters over the life of the well.

While the drilling plan can have significant impact on the operation of the well during its life, the completion of the well is often considered determinative of how a given well, once drilled, will operate. As used herein, completion is used generically to refer to procedures and equipment designed to allow a well to be operated safely and efficiently. The point at which the completion process begins may depend on the type and design of well. However, there are many options applied or actions performed during the construction phase of a well that have significant impact on the productivity of the well. Accordingly, completion plans are often prepared prior to the drilling operations based on the models and collected data. The completion plans are often updated based on data collected during the drilling operations to further optimize the operation of the well (whether injection or production).

Despite the accuracy or completeness of the data available when the completion plan is finalized and the completion is implemented in the well, the well's evolution, the reservoir's evolution, and the formation's evolution during the life of the well make most completions inadequate for the extended life of the well. Accordingly, sophisticated work-over procedures have been developed to allow operators to change the completion of a well after production and/or injection operations have begun. Additionally, several efforts have been made to develop intelligent or flexible completions that can be changed during the life of the well without requiring the withdrawal of the completion equipment from the well. Many of these intelligent completions require mechanical equipment downhole that is controlled from the surface between two or more configurations. While the adaptable completion concept is sound, the harsh conditions of the well and the long life of the well generally complicate efforts to manipulate these multi-configuration mechanical devices deep in the well. Moreover, the requirement of these systems to be activated from the surface creates a time delay while the results of the changed downhole condition increasingly manifests itself at the surface and is observed at the surface, and then the control signal can be sent to the downhole equipment that has to transition between configurations.

When producing fluids from subterranean formations, especially poorly consolidated formations or formations weakened by increasing downhole stress due to well excavation and fluids withdrawal, it is possible to produce solid material (for example, sand) along with the formation fluids. This solids production may reduce well productivity, damage subsurface equipment, and add handling cost on the surface. Controlling the production of solids or particles is one example of the objectives of the completion equipment and procedures. Several downhole solid, particularly sand, control methods are currently being practiced by the industry and are shown inFIGS. 1(a),1(b),1(c) and1(d). InFIG. 1(a), the production string or pipe (not shown) typically includes a sand screen or sand control device1around its outer periphery, which is placed adjacent to each production zone. The sand screen prevents the flow of sand from the production zone2into the production string (not shown) inside the sand screen1. Slotted or perforated liners can also be utilized as sand screens or sand control devices.FIG. 1(a) is an example of a screen-only completion with no gravel pack present.

One of the most commonly used techniques for controlling sand production is gravel packing in which sand or other particulate matter is deposited around the production string or well screen to create a downhole filter.FIGS. 1(b) and1(c) are examples of cased-hole and open-hole gravel packs, respectively.FIG. 1(b) illustrates the gravel pack3outside the screen1, the well casing5surrounding the gravel pack3, and cement8around the well casing5. Typically, perforations7are shot through the well casing5and cement8into the production zone2of the subterranean formations around the well.FIG. 1(c) illustrates an open-hole gravel pack wherein the well has no casing and the gravel pack material3is deposited around the well sand screen1.

A variation of a gravel pack involves pumping the gravel slurry at pressures high enough so as to exceed the formation fracture pressure (frac pack).FIG. 1(d) is an example of a Frac-Pack. The well screen1is surrounded by a gravel pack3, which is contained by a well casing5and cement8. Perforations6in the well casing allow gravel to be distributed outside the well to the desired interval. The number and placement of perforations are chosen to facilitate effective distribution of the gravel packing outside the well casing to the interval that is being treated with the gravel-slurry.

Flow impairment during production from subterranean formations can result in a reduction in well productivity or complete cessation of well production. This loss of functionality may occur for a number of reasons, including but not limited to: 1) migration of fines, shales, or formation sands; 2) inflow or coning of unwanted fluids (such as, water or gas); 3) formation of inorganic or organic scales; 4) creation of emulsions or sludges; 5) accumulation of drilling debris (such as, mud additives and filter cake); 6) excessive inflow of particles, such as sand, into and through the production tubulars due to mechanical damage to sand control screen and/or due to incomplete or ineffective gravel pack implementations; 7) and mechanical failure due to borehole collapse, reservoir compaction/subsidence, or other geomechanical movements.

There are several examples of technology that has been developed in efforts to address these problems. Examples of such technologies can be found in numerous U.S. patents, including those mentioned briefly here. For example, U.S. Pat. No. 6,622,794 discloses a screen equipped with a flow control device, which includes multiple apertures and channels to direct and restrict flow. The fluid flow through the screen is disclosed as being reduced by controlling downhole apertures from the surface between fully opened and completely closed positions. U.S. Pat. No. 6,619,397 discloses a tool for zone isolation and flow control in horizontal wells. The tool is composed of blank base pipes, screens with closeable ports on the base pipe, and conventional screens positioned in an alternating manner. The closeable ports allow complete gravel pack over the blank base pipe section, flow shutoff for zone isolation, and selective flow control. U.S. Pat. No. 5,896,928 discloses a flow control device placed downhole with or without a screen. The device has a labyrinth which provides a tortuous flow path or helical restriction. The level of restriction in each labyrinth is controlled from the surface by adjusting a sliding sleeve so that flow from each perforated zone (for example, water zone, oil zone) can be controlled. U.S. Pat. No. 5,642,781 discloses a well screen jacket composed of overlapped members wherein the openings allow fluid flow through alternate contraction, expansion and provide fluid flow direction change in the well (or multi-passage). Such design may mitigate solids plugging of screen jacket openings by establishing both filtering and fluid flow momentum advantages.

Numerous other examples can be identified. However, current industry well designs and completions plans include little, if any, redundancy in the event of problems or failures resulting in flow impairment. In many instances, the ability of a well to produce at or near its design capacity is sustained by only a “single” barrier to the impairment mechanism (for example, a single screen for ensuring sand control). In many instances, the utility of the well may be compromised by impairment occurring in the single barrier. As indicated above, flow impairment may occur by a variety of mechanisms and various efforts have been made to address these mechanisms, including efforts to provide redundant barriers to the impairment mechanism. However, the systems currently available fail to provide a system that provides redundancy in the prevention of two or more impairment mechanisms. For example, prevention of impairment mechanisms such as particulate inflow and particulate blockages. Therefore, overall system reliability of the presently available systems is low. Accordingly, there is a need for well completion equipment and methods to provide multiple flow pathways inside the well that provides redundant flow pathways in the event of particulate blockage, particulate inflow, or other forms of impairment.

SUMMARY

The present disclosure is directed to systems and methods for controlling fluid flow in well equipment associated with hydrocarbon wells An exemplary well flow control system includes a tubular and a flow control apparatus. The tubular is adapted to be disposed in a well to define a well annulus. The tubular has an outer member defining an internal flow conduit and at least a portion of the outer member is permeable allowing fluid communication between the well annulus and the flow conduit. The flow control apparatus is adapted to be disposed within the flow conduit of the tubular. The flow control apparatus comprises at least one conduit-defining structural member and at least one chamber-defining structural member. The at least one conduit-defining structural member is configured to divide the flow conduit into at least two flow control conduits. The at least one chamber-defining structural members is configured to divide at least one of the at least two flow control conduits into at least two flow control chambers. Each of the at least two flow control chambers has at least one inlet and at least one outlet. Each of the at least one inlet and the at least one outlet is adapted to allow fluids to flow therethrough and to retain particles larger than a predetermined size.

Implementations of flow control systems within the scope of the present invention may include several variations on the features described above. For example, fluid flow through an outlet of a flow control chamber formed in a first flow control conduit may pass into a second flow control conduit. Additionally or alternatively, the retention of particles larger than a predetermined size by the outlet may progressively increase resistance to flow through the outlet from the flow control chamber until fluid flow through the outlet is at least substantially blocked. In some implementations, the at least two flow control chambers may be disposed within the flow conduit of the tubular such that fluid flow entering through the permeable portion of the outer member passes into at least one flow control chamber. For example, the at least one inlet to the flow control chamber is provided by the permeable portion of the outer member of the tubular.

In some implementations, the at least one inlet to the flow control chamber may be adapted to retain particles of a first predetermined size and the at least one outlet from the flow control chamber may be adapted to retain particles of a second predetermined size. Additionally or alternatively, the at least one inlet and the at least one outlet of the flow control chamber are adapted to retain particles having at least substantially similar predetermined sizes. For example, the flow control chamber may be adapted to progressively retain particles larger than the predetermined size of the at least one outlet in the event that the at least one inlet is impaired. In some implementations, the at least one inlet and the at least one outlet for at least one of the flow control chambers may be fluidically offset and in fluid communication.

In some implementations of the present flow control systems, the flow within at least one of the flow control chambers may be at least substantially longitudinal and the at least one chamber-defining structural member may be disposed at least substantially transverse to the longitudinal direction. Additionally or alternatively, the flow within at least one of the flow control chambers may be at least substantially circumferential and the at least one chamber-defining structural member may be disposed at least substantially transverse to the circumferential direction. Still additionally or alternatively, the flow within at least one of the flow control chambers may be at least substantially radial and the at least one chamber-defining structural member may be disposed at least substantially transverse to the radial direction.

Exemplary implementations of the flow control apparatus may include at least one conduit-defining structural member provided by an inner tubular having permeable segments and impermeable segments. The inner tubular defines a first flow control conduit within the inner tubular and a second flow control conduit between the outer member and the inner tubular. The at least one chamber-defining structural member and the at least two flow control chambers are disposed in the second flow control conduit. Additionally or alternatively, the at least one conduit-defining structural member may be adapted to divide the flow conduit into at least three flow control conduits. In some implementations, the chamber-defining structural members may define flow control chambers in at least two of the at least three flow control conduits. In such implementations, at least one of the at least three flow control conduits may be in fluid communication with the well annulus only through one or more of the flow control chambers. In implementations having flow control chambers in two or more flow control conduits, the flow control chambers in adjacent flow control conduits may be fluidically offset and in fluid communication.

Implementations of the present flow control systems may include at least one conduit-defining structural member comprising an inner tubular having permeable segments and impermeable segments. The inner tubular may define a first flow control conduit within the inner tubular. The at least one conduit-defining structural member further comprises helically wrapped flights extending along at least a portion of the inner tubular and configured to define at least one helical flow control conduit between the outer member and the inner tubular. In such implementations, the at least one chamber-defining structural member and the at least two flow control chambers may be disposed in the at least one helical flow control conduit.

