Patent Application
20170191344
“Not Applicable”
“Not Applicable”
This invention relates generally to cathodic protection systems and more particularly to systems including anode assemblies and associated one-piece vent pipe assemblies for deep bore hole installations and methods of installing deep anode cathodic protections systems.
The protection of oil and gas pipelines from corrosion is commonly achieved by means of a deep anode assembly which is deployed into a deep bore hole adjacent the structure to be protected. The bore hole may extend several hundred feet into the earth. The anode assembly typically used in such a system includes a packaged linear anode which may be either a polymeric cable anode or a Mixed Metal Oxide (MMO) wire anode. One particularly useful elongated linear anode is commercially available from Matcor, Inc., the assignee of the subject invention, under the DURAMMO™ trademark.
Gases are produced by the operation of an anode assembly in the catholic protection system, i.e., when the anode passes DC current through the electrolyte and water in the bore hole, hydrogen, chlorine, oxygen, etc. are produced. Those gases should be vented out of the bore hole. Otherwise the gases could interfere with the performance of the anode assembly and cause damage to the cable of the system. To that end, it is a common practice to make use of an elongated vent pipe in the bore hole. In particular, a vent pipe is extended into the bore hole from top of the bore hole to a point closely adjacent its bottom and alongside the linear anode. The vent pipe includes a plurality of holes or apertures along at least a substantial portion of its length, e.g., the portion alongside the linear anode, through which gases produced by the operation of the anode can be vented to the surface. Heretofore such vent pipes have been in the form of plural linear rigid sections which are introduced sequentially into the bore hole, with the trailing end of the prior linear section being secured to the leading end of the next successive linear section. Obviously, this method of deployment is time consuming, complicated and relatively expensive. To simplify the installation process, the vent pipe may be in the form of a continuous pipe that is wound up on a reel and then uncoiled for extension into the bore hole. Matcor, Inc. has been installing coiled vent pipes under the trademark SUPERVENT for some time. The SUPERVENT™ coiled vent pipe makes use of a fabric sleeve extending about the pipe at the location of its holes. The fabric sleeve serves to enable gases to pass through it and through the holes into the interior of the pipe, while preventing coke breeze or other conductive materials located within the bore hole from gaining ingress into the interior of the pipe. The SUPERVENT™ coiled vent pipe must be small, e.g., less than 1.5″ nominal internal diameter, to enable it to be wound up on a reel.
Irrespective of the manner in which the vent pipe is deployed into the deep bore hole, since it has apertures or holes extending along a substantial length thereof, there is the potential that water from aquifers in the ground at various levels to mix by gaining access to the vent pipe. For example, water from one aquifer at a level A could mix with water at an aquifer at a level B by gaining ingress through the apertures of the vent pipe at the level A and flowing through the vent pipe to the apertures at the level B. Thus, some states, e.g., California, have enacted legislation requiring the sealing of deep bore hole vent pipes after use of the anode assembly to which they are coupled is no longer required. Such sealing can be accomplished by pumping concrete into the vent pipe. However, in order to effectively pump concrete into the vent pipe, particularly one that extends several hundred feet into the ground, requires a vent pipe of larger internal diameter than the prior art 1.5″ SUPERVENT™ coiled vent pipe. In particular, the vent pipe should be of a nominal internal diameter of at least 2 inches.
Accordingly, a need exists for a one-piece vent pipe which can be wound up on a reel and unwound readily therefrom for extension into a deep bore hole and which is of sufficiently large internal diameter to enable concrete or other viscous sealing material to be pumped therein when desired. The subject invention addresses that need and also provides a means and a method for effectively and efficiently carrying an associated elongated anode assembly into the bore hole for deployment.
All references cited and/or identified herein are specifically incorporated by reference herein.
