BACKGROUND OF THE INVENTION
In the hydrocarbon exploration and recovery art, extensive use is made of multilateral wellbores for reasons such as reduced cost and reduced surface footprint. More specifically, it is far more economically prudent to drill a single surface-down primary borehole and then multiple lateral boreholes therefrom than it is to drill the same number of total boreholes (primary and laterals) from the surface. A multilateral wellbore allows access to various zones of a hydrocarbon containing formation while minimizing the total length of boreholes as duplicative length is avoided.
One consideration to be addressed in multilateral wellbores, is the one or more junctions and the exclusion of contaminants from the wellbore at that point. Because milling a window in a casing is imprecise with respect to exact window shape, and potential damage to the material at the edge of the window, exclusionary means such as sealing or filtering thereagainst is difficult and sometimes impossible to accomplish. This leaves the junction vulnerable to influx of debris, sand or other particulate material or other contaminant that can deleteriously affect equipment installed in the wellbore or surface equipment or could reduce quality of produced fluids. Thus it is normally common to utilize particulate resistant well tools capable of continued function in the presence of the particulate laden fluid flow and other exclusionary or purification type devices but these are expensive and in the case of particulate contaminants the expected working life is still necessarily reduced over that of equipment in non particulate-laden flows. Junction technology resulting in the exclusion of particulate matter and or other contaminants from the production flow would therefore be well received by the art.
SUMMARY
A junction selective contaminant exclusion tool includes a tubular positionable within the junction and having an opening through a wall thereof, a material disposed on an outside surface of the tubular, the material being capable of increasing a radial dimension between a surface of the material in contact with the tubular and an opposite surface of the material upon exposure to a selected species.
A method for excluding selected contaminants from a wellbore junction is also disclosed. The method includes: disposing a junction at a wellbore casing window; disposing a tubular member having at least one opening through a wall thereof at the junction, the tubular member including an exclusion material thereon capable of existing in a first configuration and a second configuration, the second configuration obtainable upon exposure to a selected species; and exposing the material to the selected species.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the drawings wherein like elements are numbered alike in the several Figures:
FIG. 1 is a cross sectional view of a function portion of a wellbore having a liner hanger function and a lateral entry module therein;
FIG. 2 is an enlarged sectional view of the lateral entry module of FIG. 1;
FIG. 3 and 4 are together an enlarged view of a flange portion of the liner hanger function separated from other components thereof for illustrative purposes;
FIG. 5 is a cross-section view taken along section line 5-5 in FIG. 1;
FIG. 6 is a perspective section view at the same section point as FIG. 5;
FIG. 7 is a view similar to that of FIG. 5 but including an alternate construction; and
FIG. 8 is a view of the configuration of FIG. 7 in the activated position.
DETAILED DESCRIPTION OF THE DRAWINGS
Referring to FIG. 1, one of ordinary skill in the art will appreciate a multi-lateral wellbore junction portion 10 of a well system illustrated in axial section to reveal internal components thereof. For reference, a primary casing is identified by numeral 12. A casing window 14 is generally machined through the casing 12 by any number of window opening techniques that are not germane to this application. Through window 14 and partially resident in the primary casing 12 is a junction 16 which may be a liner hanger and in one embodiment is a hook hanger liner hanger commercially available from Baker Oil Tools, Houston, Tex. and disclosed in U.S. Pat. No. 5,477,925, for example, and which is incorporated herein by reference. Junction 16 includes a lateral leg 18 that is as will be recognized, intended to be run into a lateral borehole (not shown but implied by the location of leg 18). Included in the junction 16, in one embodiment, is a flange 20 (see FIGS. 3, 4 and 5). Flange 20 is not a separate component but is a permanently attached component of the junction 16. It has been illustrated separately here for illustrative purposes to provide a greater understanding of the invention and will be addressed further hereunder to that end. While it is desirable to include flange 20 in a junction, it is to be understood that flange 20 is not necessarily needed. The concept set forth herein is applicable to a junction that does not include a flange as well, with the seal or sieve (discussed hereunder) sealing or creating a sieve on a surface of the junction 16 instead.
The final component illustrated in FIG. 1 and germane to the invention is a tubular member positionable within the junction 16 such as a lateral entry module (LEM) 22, which is illustrated. It is important to make clear that while an LEM is depicted, this is for illustrative purposes only as the inventive concept is not limited to a configuration having an LEM. Rather, any tubular placable in a junction and with which a seal (or filter sieve) may be formed to flange 20 (or similar structure on the junction) is sufficient. It is also to be noted that a full window is not necessary in this tubular. A series of holes or a smaller hole, or a partially misaligned hole is also contemplated although such would, while still passing fluid, not allow easy reentry to the lateral. Facilitation of lateral reentry is an added benefit if an LEM is utilized. Applicants hereinafter utilize the term “LEM” simply because it is an easier term to identify than “tubular” particularly in a application for patent directed to downhole tools.
LEM 22 is similar in function to commercially available products from Baker Oil Tools, Houston, Tex. under part number H28918 but may include differences in structure as desired for particular applications.