Additionally or alternatively, one or more of the at least one outlets may be adapted to be selectively opened to control fluid flow through the outlet. In some implementations, at least one of the at least two flow control chambers may include at least two outlets adapted to retain particles of different predetermined sizes. In such implementations, each of the at least two outlets may adapted to be selectively opened to fluid flow to selectively retain particles of different predetermined sizes depending on which outlet is opened.

The inlet to at least one flow control chamber may be formed in the flow control apparatus and the outlet from the at least one flow control chamber may be formed by the permeable portion of the outer member. Additionally or alternatively, the permeable portion of the outer member may provide an inlet to at least one flow control chamber and the outlet from the at least one flow control chamber may be formed in the flow control apparatus.

The present disclosure is further directed to a flow control apparatus adapted for insertion into a flow conduit of a well tubular. Exemplary flow control apparatus include at least one conduit-defining structural member and at least one chamber-defining structural member. The at least one conduit-defining structural member may be adapted to be inserted in a flow conduit of a well tubular and to divide the flow conduit into at least two flow control conduits. The at least one chamber-defining structural member may be configured to divide at least one of the at least two flow control conduits into at least two flow control chambers. The flow control apparatus further includes at least one permeable region provided in at least one of the at least one conduit-defining structural member and the at least one chamber-defining structural member. The at least one permeable region is adapted to allow fluid communication and to retain particles larger than a predetermined size. The permeable portion is provided such that fluids flowing through the at least one permeable region passes from a first flow control conduit to a second flow control conduit within the flow conduit.

Flow control apparatus within the scope of the present invention may include variations on the components described above and/or features in addition to those described above. For example, some implementations may include swellable materials disposed at least on the at least one conduit-defining structural member and adapted to at least substantially seal against the well tubular to fluidically isolate the at least two flow control conduits from each other such that flow between flow control conduits occurs at least substantially only through the at least one permeable region. Additionally or alternatively, at least two permeable regions may be provided from at least one flow control chamber. In some implementations, the at least two permeable regions may be adapted to retain particles of different predetermined sizes. Additionally or alternatively, some implementations of the present flow control apparatus may include at least one permeable region adapted to be selectively opened to control the particle size being filtered from the flow through the permeable region.

Some implementations may include at least one conduit-defining structural member provided by an inner tubular having permeable segments and impermeable segments. The inner tubular may defines a first flow control conduit within the inner tubular and a second flow control conduit outside of the inner tubular. The at least one chamber-defining structural member and the at least two flow control chambers may be disposed in the second flow control conduit. Additionally or alternatively, the at least one conduit-defining structural member may be adapted to divide the flow conduit into at least three flow control conduits. In some implementations having at least three flow control conduits the at least one chamber-defining structural member may define flow control chambers in at least two of the at least three flow control conduits. Additionally or alternatively, in implementations having flow control chambers in two or more flow control conduits, the flow control chambers in adjacent flow control conduits may be fluidically offset and in fluid communication.

Still additional or alternative implementations include at least one conduit-defining structural member comprising an inner tubular having permeable segments and impermeable segments. The inner tubular defines a first flow control conduit within the inner tubular. The at least one conduit-defining structural member may further comprise helically wrapped flights extending along at least a portion of the inner tubular and configured to define at least one helical flow control conduit outside of the inner tubular. In such implementations, the at least one chamber-defining structural member and the at least two flow control chambers may be disposed in the at least one helical flow control conduit.

The present disclosure is further directed to methods of controlling particulate flow in hydrocarbon well equipment. The methods include providing a tubular adapted for downhole use in a well. The tubular comprises an outer member defining a flow conduit and at least a portion of the outer member is permeable and allows fluid flow through the outer member. The methods further include providing at least one flow control apparatus comprising: a) at least one conduit-defining structural member adapted to be disposed in the flow conduit of the tubular and to divide the flow conduit into at least two flow control conduits; and b) at least one chamber-defining structural member configured to divide at least one of the at least two flow control conduits into at least two flow control chambers. The methods further include disposing the tubular in a well, disposing the at least one flow control apparatus in the well, and operatively coupling the at least one flow control apparatus with the tubular. The foregoing steps of providing, disposing, and coupling may occur in any suitable order such that the assembled tubular and flow control apparatus is disposed in a well. The operatively coupled tubular and at least one flow control apparatus together provide the at least two flow control conduits and the at least two flow control chambers. Moreover, each of the at least two flow control chambers has at least one inlet and at least one outlet and each of the at least one inlet and the at least one outlet is adapted to allow fluids to flow therethrough and to retain particles larger than a predetermined size. The methods further include flowing fluids through the at least one flow control apparatus and the tubular.

Similar to the above descriptions of the flow control systems and apparatus, the present flow control methods may include numerous variations and/or adaptations depending on the conditions in which the methods are implemented. For example, in some implementations, the permeable portion of the outer member may provide at least one inlet to at least one flow control chamber and the step of flowing fluids through the at least one flow control apparatus and the tubular may include flowing production fluids through the permeable portion of the outer member and through the outlets of the flow control chambers to produce hydrocarbons from the well.

Additionally or alternatively, the step of flowing fluids through the at least one flow control apparatus and the tubular may include: 1) flowing fluid into at least one flow control chamber disposed in a first flow control conduit through at least one inlet, wherein the fluid flows through the at least one inlet in a first flow direction; 2) redirecting the fluid within the flow control chamber to flow in a second flow direction; and 3) redirecting the fluid within the flow control chamber to flow in a third flow direction to pass through the at least one outlet and into a second flow control conduit. In some implementations, the second flow direction may be at least substantially longitudinal. Additionally or alternatively, the second flow direction may be at least substantially circumferential, at least substantially radial, and/or at least substantially helical.

Still additionally or alternatively, the step of flowing fluids through the at least one flow control apparatus and the tubular may comprise injecting fluids into the well. Additionally or alternatively, flowing fluids through the at least one flow control apparatus and the tubular may comprise injecting completion fluids into the well. Flowing fluids through the at least one flow control apparatus and the tubular may additionally or alternatively comprise injecting gravel pack compositions into the well.

DETAILED DESCRIPTION

In the following detailed description, specific aspects and features of the present invention are described in connection with several embodiments. However, to the extent that the following description is specific to a particular embodiment or a particular use of the present techniques, it is intended to be illustrative only and merely provides a concise description of exemplary embodiments. Moreover, in the event that a particular aspect or feature is described in connection with a particular embodiment, such aspects and features may be found and/or implemented with other embodiments of the present invention where appropriate. Accordingly, the invention is not limited to the specific embodiments described below, but rather; the invention includes all alternatives, modifications, and equivalents falling within the scope of the appended claims.

As described above, completion systems and procedures are implemented in hydrocarbon wells in an effort to control flows through the downhole equipment and to promote efficient operation of the wells. Due to the variety of conditions under which wells are operated, it is impossible to sufficiently illustrate or capture the multitude of manners in which the present technology can be implemented. However, it should be understood that the technologies of the present disclosure may be implemented in production and/or injection wells, may be implemented in vertical wells, deviated wells, and/or horizontal wells, may be implemented in deep water wells, extended reach wells, arctic wells, and land-based wells, may be implemented in gas wells and in oil wells, and in virtually any other type of well and well operation that may be implemented in connection with the production of hydrocarbons. The configurations and implementations described herein are merely exemplary of the manners in which the technologies of the present disclosure may be used.

Turning now to the drawings, and referring initially toFIG. 2, an exemplary production system100in accordance with certain aspects of the present disclosure is illustrated. In the exemplary production system100, a floating production facility102is coupled to a subsea tree104located on the sea floor106. Through this subsea tree104, the floating production facility102accesses one or more subsurface formations, such as subsurface formation107, which may include multiple production intervals or zones108a-108n,wherein number “n” is any integer number. The distinct production intervals108a-108nmay correspond to distinct reservoirs and/or to distinct formation types encompassed by a common reservoir. The production intervals108a-108ncorrespond to regions or intervals of the formation having hydrocarbons (e.g., oil and/or gas) to be produced or otherwise acted upon (such as having fluids injected into the interval to move the hydrocarbons toward a nearby well, in which case the interval may be referred to as an injection interval). WhileFIG. 2illustrates a floating production facility102, it should be noted that the production system100is illustrated for exemplary purposes and implementations of the present technologies may be useful in the production or injection of fluids from any subsea, platform or land location.

The floating production facility102may be configured to monitor and produce hydrocarbons from the production intervals108a-108nof the subsurface formation107. The floating production facility102may be a floating vessel capable of managing the production of fluids, such as hydrocarbons, from subsea wells. These fluids may be stored on the floating production facility102and/or provided to tankers (not shown). To access the production intervals108a-108n,the floating production facility102is coupled to a subsea tree104and control valve110via a control umbilical112. The control umbilical112may include production tubing for providing hydrocarbons from the subsea tree104to the floating production facility102, control tubing for hydraulic or electrical devices, and/or a control cable for communicating with other devices within the well114.

To access the production intervals108a-108n,the well114penetrates the sea floor106to a depth that interfaces with the production intervals108a-108nat different depths (or lengths in the case of horizontal or deviated wells) within the well114. As may be appreciated, the production intervals108a-108n,which may be referred to as production intervals108, may include various layers or intervals of rock that may or may not include hydrocarbons and may be referred to as zones. The subsea tree104, which is positioned over the well114at the sea floor106, provides an interface between devices within the well114and the floating production facility102. Accordingly, the subsea tree104may be coupled to a production tubing string128to provide fluid flow paths and a control cable (not shown) to provide communication paths, which may interface with the control umbilical112at the subsea tree104.

Within the well114, the production system100may also include different equipment to provide access to the production intervals108a-108n.For instance, a surface casing string124may be installed from the sea floor106to a location at a specific depth beneath the sea floor106. Within the surface casing string124, an intermediate or production casing string126, which may extend down to a depth near the production interval108a,may be utilized to provide support for walls of the well114. The surface and production casing strings124and126may be cemented into a fixed position within the well114to further stabilize the well114. Within the surface and production casing strings124and126, a production tubing string128may be utilized to provide a flow path through the well114for hydrocarbons and other fluids. A subsurface safety valve132may be utilized to block the flow of fluids from portions of the production tubing string128in the event of rupture or break above the subsurface safety valve132. Further, packers134-136may be utilized to isolate specific zones within the well annulus from each other. The packers134-136may be configured to provide fluid communication paths between surface and the sand control devices138a-138n,while preventing fluid flow in one or more other areas, such as a well annulus.

