Abstract:
Washing undesirable matter off of the exterior of tubular conduits forming a conduit string during trip out from within a subterranean well incorporates a cylindrical housing having a removable elastomeric seal at each end of the housing. The seal has a central opening surrounded by a lip area for snug, wiping contact around the exterior of the tubular conduits during movements of the tubular string into and out of the housing. Cleaning fluid under pressure is directed through openings in a wash element within the cylinder and upon the tubular conduits. The interior of the housing may form a chamber which is maintained under vacuum for withdrawal of the cleaning fluid and the undesirable matter removed from the tubular conduits for storage and/or safe environmental disposal.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     (1) Field of the Invention  
         [0002]     The invention relates to an apparatus and method for washing undesirable matter off of tubular conduits as they are withdrawn during a trip out from within a subterranean well.  
         [0003]     (2) Brief Description of the Prior Art  
         [0004]     Subterranean wells are commonly drilled and worked over for the purpose of recovering water or hydrocarbon constituents, such as oil and gas. These wells may be found on land or upon platforms or drill ships on the oceans and seas through the world. For example,  FIGS. 1A and 1B  illustrate a typical inland rotary drilling rig and its components. A subterranean well W is shown with set casing C secured in place by cement column C- 1 . A conduit string CS is shown inserted within the well W and interior of the casing C. The conduit string CS is formed by a number of tubular conduits TC which are threaded one to another at each end at respective collars or upset portions TCC. Drill collars DC are secured along the tubular conduits TC with a drill bit DB at the lowermost end of the conduit string CS. A conductor pipe CP extends within the uppermost portion of the well W to a casinghead CH in a cellar CHC at the top surface of the well W. A stack of ram blowout preventers RBOP is placed on the casinghead and an annular blowout preventer ABOP is secured to the top of the ram blowout preventers RBOP. The conduit string CS is inserted into and withdrawn from the well W through the blowout preventers RBOP and ABOP and through a kelly bushing KB and rotary table RT extending through an opening RTO in the rig floor RF. A Kelley K extending from a swivel S suspended from a traveling block TB enables the conduit string CS to be inserted and removed during tripping into or out of the well W. The conduit string CS is made up at the rig floor RF by roughnecks RN manipulating power tongs PT to secure or remove one tubular conduit TC to or from another tubular conduit TC during make up or disassembly of the conduit string CS.  
         [0005]     As the conduit string CS is withdrawn from the well W during a trip out, the exterior of each tubular conduit TC will have considerable undesirable matter upon such exterior. This “undesirable matter” may include both liquids and solids, such as aqueous and oil based or emulsion drilling or workover fluids, barite, bentonite, polymers, well cuttings, acidic or basic corrosion inhibitors, flocculants, dispersants, shale, and other materials commonly found within the well as the result of the drilling or workover operation. Even though the roughnecks may wear special gloves and clothing, it is not at all unusual for these personnel to get a considerable amount of this undesirable matter upon their clothing, and even on their skin, in their eyes, and such, during the tripping operation. If the undesirable matter is acidic, it can cause a burning sensation upon contact with human skin. Moreover, especially on offshore wells, this undesirable matter constitutes an environmental hazard if it is not properly and immediately collected and carefully disposed of, to avoid dumping into the ocean or other environmentally sensitive area.  
         [0006]     The present invention addresses the concerns as above described.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention provides an apparatus for washing undesirable matter off of the exterior of tubular conduits forming a conduit string during trip out of the conduit string within a subterranean well. The tubular conduits may be drill or workover pipe, or the like. A cylindrical housing has first and second opposite ends. A removable elastomeric seal means is provided across each of the first and second ends. The seal means is selectively secured relative to the housing. Each seal means defines an open passageway therethrough and which is centrally positioned there across. The open passageway through each seal means is sized for introduction of the tubular conduits into and out of the cylindrical housing and the seal means. A circumferentially extending lip area of each seal means faces toward the respective passageways for snug, wiping contact around the exterior of the tubular conduits during movements of the conduit string into and out of the cylindrical housing.  
         [0008]     Wash means, which may include jet nozzles, are placed circumferentially within and around the interior of the cylindrical housing for directing a cleaning fluid under pressure toward and upon the tubular conduits as the conduit string passes through the cylindrical housing during trip out from within the subterranean well.  
         [0009]     The cleaning fluid may comprise a number of constituents. The cleaning fluid may be solely fresh water, brine, or seawater, or any combination thereof. It may be heated or converted to steam. It may contain a host of additives, such as demulsifiers, detergents, and the like. If it is to be recycled for subsequent use in the apparatus, it should be filtered and otherwise cleaned for removal of undesirable matter.  
