Boring or penetrating the earth – Processes – Boring with specific fluid
Reexamination Certificate
1998-10-29
2001-01-30
Tsay, Frank (Department: 3672)
Boring or penetrating the earth
Processes
Boring with specific fluid
C175S207000, C414S409000
Reexamination Certificate
active
06179070
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO A “MICROFICHE APPENDIX”
Not applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to oil and gas well drilling and more particularly to the handling of cuttings that are generated during oil and gas well drilling activity. Even more particularly, the present invention relates to an improved vacuum tank apparatus for use in handling cuttings that are generated during oil and gas well exploration. The tank has a specially configured hopper that communicates with an outlet header that enables air to be injected during the discharge of cuttings from the tank.
2. General Background of the Invention
In the drilling of oil and gas wells, a drill bit is used to dig many thousands of feet into the earth's crust. Oil rigs typically employ a derrick that extends above the well drilling platform and which can support joint after joint of drill pipe connected end to end during the drilling operation. As the drill bit is pushed farther and farther into the earth, additional pipe joints are added to the ever lengthening “string” or “drill string”. The drill pipe or drill string thus comprises a plurality of joints of pipe, each of which has an internal, longitudinally extending bore for carrying fluid drilling mud from the well drilling platform through the drill string and to a drill bit supported at the lower or distal end of the drill string.
Drilling mud lubricates the drill bit and carries away well cuttings generated by the drill bit as it digs deeper. The cuttings are carried in a return flow stream of drilling mud through the well annulus and back to the well drilling platform at the earth's surface. When the drilling mud reaches the surface, it is contaminated with small pieces of shale and rock which are known in the industry as well cuttings or drill cuttings.
Well cuttings have in the past been separated from the reusable drilling mud with commercially available separators that are know as “shale shakers”. Other solids separators include mud cleaners and centrifuge. Some shale shakers are designed to filter coarse material from the drilling mud while other shale shakers are designed to remove finer particles from the well drilling mud. After separating well cuttings therefrom, the drilling mud is returned to a mud pit where it can be supplemented and/or treated prior to transmission back into the well bore via the drill string and to the drill bit to repeat the process.
The disposal of the separated shale and cuttings is a complex environmental problem. Drill cuttings contain not only the mud product which would contaminate the surrounding environment, but also can contain oil that is particularly hazardous to the environment, especially when drilling in a marine environment.
In the Gulf of Mexico for example, there are hundreds of drilling platforms that drill for oil and gas by drilling into the subsea floor. These drilling platforms can be in many hundreds of feet of water. In such a marine environment, the water is typically crystal clear and filled with marine life that cannot tolerate the disposal of drill cuttings waste such as that containing a combination of shale, drilling mud, oil, and the like. Therefore, there is a need for a simple, yet workable solution to the problem of disposing of oil and gas well cuttings in an offshore marine environment and in other fragile environments where oil and gas well drilling occurs.
Traditional methods of cuttings disposal have been dumping, bucket transport, cumbersome conveyor belts, screw conveyors, and washing techniques that require large amounts of water. Adding water creates additional problems of added volume and bulk, messiness, and transport problems. Installing conveyors requires major modification to the rig area and involves many installation hours and very high cost.
Safeguard Disposal Systems, Inc. of Lafayette, Louisiana has manufactured, sold, and used publicly a cuttings disposal tank that includes hatch openings into which oil well cuttings can be placed. These prior art tanks also have attachments for enabling lift lines to be affixed to the tank so that it can be transported to and from offshore platforms and emptied when full. Further examples of these tanks are shown in one or more of the following U.S. Pat. Nos.: 5,564,509; 5,402,857; U.S Pat. Nos. Des. 337,809; and U.S Pat. Nos. Des. 296,027. U.S. Pats. Nos. 5,564,509 and 5,402,857 are incorporated herein by reference.
BRIEF SUMMARY OF THE INVENTION
The present invention provides and improved vacuum tank apparatus that can be used to vacuum drill cuttings on an oil and gas well drilling rig through an open top hatch portion of the apparatus and then to discharge those cuttings through an outlet header using suction applied to the outlet header as well as compressed injected air that is transmitted to the outlet header. The apparatus includes a frame having a plurality of corners reinforced by structural corner columns, a generally horizontally extended base the includes a plurality of base perimeter beams, and an upper end portion of the frame that includes a plurality of upper perimeter beams. The columns are structurally interconnected to both the upper perimeter beams and the base of the frame.
A shaped hopper is supported by the frame internally of the perimeter beams. The hopper includes and interior and sidewalls that are comprised of a plurality of inclined sidewall sections, each inclined wall section including an upper end portion that connects to the frame at the perimeter beams and a lower end portion that extends to another lower end portion of another inclined wall section. The two lower end portions of the inclined wall sections that are joined meet at an outlet header at the bottom of the hopper. This outlet header is mated to the lower end portions of the inclined wall sections and includes a discharge outlet for discharging material from the hopper interior via the outlet header.
The top wall of the hopper has multiple hatches including a first hatch near a first perimeter beam and a second hatch next to another perimeter beam that is parallel to the first perimeter beam.
The outlet header includes opposed open end portions that are fittings for directing fluid flow. One of the end portions is an air inlet for injecting air into the outlet header. The other end portion of the outlet header defines a fitting for connecting a suction line thereto. A secondary air fitting for enhanced cleanout and material transfer can be provided at the discharge fitting.
These two fittings enable material to be quickly discharged from the hopper even if it is very solid in nature such as granular cuttings that are the subject of oil and gas well drilling. These cuttings can be quickly discharged from the tank through the outlet header by injecting air into the outlet header at the first end portion of the outlet header and by suctioning the cuttings from the opposing end portion of the outlet header.
The outlet header thus preferably comprises a longitudinally extended trough portion with an open top that communicates with the interior of the hopper. A pair of opposed end portions of the trough have fittings for attaching flow lines to the outlet header.
The outlet header thus defines a closed structure with the lower end portion of the hopper and the fittings so that a vacuum can be held on the tank when the outlet header is not being used.
The outlet header preferably provides valves at each end portion next to the two fittings so that the flow of air into the outlet header can be valved. Additionally, the discharge of solid material from the outlet header can also be valved.
The apparatus of the present invention eliminates the dangerous and messy practices of lifting and/or tipping the tank frame on an oil rig in order to empty the tank contents.
The inclined walls of the hopper remove any need to tip or lift the tank during emptying. The hopper is configured to completely empty of material using a vacuum and with
Howrey Simon Arnold & White , LLP
M-I L.L.C.
Tsay Frank
LandOfFree
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