In addition to the above equipment, other equipment, such as sand control devices138a-138nand gravel packs140a-140n,may be utilized to manage the flow of fluids from within the well. In particular, the sand control devices138a-138ntogether with the gravel packs140a-140nmay be utilized to manage the flow of fluids and/or particles into the production tubing string128. The sand control devices138a-138nmay include slotted liners, stand-alone screens (SAS); pre-packed screens; wire-wrapped screens, membrane screens, expandable screens and/or wire-mesh screens, while the gravel packs140a-140nmay include gravel or other suitable solid material. The sand control devices138a-138nmay also include inflow control mechanisms, such as inflow control devices (i.e. valves, conduits, nozzles, or any other suitable mechanisms), which may increase pressure loss along the fluid flow path. The gravel packs140a-140nmay be complete gravel packs that cover all of the respective sand control devices138a-138n,or may be partially disposed around sand control devices138a-138n.The sand control devices138a-138nmay include different components or configurations for any two or more of the intervals108a-108nof the well to accommodate varying conditions along the length of the well. For example, the intervals108a-108bmay include a cased-hole completion and a particular configuration of sand control devices138a-138bwhile interval108nmay be an open-hole interval of the well having a different configuration for the sand control device138n.

Conventionally, packers or other flow control mechanisms are disposed between adjacent intervals108to enable production in each of the zones to be independently controlled. For example, sand production into the annulus of interval108bwould be isolated to interval108bby packers135.FIG. 2schematically illustrates wells114and particularly intervals108within wells are not uniform and that the reservoirs and formations come in a variety of configurations that are not easily adaptable to zonal isolation through packers. As an example, intervals108cand108dare schematically illustrated as adjoining inFIG. 2and illustrated as not including a packer disposed therebetween. Adjoining intervals is one example of circumstances where zonal isolation through conventional packers is not practical. Additional examples, include wells traversing excessive numbers of different formations and/or zones such that the number of required packers would not be economically practical; wells traversing formations where the properties of the formations change gradually, yet substantially, such that the gradations can not be economically partitioned through conventional packers; and various other circumstances where the costs and/or operational risks associated with packer installation render the use of a packer impractical. As yet another example of well conditions where zonal isolation through conventional packer technology is not feasible, the conditions in each of the intervals108are dynamic during the operation of the well and what was initially considered to be operably a single interval may evolve to where the most efficient operation of the well would be to isolate the single interval into multiple intervals or zones for independent control. The changing characterization of an interval to require its partitioning into multiple intervals is common in well operations and is commonly accomplished through expensive and operationally risky workover procedures.

The technologies of the present disclosure are adapted to be disposed in a well to provide a flow control apparatus in association with a downhole tubular to provide redundant impairment resolution systems.FIG. 3provides a schematic flow diagram200of methods within the scope of the present disclosure and invention. The methods ofFIG. 3begin with providing a tubular adapted for downhole use, denoted as block210. At block212, the method continues by providing a flow control apparatus, such as those that will be described herein.FIG. 3illustrates that the methods of the present disclosure may be implemented in a variety of orders or sequences of steps depending on the condition of the well in which the technologies herein will be used. For example, in a new well or in a well from which the production tubing has been removed, the method200may include operatively associating the flow control apparatus with the tubular, at214, followed by disposing the combined tubular and flow control apparatus in the well, such as illustrated at216. Additionally or alternatively, the methods200of the present disclosure may include disposing the tubular in a well, denoted as block218. The tubular may be disposed in the well before the flow control apparatus is provided, such as when the flow control apparatus is being installed in an existing production tubular. Alternatively, the tubular may be disposed in the well prior to associating the flow control apparatus with the tubular for other reasons.FIG. 3illustrates at220that the flow control apparatus may be operatively associated with a tubular that is already disposed in a well.

The steps210-220of the present methods may be implemented in any suitable order or sequence so as to eventually have a flow control apparatus operatively associated with a tubular and disposed in a well. For example, the provision of the tubular may occur many years before the provision of the flow control apparatus. Similarly, the tubular may be disposed in a well long before the flow control apparatus is provided. The schematic flow chart ofFIG. 3illustrates just two of the many routes possible for arriving at the operative condition of having a flow control apparatus associated with a tubular and disposed in a well, all of which are within the scope of the present methods.

Once the flow control apparatus is disposed in the well and associated with a tubular, the methods200continue at222by flowing fluids through the flow control apparatus and the tubular. As indicated above, the fluid flow may be in the production direction (e.g., fluids flow through the tubular then through the flow control apparatus) or in the injection direction (e.g., fluids flow through the flow control apparatus then through the tubular), both being within the scope of the present methods. Finally, methods200produce hydrocarbons, such as indicated at224, which hydrocarbons may be produced from the well in which the flow control apparatus is disposed or from associated wells (such as when the flow control apparatus is used in injection wells).

The discussion herein of the present systems and methods primarily describes the components and features in a production context. For example, flow control conduits and chambers are described below as having inlets and outlets associated with structural members, which inlets and outlets may be context specific. For example, a permeable portion of a structural member may provide an outlet in a production operation context and may provide an inlet in an injection operation context. Similarly, the production-centric discussion herein describes features and aspects configured to prevent sand or particles from entering a production conduit in communication with the surface. By analogy, each and all of the implementations described herein and/or those within the scope of the present invention may have labels and nomenclature suitable adapted for the injection operations. For example, in an injection operation the well annulus is the conduit in direct communication with the target (i.e., the formation) in the same manner that the production conduit is in direct communication with the target in the production operation (i.e., the surface).

Accordingly, while many of the implementations described herein include nomenclature and/or descriptions written in the production context, the present invention is not so limited. Adaptations of the present implementations for use in injection operations typically involve nothing more than changing the nomenclature used to refer to the components. In some implementations, the precise disposition of a component may change in an injection operation. However, the relative disposition of elements or components will remain with the scope of the principles and implementations described herein. More specifically, the flow control systems within the present disclosure, whether used in production operations, injection operations, treatment operations, or otherwise, include a tubular and a flow control apparatus. The tubular defines a well annulus outside thereof and includes an outer member defining a flow conduit within the outer member. At least a portion of the outer member is permeable providing fluid communication between the well annulus and the flow conduit. The flow control apparatus is disposed within the flow conduit and comprises at least one conduit-defining structural member and at least one chamber-defining structural member. The at least one conduit-defining structural member is configured to divide the flow conduit into at least two flow control conduits. The at least one chamber-defining structural member is configured to divide at least one of the at least two flow control conduits into at least two flow control chambers. Each of the at least two flow control chambers has at least one inlet and one outlet, each of which is adapted to allow fluids to flow therethrough and to retain particles larger than a predetermined size.

FIG. 4illustrates a section240of a well242in a formation244. The well section240is illustrated as being a vertical section of the well242, but is illustrated here as merely exemplary as the technology may be used in vertical, horizontal, or otherwise oriented wells. As illustrated inFIG. 4, the well242includes flow control systems246disposed in operative association with production zones of the formation244. More specifically,FIG. 4illustrates that the present technologies may be implemented in a variety of configurations and/or combinations of technologies to provide flow control systems246according to the various implementations described, taught, and suggested herein. For example,FIG. 4illustrates that the flow control systems246include tubulars248, which may be provided in a first tubular configuration248aand/or in a second tubular configuration248b,each of which provide permeable and impermeable sections in different manners as will be described further in connection with subsequent Figures. The tubulars248, while different, have some elements in common. For example, each of the tubulars248includes an outer member250that defines a flow conduit252within the tubular. Additionally, each of the outer members250includes a permeable portion254adapted to allow fluid flow through the outer member into the flow conduit.

FIG. 4further illustrates that the tubulars248include flow control apparatus256, which may be of any of the configurations disclosed herein. Two exemplary flow control apparatus256are illustrated inFIG. 4. The details of the flow control apparatus' structure and functionality will be described in greater detail in connection with later Figures herein. However, as an introduction,FIG. 4illustrates that fluid flow, represented by flow arrows258, from the formation244into the tubular248follows a tortuous path through at least two flow control mechanisms, here represented as permeable segments associated with the outer member248and the flow control apparatus256. In some implementations of the present technology, it may be preferred to use a common configuration for each of the flow control systems246along the length of a downhole tubular joint, along the length of a zone isolated by packers, and/or along the length of an entire operative portion of a downhole string. In other implementations, such as illustrated inFIG. 4, the characteristics of the well, the formation, and/or the reservoir may suggest the use of different flow control system configurations in a single well. For example, as illustrated schematically inFIG. 2, it is possible that two production intervals, such as zones108cand108d,are sufficiently close together that zonal isolation through conventional packers is not practical. The different zones may include formations having different characteristics requiring differing completions for optimal operation. A configuration such as shown inFIG. 4where different flow control system configurations are disposed adjacent to each other may allow the differing intervals to be completed, and flows therefrom to be controlled, differently without requiring packers disposed between intervals. Similarly, the use of multiple flow control system configurations may be suitable in a variety of other common field conditions.

FIGS. 5A and 5Billustrate a flow control system246in a coaxial configuration260, which configuration is also shown inFIG. 4. The coaxial configuration260is one example of the various implementations of flow control systems246within the scope of the present disclosure.FIG. 5Aillustrates the coaxial configuration260in a fully open state whileFIG. 5Billustrates the coaxial configuration having a flow control chamber262blocked by sand264or other particulates (hereinafter referred to generically as sand) from the formation244. As seen inFIG. 5A, the flow control system246in a coaxial configuration260includes a tubular248, which includes an outer member250that defines a flow conduit252within the outer member. Tubulars248may include nothing more than the outer member250or may comprise the outer member250together with various other apparatus, such as apparatus common in downhole production strings. In implementations where the tubular248includes additional apparatus, it should be understood that the descriptor “outer” in outer member250is relative to the flow conduit252defined by the outer member250rather than relative to the tubular248. Tubular248and outer member250are illustrated inFIG. 5Aas cylindrical members according to convention in the industry; however, other shapes and configurations may be used as well, such as ellipsoid or polygonal. The shape of the tubular248may impact the shape of the flow conduit252and/or the configuration of the flow control apparatus256disposed within the flow conduit252. Additionally or alternatively, the configuration of the outer member250may have a greater impact on the configuration of the flow conduit252and/or flow control apparatus. For example, the outer member250may be adapted to provide permeable portions254and impermeable portions266in different locations along its length and/or periphery, which may affect the flow profile and, therefore, the configuration of the flow control apparatus256. Accordingly, whileFIGS. 5A and 5Billustrate an exemplary coaxial configuration260, other coaxial configurations are within the scope of the present disclosure. Similarly, the remaining configurations or implementations described and illustrated herein are merely representative and variations and shapes and dimensions of the various parts are within the scope of the present invention.

