Abstract:
A well cellar system includes a substantially planar base, the base defining an aperture sized to receive a conductor pipe. The well cellar system also includes at least one substantially inflexible side member attached to the base, the at least one side member and the base defining a cavity. A seal between the at least one side member and the base substantially prevents the flow of fluids between the at least one side member and the base. The attachment between the base and the conductor pipe substantially prevents the flow of fluids between the base and the conductor. An additional embodiment incorporates an extension ring to minimize/eliminate runoff entering the cellar. One version of the extension ring includes a telescoping section which moves between an extended and retracted position representing its to operative positions. Yet a further embodiment provides a rain cap to reduce the amount of precipitation which enters the cellar and becomes hazardous waste. A still further embodiment is configured with cement ports for securing a conductor pipe in an oversized whole. This embodiment also has a grout port to restabilize the cellar following soil subsidence. A final embodiment is configured as a sectional version which can be more easily installed or placed in an existing well cellar to seal it.

Description:
Applicant claims the benefit of parent patent application Ser. No. 11/338,912 filed Jan. 23, 2006. In the field of oil and gas exploration/production, a well cellar can be positioned below ground level underneath a drilling rig. Such well cellars may contain equipment such as blow out preventers, valves, and other equipment associated with drilling, completion and other well operations. The walls of the well cellar provide structural support to prevent collapse of the surrounding earth onto the equipment. The well conductor pipe extends through the well cellar into the underlying subterranean formation. During drilling, completion and other well operations, fluids from the drilling rig and production equipment, such as lubricants, drilling mud, completion fluids, and oil, can leak or spill into and out of the well cellar. These spills can create ecological problems, polluting soil samples as well as surface and subsurface aqueous sources. Such corrupted soil areas must be remediated before a well is capped, adding expense to taking a well off-line. 
     TECHNICAL FIELD 
     This invention relates to well sites, and more particularly to well cellars. 
     BACKGROUND 
     Summary 
     The well cellar system of the present invention includes a substantially planar base. The base defines an aperture sized to receive a conductor pipe. At least one side member is attached to the base. The at least one side member and the base defines a cavity. Seal means between the at least one side member and the base substantially prevents flow of fluids between the at least one side member and the base. An attachment between the base and the conductor pipe substantially prevents flow of fluid between the conductor pipe and the base. This sealed well cellar eliminates soil and water pollution which is common with existing systems. 
     The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The preferred embodiments are described in conjunction with the following drawings in which like reference numerals in the various figures indicate like elements. The drawings are not to scale as certain features are exaggerated for clarity of illustration. 
         FIG. 1  is a schematic side view of a well cellar system in use; 
         FIG. 2  is a detail cross-sectional view of a first embodiment of well cellar system; 
         FIG. 3  is a schematic side view of a second embodiment of well cellar system; 
         FIG. 4A  is a schematic side view of a well cellar featuring an extension ring; 
         FIG. 4B  is a perspective side view of the extension ring shown in  FIG. 4A ; 
         FIG. 5  is a schematic side view of a well cellar featuring a rain hood; 
         FIG. 6A  is a cross-sectional side view of a modified well cellar as seen along  6 A- 6 A in  FIG. 6B ; 
         FIG. 6B  is a top view of the base plate utilized in the  FIG. 6A  embodiment; 
         FIG. 7A  is a schematic side view of one half of a third embodiment; 
         FIG. 7B  is a top view of the third embodiment depicted in  FIG. 7A ; 
         FIG. 8A  a partial sectional side view of well cellar depicting a telescoping extension ring; 
         FIG. 8B  is a partial sectional side view showing the extension ring in the collapsed position; and, 
         FIG. 8C  is a partial sectional side view showing the extension ring in the extended position. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , a well cellar system  10  includes a substantially planar base  12  attached to side members or walls  14 . Well cellar system  10  can be disposed in an excavation where soil is removed from the ground around the well site. Walls  14  are substantially inflexible to provide structural support to prevent collapse of the surrounding earth into cavity  15  defined by base  12  and walls  14 . An aperture  16  which extends through base  12  receives conductor pipe  18 . In this instance, conductor pipe  18  is attached to piping  22  which can be, for example, diverter piping. In some instances, valves, blow out preventers, and other equipment associated with drilling and/or completion operations are disposed in cavity  15 . Some embodiments include a riser  24  attached to base  12  around aperture  16  that extends substantially concentrically around conductor pipe  18 . The riser  24  may attach and, in some instances seal or substantially seal, to the conductor pipe  18 . 