In accordance with one aspect of the invention there is provided a one-piece vent pipe assembly for use in a cathodic protection system having an elongated anode assembly located in a deep bore hole in the earth. The anode assembly extends along a substantial distance adjacent the bottom of the bore hole. The vent pipe assembly comprises a tube, a fabric sleeve and a reel. The tube is formed of a plastic material and has a distal end and an apertured portion located adjacent the distal end. The tube includes an array of holes in the apertured portion of the tube. The fabric sleeve extends about the apertured portion of the tube. The tube and fabric sleeve are coiled up on the reel, but arranged to be uncoiled therefrom for extension into the bore hole, whereupon the apertured portion of the tube is located in a bottom portion of the bore hole and extending alongside the elongated anode assembly. The holes in the tube enable gases produced by the operation of the anode assembly to gain ingress from the bore hole through the fabric sleeve into the interior of the tube to be vented from the tube. The tube has a predetermined nominal internal diameter sufficient to enable a viscous settable material, e.g., concrete, to be pumped into the tube to seal the interior thereof when the tube is no longer desired to vent gases produced by the operation of the anode assembly.
In accordance with another aspect of this invention a system including an anode assembly and one-piece vent pipe assembly is provided for use in a cathodic protection system. The anode assembly comprises an elongated anode and a pair of cables connected to respective end portions of the anode. The anode assembly is arranged to be located in a deep bore hole in the earth, whereupon the elongated anode extends along a substantial distance adjacent the bottom of the bore hole. The vent pipe assembly comprises a tube, a fabric sleeve and a reel. The tube is formed of a plastic material and has a distal end and an apertured portion located adjacent the distal end. The tube includes an array of holes in the apertured portion of the tube. The fabric sleeve extends about the apertured portion of the tube. The tube, the fabric sleeve and the anode assembly are coiled up on the reel, but arranged to be uncoiled therefrom for extension into the bore hole, whereupon the apertured portion of the tube is located in a bottom portion of the bore hole and extending alongside the elongated anode assembly. The holes in the tube enable gases produced by the operation of the anode assembly to gain ingress from the bore hole through the fabric sleeve into the interior of the tube to be vented from the tube. The tube has a predetermined nominal internal diameter sufficient to enable a viscous settable material to be pumped into the tube to seal the interior thereof when the tube is no longer desired to vent gases produced by the operation of the anode assembly.
In accordance with another aspect of this invention there is provided a method of installing a system including an anode assembly and a one-piece vent pipe assembly into a deep bore hole in the earth. The anode assembly comprises an elongated anode and a pair of cables connected to respective end portions of the anode. The vent pipe assembly comprises a tube, a fabric sleeve and a reel. The tube is formed of a plastic material and has a distal end and an apertured portion located adjacent the distal end. The tube has a predetermined nominal interval diameter sufficient to enable a viscous settable material to be pumped into the tube to seal the interior thereof. The tube includes an array of holes in the apertured portion of the tube. The fabric sleeve extends about the apertured portion of the tube. The tube, the fabric sleeve and the anode assembly are coiled up on the reel. The method basically entails providing a weight on the distal end of the tube and introducing the distal end of the tube into the bore hole, whereupon the tube, the fabric sleeve and the anode assembly are uncoiled from the reel and extend into the bore hole, with the apertured portion of the tube located in a bottom portion of the bore hole, the elongated anode assembly extending along the aperture portion of the tube and the cables extending upward through the bore hole.
A further aspect of the method of this invention entails coupling the cables to a cathodic protection system to operate the anode assembly. The holes in the tube are arranged to enable gases produced by the operation of the anode assembly to gain ingress from the bore hole through the fabric sleeve into the interior of the tube to be vented from the tube.
One preferred aspect of the method of this invention entails drilling into the earth to form the bore hole and mixing coke breeze and water into a slurry and pumping the slurry via another pipe into the bore hole, whereupon the slurry surrounds the anode assembly, the apertured portion of the tube and the fabric sleeve.
Another preferred aspect of the method of this invention entails pumping a viscous settable material into the tube to seal the interior thereof when the tube is no longer desired to vent the gases from the tube, whereupon any water from aquifers at various levels in the ground contiguous with the bore hole will not be able to flow into the tube to mix together.