Flow control systems246of the present disclosure include the outer tubular250, as described above, and a flow control apparatus256, which is disposed within the flow conduit252. The flow control apparatus256comprises at least one conduit-defining structural member268and at least one chamber-defining structural member270. The at least one conduit-defining structural member268may be in any configuration adapted to divide the flow conduit252into at least two flow control conduits272. As illustrated inFIG. 5A, the conduit-defining structural member268includes a tubular member274disposed within the outer member250of the tubular248. InFIG. 5A, the tubular member274and the outer member250are concentric, leading to the nomenclature of the coaxial configuration; however, it should be understood that the tubular member274may be disposed in any position within the flow conduit252, including offset from the axis of the tubular248and/or adjacent to the outer member250. The at least one conduit-defining structural member268used to divide the flow conduit252into at least two flow control conduits272may comprise a single physical member or may comprise multiple members, such as tubular members, walls, baffles, etc.

The flow control apparatus256also includes at least one chamber-defining structural member270, as indicated above and representatively illustrated inFIG. 5A. InFIG. 5A, the chamber-defining structural member270is provided by a disk276spanning the annulus between the tubular member274and the outer member250. Accordingly, the flow conduit252defined by the outer member250is divided into at least two flow control conduits272and at least two flow control chambers262. Similar to the conduit-defining structural member268, the chamber-defining structural member270may be provided in any suitable configuration, which may be influenced by the configuration of the outer member250and/or the configuration of the conduit-defining structural members268. Similarly, the number of and the spacing between the chamber-defining structural members270may vary in implementations within the scope of the present disclosure. In the coaxial configuration260ofFIG. 5A, the chamber-defining structural members270may be positioned within flow conduit252at even intervals and/or may be positioned in the flow conduit based at least in part on the measured or expected properties of the formation244in the region outside of the tubular248.

A consideration of bothFIGS. 5A and 5Bwill illustrate the functionality of the flow control systems246described herein. The functionality is first described in general terms and then more specifically with reference to the specific elements shown inFIGS. 5A and 5B. As described above, the flow control systems246ofFIGS. 5A and 5Bare identical but in two different states of operation. Flow control systems246of the present invention provide at least two flow control conduits272from a single flow conduit252. Additionally, at least one of the flow control conduits272is divided into at least one flow control chamber262. The at least one flow control chamber262includes at least one inlet278and at least one selective outlet280. The at least one inlet278allows fluid from outside the tubular248, such as from the well annulus282between the formation244and the tubular248, through the outer member250and into the flow conduit252, or, more specifically, into the flow control chamber262. The inlet278is adapted to provide at least one barrier to flow impairment, such as by screening sand264from the flow. Accordingly, permeable portions254may provide the inlet278that also provides the barrier to flow impairment (e.g., sand control). The inlet278may provide the flow impairment barrier through any suitable configuration, such as using conventional sand control mechanisms of wire-wrapped screens, perforated tubing, pre-packed screens, slotted liners, mesh screens, sintered metal screens, etc.

Once the produced fluid has entered the flow control chamber262, the fluid flows toward the outlet280, which is illustrated inFIG. 5Aas being offset from the inlet278. The outlet280is also configured as a flow impairment barrier to provide redundancy in the efforts to counteract the various downhole conditions that can impair fluid flow. For example, and as illustrated inFIG. 5A, the outlet280from the flow control chamber262may be configured as a permeable segment adapted to retain sand264or other particles larger than a predetermined size. The configuration of the outlet may vary depending on the mechanism of flow impairment being counteracted. Additionally or alternatively, multiple outlets may be provided from a flow control chamber262, as will be seen in connection with other Figures herein. The coaxial configuration260could be adapted to include two outlets by providing perforations, mesh, or other form of permeability in the chamber-defining structural member270. In some implementations of the present invention, the configuration of the outlet and the inlet may be coordinated to provide redundancy against the same flow impairment mechanism(s). Additionally or alternatively, the inlet and/or the outlet may be configured to address additional and/or different mechanisms.

FIG. 5Billustrates the redundancy of the present flow control systems246. InFIG. 5B, the inlet278to the flow control chamber262has been mechanically damaged to allow sand264into the flow control chamber262, as illustrated by the hole284in the permeable portion254. While sand passing through the sand control devices of conventional production tubing is a significant flow impairment,FIG. 5Billustrates that the redundant controls of the present inventions provides the outlet280from the chamber262with suitable flow control equipment to restrict the flow of particulates larger than a predetermined size from the flow exiting the flow control chamber. Accordingly, the sand264accumulates in the chamber until the outlet280is effectively blocked by the sand and the flow through the chamber is at least substantially blocked. In the implementation ofFIGS. 5A and 5B, the flow from the outlet passes into another flow control conduit that is not divided into chambers and the fluids travel to the surface. In other implementations, the flow through the outlet280from one flow control chamber262may pass into another flow control chamber262having one or more outlets adapted to provide a barrier against a flow impairment mechanism. For example, to counteract the risks of sand production through the produced fluids and/or the risks of sand undesirably blocking flow paths. When the fluid flow passes from one flow control chamber to another flow control chamber, the chambers may be arranged in series to provide staged control and/or to address multiple flow impairment mechanisms. For example, a first flow control chamber may be adapted to control larger sand particles while a second flow control chamber may be adapted to control smaller sand particles, etc.

Advantageously, the flow control systems246of the present invention allow production to continue from an interval or zone in which one form of flow impairment has occurred.FIG. 5Billustrates this by showing that the unblocked flow control chamber262continues to produce fluids even after the outer screen (inlet278) of the blocked flow control chamber262has failed and allowed sand to enter the flow conduit252. Moreover, while flow through the lower flow control chamber is blocked, or at least substantially restricted, flow from the formation244may proceed through the well annulus282to enter the tubular248through the inlet278associated with the upper, unblocked flow control chamber. The flow path through the well annulus282provides yet another form of redundancy provided by the present flow control systems. Specifically, in the event that the lower flow control chamber is blocked by scale accumulation on the inlet thereto or other blockages on the outer member and inlet, the flow from the formation may continue through the well annulus282to enter adjacent flow control chambers.

The flow control systems246of the present disclosure, such as those illustrated inFIGS. 5A and 5B, may be adapted to offset the flow control chamber outlet280from the flow control chamber inlet278, such as in the manner shown inFIGS. 5A and 5B. One of the flow impairment mechanisms that completion equipment attempts to prevent or address is the inflow of sand264while allowing fluids to flow into the flow conduit. Conventional methods utilize a screen or other permeable medium to restrict the flow of particulates while allowing fluids to pass. However, the permeability inherently reduces the structural integrity of the permeable portions. As solids-laden fluids impact the permeable segments it is common for these segments to fail and have a hole open in the permeable portion, such as illustrated by the hole284inFIG. 5B. Such holes defeat the sand-control objectives of the permeable segments and sand is allowed to flow into the production equipment. The risk of mechanical failure of the permeable segments increases in cased and/or fractured wells where produced fluids enter the well annulus282at discrete, focused sources.

The offset relationship between the flow control chamber inlet278and the flow control chamber outlet280, which may be incorporated into one or more of the implementations herein, may provide an additional barrier against flow impairment due to mechanical failure of the completions equipment. Referring toFIG. 5as an exemplary implementation, flow entering the flow control chamber262passes through the inlet278in a first direction; flows through the flow control chamber in a second direction; and exits through the outlet280by flowing in yet a third direction. The flow control apparatus256includes impermeable portions266adapted to provide a strengthened structural member in the vicinity of the inlet278to the flow control chamber262. Accordingly, while the inlet278may cause fluids to be more concentrated in a particular flow direction, the flow control apparatus256is adapted to redirect that energy into a second flow direction, dissipating the energy carried by the entrained particles and encouraging the particles to drop out of the flow. This initial turn may be sufficient to sufficiently reduce the mechanical failure risk imposed by entrained particles impacting permeable segments. However, some implementations, such as illustrated inFIGS. 5A and 5Bimpose yet another flow direction change before passing through the outlet280. The tortuous path followed by the particles attempting to flow through the production tubular248with the produced fluids reduces the energy of the particles and facilitates the task of the permeable portion providing the outlet280from the flow control chamber. The tortuous path may be induced in a variety of manners, some of which are illustrated and described in the present disclosure, and all of which are within the scope of the present invention.

Turning now toFIGS. 6A-6F, further implementations and features of flow control systems within the scope of the present invention will be described. The illustrations ofFIGS. 6A-6Fare highly schematic and intended to represent combinations of permeable surfaces and impermeable surfaces that may be used to form flow control conduits and flow control chambers within the scope of the present invention. While the permeable portions are represented by dashed lines are visually similar to conventional wire-wrapped screens, which may be used in the present invention, the permeable portions illustrated here are more broadly and schematically representing any of the variety of manners through which fluids may be allowed to pass through the outer member into the flow control chamber. For the sake of clarity in describing the various schematics ofFIGS. 6A-6F, reference numbers will be used in connection withFIGS. 6A-6Fthat are different from those reference numbers used to refer to similar or identical elements or features inFIGS. 4 and 5. Similarly, the remaining Figures herein may use different reference numerals to aid in the clarity of the description of those Figures. The terms and nomenclature used to refer to common elements and features are consistent across the Figures and may be referred to in considering the similarities between the various implementations disclosed herein.

Beginning withFIGS. 6A-6C, three different operational configurations of a flow control system300are schematically illustrated. The flow control system300ofFIGS. 6A-6Cis illustrated as including an outer member302forming a well annulus304between the formation306and the outer member302. However, for purposes of discussion and simplicity in illustration, only half of a side cross-sectional view is illustrated. As discussed previously, the outer member302also defines a flow conduit308within the outer member302. Additionally, the flow control system300further includes flow control apparatus310, which includes conduit-defining structural members312adapted to divide the flow conduit308into at least two flow control conduits314and chamber-defining structural members316adapted to divide at least one of the flow control conduits314into at least two flow control chambers318. As one exemplary implementation that may be represented by the schematic ofFIGS. 6A-6C, the coaxial configuration ofFIGS. 5A and 5Bwould have a side cross-sectional view comparable to that ofFIGS. 6A-6C.