     As used herein, the term conductor pipe is used to indicate a conductor pipe, riser pipe, surface casing, or other tubular member installed at or about the ground surface. As is discussed in more detail below, the seal between base  12  and walls  14  prevents or substantially prevents the flow of fluids between the at least one side member  14  and the base  12 . Likewise, the seal between the base  12  and the conductor  18  prevents or substantially prevents the flow of fluids between the conductor pipe  18  and base  12 . Fluids  17  from drilling rig  20 , such as lubricants, drilling mud, stimulation fluids, and oil, can leak or spill into cavity  15 . Sealing or substantially sealing the flow of such fluids out of cavity  15  can limit leakage into and contamination of the earth adjacent cavity  15 . Avoiding this contamination eliminates costly cleanup of soil and water surrounding the site. 
     In some instances, a fluid impermeable liner  26  is attached to walls  14  and extends radially outward and laterally across the ground surface  28 . Liner  26  may be clamped (see hoop-shaped clamp  27 ,  FIG. 2 ) to the perimeter of walls  14 . In some instances, a sealing compound, glue or gasket can be used to ensure a seal between liner  26  and walls  14 . A berm  30  can be placed around the outer edges of impermeable liner  26  to contain fluids leaking onto the impermeable liner. Impermeable liner  26  can be manufactured of polymer sheet materials. In some instances, ground surface  28  and impermeable liner  26  are sloped towards cavity  15 . This tends to direct fluids leaking onto impermeable liner  26  to cavity  15  which can act as a sump for the collection of the fluids. Berm  30  can be an integral part of impermeable liner  26 . In some instances, berm  30  is sealed to liner  26  to prevent leakage between the berm  30  and the liner  26 . 
     For some applications, a fluid level sensor can be installed to monitor the level of fluids in cavity  15 . In this instance, a high level alarm sensor switch  32  is mounted on wall  14  and triggered when contacted by fluids in cavity  15 . A float sensor could alternatively be used. Other fluid level sensors include, for example, a pressure based sensor that monitors the level of fluids in cavity  15  on an ongoing basis (as opposed to high level alarm sensor switch  32  which is only activated when the fluids in the cavity reach a pre-set level). Data from such sensors can be used as input for controllers operating appropriate pumps (not shown) that can be installed to remove fluids from cavity  15 . Such pumps can be permanently installed or temporarily installed as needed. 
     Padeyes  34  are mounted on walls  14 . Padeyes  34  can be used in removal of well cellar system  10  or components thereof from the surrounding earth after the well cellar system is no longer desired, for example by attaching an appropriate piece of heavy machinery such as, for example, a backhoe to padeyes  34  and simply pulling walls  14  (or the entire well cellar system  10 ) out of the earth. Padeyes  34  may also be used during installation of cellar  10  for assisting in placing the cellar  10  into the cavity in the earth, holding upright during back-filling, etc. 
     Referring to  FIG. 2 , cavity  15  has a width W 1 . As used herein, width W 1  is the diameter of the pipe when the walls  14  are formed by a pipe. In some instances, a width W 1  measured at base  12  is smaller than a width W 2  measured at the open end of cavity, so that the walls  14  slope inward toward the base  12 . The inwardly sloping walls  14  aid in removing the well cellar system  10  from the earth, because when the well cellar system  10  is lifted vertically up from the excavation, the walls  14  come out of contact with the surrounding earth. In this embodiment, walls  14  are formed with a width (diameter) W 2  of about 60 inches (152.4 cm) at the open end of the cavity and a width (diameter) W 1  of about 58 inches (147.3 cm) at the base  12 . Other dimensions of W 1  and W 2 , as well as W 1  and W 2  being equal, are within the scope of the invention. For example, in areas subject to permafrost and thawing, it may be desirable for W 1  and W 2  to be equal to prevent post jacking of the well cellar system  10 . 