Referring now to the various figures of the drawing wherein like reference characters refer to like parts, there is shown at 20 in
As best seen in
The vent pipe assembly 24 basically comprises a unitary, one-piece pipe or tube 34 and a fabric sleeve 36. The tube 34 is formed of any suitable plastic material and has a nominal internal diameter of at least approximately 2 inches. One particularly effective plastic material is UV resistant SDR 13.5 Polyethylene (PE), with the tube having a wall thickness of approximately 0.176 inch. The tube 34 includes a distal end 38 and an apertured portion 40 located adjacent the distal end. The apertured portion 40 includes an array of holes 42 therein. The holes of the array serve as the means to enable gases produced by the operation of the anode assembly to pass therethrough into the interior of the vent pipe for passage through the vent pipe to the surface. The fabric sleeve 36 basically comprises a tube formed of any suitable fabric material, e.g., textured wide poplin polyester, and is disposed about the periphery of the apertured portion 40 of the vent pipe 24 to prevent the coke breeze from gaining ingress into the interior of the vent pipe, while enabling gases to enter into the vent pipe through the array of holes 42.
As best seen in
In accordance with one exemplary preferred embodiment of the invention, the spacing between the first and second positions of the pairs of holes 42A and 42B is approximately 3 inches and each of the holes is approximately of 0.375 inch nominal internal diameter.
The deployment of the system 20 will now be described with reference to protecting an underground structure, e.g., an oil or gas pipeline (not shown). At the location of the structure to be protected a bore hole 10 is drilled into the earth. In accordance with one exemplary embodiment of the invention the bore hole is of a nominal internal diameter of 8 inches. The tube 34 with the fabric sleeve 36 on the distal end portion thereof, along with the anode assembly 24 is wound up on the reel 26 having a hub whose diameter is 45 inches is brought to the site of the bore hole. To that end that assembly is disposed on a shipping skid 44 (
In accordance with one exemplary embodiment of this invention the active area of the bore hole is then filled with a coke backfill 12, e.g., Asbury 218L coke breeze (45 lbs/cubic foot) in the form of a slurry. The slurry is preferably pumped into the bore hole via another pipe, e.g., a 1″-2″ PVC stinger pipe (not shown) to fill the active area and completely surround the portion of the system 20 located in the active area. In the exemplary embodiment shown in
The pumping operation should be continued uninterrupted until the active area is completely filled with the slurry 12. Once the coke breeze backfill has been deployed and has settled, the system 20 is ready for electrical hook-up to the cathodic protection system. The Portland cement/Bentonite fill 14 can then be introduced into the inactive area of the bore hole to complete the deployment and installation of the system.
The system 20 can then be operated for as long as required to protect the underground structure, e.g., the gas or oil pipeline, etc., from corrosion. When such action is no longer necessary or desired, the anode assembly can be disconnected from the cathodic protection system or otherwise de-energized. Cement or some other settable sealing material can then be pumped into the upper (cut-off) end of the tube 34 of the pipe assembly 24 to seal it, i.e., fill it and thus close off the holes 42. Once the vent pipe is sealed shut, water from aquifers at various levels in the ground contiguous with the bore hole will not be able to flow into the tube 34 to mix together, whereupon contamination of one aquifer will not result in contamination of another aquifer by virtue of mixing of their waters via the pipe assembly 24.
It should be noted that the exemplary embodiment of the system 20 and its method of deployment are merely exemplary. Thus, for example, the system may take other forms providing that it includes a one-piece vent tube which can be provided rolled up on a reel and which tube has a sufficiently large internal diameter to accommodate the pumping of a viscous sealing agent, such as but not limited to concrete, therein to seal it. Moreover, the method of deployment can entail other steps than those described above, e.g., while less desirable the anode assembly can be deployed into the bore hole separately from the deployment of the one-piece coiled vent pipe assembly.
Without further elaboration the foregoing will so fully illustrate our invention that others may, by applying current or future knowledge, adopt the same for use under various conditions of service.
This application is a division of application Ser. No. 14/468,899, filed on Aug. 26, 2014, entitled System Including One-Piece Coiled Vent Pipe For Deep Anode Cathodic Protection And Method Of Installing The Same, which is assigned to the same assignee as this application and whose disclosure is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14468899 | Aug 2014 | US |
| Child | 15461790 | US |