FIGS. 6A-6Cillustrate a flow control system300having outlets320from the flow control chambers318that are adapted to be selectively opened. As seen inFIG. 6AcomparingFIGS. 6A-6C, the outlets320are both closed inFIG. 6A, preventing fluid flow through the flow control chambers318. Accordingly,FIG. 6Aillustrates a first operating configuration for flow control systems within the scope of the present disclosure in which the flow control system effectively acts as a blank pipe section. As illustrated by flow arrow322, fluid in the well annulus304effectively stays in the well annulus as it passes the flow control system300. Similarly, as illustrated by flow arrow324, fluid within the flow control conduit314a(which may have entered the flow control conduit from a portion of the well closer to the toe) stays within the flow control conduit314a.

FIG. 6Billustrates the flow patterns when one of the outlets320is opened. As illustrated inFIGS. 6A-6C, the chamber-defining structural members316are more than a simple disk as illustrated inFIG. 5and include both permeable segments and impermeable segments, which together are adapted to provide the selectively opening outlet320introduced above. The outlet320may be selectively opened through any of a variety of techniques, including chemical means (dissolution or other modifications of portions of the impermeable segment incorporating stimulus-responsive materials), mechanical means (sliding sleeves or other elements that are moved via hydraulic, electric, or other signals and controls), or other means (such as perforations or other available downhole tools). It should be understood that the physical implementation of a selectively opening outlet320may be as schematically illustrated here or in any other suitable method, such as a wire-wrapped screen having spaces filled by a material that can be dissolved or reduced in size to allow flow between the wrapped wires.

As illustrated, once the outlet320is opened fluid from the well annulus304passes into the flow control chamber318a,through the outlet320, and into the flow control conduit314afor communication further up the well toward the surface.FIG. 6Billustrates that a selectively opening outlet320allows operator control over which flow control chambers318are operative at any given time, which may be used to control production rates or to control the type of completion applied (such as restricting smaller or larger particles). In some implementations, the selectively opening outlets320allow an operator to stage the production from a particular production zone. For example, as illustrated inFIGS. 6B, fluids are produced through flow control chamber318aand associated outlet while flow through flow control chamber318bis blocked by the closed outlet. Subsequently, and as illustrated inFIG. 6C, the flow through flow control chamber318ais blocked by the accumulation of sand326by the outlet320a,which is adapted to retain particles larger than a predetermined size. When the production through flow control chamber318ais substantially blocked by the accumulated sand326, flow control chamber318band outlet320bmay be opened to allow continued production from the production zone while continuing to protect the production operation from flow impairment, such as sand inflow in this example. By staging the production in a production zone, the flow rate from that zone can be maintained for a much longer period of time without requiring a full workover. In some implementations, the outlet320bmay be adapted to apply a different degree of sand control compared to the outlet320a.For example, the sand control features of outlet320bmay be allow larger particles to pass through to prevent accumulation of sand326at the outlet blocking flow through outlet320b,which may allow the production to continue with a controlled amount of sands or fines production. Additionally or alternatively, the spacing between the inlets328to the respective flow control chambers may be sufficiently far to effectively limit or prevent sand from one formation zone (e.g., the zone adjacent to flow control chamber318a) passing to the inlet of an adjacent flow control chamber through the well annulus304. Accordingly, the configuration of the outlets320aand320bin adjacent flow control chambers may be different to retain the sand that is anticipated from the different formation zones. The configuration of outlets to retain particles larger than a predetermined size may be done on a chamber-by-chamber basis or may be done for the entire well. In any event, the predetermined size that is retained by a given outlet may be influenced by the formation, by the well, by the completion, by the manner in which the well is to be used, by the manner in which the flow control system is designed, and a variety of other factors.

FIG. 6Cfurther illustrates that one or more of the chambers may be provided with a bare outlet332without sand control features, such as the outlet332illustrated in flow control chamber318a.Such an outlet may be provided in a variety of circumstances where the economics or circumstances of the well no longer necessitate or suggest the desirability of the present, redundant flow control systems. For example, the redundant controls of the present flow control systems may be implemented during a period of time to maximize the life of the completion and productivity of the well interval while minimizing the sand production. However, there may be a time in the life of the well that some amount of sand production is acceptable as compared to a complete workover. For example, if all of the flow control systems in a completion have become blocked and the next step is to withdraw the production tubing for a workover, it may be preferred to open a bare outlet332in one or more of the flow control chambers to continue the production for a time with anticipated sand or fines production.

WhileFIGS. 6A-6Cillustrate flow profiles in a flow control system300having staged utilization of the different flow control chambers318, the flow profile through an inlet328, through the flow control chamber318, and through an outlet320is representative of the flow profiles of the implementations described in the present invention. Similarly, the schematic representation of the locations and orientations of the flow control chambers, the flow control conduits, the outer member, the conduit-defining structural members, the chamber-defining structural members, the inlets, the outlets, etc. are all representative only and may be embodied or implemented in any suitable configuration, including those described in greater detail herein. As described above, any one or more of these components may be referred to differently in an injection context rather than the production context described above. For example, outlet320may be considered an inlet to the flow control chamber and inlet328may be considered an outlet from the flow control chamber.

FIGS. 6D-6Fprovide further schematic illustrations of flow control systems300within the scope of the present invention. The flow control system300ofFIG. 6D-6Fincludes many of the same features described above but arranged in a different implementation. Flow control system300includes an outer member302adapted to provide an inlet328therethrough and to define a flow conduit308therewithin. The flow control system300is disposed in a well such that the outer member302defines a well annulus304between the formation306and the outer member. Similar to the implementation described above, the flow control system300ofFIGS. 6D-6Fincludes a flow control apparatus310adapted to be disposed within the outer member302. The flow control apparatus310includes at least one conduit-defining structural member312defining at least two flow control conduits314within the flow conduit308. Additionally, the flow control apparatus310includes at least one chamber-defining structural member316configured to divide at least one flow control conduit314into at least two flow control chambers318. Additionally, the flow control apparatus310is configured to provide at least one outlet320from the flow control chamber318.

As can be seen inFIGS. 6D-6F, the flow control systems300within the scope of the present inventions may include two or more outlets320per flow control chamber318. Following the progression of operations fromFIG. 6DtoFIG. 6F, it can be seen that a first outlet320is opened inFIG. 6Dto allow flow through the flow control chamber318. The outlet320is provided with a permeable portion330or other features to counteract at least one flow impairment mechanism. For example, the outlet320may be provided with a screen or mesh to retain particles larger than a predetermined size. Additionally or alternatively, the outlet320may be adapted to counteract mechanical failure of the screen or mesh by being fluidically offset from the inlet328, as discussed above. As illustrated inFIG. 6D, one outlet320is open while the other is closed. In some implementations, two or more outlets may be open at the same time depending on the flow parameters desired for the particular well, zone, and/or chamber of the production equipment.

As illustrated inFIG. 6E, the second outlet320is opened once the first outlet320is effectively and/or substantially closed by the accumulation of sand or other particles326. The selective opening of the outlets320allows the operator to control the flow through the individual flow control chambers. In some implementations, the selective opening of the outlets is controlled from the surface through any suitable means. The control from the surface for opening an outlet is acceptable because delays in opening an outlet do not introduce increased risks of flow impairment or damage to the production equipment. Additionally or alternatively, control of the various selectively opening outlets320may be effected passively, or without direct operator or surface intervention. For example, the second opened outlet320inFIG. 6Emay be configured to open when pressure from the flow control chamber318exceeds a predetermined set point selected to indicate that the first outlet is sufficiently blocked by particles. Additionally or alternatively, the positioning of the second outlet within the chamber may be sufficient to render it effectively closed until the first outlet becomes sufficiently blocked. For example, inFIG. 6E, the flow in the well annulus304is illustrated as moving from right to left. The flow will tend to enter the inlet328and continue in the right to left manner towards the first opening320(illustrated as open inFIG. 6Dand closed inFIG. 6E). Natural flow forces will not direct substantial flows toward the second outlet320until there is sufficient back pressure against the first outlet.

As described above, in some implementations the staged or selectively opening outlets may be implemented for the purpose of maintaining production rates over an extended period of time from the same segment of the formation. Additionally or alternatively, staged or selectively opening outlets may be implemented for the purpose of counteracting different flow impairment mechanisms and/or different degrees of risks of flow impairment. As one example of such an implementation, a first outlet may be configured to retain a first predetermined size of particles while the second outlet may be configured to retain a second, larger predetermined size of particles. Accordingly, the well, or region of the well, may be operated for a first time during which all particles larger than the smaller, first predetermined size are retained and accumulated against the outlet. When the second outlet is opened, flow may resume or continue from that chamber and will allow particles smaller than the second predetermined size to pass through the outlet. Such an implementation may be suitable when differing degrees of flow quality and/or risks are tolerated at different stages in the life of a well.FIG. 6Fillustrates a still further configuration of the flow control system300wherein both of the outlets320including permeable portions330are blocked. In such a condition flow through the chamber318would be blocked. However, in some implementations, it may be acceptable to open a bare outlet332that is not adapted to retain particles or otherwise prevent or counteract a flow impairment mechanism. Flow may then resume through the flow control chamber318. Such an implementation may be used when the sand production risk has been minimized or when the risks of sand production are acceptable in light of the other conditions associated with the continued operations of the well, such as the workover costs, etc.

FIGS. 7A-7Cschematically illustrate still additional implementations of flow control systems within the scope of the present invention. As described above,FIGS. 5A and 5Billustrated a coaxial configuration of the flow control systems andFIGS. 6A-6Fillustrated schematically flow diagrams characteristic of various configurations and implementations to be described herein.FIG. 7Aillustrates an end view of a trifurcated flow control system350. As with the other implementations described and claimed herein, the trifurcated flow control system350includes an outer member302defining an internal flow conduit308. As illustrated inFIG. 7A, the flow conduit308is trifurcated by a flow control apparatus310including conduit-defining structural members312in the form of three partitions352. The partitions352divide the flow conduit308into three flow control conduits314, any one or more of which may be divided further by chamber-defining structural members (not shown). The trifurcated configuration350ofFIG. 7Ais representative of the various manners in which conduit-defining structural members may be disposed to divide the flow conduit308into two or more flow control conduits314. The partitions352may be configured as solid panels and/or may be configured to provide outlets (not shown inFIG. 7A), such as those described elsewhere herein, to allow flow between adjacent flow control conduits314and/or chambers. Additional, more detailed examples of trifurcated and/or multi-furcated flow control systems350are provided below.

