Liquid purification or separation – Filter – Movable medium
Reexamination Certificate
1998-09-03
2001-05-01
Barry, Chester T. (Department: 1724)
Liquid purification or separation
Filter
Movable medium
C175S066000, C175S206000, C209S272000
Reexamination Certificate
active
06223906
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a flow divider box embodying a separation unit driving a scalper screen for the removal and separation of sticky shales, heavy clays, or large amounts of drill solids from the drilling mud or drilling fluid in the mud returns circulating out of an oil and gas well bore. A flow divider box with an array of collector boxes containing baffle plates and adjustable gates regulating the fluid flow redistribution of the drilling fluid or drilling mud to independent shakers.
2. Brief Description of the Prior Art
The mud system is an integral part of an oil and gas drilling rig, land or marine. Drilling mud or drilling fluid is continually recycled because of the huge cost factor and for environmental reasons. The drilling mud or drilling fluid is used to hold formation pressures in balance, to create and maintain well bore filter cake, create hydraulic horsepower at the bit, hydrostatic testing, shifting of spherical valve elements downhole, and removal of formation solids, cuttings, sand, etc., through the mud return annulus. As the drilling mud or drilling fluid flows from the bell nipple flow line its solids content is refined and removed, through a series of solids control equipment, each removing or separating the plate-like mica structure to a smaller physical size.
It is of the utmost advantage to remove as much solids as practical to reduce down time resulting from plugged flow lines, fluid end repair, drill string erosion, redrilling of the solids or sediments as the drilling mud or drilling fluid recycles itself through the mud system loop.
The conventional mechanical solids control equipment used for removing solids from drilling mud or drilling fluid involves shale shakers and vibratory screens, desilters, desanders, mud cleaners, and centrifuge. This equipment operates at different levels of particle size rejecting solids and retaining desirable solids which can be part of the drilling mud or drilling fluid additives or chemicals.
The mechanical shale shaker screens are limited to short life, and the screens become coated with sticky clays closing the pores or mesh openings resulting in fluid or mud loss. This adds to the problem as additional water must be added to the drilling mud system. This involves the addition of chemical and mud additives to restore the correct and desired mud properties and mud weight, hence the cost of drilling is increased.
The present invention overcomes the aforementioned drawbacks and disadvantages of the prior art and provides additional advantages as well.
The present invention is installed in the flow path of the drilling mud or drilling fluid in the mud system of a drilling rig, upstream of the conventional solids control equipment, and while drilling virgin or young shales it separates and discharges large amounts of drill solids, gumbo, and heavy clays, from the drilling mud or drilling fluid prior to drilling mud or drilling fluid flowing to the aforementioned conventional solids control equipment.
Now by employing a flow divider box in the drilling mud or drilling fluid flow path line, the sediments are managed through an array of individual collector boxes containing baffle plates and gates that regulate the fluid flow redistribution of the sediments in suspension in the drilling mud or drilling fluid before being individually channeled through cylindrical discharge lines.
The present invention is equipped with manual or hydraulic gates adjustable to complement the drilling program as to gallons per minute pumped, and the drilling fluids program itself. The flow divider box having an array of collector boxes supplies drilling mud or drilling fluid to individual shale shakers, and embodies a removal cartridge type separation unit geometrically installed in the flow divider box, that removes large amounts of drill solids, gumbo, and heavy clays from the drilling mud or drilling fluid upstream of the conventional shale shakers.
SUMMARY OF THE INVENTION
A flow divider box disposed beneath a continuous-loop scalper screen mud separation unit that conveys and discharges large amounts of drill solids at the end of the separation unit serves as first line separation equipment in the flow path of drilling fluid or drilling mud to separate drilled solids and redistribute sediments and drilling fluid and drilling mud to selected shale shakers and other conventional solids control equipment. The flow divider box and mud separation unit is positioned in the fluid flow path of the drilling fluid or drilling mud, upstream of the conventional solids control equipment.
The mud separation unit is removably installed in the flow divider box and is equipped with a wide tensioned mud scalper screen driven in a continuous loop around a toothed drive roller and a rear roller propelled by a motor through a gear reduction box. The separation unit is geometrically positioned on rails a predetermined distance apart on the sides of the flow divider box at an angle less than vertical.
The flow divider box has an attached discharge chute to direct drill solids or gumbo overboard or into a reserve pit, a large cleanout flange parallel with the bottom of the flow divider box for the removal of sediments, and cylindrical discharge flow lines.
The flow divider box contains individual independent collector boxes employing a sliding gate that are adjustably positioned to regulate the fluid flow redistribution of the drilling fluid or drilling mud. The gates allow the drilling fluid or drilling mud to rise to baffle or gauge level, creating a hydrostatic head column at the cylindrical discharge flow lines.
The cylindrical discharge flow lines are of sized diameters and are offset from the bottom centerline of the flow divider box. Full advantage of the volume and hydrostatic head is taken of the drilling fluid or drilling mud to move silt and sediments away from the concave openings of the cylindrical discharge flow lines and the box bottom to optimize the self-cleaning feature.
The flow divider box complements the drilling program as to the number of shale shakers, etc., in operation, gallons per minute pumped, hole size, annular velocity, and the drilling fluids program, as the continuous loop scalper screen moves along the longitudinal axis of the flow divider box redistributing sediments, drilling fluid and drilling mud through an array of autonomous collector boxes, into cylindrical discharge flow lines conveying the sediments, drilling fluid and drilling mud to the downstream solids control equipment, shale shakers, desilters, desanders, etc.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the present invention and together with the description, serve to explain the principles of the present invention.
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Barry Chester T.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
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