     As noted above,  FIG. 2  depicts walls  14  formed by a section of pipe attached to base  12 , the walls and base defining a cylindrical or substantially cylindrical cavity  15 . Appropriate pipe includes, for example, corrugated culvert pipe. In other embodiments, walls  14  can be rectangular sheets attached to base  12 , the walls and base defining a cavity with a square, rectangular, or other polygonal footprint. Similarly, base  12  and walls  14  can be formed of materials including, for example, steel, aluminum, polymer, polymer reinforced composite, and other materials that provide the necessary structural support and impermeability. It is contemplated that the best mode could take the form of a molded plastic barrel with an opening  16  with means to seal base  12  to the conductor pipe  18 . 
     In some embodiments, walls  14  include a flange  36  extending radially inward from an edge of walls  14  adjacent base  12 . A gasket  38  is disposed between base  12  and flange  36  with both the flange and the gasket extending substantially around the outer perimeter of the base. The gasket  38  seals or substantially seals walls  14  to base  12 . In other embodiments, flange  36  and gasket  38  are replaced by an alternate sealing mechanism such as, for example, a perimeter weld or a bead of polymer sealant. In some embodiments, walls  14  are bolted to base  12  using bolts  40  that extend through flange  36  into the base  12 . Bolts  40  may optionally be configured to fail (i.e., be frangible) thus allowing the detachment of walls  14  from base  12  to leave base  12  in place when wall  14  and other components of the well cellar system  10  are removed from the excavation. Higher strength bolts  40  may be included together with the frangible bolts  40  to support base  12  during installation. After installation, the higher strength bolts  40  or their respective nuts may be removed, so that walls  14  and base  12  are attached only by the frangible bolts  40 . 
     In some embodiments, riser  24  is sealingly attached by welding, gluing or other mechanical attachment to affix it to conductor pipe  18 . Riser  24  can attach to the conductor pipe  18  in other manners. For example, riser  24  can include riser walls  42  extending around the aperture substantially perpendicular to base  12  and a riser collar  44 . Riser collar  44  includes a gasket ring  46 , a slip segment ring  48 , and a cover ring  50  which are annular in shape and sized to receive conductor pipe  18 . Gasket ring  46 , slip segment ring  48 , and cover ring  50  are bolted, clamped or otherwise, held together. 
     Gasket ring  46  includes a shoulder which supports a ring gasket  52  in a recess that is partially defined by a surface  54  of slip segment ring adjacent the gasket ring. Wedge shaped slip segments  56  are disposed against the inner surface of slip segment ring  48  such that as the bolts holding gasket ring  46 , slip segment ring  48  and cover ring  50  are tightened, slip segments  56  move radially inward to grip conductor pipe  18 . Ring gasket  52  seals or substantially seals between riser  24  and conductor pipe  18  and prevents the flow of fluids out of cavity  15  into the surrounding earth even if the fluids rise above the top of the riser  24 . 
     In another example, in some embodiments, a bradenhead, “A” section, wellhead, or starting head can be welded or otherwise affixed to base  12  or riser  24 . In such embodiments, the slips and sealing functions are provided by the bradenhead, “A” section, wellhead or starting head. In another example, base  12  may omit the riser  24  and can incorporate gasket ring  46 , slip segment ring  48 , cover ring  50 , slip segments  56  and ring gasket  52  or similar sealing and gripping mechanism. In alternate embodiments, riser  24  may exclude ring gasket  52 , segment ring  48  and cover ring  50  and be welded or otherwise sealingly affixed to conductor pipe  18  after the conductor pipe is inserted through the riser and opening  16  in base  12 . In alternate embodiments, base  12  may omit riser  24  be welded or otherwise sealingly affixed to conductor pipe  18 . In such embodiments, the weld or other sealing material prevents the flow of fluids out of cavity  15  between the conductor pipe and well cellar system  10 . In yet other embodiments, riser  24  can be sealingly affixed to conductor pipe  18  with a clamp mechanism (not shown). 