FIG. 7Bprovides a schematic end view of another implementation of a furcated flow control system.FIG. 7Bschematically illustrates a flow control system300in a coaxial-furcated configuration360. The coaxial-furcated configuration360is yet another example of the various manners in which a flow control apparatus310may be implemented within an outer member302of a flow control system300. As illustrated, the coaxial-furcated configuration360includes a plurality of conduit-defining structural members312, including an inner tubular362and three partitions364extending between the outer member302and the inner tubular362, partitioning or dividing the annulus therebetween into multiple flow control conduits314. Additionally, the inner tubular362provides yet another flow control conduit314. Any one or more of these flow control conduits314may be divided into flow control chambers (not shown) through the use of chamber-defining structural members (not shown), which may be adapted to conform or substantially conform to the dimensions of the flow control conduits314. In exemplary implementations, each of the exterior flow control conduits314amay be formed into flow control chambers while the inner flow control conduit314bmay be left open for unimpeded flow of fluids through the tubing string. Similar to the schematic illustration ofFIG. 7A, the conduit-defining structural members312ofFIG. 7B, including the inner tubular362and the partitions364, may be configured as solid panels and/or may be configured to provide outlets (not shown inFIG. 7B), such as those outlets described elsewhere herein, to allow flow between adjacent flow control conduits and/or chambers.

FIGS. 8A-8Dprovide yet another exemplary implementation of a coaxial-furcated configuration360. The implementation illustrated inFIG. 8Ashows that the flow control apparatus310may include multiple conduit-defining structural members312disposed and configured in any suitable manner to create at least two flow control conduits314from the flow conduit308defined by the outer member302. As illustrated inFIG. 8A, the coaxial-furcated configuration360effectively provides a plurality of concentric flow control conduits314a,314b,314cthrough the use of multiple inner tubulars362. The outer member includes at least one inlet328to the flow conduit308, and particularly to the flow control conduit314a.

With continuing reference toFIG. 8A, once the fluid has entered the flow conduit308, it is able to flow within the flow control chamber318adefined by the conduit-defining structural members312, the chamber-defining structural members316and the outer member302. Fluid in the outer flow control conduit314aor outer flow control chamber318amay then exit the flow control chamber through outlets320provided in the conduit-defining structural member312, which may be any suitable form of outlet providing fluid communication between the outer flow control conduit314aand the intermediate flow control conduit314b.The configuration of the outlet320may vary depending on the flow impairment mechanism for which the flow control system300is adapted. Exemplary outlets may provide a permeable portion, such as described above, adapted to retain particulate material larger than a predetermined size.

As illustrated by the configuration of the outer member302, the inlet328providing fluid communication between the well annulus304and the flow conduit308may be adapted to counteract flow impairment as described herein. For example, the inlet328may be a wire-wrapped screen, a mesh, or configuration adapted for sand control. Exemplary configurations of the outer member302may include an inlet328provided by a wire-wrapped screen having gaps between adjacent wires that is sufficient to retain formation sand produced into the wellbore larger than a predetermined size. Other portions of the outer member302may be provided in any suitable manner such as blank pipe, impermeable material wrapped on the outside of a permeable media, or a wire-wrapped screen without a gap between adjacent wires. Manufacturing of a wire-wrapped screen is well known in the art and involves wrapping the wire at a preset pitch level to achieve a certain gap between two adjacent wires. Some implementations of suitable outer members may be manufactured by varying the pitch used to manufacture conventional wire-wrapped screens. For example, one portion of an outer member may be prepared by wrapping a wire-wrapped screen at a desired pitch that would retain formation sand larger than a predetermined size and wrapping the next portion at near zero or zero pitch (no gap) to create an essentially impermeable media section. Other portions of the outer member302could be wrapped at varying pitches to create varying levels of permeable sections or impermeable sections.

The inner tubulars362may be provided in a manner similar to the manner described for the outer member302using wire-wrapped screen techniques. Using the variety of wire configurations available and the variety of pitches, the outlets320provided by the permeable portions may be provided in a multitude of configurations suitable for retaining particles of any predetermined size. Additionally or alternatively, the permeable portions on the flow control apparatus310(as compared to the permeable inlet on the outer member302) may be provided in other suitable manners to provide the desired functionality, such as the selectively opening outlets320described in connection withFIG. 6. In implementations where the outlet320from the flow control chamber318is fluidically offset from the inlet328to the flow control chamber, greater flexibility in the configuration of the outlet may be available. As discussed above, the fluidically offset inlet328and outlets320provide an impermeable, and therefore stronger, conduit-defining structural member312in the region in the fluidic path from the well annulus304through the inlet328to resist mechanical damage to the chamber-defining structural member312due to the force of the incoming fluid and/or particles.

In the exemplary configuration shown inFIGS. 8A-8D, the flow conduit308is divided into two annular flow control conduits314by the inner tubulars362which are further divided into longitudinal flow control conduits by the partitions364extending within the annular flow conduits (as seen inFIGS. 8B-8D). Flow entering a flow control conduit314through an inlet328encounters the impermeable member of the conduit-defining structural member312, as seen by flow arrow366inFIG. 8A. The flow is then diverted, together with the dissipation of energy carried by the fluids and particles in the flow, longitudinally within the longitudinal flow control conduits314created and defined by the flow control apparatus and conduit-defining structural member312, as seen by flow arrows368. The flow is then isolated longitudinally by the chamber-defining structural members316. Outlets320, which may be selectively opening outlets, provide fluid communication between the outer longitudinal flow control conduit314aand the intermediate longitudinal flow control conduit314b.As discussed above and similar to the inlet328, the outlets320may be provided by a permeable portion or in another suitable configuration to retain particles larger than a predetermined size. The flow within the intermediate flow control conduit314bmay then pass through outlet320into the inner flow control conduit314c,as seen by flow arrows370, or may flow longitudinally along the intermediate flow control conduit314b,as seen by flow arrows372. For example, in the event that one of the outlets320from the intermediate flow control conduit314bbecomes blocked by particle accumulation, the fluids may flow longitudinally to the other outlet320to maintain production from the respective section of the production tube. Additionally or alternatively, the outlets from the intermediate flow control conduit314bmay be fluidically offset (not shown) from the outlets from the outer flow control conduit314c.Once the fluids pass through the outlet320from the intermediate flow control conduit314bto the inner flow control conduit314c,the fluids are in fluid communication with the surface and are part of the production flow represented by flow arrows374.

In some implementations, the outer flow control conduit314aand associated outlet may be adapted to provide an initial filter to retain larger particles while allowing finer particles to pass through and the intermediate flow control conduit314band associated outlet may be adapted to provide a final filter to remove smaller particles. Additionally or alternatively, the outer and intermediate flow control conduits and associated outlets may be substantially similar and provide redundancy at the same level of filtration rather than differing degrees of filtration. In any event, should the inlet328fail and allow particles to enter the flow conduit308, the outer flow control conduit314aand associated outlet provide a first barrier to the infiltration of sand into the production stream374. Additionally, in the event that the outlet320from the outer flow control conduit314ais designed to allow some particles through or in the event of mechanical failure of the outlet, the intermediate flow control conduit314band associated outlet provide a second barrier to the infiltration of sand into the production stream. Coupled with the energy dissipation of the fluidically offset inlets and outlets, the flow control systems300of the present disclosure provide enhanced abilities to prevent flow impairment due to the multiple redundant flow paths formed within the outer member302and the flow conduit308. In the event that each of the outlets from a given flow control chamber318is blocked or substantially blocked due to particle accumulation (or due to the possible configuration as selectively opening), production fluids from the adjacent formation may enter the well annulus304and proceed to an adjacent segment of the production tubing string that is not yet blocked. Accordingly, the redundant flow paths and redundant systems to allow production operations to continue while preventing sand infiltration and overcoming other forms of flow impairment.

FIGS. 8B,8C, and8D are cross-sectional views ofFIG. 8Aat the designated locations ofFIG. 8Awherein like elements fromFIG. 8Aare given the same reference numbers. These figures illustrate the changes from permeable walls (dashed lines) to impermeable walls (solid lines) based on the location in the wellbore. Additionally, while not illustrated inFIGS. 8A-8D, any one of the conduit-defining structural members312, such as the partitions364, may be provided with permeable portions to provide an outlet from one longitudinal flow control conduit to an adjacent flow control conduit. Fluid communication between longitudinal flow control conduits illustrated inFIGS. 8A-8Dmay provide still further redundancies in the flow paths to permit fluid flow while countering the flow impairment mechanisms. The configuration and disposition of the outlets formed in the partitions364may incorporate the fluidic offset principles described above, such as by being disposed longitudinally offset from the inlet328. Additionally or alternatively, outlets on partitions may be disposed in longitudinal alignment with the inlet328while still providing the fluidic offset advantages described above. As described above, the fluidic offset between inlets and outlets may be implemented to dissipate the energy in incoming flows against a solid, and therefore more resistant, conduit-defining structural member rather than an outlet. The offset causes the incoming flow to change directions upon entering the flow control conduit (e.g., from a radially directed flow through the inlet to a longitudinally directed flow inFIG. 8A). The longitudinally offset outlets illustrated inFIG. 8Aforce another flow direction change as the flow passes through the outlet (e.g., from longitudinal flow in the conduit to radial flow through the outlet). In implementations providing one or more outlets in the partitions364, similar flow directional changes are created. For example, radial flow through the inlet is changed to circumferential flow due to the relationship between the solid inner tubular and the outlet in the partition.

FIGS. 9A-9Dprovide an example of the flow control system300further adapted for use in operations requiring flow in the reverse or injection direction, such as treatment operations and/or gravel packing operations.FIGS. 9A-9Dare analogous in many respects to the coaxial-furcated configuration360ofFIGS. 8A-8Dand similar reference numerals refer to similar elements without their express recitation here in connection withFIGS. 9A-9D. As illustrated inFIGS. 9A-9D, one or more of the flow control conduits314may be configured as an injection conduit376. The exemplary configuration illustrated includes a shunt tube378disposed within the injection conduit376and nozzles380extending from the shunt tube through the outer member302. When a shunt tube378is used, the injection conduit376may have sufficient space remaining to allow the flow control conduit to be used for production purposes as well. Alternatively, the flow control conduit in which the shunt tube is disposed may be adapted for exclusive use as a conduit for the shunt tube. Additionally or alternatively, one or more of the flow control conduits314may be adapted for injection operations without the use of shunt tubes378. For example, the use of solid, impermeable conduit-defining structural members and appropriate inlets and outlets may enable one flow control conduit to be used for injection operations while an adjacent flow control conduit is adapted for production operations. The incorporation of shunt tubes378and/or injection conduits376may allow the present flow control systems to be used in gravel packing operations, such as disclosed in U.S. Pat. Nos. 4,945,991, 5,082,052, and 5,113,935.