         [0010]     The apparatus of the present invention also comprises means, such as a wash fluid conduit including a cylindrical ring affixed to the interior surface of the cylindrical housing, the wash fluid conduit being in fluid communication with the wash means and with a source of cleaning fluid.  
         [0011]     The seal means incorporated into the present invention may serve up to three functions. First, in combination with the cylindrical housing, it defines a chamber within which the washing procedure is conducted. Secondly, it provides snug engagement of the apparatus onto the tubular conduits during the trip out of the conduit string from within the subterranean well. Finally, the seal permits the chamber to be placed in a vacuum by a vacuum means for suction of the cleaning fluid containing the undesirable matter out of the apparatus during the washing procedure.  
         [0012]     The pressure of the cleaning fluid directed upon the tubular conduits being cleaned is maintained between about 100 p.s.i. and about 10,000 p.s.i. during washing of the tubular conduits within the housing. Heating means may also be included as part of the apparatus for heating of the cleaning fluid at any desired temperature, including conversion into steam. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIGS. 1A and 1B  together constitute a schematic illustration of the components of a typical rotary drilling rig, with the apparatus of the present invention shown in position below the rig floor and above the respective stacks of blowout preventers.  
         [0014]      FIG. 2  is an exploded exterior view of components comprising parts of the apparatus of the present invention.  
         [0015]      FIG. 3  is a perspective exterior view of the housing component with a tubular conduit disposed therein during washing.  
         [0016]      FIG. 4  is a perspective view, taken along line  4 - 4  of  FIG. 3 , looking down and into the interior of the cylindrical housing of the apparatus.  
         [0017]      FIG. 5  is a horizontal cross-sectional view of the housing, taken along line  5 - 5  of  FIG. 3 .  
         [0018]      FIG. 6  is a schematic illustration of the vacuum, pump and storage components of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0019]     Now, first referring to  FIG. 1B , the apparatus  100  of the present invention includes a cylindrical housing  100 A which is shown as preferably positioned for operation just above the upper end of an annular blowout preventer ABOP.  
         [0020]      FIG. 2  is an exploded view of the housing  101 A and associated components. The cylindrical housing  101 A is preferably made of stainless or other steel or metal and has a smooth interior wall  101  ( FIG. 5 ) and an exterior elongated outer surface  102 . The housing  101 A has an upper end  103  and a lower end  104  across which are placed upper and lower removable elastomeric seal means  105  and  106 , respectively. The seal means  105  and  106  preferable are composed of gum rubber. Gum rubber is a commercially available commodity. Preferably, I use a gum rubber for making the gasket seal means  105 ,  106  identified as “Style #135”, sold by Ross Seal Company, P.O. Box 73345, Houston, Tex., 77273-0345. This product is a full floating natural gum rubber. It is tan in color with a smooth finish. It has a Durometer (Shore A) reading of between 35 and 45. Its typical tensile strength is between about 3,000 and 4,000 p.s.i. Its ultimate elongation is 600%, minimum. Its approximate weight is 2.9 pounds per square yard. It may be used at operating temperatures from −20 degrees F. to +180 degrees F., at a maximum pressure exposure of about 250 p.s.i.  
         [0021]     Each seal means  105  and  106  has a centrally located opening defining a passageway  107 ,  108  having a diameter such that a circumferentially extending lip area,  105 A,  105 B, of each seal means  105  and  106  defines the outer boundary or diameter of the passageways  107 ,  108  and may snugly contact the outer surface of the tubular conduits TC passing through the interior of the housing  101 A during trip out and during the washing process, as described below. The upper and lower ends  103  and  104  of the housing  101 A contain a series of circumscribed screw bores  109  for insertion there through of screws or bolts  110 . Upper and lower gaskets  111 ,  112  are placed above and below, respectively, the elastomeric seal means  105  and  106 , the gaskets also having screw bores  113  there around. Likewise, screw bores  114  are provided around the outer edge of each seal means  105  and are in alignment with the bores  113  and  114 . The lower gaskets  112  are placed around the respective ends  103  and  104 . Thereafter, the elastomeric seal means  105  and  106  are respectively placed outwardly of the gaskets  112  and the upper gasket  111  is placed around the outer face of the respective seal means  105 ,  106 . The screw bores  109 ,  113  and  114  are placed into alignment such that screws  115  are threadedly engaged within the bores  109 ,  113  and  114  to selectively secure the seal means  105  and  106  onto the cylindrical housing  101 A. When the seal means  105  and  106  are in such placement upon the housing  101 A, and a tubular conduit TC is inserted through the seals  105 ,  106  and the housing  101 A, an interior chamber  101 A- 1  is so defined. The procedure is reversed when replacement of the seal means  105  and  106  is required.  