     As noted, riser  24  can be welded or otherwise sealingly affixed to base  12 . Riser  24  can receive conductor pipe  18  to laterally and vertically support conductor pipe  18  and equipment attached thereto. Base  12  can be reinforced with I, L, C, boxed or other shaped channel or tubing to increase stiffness in and out of the plane of base  12 . Gussets (not specifically shown) may be provided between riser  24  and base  12  to further increase stiffness. In many instances, it is desirable to leave an annular space between riser  24  or base  12  and conductor pipe  18  to allow for passage and/or circulation of fluids such as water, drilling mud (sometimes including cuttings), cement or other fluids during installation of the conductor pipe before the seal is made. The annular space may be subsequently sealed, for example, as provided herein. 
     Referring to  FIG. 3 , riser  24  may be omitted and a flanged fitting  58  may be provided and sealed to conductor pipe  18 . Flanged fitting  58  compresses an aperture seal member  60  against base  12  to seal or substantially seal the flow of fluids out of cavity  15  between the conductor pipe and well cellar system  10 . Flanged fitting  58  may be welded to conductor pipe  18  also providing a seal. Similarly, in some alternate embodiments, both flanged fitting  58  and riser  24  are omitted and conductor  18  is welded directly to base  12 . 
     Attaching base  12  to conductor pipe  18 , either directly or via riser  24 , provides vertical support to conductor pipe  18  and attached equipment to reduce, and in some instances, prevent settling of conductor pipe  18  under vibration and its own weight. Further, as depicted in  FIG. 3 , a hoop-shaped angle iron  64  can be welded, or otherwise affixed to, interior surface of wall  14  to provide a support for a work surface which may be subsequently installed, as needed. Upper edge of wall  14  may be formed with outwardly extending flange  66  to facilitate attachment of liner  26  by bolting ring  68  thereto sandwiching liner  26 . Liner  26  is only attached during drilling, and the like, and will be subsequently removed for conventional operations. 
     A sealed well cellar of the present invention featuring an extension ring is depicted generally in  FIG. 4A  at  10   a . One of the problems with existing well cellars is a natural outgrowth of the ability to perform their function well. Well cellars are designed to collect any fluids which are deposited around the conductor pipe  18 . This would include runoff from rain and snow. Once this water is added to the well fluids contained in the well cellar, it becomes a hazardous waste which has to be pumped out of the cellar and disposed of in a prescribed manner. It would, therefore, be advantageous to minimize the amount of runoff which finds its way into the well cellar. An annular extension ring  70   a  is provided which can be attached to flange  66   a  of wall  14   a . As shown in  FIGS. 4A and 4B , vertical wall  72   a  has flanges  73   a ,  74   a  extending outwardly therefrom, flange  73   a  being attached by means of bolts  75   a  to flange  66   a . A gasket can be included to ensure sealing to prevent leakage between flange  66   a  and  73   a . Extension ring  70   a  will typically be formed in two halves  70   a   1  and  70   a   2  to facilitate installation. Halves  70   a   1  and  70   a   2  will be seam welded to ensure that there is no leakage. The configuration of extension ring  70   a  depicted here is by way of example only and the flanges need not be included. Extension ring  70   a  prevents runoff from around well cellar  10   a  from entering into the container formed thereby and becoming hazardous waste. 
     A sealed well cellar of the present invention featuring a rain cap is depicted in  FIG. 5  generally at  10   b . In order to further reduce entry of rain, snow, etc., into the well cellar  10   b , a rain cap  76   b  is provided. Rain cap  76   b  has a downwardly extending flange  78   b  which overlaps extension ring  70   b . The primary surface  79   b  slopes downwardly away from conductor pipe  18   b  to permit rain water to runoff and minimize the liquid which finds its way into the well cellar  10   b . Rain cap  76   b  can be custom built for the Christmas tree  81   b  with which it is used, will generally be formed of two or three pieces to facilitate its installation, and could be formed with a hinge and/or a hatch to provide access to the well cellar  10   b , as it becomes necessary. 