FIGS. 10A and 10Bprovide a cut-away side view and a cross-sectional view, respectively, of yet another implementation of flow control systems400within the scope of the present invention. While the eccentric configuration402is illustrated and described separately from the implementations and configurations described above, the features and aspects of this implementation, as with the other implementations and configurations described herein, are interchangeable between configurations. For example, configurations of the outlets and inlets described above in connection with the coaxial implementation, the furcated implementation, and/or the coaxial-furcated implementation may be utilized in the eccentric configuration402without specific repetition of such features or configurations in connection with the eccentric configuration. Similar to the implementations described above, the eccentric configuration402incorporates flow path redundancy and redundant flow impairment countermeasures to enhance the longevity and functionality of the downhole equipment. The eccentric configuration402ofFIGS. 10A and 10Bis illustrated in the context of countering the sand infiltration flow impairment mechanism, but is also effective in countering the effects of scale build-up on inlets to the production equipment. Additionally, to the extent that increases in sand production are often associated with corresponding increases in water production, the present flow control systems may be effective in countering the water production flow impairment mechanism.

As illustrated inFIGS. 10A and 10B, the eccentric configuration402includes a tubular404having an outer member406that defines a flow conduit408. Within the flow conduit408is disposed a flow control apparatus410having conduit-defining structural members412adapted to divide the flow conduit408into at least two flow control conduits414and having chamber-defining structural members416adapted to divide at least one of the flow control conduits414into at least two flow control chambers418. The outer member406is also provided with an inlet420represented by the perforations422. The perforations422or other inlet means providing fluid communication between the well annulus424and the flow control conduit414may be adapted to retain particles larger than a predetermined size or may be otherwise adapted to counter a flow impairment mechanism. The flow control apparatus410also includes an outlet426adapted to provide fluid communication between the outer flow control conduit414aand the inner flow control conduit414b.The outlet426is represented or illustrated by perforations428and may be provided in any suitable manner to counter one or more flow impairment mechanisms, such as described elsewhere herein. As illustrated inFIGS. 10A and 10Bthe outer member406and components of the flow control apparatus410may be provided by conventional pipes provided with perforations to provide the appropriate inlets and outlets. While the perforations themselves may be adapted to retain particles larger than a predetermined size (or provide some other countermeasure to flow impairment), the outer member406and/or the flow control apparatus410may include sandscreens434, which may extend along the entire length of the member as illustrated or only over the perforated lengths.

With reference toFIG. 10B, it can be seen that the eccentric configuration402is provided with two types of conduit-defining structural members412, including an inner tubular430disposed eccentrically within the outer member406and dividing the flow conduit408into an inner flow control conduit414band an outer flow control conduit, which is further divided by partition432into a first outer flow control conduit414aand a second outer flow control conduit414c.The degree of eccentricity and the relative sizes of the various flow control conduits are representative only and may be varied depending on the implementation.

FIGS. 10A and 10Billustrate the manners in which the redundant flow paths can extend the life of a completion despite efforts of the formation to impair the production operations, such as through sand production. Considering the implementation ofFIG. 10A, flow control chamber418ais illustrated as having a failed sandscreen at the inlet420thereto allowing sand436to enter the flow control chamber418a.As sand accumulates in flow control chamber418a,the resistance to flow increases and less fluid passes through the outlet426from the flow control chamber418a.Accordingly, less fluid enters the flow control chamber418a,as illustrated by the dashed flow lines438. The chamber-defining structural member416and the outlet426blocked or substantially blocked by the infiltrated sand creates an effective isolated stage while allowing continued production of fluids from adjacent the isolated stage through the well annulus424and the flow control chamber418b,following the detoured flow path represented by detour flow line440.

The illustration ofFIG. 10Aillustrates two advantageous scenarios that may occur during operation of a well provided with a flow control system of the present invention. As described above, the infiltrated flow control chamber418abecomes packed with sand436. While the outlet426may become completely blocked by the accumulated sand, it is also possible that the outlet426functions as a conventional sandscreen and the infiltrated sand436functions as a natural sand pack within the isolated flow control chamber418a.The possibility of a natural sand pack forming from the infiltrated sand may depend on the nature of the formation in which the flow control system400is disposed. Additionally, however, the configuration of the flow control chamber418aand the outlet426therefrom may promote or discourage the formation of a natural sand pack from the infiltrated sand. In some implementations, the completion engineers and/or equipment manufacturers may adapt the flow control apparatus410to encourage the formation of a natural sand pack in the infiltrated flow control chambers. The natural sand pack in flow control chamber418amay allow continue hydrocarbon production through the flow control chamber while retaining sand from entering the inner flow control conduit414band further protecting the outlet420from mechanical damage.

Additionally or alternatively, the redundant, detour flow path440provided by the flow control system400dissipates the energy of sand entrained in the flow entering the well annulus adjacent the infiltrated flow control chamber418a.As illustrated inFIG. 10A, the sand entrained fluid enters the well annulus424and is forced to travel longitudinally through the annulus before encountering another inlet420through the outer member406. As described above, the change in direction forced by the fluidic offsets dissipates energy that may be stored in entrained sand.FIG. 10Aillustrates that the fluidic offset may be established in the well annulus as well as in the flow control conduits within the flow conduits of the present flow control systems.

FIG. 10Billustrates yet another manner in which the eccentric configuration402provides redundant flow paths and redundant protection from flow impairment. As illustrated inFIG. 10B, infiltrated sand436may enter only one of the outer flow control conduits, such as the first outer flow control conduit414a.In such circumstances, the produced fluids may flow circumferentially around the outer member406to enter the second outer flow control conduit414c,which not yet infiltrated in the illustration ofFIG. 10B. Similar to the circumstances illustrated inFIG. 10A, the infiltrated flow control chamber418amay provide a natural sand pack in some implementations allowing produced fluids to continue through the infiltrated flow control chamber418a,albeit at lower rates. Additionally or alternatively, the circumstances ofFIG. 10Billustrate that the detoured flow paths440may run circumferentially as well as or as an alternative to the longitudinal flow illustrated inFIG. 10A.

As described above in connection with the other configurations of the present invention, the various structural members of the flow control apparatus410may be adapted to provide permeable segments as appropriate to create the redundant flow paths and the redundant particle retention systems described herein. For example, partition432and/or chamber-defining structural members416may be provided with perforations, mesh, wire-wrap or other means to provide fluid communication between flow control conduits and/or flow control chambers.

Turning now toFIGS. 11A and 11B, an enlarged view of the other flow control system fromFIG. 4is illustrated. Similar to the discussion related toFIGS. 5A and 5B, the operation of this flow control system configuration will now be described in greater detail.FIGS. 11A and 11Billustrate a partial cutaway view of a flow control system500in a stepped configuration502. As with prior illustrations, the flow control system500is disposed within a well504in a formation506, forming a well annulus508between the flow control system and the formation. While the flow control system500, as well as other implementations described herein, is illustrated representatively as being in an open hole well, the systems and methods of the present invention are useful in cased hole wells as well.

The stepped configuration502of the flow control system500includes a tubular510that includes an outer member512. As illustrated, the tubular510includes a perforated base pipe and a wire-wrapped screen. In this implementation, the perforated base pipe provides the outer member512that defines a flow conduit514and that provides an inlet516to the flow conduit allowing fluid communication between the flow conduit and the well annulus508. The perforations518are one example of an inlet to the flow conduit514. Similarly, the perforated basepipe is only one example of the variety of manners of providing an outer member having an inlet and defining a flow conduit. Other suitable means are known to those of skill in the art and are included within the scope of the present invention. It should be noted that the tubular associated with flow control conduit526cis not provided with perforations or other means for providing an inlet to the flow conduit. Accordingly, the only way for fluid to enter the flow control conduit526c(described further below) is by passing through a flow control chamber. Flow control conduits that only are in fluid communication with the formation or well annulus through a flow control chamber may be considered a production flow control conduit, which may be in communication with the surface.

With continuing reference toFIGS. 11A and 11B, the stepped configuration502of the flow control system500includes a flow control apparatus520disposed within the flow conduit514. Similar to those implementations described elsewhere herein, the flow control apparatus520includes conduit-defining structural members522and chamber-defining structural members524. The conduit-defining structural members522are adapted to divide the flow conduit514into at least two flow control conduits526. In the illustrated implementation of a stepped configuration, the conduit-defining structural members522are provided by a plurality of partitions528arranged to trifurcate the flow conduit. Additionally or alternatively, additional conduit-defining structural members may be provided to further divide the flow conduit514. The partitions528of the conduit-defining structural members522include both permeable sections530and impermeable sections532. The permeable sections530are adapted to allow fluid communication between adjacent flow control conduits526while retaining particles larger than a predetermined size. Accordingly, the permeable sections530are one manner of providing an outlet534from the flow control chambers536defined by the chamber-defining structural members.

The impermeable sections532are adapted to prevent flow fluid therethrough. As illustrated inFIG. 11A, the impermeable sections532are disposed in operative association with the perforations518. The impermeable sections of the flow control apparatus may be arranged or adapted to be in direct fluid communication with the inlet516so as to absorb and/or deflect the energy carried by the entering fluids and particles. Additionally or alternatively, the impermeable sections532may be disposed so as to cause the outlets534from the flow control chambers536to be fluidically offset from the inlets516. While the illustrated implementation provides impermeable sections532on only one partition forming flow control conduit526b,other implementations may provide alternative configurations including impermeable sections on both partitions and/or in different relationships.

The stepped configuration502ofFIGS. 11A and 11Bprovide three flow control conduits526a-526cwith two flow control conduits divided into a plurality of flow control chambers536. As illustrated, the flow control chambers536in each flow control conduit are stacked longitudinally in the flow conduit while the flow control chambers in adjacent flow control conduits526are offset from each other. Moreover, as illustrated inFIGS. 11A and 11B, the partition528aincludes permeable sections to allow fluid flow between flow control chambers in adjacent flow control conduits. Accordingly, in this implementation, the partition provides at least one outlet from the flow control chambers536. Additionally, as illustrated inFIGS. 11A and 11B, the partitions528band528cinclude permeable sections530adapted to allow flow from the flow control chambers536into the flow control conduit526c,which is not divided into flow control chambers.