         [0022]     The elongated outer surface  102  of the cylindrical housing has two ports  102 A and  102 B for communication with the interior chamber  101 A- 1 . The first port  102 A provides means for selective sealing attachment of a wash fluid line  116  extending from the housing  101 A to a pump and motor  117  ( FIG. 6 ) and container  118  for storage of the selected wash fluid WF. The second port  102 B provides means for selective sealing attachment of a vacuum line  119  extending from the interior of the housing  101 A to means for generating a vacuum (pump and motor)  120  and a storage tank  121  ( FIG. 6 ), for applying a vacuum within the chamber  101 A- 1  to urge spent wash fluid WF and undesirable matter UM into the storage tank  121  for proper disposal.  
         [0023]     Now, with reference to  FIGS. 4 and 5 , a series of jet nozzles  122  having openings  122 A providing a pattern  122 B of spray for the pressurized wash fluid WF are secured into sections of metallic or similar piping  123  joined together between the nozzles and having an interior passageway for communication with the wash fluid line  116 . The piping sections  123  may be secured to the interior wall  101  of the housing  101 A at spot welds  123 A. The spray pattern  122 B resulting from the angles of the openings  122 A of the nozzles  122  may be adjusted for maximum cleaning with little or no experimentation. The nozzles  122  may be placed and spaced to provide alternating or varying patters  122 B of spray for the wash fluid WF. Several sections of spray nozzle series may be provided on piping  123  in a vertical array of choice. The spray pattern desired may be influenced by the make up of the undesirable matter on the conduit string CS withdrawn from a particular well W, as well as the specific chemical composition of the wash fluid WF, the temperature at injection and the pressure applied through the nozzles  122 . The injection pressure of the wash fluid WF through the opening at the nozzles is typically provided at from between about 100 p.s.i. and about 10,000 p.s.i.  
         [0024]     The wash fluid WF may be used in the cleaning process at ambient temperature or may be heated to any desired level up to and including conversion to steam, by use of gas or electrically powered heater  124 .  
       Operation  
       [0025]     Now referring to  FIG. 6 , the selected wash fluid WF is made up and stored in the wash fluid container  118 , located in any proximity to the well W as desired, and the lines  116  and  119  made ready for connection to the connector/ports on the outer housing wall or surface  102 . The housing and seal means, assembled as above, is then located on the rig floor. When it is desired to trip out the conduit string CS from within the well W, the apparatus  100  (housing, seal gaskets) is placed over the uppermost end of the top tubular conduit TC, which is held in place above the rotary table RT in the Kelly bushing KB. The swivel and traveling block TB are drawn upwardly from the upper end or collar of the tubular conduit TC, so held, and the apparatus  100  positioned over the tubular conduit TC such that the conduit TC is introduced through the lower gasket  112  opening  108 , such that the lip area  105 B contacts the outer surface of the tubular conduit TC but the contact is insufficient to effectively resist or prevent movements of the tubular conduit TC through the housing  101  during tripping in or out of the well W. The apparatus  100  is held by roughnecks and slight downward force is applied to the housing  101  to urge the tubular conduit TC through the interior of the housing  101  and thence through the opening  107  in the upper seal gasket  111 , with the lip surface  105 A contacting the outer surface of the tubular conduit TC as the collar at the upper end of the tubular conduit TC moves upwardly and out of the seal gasket  111 . The Kelley and swivel are lowered and connection to the collar of the upper tubular conduit is effected by use of power tongs, or the like. The apparatus  100  now is moved down below the rig floor RF and into the cellar C and rig flooring placed over it. The lines  116  and  119  are now connected to the connector/ports on the outer wall or surface  102 . The conduit string CS may now be tripped out of the well. At the same time, the pump for the wash fluid WF is activated and the fluid is ejected through the openings in the nozzles  122 . The vacuum pump VP is activated. As the tripping operation is begun, the tubular conduits TC pass within the housing  101  and are washed. The undesirable matter removed therefrom is vacuumed out of the housing  100 , together with the spent wash fluid WF, for storage in the container and for proper disposal thereafter.  
         [0026]     Although the invention has been described in terms of specified embodiments which are set forth in detail, it should be understood that this is by illustration only that the invention is not necessarily limited thereto, since alternative embodiments and operating techniques will become apparent to those skilled in the art in view of the disclosure. Accordingly, modifications are contemplated which can be made without departing from the spirit of the described invention.