     A sealed well cellar of the present invention having additional beneficial features is depicted in  FIG. 6A  generally at  10   c . In certain gas/oil well installations, the conductor pipe  18  is installed using a pile driving hammer. With those wells, any sealed well cellar of the first two embodiments could be installed by excavating a suitable opening around conductor pipe  18 , sliding the cellar  10  there over, and welding the base plate thereto (or providing some alternative method of sealing). If backfilling is needed to fully stabilize the cellar  10  in its opening, this can be done as well. In other well installations, an oversized hole is drilled into which the conductor pipe  18  is inserted. It is for this well installation that this fifth embodiment is best suited. 
     Well cellar  10   c  has a specially configured, substantially flat base plate  12   c  which includes a centering ring  16   c  which receives conductor pipe  18   c . A plurality of ribs  17   c  fan out from centering ring  16   c  and are welded at their outward extent to wall  14   c . A plurality of cement ports  21   c  ( FIG. 6B ) are positioned around the periphery of centering ring  16   c  and extend between centering ring  16   c  and an inner edge  11   c  of flooring plate sections  12 ′ c . Flooring plate sections  12 ′ c  which are preferably fabricated of steel plate, are welded atop the skeleton structure formed by ribs  17   c  and wall  14   c . A portion of flooring plate  12 ′ c  has a grouting port  82   c  which receives port plug  84   c  as a closure. Riser  24   c  extends through and is welded to the skeletal structure formed by ribs  17   c  at the outer periphery of cement ports  21   c . This can be done by making ribs  17   c  of two pieces, one two fit inside riser  24   c  and one outside, or by grooving the bottom edge of riser  24   c  to enable it to sit down on ribs  17   c.    
     The method of installing this embodiment of sealed well cellar includes the steps of digging a hole for, and installing well cellar  10   c  (before or after the installation of the pipe  18   c , depending on the stability of the soil); following installation of the conductor pipe  18   c , cementing pipe  18   c  in the hole to stabilize its position by pouring cement through cement ports  21   c  in said substantially flat base plate  12   c ; sealingly attaching said well cellar  10   c  to the conductor pipe including closing off cement ports  21   c . An annular plate  86   c  (which is preferably made of multiple parts to facilitate its installation) is provided for that purpose. Plate  86   c  will be welded to conductor pipe  18   c  and to an upper edge of riser  24   c  to close off cement ports  21   c . Should the soil beneath well cellar  10   c  subside or shift resulting in a partial destabilization of cellar  10   c , grout plug  84   c  can be withdrawn from grout port  82   c  to permit materials such as a slurry of grout or sand to be injected through the port to stabilize the well cellar  10   c  and prevent its failing as occurs with conventional cellars when subsidence occurs. 
     A third embodiment is depicted in  FIG. 7B  generally at  10   d . Well cellar  10   d  is sectional including at least two parts for ease of installation. The inwardly directed edges of halves  10   d   1  and  10   d   2  have flanges  92   d  formed thereon and at least one of those flanges has a gasket  94   d  ( FIG. 7A ) attached thereto by screws  96   d . By drawing down bolts  98   d  flanges  92   d  compress gasket  94   d  creating a seal. This sectional embodiment  10   d  is particularly well suited as a replacement well cellar or as a liner for an existing well cellar to convert it to a sealed well cellar. 
     A sealed well cellar of the present invention featuring an extensible extension ring is depicted in  FIG. 8A  generally at  10   e . In this embodiment, annular extension ring  70   e  can be collapsed ( FIG. 8B ) to a position enabling well cellar  10   e  to collect fluids (i.e., to function in the drilling and servicing modes). When drilling/well servicing has been completed, a plurality of camming clamps  75   e  are attached to vertical wall  72   e  by bolts  77   e  to hold extension ring  70   e  in its upward or extended position ( FIGS. 8A and 8C ). Outwardly directed lower flange  71   e  compresses gasket  46   e  to prevent leakage through the structure of extension ring  70   e.    
     Various changes, alternatives and modifications will become apparent to one of ordinary skill in the art following a reading of the foregoing specification. It is intended that any such changes, alternatives and modifications as fall within the scope of the appended claims be considered part of the present invention.