The stepped configuration502operates or functions in a manner similar to the configurations described elsewhere herein. For example, the flow control apparatus520divides the flow conduit into a plurality of flow control conduits and flow control chambers. The flow control conduits and flow control chambers provide redundant flow paths through the tubular and provide redundant countermeasures to resist flow impairment, particularly flow impairment due to sand production and/or particle accumulation or scaling. The flow arrows538ofFIG. 11Aillustrate the multiple redundancies built into the stepped configuration502. Depending on the configuration of the impermeable sections and the permeable sections of the conduit-defining structural members, the incoming radial fluid flow may be redirected longitudinally and/or circumferentially before exiting the flow control chamber. The availability of multiple outlets and flow paths from each chamber may also allow each flow control chamber to become more fully packed with infiltrated sand.

The combination ofFIGS. 11A and 11Billustrate what happens to the flow control system in the stepped configuration when the inlet to the flow conduit is impaired and begins to allow sand to enter the flow conduit. As illustrated inFIG. 11B, the inlet516to the flow control chamber536ais impaired due to erosion or other mechanical wear and a hole540is opened in the wire-wrapped screen permitting the entry of sand542into the flow control chamber536a.The sand542may begin to accumulate against any one of the permeable sections530providing an outlet534. Due to the increased number of outlets and the ability of the flow to continue through one outlet while sand is accumulating against another outlet, production through the flow control chamber536amay continue at a higher rate and for a longer period of time. Additionally, as described elsewhere herein, the stepped configuration and the provision of multiple outlets and flow paths may contribute to the formation of an internal natural sand pack by the infiltrated sand that may allow the production of fluids to continue through flow control chamber536awith reduced risk of sand infiltration into the production flow control conduit526c.Still additionally, the stepped configuration502may promote prolonged production rates and prolonged production periods between workovers due to the proximity of the adjacent flow control chambers. As seen inFIG. 11B, when flow control chamber536ais blocked or otherwise packed by sand, formation fluids that would otherwise enter chamber536aare able to be redirected, with corresponding energy dissipation, to enter an adjacent flow control chamber by traveling circumferentially around the outer member or longitudinally along the outer member.

The above description provides numerous illustrations of flow control systems within the scope of the present invention. Each of the systems are representative of the variety of systems that may be developed within the scope, teaching, and claims of the present invention. Moreover, it should be understood that each of the features of the various implementations may be interchangeable between the various implementations. For example, the selectively opening outlets described in connection withFIGS. 6A-6Fmay be incorporated into any of the other implementations. The inlets and the outlets to the flow control chambers of the various implementations may be selectively opened in a variety of manners including, selective perforating, rupture disks, pressure-sensitive valves, sliding sleeves, RFID controlled flow devices, etc. Additionally or alternatively, as described in connection with several implementations, the inlets and/or outlets may be adapted to allow fluid communication while preventing sand infiltration in a variety of suitable manners, including wire-wrapped screen, perforations, mesh, varied-pitch wire-wrapped screens, etc., and may be provided in any combination of filtration degrees, including filtering different size particles, filtering similarly size particles, or both.

Additionally, as described in connection withFIG. 3, the flow control systems within the scope of the present disclosure may be assembled or constructed in a variety of manners, including construction or assembly before insertion into the well and assembly after the components are already run into the well. For example, the flow control systems may be manufactured as standalone completion equipment ready to be coupled to other lengths of production or injection tubing. Additionally or alternatively, the flow control systems may include flow control apparatus adapted to be run through production tubing that is already disposed in the well. Inserting a flow control apparatus into an already downhole tubular may be accomplished through the use of a variety of available rig equipment and systems. Depending on the condition of the downhole tubular and the configuration of the flow control apparatus, the tolerance between the flow control apparatus and the inner diameter of the tubular may vary. In some implementations, swellable material may be disposed in a suitable manner on the flow control apparatus to close the tolerances required during the running of the flow control apparatus into position. The swellable material may be activated or swelled in any suitable manner, such as practiced in other applications within the industry. Additionally or alternatively, the tolerance between the flow control apparatus and the inner diameter of the tubular member may be sufficiently small to not require swelling material to seal between the tubular and the flow control apparatus. In some implementations, the flow control apparatus may not be intended to create a perfect seal between the apparatus and the tubular. For example, the configuration of the flow control apparatus, the flow control conduits, and the flow control chambers may render the pressure loss between the apparatus and the tubular sufficiently small that the fluid flow would be negligible.

The flow control systems of the present invention provide improved protection or countermeasures against a variety of flow impairment mechanisms to allow operations to continue for a longer period of time. The redundant flow paths are adapted to allow operations to continue even when a section of the well is impaired, such as by virtue of excess sand production, by virtue of scaling, or by virtue of blocked inlets. Similarly, the redundant sandscreens to prevent sand infiltration allow prolonged production from a section of the well when formation sand is being produced. By incorporating both redundant flow paths and redundant sandscreens, multiple flow impairment mechanisms are countered with a single system, that in many implementations may be disposed in a well and allowed to respond autonomously without operator intervention.

In some implementations, the flow control conduits are adapted to direct the incoming fluids in a longitudinal direction before encountering a chamber-defining structural member that changes the fluid's direction to pass through an outlet. For example, the coaxial configuration ofFIGS. 5A and 5Bpromotes longitudinal flow in the outer flow control conduit before redirecting the flow radially to pass into the inner flow control conduit. In other implementations, the flow control conduits are adapted to direct the flow radially followed by a one or more directional changes either longitudinally or circumferentially before entering the production flow. Still additionally, in some implementations, the incoming flow through the inlet may be directed circumferentially and/or helically (circumferentially and longitudinally) through on or more flow control conduits before encountering a chamber-defining structural member changing the direction of the flow to cause the fluid to pass through an outlet and into a production flow control conduit. For example, the multiple outlets of the stepped configuration described herein allows fluid to flow both longitudinally within a flow control chamber and circumferentially between flow control chambers before passing through an outlet into the production flow control conduit. Other implementations may include conduit-defining structural members and/or chamber-defining structural members in any suitable configuration. As just one of the variety of examples, conduit-defining structural members may be disposed helically around an inner tubular. The helically wrapped conduit-defining structural members may direct flow helically around the inner tubular until encountering a chamber-defining structural member that impedes the helical flow and directs the flow through an outlet to the production flow control conduit provided by the inner tubular. In some implementations, the chamber-defining structural members may be disposed transverse to the fluid flow direction imposed or encouraged by the flow control conduits.

Each of the implementations within the scope of the present invention may be adapted to suit a particular well or section of a well. For example, the number of flow control conduits and flow control chambers may be varied as well as the length, width, depth, direction, etc. of the conduits and chambers. While the permutations of conduit-defining structural members and chamber-defining structural members may be endless, engineers and operators may identify several that are more suited for use due to one or more of ease of manufacture, ease of use, effectiveness in preventing sand production, effectiveness in maintaining production rates, ability to customize configurations, etc. Each such permutation is within the scope of the present invention.

EXAMPLE

The flow control systems of the present invention were demonstrated in a laboratory wellbore flow model. The laboratory wellbore model for the flow control system had a 25 centimeter (10-inch) OD, 7.6 meter (25-foot) Lucite pipe to simulate an open hole or casing. The apparatus to test the completion equipment was positioned inside the Lucite pipe and includes a series of three tubing sections. The three tubing sections consisted of 1) a flow control system having a mechanically damaged input region in the outer member, 2) a flow control system having an intact input region in the outer member, and 3) a conventional screen having a mechanically damaged sandscreen. Each tubing section was 15 centimeters (6 inches) in diameter and 1.8 meters (6-feet) long. The flow control systems included a 91 centimeter (3-foot) long slotted liner and a 91 centimeter (3-foot) long blankpipe as the tubular or outer member. The flow control apparatus disposed within the flow conduits included a 7.5 centimeter (3-inch) OD, inner tubular (conduit-defining structural member), which consisted of a 1.2 meter (4-foot) long blankpipe and a 61 centimeter (2-foot) long wire-wrapped screen. The outer member and the inner tubular in the modeled flow control systems were concentric, following the exemplary coaxial configuration described above. During the test, water containing gravel sand was pumped into the annulus between the tubing assembly (completion system) and the Lucite pipe (open hole or casing).

The slurry (water and sand) first flowed through the annulus and into the damaged flow control system. The sand entering the damaged flow control system was retained and packed in the flow control chamber defined between the inner tubular and the outer member. The growing sand pack increased the flow resistance and slowed down the sand entering the damaged flow control system. As the sand entering the damaged flow control system was diminishing, the slurry (water and sand) was diverted further downstream to the adjacent undamaged flow control system. The gravel sand was packed in the annulus between the undamaged flow control system and the Lucite pipe. Since this flow control system was intact, the sand was retained by the inlet in the outer member. As the undamaged flow control system was externally packed, the slurry was diverted to the next damaged conventional screen. The sand flowed around and into the damaged conventional screen. Since the conventional screen was not equipped with any secondary or redundant means for control sanding infiltration, the sand continuously entered the eroded screen and could not be controlled.

The experiment illustrated the concepts of the flow control systems during the gravel packing portion of well completion operations. If part of the sand screen media is damaged during screen installation or eroded during gravel packing operations, a flow control system as described herein is able to retain gravel by secondary or redundant means to counter sand infiltration or other flow impairment to thereby enable continuation of normal gravel packing operations. However, a conventional screen could not control gravel loss and would potentially cause an incomplete gravel pack. The incomplete gravel pack with a conventional screen later causes formation sand production during well production. Excessive sand production reduces well productivity, damages downhole equipment, and creates a safety hazard on the surface.

This experiment also illustrated the concepts underlying the flow control systems of the present invention during well production in gravel packed completion or stand-alone completion. If part of the screen media intended to prevent sand infiltration is damaged or eroded during well production, a flow control system as described herein can 1) retain gravel or natural sand (e.g., formation sand) in the flow control chambers of the flow control systems, 2) maintain the annular gravel pack or natural sand pack integrity, 3) divert flow to other intact screens, and 4) continue sand-free production. In contrast, a damaged conventional screen will cause a continuous loss of gravel pack sand or natural sand pack followed by continuous formation sand production.

While the present techniques of the invention may be susceptible to various modifications and alternative forms, the exemplary embodiments discussed above have been shown by way of example. However, it should again be understood that the invention is not intended to be limited to the particular embodiments disclosed herein. Indeed, the present techniques of the invention are to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.