Referring to FIGS. 1 and 2 together, the LEM 22 includes an uphole end portion 24, a body 26, a window 28, and a downhole end portion 30. The uphole and downhole end portions 24 and 30 are of a material thickness greater than the body 26 with the differential in thickness being located at the outside dimension of the LEM 22. This provides for a continuous inside dimension surface 32 and a stepped outside surface where the greater dimension surface 34 is defined by the outside dimension of ends 24 and 30 and the lesser dimension surface 36 is defined by the outside dimension of the body 26. Joining the surfaces 34 and 36 is an annular shoulder surface 38 and 40 (one at each end of the LEM 22). As will be appreciated from the drawings, an effective recess is created by surface 34, surface 38 and surface 40. Within the recess, a seal material or a sieve material is located and is relatively protected during run-in.
To illustrate the seal or sieve material reference is made to FIG. 2 where a cross section makes the nature of the seal or sieve material understandable. To a careful observer, it will be apparent that the outside dimension of the seal material 42 is of a lesser dimension than that of surface 34. This is to reduce the potential for damage to the seal during run-in. In this embodiment, the seal material 42 is lined for elastomer but it is to be appreciated that any material capable of creating a seal with flange 20 of the liner hanger is possible. Included in possible materials (though not an exhaustive list and thus not intended to be limiting) are elastomers in general, elastomers that swell upon exposure to certain chemicals (e.g. diesel, water, etc.) shape memory materials (including shape memory foams such as those disclosed in U.S. Application No. 60/852,275, filed on Oct. 17, 2006, which is incorporated herein by reference in its entirety, shape memory polymers, reinforced shape memory polymers, shape memory alloys.)
For swellable materials, the material configuration will be such that it does not significantly impede run-in while at the same time having sufficient swelling ability to bridge between surface 36 of LEM 22 and a surface 44 of flange 20 (see FIGS. 3-6). Shape memory materials on the other hand may be those having macro shapes that change such as a tubular (possibly cylindrical) configuration in one state and a flanged configuration in another state. Further, the shape memory materials may be such as to have a compressed condition that exhibits a relatively small differential between one side surface and another side surface in one state and then a markedly larger differential between one side surface and the other in a second state. The ordinarily skilled artisan will be familiar with slow recovery polyurethane foam earplugs, which while not exhibiting properties of use for this disclosure are a good example of the change in material dimension that is being described herein. Such changes in dimension may be effected by a number of species such as purely by heat or chemical species at the target location or may be augmented by an adhesive or other bonding agent that either physically restrains collapsed cells of a foam to themselves until a selected period of time after compression or until a selected chemical exposure (water, oil, etc.) occurs for a sufficient time to defeat the bond and thus allow the material to come away from the surface 36 at selected areas (in the first example) or to expand the cellular structure (in the second example). It is further to be noted that each of the materials noted may be either fluid impermeable or fluid permeable. Where the material is fluid impermeable, a seal is created and consideration is warranted regarding the pressure differential thereacross either from the standpoint of maintaining the pressure differential below a selected maximum or ensuring that the seal itself is created with sufficient contact pressure that the maximum expected pressure can be held without extrusion of the seal. In the event the seal is fluid permeable, pressure differential is less an issue for consideration as most situations will be self-equalized. In this case, only particulate matter is excluded. Further, it is contemplated that different materials 42 may be employed simultaneously in various locations between surface 36 and 44 such as for example alternating between a seal and a sieve perimetrically to facilitate a particular application.
In any of the above cases, the material is intended when deployed to extend from surface 36 to a surface 44 (see FIGS. 3, 5 and 6). With reference to FIG. 6, it is apparent that the area requiring sealing at surface 44 is relatively narrow. FIGS. 3 and 4 are helpful in illustrating this. For this reason, and although the seal or sieve material 42 is illustrated extending cylindrically about the entire circumference of LEM 22, this is not necessary for sealing or for the sieve. Rather, providing the seal or sieve material 42 is located so that it will contact at least a perimetral region of surface 44 around a window 46 of flange 20, the intent of the seal or sieve will be realized by providing for exclusion of at least particulate matter and possibly fluid from entry to the junction through the window machined in the casing. Applying the material 42 cylindrically about LEM 22 eases required consideration of alignment to produce the desired seal/sieve.
Referring now to FIGS. 7 and 8, an alternative embodiment is illustrated. In this embodiment, additional consideration is given to seal or sieve support to alleviate possible extrusion thereof. In both of the Figures, a support lip (50 and 52) is added to at least a portion of LEM window 28. In the Figures, the lips 50 and 52 are illustrated bilaterally in the cross section view. The lips could actually be a single lip extending perimetrically around the window 28 or could be short sections or even could be configured as only one lip in a single small portion of the window perimeter. Nevertheless, as illustrated in FIGS. 7 and 8, one can ascertain one location of the lips and how they function by comparison of the two figures. It is to be appreciated that each lips 50 and 52 include a surface 54 and 56, respectively. As illustrated surfaces 54 and 56 are not aligned with edge regions 60 and 62 of flange 20, however the degree of alignment is variable and may be set where desired in particular applications. In some applications the surfaces 54 and 56 will be aligned directly with edge regions 60 and 62.
While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
Patent Application
20080099201
